KR100917202B1 - Digital broadcasting system and method of processing data in digital broadcasting system - Google Patents

Abstract

The present invention relates to a digital transmission system and a data processing method that are resistant to errors when transmitting mobile service data. To this end, the present invention performs additional encoding on the mobile service data and transmits it. By doing so, it is possible to robustly cope with fast channel changes while giving robustness to the mobile service data.

Mobile, encoding, error

Description

Digital broadcasting system and method of processing data in digital broadcasting system

The present invention relates to a digital broadcasting system and a data processing method for transmitting and receiving digital broadcasting.

In the digital broadcasting, VSB (Vestigial Sideband) transmission method adopted as a digital broadcasting standard in North America and Korea is a single carrier method, so the reception performance of the receiving system may be degraded in a poor channel environment. In particular, in the case of a portable or mobile broadcast receiver, since the robustness against channel change and noise is further required, when the mobile service data is transmitted through the VSB transmission method, the reception performance is further deteriorated.

Accordingly, an aspect of the present invention is to provide a digital broadcasting system and a data processing method that are resistant to channel variation and noise.

The present invention provides a digital broadcasting system and a data processing method for improving the reception performance of a reception system by performing additional encoding on mobile service data and transmitting the same to a reception system.

The present invention provides a digital broadcasting system and a data processing method for improving the reception performance of a reception system by inserting and transmitting known data known by a promise of a transmission / reception side into a predetermined area of a data area.

In order to achieve the above object, a transmission system according to an embodiment of the present invention may include a service multiplexer and a transmitter. The service multiplexer may multiplex the mobile service data and the main service data at a preset data rate and transmit them to the transmitter. The transmitter may perform additional encoding on mobile service data transmitted from the service multiplexer, and collect a plurality of mobile service data packets on which encoding is performed to form a data group. The transmitter may multiplex a mobile service data packet including mobile service data and a main service data packet including main service data in packet units and transmit the packet to a receiving system. In this case, the transmitter may multiplex the data group and the main service data packet into a burst structure, and the burst may be divided into a burst on period including a data group and a burst off period without a data group.

The data group may be divided into a plurality of areas according to the degree of interference of the main service data. Long known data streams may be inserted periodically in an area free of interference of the main service data.

A receiving system according to an embodiment of the present invention may use the known data stream for demodulation and channel equalization.

When the reception system receives only mobile service data, the reception system may power on only in the burst on period to process mobile service data.

A receiving system according to another embodiment of the present invention may include a signal receiver, a known data detector, and a channel equalizer.

The signal receiver receives a broadcast signal including mobile service data and main service data. The mobile service data may constitute a data group, and the data group may be divided into a plurality of areas, and a known data string may be linearly inserted into a portion of the plurality of areas, and at the beginning of the known data column. Initialization data used to initialize the memory in the transmitter's trellis encoder is located. The known data detector detects known data linearly inserted into the data group. The channel equalizer channel equalizes the mobile service data using the detected known data.

N known data strings may be inserted in some regions of the plurality of regions in the data group, and a transmission parameter may be inserted between a first known data string and a second known data string among the N known data strings.

The receiving system may further include a transmission parameter detector for detecting the transmission parameter and a block decoder for symbol decoding the mobile service data on a block basis based on the detected transmission parameter.

The receiving system may further include a power control unit for controlling a power to receive a data group including mobile service data to be received by using the detected transmission parameter.

The data group may constitute an RS frame, wherein the RS frame includes at least one data packet for the mobile service data, an RS parity generated based on the at least one data packet, and the at least one data packet; It may include a CRC checksum generated based on the RS parity.

The receiving system may further include an RS frame decoder that performs CRC decoding and RS decoding on the basis of RS frames on the mobile service data to correct an error generated in the mobile service data in the RS frame.

The receiving system may further include a derandomizer for derandomizing the RS decoded mobile service data.

In a data processing method of a reception system according to an embodiment of the present invention, a broadcast signal including mobile service data and main service data may be received, and the mobile service data may constitute a data group, and the data group may include a plurality of data groups. The data stream is linearly inserted into a portion of the plurality of regions, and the initialization data used to initialize the memory in the trellis encoder of the transmitter is located at the beginning of the known data string. And detecting known data linearly inserted in the data group, and channel equalizing the mobile service data using the detected known data.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

The digital broadcasting system and the data processing method according to the present invention are advantageous in that they are resistant to errors and compatible with existing receivers when transmitting mobile service data through a channel.

The present invention has the advantage that the mobile service data can be received without error even in a ghost and noisy channel.

The present invention can improve the reception performance of the reception system in an environment with a high channel change by inserting and transmitting known data in a specific position of the data area.

The present invention can reduce the power of the reception system by multiplexing the mobile service data into a burst structure when multiplexing the mobile service data with the main service data.

In particular, the present invention is more effective when applied to portable and mobile receivers in which channel variation is severe and robustness to noise is required.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention that can specifically realize the above object will be described. At this time, the configuration and operation of the present invention shown in the drawings and described by it will be described as at least one embodiment, by which the technical spirit of the present invention and its core configuration and operation is not limited.

Definition of terms used in the present invention

The terms used in the present invention were selected as widely used general terms as possible in consideration of the functions in the present invention, but may vary according to the intention or custom of the person skilled in the art or the emergence of new technologies. In addition, in certain cases, there is a term arbitrarily selected by the applicant, and in this case, the meaning will be described in detail in the corresponding description of the invention. Therefore, it is intended that the terms used in the present invention should be defined based on the meanings of the terms and the general contents of the present invention rather than the names of the simple terms.

Among the terms used in the present invention, the main service data is data that can be received by the fixed receiving system and may include audio / video (A / V) data. That is, the main service data may include A / V data of a high definition (HD) or standard definition (SD) level, and may include various data for data broadcasting. Known data is data known in advance by an appointment of the transmitting / receiving side.

In addition, the mobile service data in the present invention includes at least one of the mobile (Mobile) data, the service data (Pedestrian), handheld (Handheld) service data, in the present invention for convenience of description This is called service data. In this case, the mobile service data may include not only M / P / H (Mobile / Pedestrian / Handheld) service data, but also any service data indicating movement or portability. Accordingly, the mobile service data may include the M / P / H. It will not be limited to service data.

The mobile service data defined as described above may be data having information such as a program execution file, stock information, or the like, or may be A / V data. In particular, the mobile service data may be A / V data having a smaller resolution and a smaller data rate than the main service data as service data for a portable or mobile terminal (or broadcast receiver). For example, if the A / V codec used for the existing main service is an MPEG-2 codec, the MPEG-4 codec that has better image compression efficiency as the A / V codec for mobile services. AVC (Advanced Video Coding), SVC (Scalable Video Coding), etc. may be used. In addition, any kind of data may be transmitted as the mobile service data. For example, TPEG (Transport Protocol Expert Group) data for broadcasting traffic information in real time may be serviced.

In addition, data services using the mobile service data include weather services, transportation services, securities services, viewer participation quiz program, real-time polls, interactive educational broadcasting, game services, drama plot, characters, background music, shooting location, etc. Informational services, information on past sports history, profile and performance of athletes, and information on programs by media, time, or subject that enables product information and ordering. Etc., but the present invention is not limited thereto.

The transmission system of the present invention enables multiplexing of main service data and mobile service data on the same physical channel without backward affecting the reception of main service data in an existing receiving system.

The transmission system of the present invention performs additional encoding on mobile service data and inserts and transmits data that is known in advance to both the transmitting and receiving sides, that is, known data.

When the transmission system according to the present invention is used, the reception system enables mobile reception of mobile service data, and also enables stable reception of mobile service data against various distortions and noises generated in a channel.

Schematic description of the transmission system

1 is a schematic diagram showing an embodiment of a transmission system for applying the present invention, and may include a service multiplexer 100 and a transmitter 200.

The service multiplexer 100 is located in a studio of each broadcasting station, and the transmitter 200 is located in a site away from the studio. In this case, the transmitter 200 may be located in a plurality of different areas. In one embodiment, the plurality of transmitters may share the same frequency, in which case the plurality of transmitters all transmit the same signal. In the receiving system, the channel equalizer can then recover the original signal by compensating for the signal distortion caused by the reflected wave. In another embodiment, the plurality of transmitters may have different frequencies for the same channel.

Various methods may be used for data communication between the service multiplexer and each transmitter located at a remote location, and as an example, an interface standard such as Synchronous Serial Interface for transport of MPEG-2 data (SMPTE-310M) may be used. . In the SMPTE-310M interface standard, the output data rate of the service multiplexer is determined to be a constant data rate. For example, it is set at 19.39 Mbps for 8VSB, and 38.78 Mbps for 16VSB. In addition, the conventional 8VSB type transmission system can transmit a transport stream (TS) packet having a data rate of about 19.39 Mbps on one physical channel. In the transmitter according to the present invention having backward compatibility with the existing transmission system, the mobile service data is further encoded and then multiplexed in the form of the main service data and the TS packet, and the data of the multiplexed TS packet is transmitted. The rate is about 19.39 Mbps.

In this case, the service multiplexer 100 receives at least one type of mobile service data and program specific information (PSI) / program and system information protocol (PSIP) table data for each mobile service, respectively, and transmits a transport stream (TS). Encapsulate into packets. In addition, the service multiplexer 100 receives at least one kind of main service data and PSI / PSIP table data for each main service and encapsulates them into TS packets. Subsequently, the TS packets are multiplexed according to a preset multiplexing rule and output to the transmitter 200.

Service multiplexer

FIG. 2 is a detailed block diagram illustrating an embodiment of the service multiplexer. The controller 110 controls overall operation of the service multiplexer, a PSI / PSIP generator 120 for a main service, and a mobile service. The PSI / PSIP generator 130 may include a null packet generator 140, a mobile service multiplexer 150, and a transport multiplexer 160.

The transport multiplexer 160 may include a main service multiplexer 161 and a transport stream (TS) packet multiplexer 162.

Referring to FIG. 2, at least one kind of compressed coded main service data and PSI / PSIP table data generated by the PSI / PSIP generator 120 for the main service are included in the main service multiplexer of the transport multiplexer 160. 161). The main service multiplexer 161 encapsulates input main service data and PSI / PSIP table data in the form of MPEG-2 TS packets, respectively, and multiplexes these TS packets to form a TS packet multiplexer 162. Will output The data packet output from the main service multiplexer 161 will be referred to as a main service data packet for convenience of description.

In addition, at least one type of compressed-coded mobile service data and PSI / PSIP table data generated by the PSI / PSIP generator 130 for the mobile service are input to the mobile service multiplexer 150.

The mobile service multiplexer 150 encapsulates input mobile service data and PSI / PSIP table data in the form of MPEG-2 TS packets, respectively, and multiplexes these TS packets to form a TS packet multiplexer 162. Will output The data packet output from the mobile service multiplexer 150 will be referred to as a mobile service data packet for convenience of description.

In this case, identification information is required for the transmitter 200 to process the main service data packet and the mobile service data packet separately. The identification information may use a predetermined value by an appointment of a transmitting / receiving side, may be configured as separate data, or may be used by modifying a value of a predetermined position in the data packet.

According to an embodiment of the present invention, different PIDs (Packet Identifiers) may be allocated to the main service data packet and the mobile service data packet.

In another embodiment, by modifying the sync byte in the header of the mobile service data packet, the sync byte value of the corresponding service data packet may be used to distinguish. For example, the sync byte of the main service data packet outputs the value specified in ISO / IEC13818-1 (for example, 0x47) without modification, and the sync byte of the mobile service data packet is modified and outputted. The data packet and the mobile service data packet can be distinguished. On the contrary, by modifying the sync byte of the main service data packet and outputting the sync byte of the mobile service data packet as it is, the main service data packet and the mobile service data packet can be distinguished.

There may be various ways to modify the sync byte. For example, the sync byte may be inverted bit by bit or only some bits may be inverted.

As such, any identification information capable of distinguishing the main service data packet from the mobile service data packet may be used. Thus, the present invention will not be limited to the above-described embodiments.

Meanwhile, the transport multiplexer 160 may use the transport multiplexer used in the existing digital broadcasting system. That is, in order to transmit the mobile service data multiplexed with the main service data, the data rate of the main service is limited to a data rate of (19.39-K) Mbps, and the K Mbps corresponding to the remaining data rate is allocated to the mobile service. This allows you to use the transport multiplexer that is already in use without changing it.

The transport multiplexer 160 multiplexes the main service data packet output from the main service multiplexer 161 and the mobile service data packet output from the mobile service multiplexer 150 to transmit to the transmitter 200.

However, there may occur a case where the output data rate of the mobile service multiplexer 150 is not K Mbps. In this case, the mobile service multiplexer 150 multiplexes and outputs null data packets generated by the null packet generator 140 such that the output data rate is K Mbps. That is, the null packet generator 140 generates a null data packet and outputs it to the mobile service multiplexer 150 in order to constantly adjust the output data rate of the mobile service multiplexer 150.

For example, if the service multiplexer 100 allocates K Mbps of 19.39 Mbps to mobile service data and allocates the remaining (19.39-K) Mbps to main service data, the service multiplexer 100 is actually assigned. The data rate of the mobile service data multiplexed at < RTI ID = 0.0 > This is because, in the case of the mobile service data, the amount of data is increased by performing additional encoding in a pre-processor of the transmitter. As a result, the data rate of mobile service data that can be transmitted by the service multiplexer 100 becomes smaller than K Mbps.

For example, the preprocessor of the transmitter performs encoding at least 1/2 code rate on the mobile service data, so that the amount of output data of the preprocessor is more than twice the amount of input data. Therefore, the sum of the data rate of the main service data multiplexed in the service multiplexer 100 and the data rate of the mobile service data is always less than or equal to 19.39 Mbps.

Therefore, in order to adjust the final output data rate output from the service multiplexer 100 to a constant data rate (for example, 19.39 Mbps), the null packet generator 140 generates a null data packet by a data rate that is short. To the mobile service multiplexer 150.

Then, the mobile service multiplexer 150 encapsulates the input mobile service data and PSI / PSIP table data in the form of MPEG-2 TS packets, respectively, and multiplexes the TS packets and null data packets. Output to the packet multiplexer 162.

The TS packet multiplexer 162 multiplexes the main service data packet output from the main service multiplexer 161 and the mobile service data packet output from the mobile service multiplexer 150 to the transmitter 200 at a 19.39 Mbps data rate. send.

According to an embodiment of the present invention, the mobile service multiplexer 150 receives a null data packet. This is only one embodiment. In another embodiment, the TS packet multiplexer 162 receives a null data packet and adjusts the final data rate to a constant data rate. The output path and the multiplexing rule of the null data packet are controlled by the controller 110. The controller 110 controls the multiplexing and null packet generators 140 in the mobile service multiplexer 150, the main service multiplexer 161 of the transport multiplexer 160, and the TS packet multiplexer 162. Control the generation of null data packets.

At this time, the transmitter 200 discards the null data packet transmitted from the service multiplexer 100 without transmitting it to the receiving system.

In order to discard the null data packet without transmitting the transmitter 200, identification information for distinguishing the null data packet is required. The identification information for distinguishing the null data packet may use a value predetermined by an appointment of the transmitting / receiving side or may be configured as separate data. For example, the sync byte value in the header of the null data packet may be modified to be used as identification information, or a transport_error_indicator flag may be used as identification information.

According to an embodiment of the present invention, the transport_error_indicator flag of a header in a null data packet is used as identification information for distinguishing a null data packet. In this case, the transport_error_indicator flag of the null data packet is set to 1, and the transport_error_indicator flag of all data packets other than the null data packet is reset to 0 to distinguish the null data packet. That is, when the null packet generator 140 generates a null data packet, if the transport_error_indicator flag is set to '1' in the field of the header of the null data packet and transmitted, the transmitter 200 may separate the discard packet.

The identification information for distinguishing the null data packet may be any one capable of distinguishing the null data packet, and thus the present invention will not be limited to the above-described embodiments.

In another embodiment, the present invention provides a transmission parameter in at least a portion of the null data packet, or at least one table of a PSI / PSIP table for a mobile service, or an Operations and Maintenance (OM) packet (or OMP). May be included. In this case, the transmitter 200 extracts the transmission parameter and outputs the transmission parameter to the corresponding block, and transmits the transmission parameter to the receiving system if necessary.

That is, a packet called OMP (Operations and Maintenance Packet) is defined for the purpose of operation and management of the transmission system. As an example, the OMP follows the format of an MPEG-2 TS packet and its PID has a value of 0x1FFA. The OMP consists of a header of 4 bytes and a payload of 184 bytes. The first byte of the 184 bytes indicates the type of the OM packet as the OM_type field.

In the present invention, the transmission parameter may be transmitted in an OMP format. In this case, the transmitter 200 may inform the transmitter 200 that the transmission parameter is transmitted to the OMP using a predetermined value among unused field values of the OM_type field. That is, the transmitter 200 may find the OMP by looking at the PID, and parse the OM_type field in the OMP to determine whether the transmission parameter is included after the OM_type field of the corresponding packet.

The transmission parameter is additional information necessary for processing mobile service data in a transmission / reception system. For example, the transmission parameter includes data group information, region information in a data group, RS frame information, super frame information, and burst information. , Turbo code information, RS code information, and the like. The burst information may include burst size information, burst period information, time to the next burst, and the like. The burst period means a period in which bursts transmitting the same type of mobile service are repeated, and the burst size means the number of data groups included in one burst. The data group includes a plurality of mobile service data packets, and these data groups are gathered to form a burst. The burst section refers to the start of the current burst to the start of the next burst, and includes a section including a data group (also called a burst on section) and a section without a data group (or a burst off section). (Also referred to as below). One burst on interval consists of a plurality of fields, one field includes one data group.

In addition, the transmission parameter includes information on how signals in a symbol region are encoded to transmit mobile service data, and multiplexing information on how to be multiplexed between main service data and mobile service data or various types of mobile service data. May be included.

The information included in the transmission parameter is only one embodiment for better understanding of the present invention, and the present invention is not limited to the above embodiment because addition and deletion of information included in the transmission parameter can be easily changed by those skilled in the art. Will not.

In addition, the transmission parameters may be provided from the service multiplexer 100 to the transmitter 200, or the transmitter 200 itself may be set by a controller (not shown) or received externally.

transmitter

3 is a block diagram illustrating a transmitter 200 according to an embodiment of the present invention, a demultiplexer 210, a packet jitter mitigator 220, and a pre-processor 230. , A packet multiplexer 240, a post-processor 250, a sync multiplexer 260, and a transmission unit 270.

When the data packet is received from the service multiplexer 100, the demultiplexer 210 must distinguish whether the received data packet is a main service data packet, a mobile service data packet, or a null data packet.

In one embodiment, the demultiplexer 210 may distinguish between the mobile service data packet and the main service data packet using a PID in the received data packet, and may distinguish a null data packet using a transport_error_indicator field.

The main service data packet separated by the demultiplexer 210 is output to the packet jitter reducer 220, the mobile service data packet is output to the preprocessor 230, and the null data packet is discarded. If the null data packet includes a transmission parameter, the null data packet is discarded after the transmission parameter is extracted and output to the corresponding block.

The preprocessor 230 may be located at any specific location according to the purpose of data to be transmitted on the additional encoding and transmission frame for the mobile service data in the mobile service data packet which is demultiplexed and output from the demultiplexer 210. Perform the data group formation process to make it possible. This is to allow the mobile service data to respond quickly and strongly to noise and channel changes. The preprocessor 230 may refer to the transmission parameter in further encoding. In addition, the preprocessor 230 collects a plurality of mobile service data packets to form a data group, and allocates known data, mobile service data, RS parity data, MPEG header, and the like to a predetermined area within the data group.

Preprocessor in the transmitter

4 is a block diagram illustrating an embodiment of a preprocessor 230 according to the present invention, which includes a data randomizer 301, an RS frame encoder 302, a block processor 303, a group formatter 304, and data. A deinterleaver 305, and a packet formatter 306.

The data randomizer 301 in the preprocessor 230 configured as described above renders the mobile service data packet including the mobile service data input through the demultiplexer 210 and outputs it to the RS frame encoder 302. In this case, by performing the randomization on the mobile service data in the data randomizer 301, the data randomizer 251 of the postprocessor 250 may omit the randomizing process on the mobile service data. The data randomizer 301 may perform randomizing by discarding sync bytes in the mobile service data packet. Alternatively, rendering may be performed without discarding the sync byte, which is a designer's option. According to an embodiment of the present invention, the rendering is performed without discarding the sync byte in the corresponding mobile service data packet.

The RS frame encoder 302 configures an RS frame by collecting a plurality of randomized and input mobile service data packets and performs at least one of an error correction encoding process and an error detection encoding process in units of RS frames. . This makes it possible to cope with extremely poor and rapidly changing propagation environment by giving robustness to mobile service data and obstructing clustering errors that can be caused by changes in radio environment.

In addition, the RS frame encoder 302 may configure a super frame by collecting a plurality of RS frames, and perform row permutation in units of super frames. The row permutation is also referred to as row interleaving, and in the present invention, it is referred to as row mixing for convenience of description.

That is, when the RS frame encoder 302 mixes each row of the super frame with a predetermined rule, the positions of the rows before and after row mixing in the super frame are changed. When the row mixing is performed in the unit of the super frame, even if a large amount of error occurs in a single RS frame to be decoded, the errors are distributed in the entire super frame, so that these errors are distributed throughout the super frame. The decryption ability is improved.

According to an embodiment of the present invention, the RS frame encoder 302 uses RS coding for error correction coding and cyclic redundancy check (CRC) coding for error detection coding. Parity data to be used for error correction is generated when the RS encoding is performed, and CRC data to be used for error detection is generated when CRC encoding is performed.

The RS coding is one of forward error correction (FEC). The FEC refers to a technique for correcting an error occurring in a transmission process. The CRC data generated by the CRC encoding may be used to indicate whether mobile service data is damaged by an error while being transmitted through a channel. The present invention may use other error detection encoding methods in addition to CRC encoding, or may increase the overall error correction capability at the receiving end by using an error correction encoding method.

In this case, the RS frame encoder 302 refers to a transmission parameter set in advance and / or a transmission parameter provided by the service multiplexer 100 in order of RS frame configuration, RS encoding, CRC encoding, super frame configuration, and super frame unit. Raw mixing and the like.

In the preprocessor RS  Frame encoder

5A to 5E illustrate an embodiment of an encoding process of an RS frame encoder 302 according to the present invention.

That is, the RS frame encoder 302 first divides the input mobile service data byte into predetermined length units. The predetermined length is a value determined by a system designer. In the present invention, 187 bytes is described as an embodiment, and for convenience of description, the 187 byte unit will be referred to as a packet.

For example, if the mobile service data input as shown in (a) of FIG. 5 is an MPEG transport stream (TS) packet configured in units of 188 bytes, the first sync byte is removed to 187 bytes as shown in FIG. Configure one packet. The reason for removing the sync byte is that all mobile service data packets have the same value. In this case, the synchronization byte removal may be performed when the data randomizer 301 at the front end is rendered. In this case, the process of removing the sync byte from the RS frame encoder 302 is omitted, and when the sync byte is added by the receiving system, the sync byte may be added by the data de-randomizer instead of the RS frame decoder.

Therefore, if there is no fixed one byte (eg, a sync byte) in the mobile service data packet input to the RS frame encoder 302 or the input mobile service data is not in the form of a packet, the input mobile service data is inputted. Is divided by 187 bytes, and a packet is composed of divided 187 bytes.

Subsequently, as shown in (c) of FIG. 5, N packets of 187 bytes are collected to form one RS frame. In this case, the configuration of one RS frame is achieved by sequentially inserting a packet of 187 bytes in a row direction into an RS frame having a size of N (row) * 187 (column) bytes.

In the present invention, the RS frame thus generated is referred to as a first RS frame for convenience of description. That is, only the pure mobile service data is included in the first RS frame, which is equivalent to 187 rows of N bytes.

When the mobile service data in the RS frame is divided into a predetermined size and then transmitted in the same order as the input order for composing the RS frame, if an error occurs at a specific point in time between transmission and reception, the error occurs on the RS frame. To be gathered. In this case, by using RS erasure decoding in error correction decoding in the receiving system, the error correction capability can be improved.

At this time, all N columns of the RS frame include 187 bytes as shown in FIG.

In this case, Nc-Kc (= P) parity bytes are generated by performing (Nc, Kc) -RS encoding on each column, and the generated P parity bytes are added after the last byte of the column (187). + P) You can create a column of bytes. Here, Kc is 187 as in FIG. 5C, and Nc is 187 + P. For example, if P is 48, (235,187) -RS encoding may be performed to create a column of 235 bytes.

When the RS encoding process is performed on all N columns of FIG. 5C, an RS frame having a size of N (row) * (187 + P) (column) bytes as shown in FIG. 5D is obtained. I can make it. In the present invention, for convenience of description, an RS frame to which RS parity is added is also referred to as a second RS frame. That is, the second RS frame is equivalent to 187 + P rows of N bytes.

As shown in (c) or (d) of FIG. 5, each row of the RS frame includes N bytes. However, an error may be included in the RS frame according to the channel condition between the transmission and reception. When an error occurs in this way, it is possible to use CRC data (or CRC code or CRC checksum) to check an error for each row.

The RS frame encoder 302 may perform CRC encoding on the RS coded mobile service data to generate the CRC data. The CRC data generated by the CRC encoding may be used to indicate whether the mobile service data is damaged by an error while being transmitted through a channel.

The present invention may use other error detection encoding methods in addition to CRC encoding, or may increase the overall error correction capability at the receiving end by using an error correction encoding method.

5 (e) shows an example of using a 2-byte (i.e. 16-bit) CRC checksum as CRC data, and after generating a 2-byte CRC checksum for N bytes of each row, an N-byte rear end is generated. It is adding. By doing this, each row is expanded to N + 2 bytes.

Equation 1 below shows an example of a polynomial that generates a 2-byte CRC checksum for each row of N bytes.

g (x) = x ¹⁶ + x ¹² + x ⁵ + 1

Since adding a 2-byte CRC checksum to each row is an embodiment, the present invention will not be limited to the example described above.

In the present invention, for convenience of description, an RS frame to which an RS parity and a CRC checksum are added may be referred to as a third RS frame. That is, the third RS frame is equivalent to 187 + P rows of N + 2 bytes.

After all the RS coding and CRC coding described above, an RS frame of N * 187 bytes is extended to an RS frame of (N + 2) * (187 + P) bytes.

Looking at the error correction scenario of this extended RS frame, the bytes in the RS frame is transmitted on the channel in the row direction. At this time, if a large amount of error occurs in the limited transmission time, the error occurs in the row direction in the RS frame of the decoding process of the receiving system. However, in view of the RS code performed in the column direction, an error is distributed, and thus an effective error correction can be performed. In this case, although a parity byte (P) is increased as a method for more robust error correction, an appropriate compromise is required because it decreases the transmission efficiency. In addition, erasure decoding can be used to improve the error correction capability.

In addition, the RS frame encoder 302 of the present invention performs a row permutation (super frame) in order to further improve the error correction capability of the RS frame.

6 illustrates an embodiment of a row mixing process in units of super frames.

That is, G frames encoded as shown in FIG. 5 are collected as shown in FIG. 6A to form a super frame. At this time, since each RS frame is composed of (N + 2) * (187 + P) bytes, one super frame is (N + 2) * (187 + P) * G bytes size.

When the rows of the super frame configured as described above are mixed according to a predetermined rule, the positions of the rows before and after row mixing in the super frame are changed. That is, as shown in (b) of FIG. 6, the i-th row of the super frame before row mixing is positioned in the j-th row of the same super frame as shown in (c) of FIG. 6 after row mixing is performed. This relationship between i and j can be known through a row mixing rule as shown in Equation 2 below.

Even after row mixing in the super frame unit is performed, each row of the super frame is composed of N + 2 bytes.

After all the row mixing in the super frame unit is performed, it is divided into G row mixed RS frames and provided to the block processor 303 as shown in FIG.

Note that the RS parity and the number of columns of each RS frame constituting one super frame must be the same.

Similar to the error correction scenario of the RS frame described above, in the case of a super frame, since a large amount of error occurs, the error frame is distributed throughout the super frame even though an error that cannot be corrected is included in one RS frame to be decoded. The decoding capability is further improved compared to the RS frame.

As such, the mobile service data in which the RS frame encoder 302 encodes the RS frame unit and the row mixing in the super frame unit is output to the block processor 303.

The block processor 303 encodes the input mobile service data at a D / E (where D <E) code rate and outputs the encoded data to the group formatter 304.

That is, the block processor 303 divides the mobile service data input in byte units into bits, encodes the divided D bits into E bits, and converts them into byte units and outputs them. For example, if one bit of input data is encoded into two bits and outputted, D = 1 and E = 2. If one bit of input data is encoded into four bits and outputted, D = 1 and E = 4. In the present invention, for convenience of description, the former is referred to as encoding at 1/2 code rate (or sometimes referred to as 1/2 encoding), and the latter is referred to as encoding at 1/4 code rate (or referred to as 1/4 encoding). do.

In the case of using the 1/4 encoding, it is possible to have a high error correction capability because of the higher code rate than the 1/2 encoding. For this reason, the data encoded at the 1/4 code rate in the later group formatter 304 is allocated to an area where reception performance may be deteriorated, and the data encoded at 1/2 code rate may have better performance. If we assign to, we can get the effect of reducing the difference in performance.

In this case, the block processor 303 may also receive signaling information including a transmission parameter, and the signaling information also performs 1/2 encoding or 1/4 encoding as in the mobile service data processing process. The signaling information is also regarded as mobile service data and processed.

Meanwhile, the group formatter 304 inserts the mobile service data output from the block processor 303 into a corresponding region in the data group formed according to a predefined rule, and also provides various position holders or bases in relation to data deinterleaving. Data (or known data position holders) is also inserted into the corresponding area in the data group.

In this case, the data group may be divided into at least one layered area, and the type of mobile service data inserted into each area may vary according to characteristics of each layered area. For example, each region may be classified based on reception performance in a data group. In addition, one data group may be configured to include field synchronization.

According to an embodiment of the present invention, one data group is divided into A, B, and C regions in the data configuration before data deinterleaving. In this case, the group formatter 304 may allocate the mobile service data input by RS coding and block coding to the corresponding region with reference to the transmission parameter.

FIG. 7A illustrates a form in which data after data interleaving is divided and listed, and FIG. 7B illustrates a form in which data before data interleaving is classified and listed. That is, the data structure as shown in FIG. 7A is transmitted to the receiving system. In other words, one transport packet is interleaved by the data interleaver, distributed by several data segments, and transmitted to the receiving system. In this case, since a packet of 207 bytes has the same amount of data as one data segment, the packet before data interleaving may be used as a concept of a segment.

The data group formed in the structure shown in FIG. 7A is input to the data deinterleaver 305.

FIG. 7A illustrates an example in which a data group is largely divided into three regions, for example, region A, region B, and region C in the data configuration before data deinterleaving. It is showing.

In addition, according to an embodiment of the present invention, the A to C regions are divided into a plurality of sub-regions, respectively.

In FIG. 7A, the A region is divided into five subregions A1 to A5, the B region is divided into two subregions B1 and B2, and the C region is divided into three subregions C1 to C3. An example is shown.

The areas A to C are classified based on areas having similar reception performance in the data group. In this case, the type of mobile service data to be inserted may vary according to characteristics of each region.

In the present invention, dividing the A to C region based on the degree of interference of the main service data will be described as an embodiment.

Here, the reason why the data group is divided into a plurality of areas is used for different purposes. That is, an area where there is no or little interference of the main service data may exhibit stronger reception performance than an area that is not. In addition, in the case of applying a system for inserting and transmitting known data into a data group, an area where there is no interference of main service data (for example, A area) when periodically inserting long known data into a mobile service data periodically It is possible to periodically insert known data of a certain length into the. However, it is difficult to periodically insert base data in the area where the main service data interferes (for example, B and C areas) due to the interference of the service main service data, and also to insert long known data continuously.

At this time, the data group is formed including the position where the field sync is to be inserted. The group formatter 304 operates regardless of the insert position of the field sync, and the actual field sync is previously defined by the sync multiplexer 260 at the rear stage. Insert at field sync insertion position. 7B shows a data structure before data interleaving, in which 118 segments are allocated to one data group. The data group of FIG. 7B shows an embodiment of configuring 118 segments including 38 segments forward and 80 segments backward based on the position at which the field sync is to be inserted.

Next, a specific example in which the areas A (A1 to A5), B (B1 and B2) and C (C1 to C3) are allocated in the data group will be described with reference to FIG. 7A. The size of the data group of FIG. 7A, the number of layered areas and the size of each area in the data group, the number of mobile service data bytes that can be inserted into each layered area, and the like are one embodiment for describing the present invention.

That is, the area A includes areas A2 to A5 in which long known data sequences in the data group can be periodically inserted and main service data are not mixed. The area A also includes an area A1 between the field synchronization area to be inserted into the data group and the area to which the first known data string is to be inserted.

As an example, in FIG. 7A, mobile service data of 2428 bytes in an A1 area, 2580 bytes in an A2 area, 2772 bytes in an A3 area, 2472 bytes in an A4 area, and 2772 bytes in an A5 area may be inserted. The trellis initialization, known data, MPEG header, RS parity, etc. are excluded from the mobile service data.

As described above, in the area A having known data streams back and forth, since the equalization can be performed using the channel information obtained from the known data and the field synchronization, a robust equalization performance can be obtained.

The B area is a B1 area located in front of the first 8 segments of the field sync area in the data group (temporally located in front of the A1 area), and B2 located within 8 segments after the last known data column inserted into the data group. Region (temporally located behind region A). For example, 930 bytes can be inserted into the B1 region and 1350 bytes of mobile service data can be inserted into the B2 region. Similarly, trellis initialization, known data, MPEG header, RS parity, etc. are excluded from the mobile service data.

In the case of the B region, the receiving system can perform equalization using the channel information obtained in the field synchronization section, and can also perform equalization using the channel information obtained from the last known data sequence. Can respond to changes.

The C area includes the first ninth segment of the field sync area, and includes a C1 area (temporally located in front of the A area) located within 30 segments in front of it, and a ninth segment after the last known data column in the data group. C2 region located within 12 segments (it is located behind A region in time), and C3 region located within 32 segments following said C2 region.

For example, 1272 bytes in the C1 region, 1560 bytes in the C2 region, and 1312 bytes in the C3 region may be inserted. Similarly, trellis initialization, known data, MPEG header, RS parity, etc. are excluded from the mobile service data.

In this case, since the C1 region located in front of the A region in time is far from the field synchronization, which is the closest known data, the receiving system may use channel information obtained from the field synchronization at the time of channel equalization in the receiving system, or the most recent data group. Recent channel information can also be used. In the C2 and C3 regions located behind the A region in time, the equalization may not be perfect when the channel is rapidly changed even if the receiving system uses the channel information obtained from the last known data stream when the channel is equalized. . Therefore, the C region may have lower equalization performance than the B region.

Assuming that a data group is allocated to a plurality of layered areas as described above, the above-described block processor 303 may encode mobile service data to be inserted into each area at different code rates according to the characteristics of the layered area.

For example, the mobile service data to be inserted into areas A1 to A5 in the area A is encoded by the block processor 303 at a 1/2 code rate, and the encoded mobile service data is encoded into the group formatter 304. In the A1 ~ A5 region can be inserted.

The mobile service data to be inserted into the B1 and B2 areas in the B area is encoded by the block processor 303 at a 1/4 code rate with higher error correction capability than the 1/2 code rate. Data may be inserted into the B1 and B2 areas by the group formatter 304.

The mobile service data to be inserted in the C1 to C3 areas of the C region is encoded by the block processor 303 at a code rate having a 1/4 code rate or a stronger error correction capability than the 1/4 code rate. The coded data may be inserted into the C1 to C3 areas by the group formatter 304, or may be left as a reserved area for later use.

In addition to the encoded mobile service data output from the block processor 303, the group formatter 304 also includes an MPEG header position holder, an unstructured RS parity position holder, and a main in relation to data deinterleaving at a later stage as shown in FIG. 7A. Insert the service data location holder. The reason for inserting the main service data location holder is that the mobile service data and the main service data are mixed between B and C regions based on the input of the data deinterleaver as shown in FIG. 7A. As an example, the position holder for the MPEG header may be assigned to the front of each packet based on the output data after the data deinterleaving.

The group formatter 304 then inserts known data generated by a predetermined method or inserts known data position holders for inserting known data later. In addition, a position holder for initializing the Trellis Encoding Module 256 is inserted into a corresponding region (ie, a red region). In one embodiment, the initialization data location holder may be inserted before the known data row.

For example, in the data structure as shown in FIG. 7A, five known data areas (ie, blue areas) are allocated to area A in the data group in order to insert known data or known data position holders.

For convenience of description, five known data areas will be referred to as first to fifth known data areas.

The first known data area is allocated at a position about 16 segments away from the position where the field sync is to be inserted, and the second known data area is allocated at a position about 16 segments away from the first known data area. The third known data area is also allocated at a position about 16 segments away from the second known data area, and the fourth known data area is allocated at a position about 16 segments away from the third known data area. Similarly, the fifth known data area is allocated at a position about 16 segments away from the fourth known data area. In this case, the lengths of the first to fifth known data areas may be the same or may be different from each other. According to the present invention, at least one of the first to fifth known data areas is different from one another in length.

In the present invention, inserting known data into the first to fifth known data areas in the group formatter 304 will be described as an embodiment.

In this case, at least one area of the first to fifth known data areas, for example, the first known data area includes the same pattern repeated two or more times in the known data. For convenience of description, the repeated known data pattern will be referred to as a first known data pattern. The first known data pattern may be used for initial carrier frequency synchronization acquisition in a receiving system, or may be used for estimating the field synchronization position or the position of another known data region.

Each of the first to fifth known data areas includes a known data column having the same pattern, and will be referred to as a second known data pattern to distinguish it from the first known data pattern. According to an embodiment of the present invention, the lengths of the first known data pattern and the second known data pattern are different from each other.

The length of the known data string of the second known data pattern and the total known data string of the corresponding known data area may be the same or different. In other cases, the entire known data column is longer than the known data column of the second known data pattern, and the second known data pattern is included in the entire known data column.

In the present invention, 1424 symbols (that is, 356 bytes) are inserted into the first through fifth known data areas in the second known data pattern, respectively. The second known data pattern inserted into the first to fifth known data areas may be used as a training sequence in a receiving system or may be used to estimate a channel impulse response (CIR).

In addition, the group formatter 304 may insert additional information data such as signaling, which informs the overall transmission information, separately from the mobile service data, into the data group. As the signaling information, transmission parameters related to transmission and reception of broadcast signals may be set.

In this case, the mobile service data size that can be inserted into one data group is determined by the size of the trellis initialization position holder, known data (or known data position holder), MPEG header position holder, RS parity position holder, etc. inserted into the data group. Can vary.

FIG. 8 illustrates a part of the A area in the data group in the data frame having the data structure as shown in FIG. 7A, and is an enlarged view of the field sync segment to the third known data area. The data frame of FIG. 8 represents data inserted and transmitted in each area in symbol units. Here, one byte consists of four symbols and one symbol consists of two bits.

In the data frame shown in FIG. 8, the field sync segment consists of 832 symbols. Some of the 832 symbols may include a known data string.

Each known data area includes an initialization data area (ie, a red area) for transmitting trellis memory initialization data. For example, 48 symbols may be allocated to the initialization data area. In this case, the initialization data required to initialize one trellis encoder among the 12 trellis encoders is 2 symbols. Therefore, 24 symbols are needed to initialize the 12 trellis encoders. Therefore, the remaining 24 symbols in the initialization data area of each known data area can be used as known data.

At least one of the first to fifth known data areas (eg, the first known data area) includes a first known data pattern, and the first to fifth known data areas each include a second known data pattern. Include.

The second known data pattern may be included immediately after the trellis memory initialization data in the corresponding known data area, or may be included after another pattern of known data sequences. This is because the start positions of the first to fifth known data areas and the lengths of the first to fifth known data areas are different, so as to maintain a constant interval between the second known data patterns.

The first known data area located approximately 16 segments after the field sync segment includes a trellis memory initialization data area (red area), a third known data pattern area (blue hatched area), and a second known data pattern area ( CIR TS area), a fourth known data pattern area (reserved TS area), and a first known data pattern area (ACQ TS area).

The trellis memory initialization data area (red area) is, for example, an area in which 24 symbols are allocated and trellis memory initialization is performed at the transmitting side. The third known data pattern region (blue shaded region) is a region which is preliminarily allocated so that the second known data pattern maintains the same interval as the second known data pattern of the other known data region. The third known data pattern included in the data pattern region may be used in the receiving system or may be preliminarily placed.

For example, 1424 symbols are allocated to the second known data pattern region (CIR TS region), and a second known data pattern that can be used for channel equalization is inserted. The starting position in the segment of the second known data pattern area is the same in all known data areas.

For example, 252 symbols are allocated to the fourth known data pattern region (reserved TS region). According to the embodiment of the present invention, the transmission parameter is inserted into the fourth known data pattern region and transmitted. For example, mode information indicating a code rate of each region in the data group may be inserted. For convenience of description, a mode indicating a code rate of each region in the data group will be referred to as a serial concatenated convolution code (SCCC) mode. For example, if SCCC mode information having six different patterns is inserted into the fourth known data pattern region as a transmission parameter, that is, signaling information, the receiver receives the fourth known data pattern before performing decoding according to the SCCC mode. The received signal can be decoded by obtaining information on the SCCC mode from the region.

Table 1 below shows an example of the SCCC mode.

For example, if the SCCC mode value extracted from the fourth known data pattern region is 2, the A and C regions in the data group are encoded at 1/2 code rate, and the B region is encoded at 1/4 code rate. Indicates that the That is, the transmitting side of the present invention may generate six patterns corresponding to the respective mode values shown in Table 1 by a promise of the transmitting / receiving side, and insert the corresponding patterns into the fourth known data pattern area for each data group. have.

In this case, the SCCC mode information can be obtained from the fourth known data pattern region before the block decoder 1005 of the receiving system performs decoding according to the SCCC mode.

In the meantime, a plurality of first known data patterns are inserted in the first known data pattern area (ACQ TS area) in order to obtain initial carrier frequency synchronization. For example, one first known data pattern is allocated to 576 symbols. Therefore, in FIG. 8, a plurality of first known data patterns of 576 symbols used for initial carrier frequency synchronization acquisition are successively inserted into the first known data pattern region.

The second known data area located about 16 segments after the first known data area includes a trellis memory initialization data area (red area), a third known data pattern area (blue hatched area), and a second known data area. Pattern region (CIR TS region).

In the trellis memory initialization data area (red area) of the second known data area, 24 symbols are allocated, for example, and data used for trellis memory initialization is inserted. The third known data pattern region (blue shaded region) is a region which is preliminarily allocated so that the second known data pattern maintains the same interval as the second known data pattern of the other known data region. The third known data pattern included in the data pattern region may be used in the receiving system or may be preliminarily placed.

For example, 1424 symbols are allocated to the second known data pattern region (CIR TS region), and a second known data pattern that can be used for channel equalization is inserted. The starting position in the segment of the second known data pattern area is the same in all known data areas.

The third known data area located about 16 segments after the second known data area includes a trellis memory initialization data area (red area) and a second known data pattern area (CIR TS area) used for channel equalization. Include.

The initialization data area (red area) in the third known data area includes 12 bytes, in which only two symbols are used to initialize the trellis memory for each byte. Therefore, the remaining two symbols in each byte, that is, the remaining 24 symbols of the initialization data region, can be used for channel equalization.

In this data structure, there are 11892 symbols of general data between the field sync area and the first known data area, 10480 symbols of general data between the first known data area and the second known data area, and the second known data area and the third known data area. 11888 symbols of general data may be inserted and transmitted between the known data areas. The general data corresponds to the remaining data except for the field sync and the known data area, for example, main service data, mobile service data, RS parity data, MPEG header data, and the like.

9 illustrates an arrangement of a signal of a transmission parameter when a transmission parameter is transmitted as signaling information in a data group, that is, a mobile service data area. FIG. 9A illustrates signaling information having a size of 4 bytes. The signaling information includes a service ID according to a program, an RS mode of an A and a B region, and an RS of a C region of a signal frame of FIG. 7A. Mode, super frame size (SFS), permuted frame index (PFI) that the RS frame occupies in the super frame, burst size (BS), group index (GI) ) And time to next burst (NBN) information. 9 (a) shows an example in which the size of the illustrated information is allocated to the size of 4 bytes when the illustrated information is included, and the size of each of the above information is indicated in the form of an array in parenthesis. It was.

FIG. 9B illustrates signal arrangement when the signaling information of FIG. 9A is located in the data group of FIG. 7A. As the error correction mode for the data of the A region in the data group, when the SCCC mode of 1/2 code rate is used, 4 bytes of signaling information data illustrated in FIG. 9A and 4 bytes of duplicated signaling information thereof Data and 24 bytes of RS parity data may be included in the area A of the data group of 7a (hereinafter referred to as first error correction mode).

Alternatively, when the SCCC mode of 1/4 code rate is used for the data in the A area of the data group, 4 bytes of signaling information data and 12 bytes of RS parity data as shown in (c) of FIG. It may be included in the area A (hereinafter referred to as a second error correction mode).

FIG. 10 is a diagram illustrating an example in which signaling information is arranged in a data group. The signaling information illustrated in FIG. 9 may be multiplexed with mobile service data and included in the A area to be transmitted. 10 illustrates the location of signaling information when multiplexed mobile service data and signaling information are interleaved in a data interleaver of a transmission system.

If the mobile service data including the transmission parameter illustrated in (b) of FIG. 9 is interleaved after being encoded in the first error correction mode (that is, 1/2 code rate), 32 bytes of (b) of FIG. 6 bytes are located in the A1 area (between the field sync and the first known data area), and 8 bytes are located in the A2 area (between the first known data and the second known data area). In the 32 bytes of FIG. 9B, six bytes of transmission parameters (eg, RS parity of the transmission parameters) may be located in the A3 region, the A4 region, and the A5 region. On the other hand, when the mobile service data including the transmission parameter illustrated in (c) of FIG. 9 is interleaved after being encoded in the second error correction mode (that is, 1/4 code rate), 16 of FIG. Three bytes of the bytes may be located in the A1 area (between the field sync and the first known data area), and four bytes may be located in the A2 area (between the first known data and the second known data area). In the A3 region, the A4 region, and the A5 region, transmission parameters (eg, RS parity of the transmission parameters) of 3 bytes of the 16 bytes of FIG. 9C may be located.

The receiving system of the broadcasting system can obtain the position of the transmission parameter illustrated in FIG. 10 from the mobile service data area according to a rule defined with the transmitting system. The receiving system may perform SCCC decoding by acquiring signaling information set in the known data area or the field synchronization area illustrated in FIG. 8 before decoding according to the SCCC mode. In addition, the receiving system may receive information related to the burst from the signaling information illustrated in FIG. 9 and receive only a signal included in the burst.

On the other hand, the output of the group formatter 304 is input to the data deinterleaver 305, the data deinterleaver 305 is a reverse process of data interleaving the data and position holder in the data group output from the group formatter 304 Deinterleaving is performed to output to the packet formatter 306. That is, when the data and position holder in the data group configured as shown in FIG. 7A are deinterleaved by the data deinterleaver 305, the data group output to the packet formatter 306 has a structure as shown in FIG. 7B.

The packet formatter 306 removes the main service data location holder and the RS parity location holder which have been allocated for deinterleaving among the deinterleaved input data, collects the remaining parts, and then collects null packets in the 4-byte MPEG header location holder. Insert and replace the MPEG header with the PID (or PID not used in the main service data packet).

The packet formatter 306 may also insert the actual known data into the known data position holder when the group formatter 304 inserts the known data position holder, or later inserts the known data position holder for replacement. You can output as is without adjustment.

The packet formatter 306 then divides the data in the packet-formatted data group into mobile service data packets (ie, MPEG TS packets) in units of 188 bytes and provides them to the packet multiplexer 240.

The packet multiplexer 240 multiplexes the mobile service data packet output from the preprocessor 230 and the main service data packet output from the packet jitter reducer 220 according to a predefined multiplexing method. Output to the data renderer 251 of the processor 250. The multiplexing method can be adjusted by various variables of the system design.

As one of multiplexing methods of the packet multiplexer 240, a burst section is provided on a time axis, and a plurality of data groups are transmitted in a burst on section within a burst section, and only main service data is transmitted in a burst off section. Can be. The burst period here means from the start of the current burst to the start of the next burst.

In this case, the main service data may be transmitted in the burst on period. The packet multiplexer 240 may know the number, period, etc. of data groups included in one burst with reference to the transmission parameter, for example, a burst size or a burst period.

In this case, the mobile service data and the main service data may be mixed in the burst on section, and only the main service data exists in the burst off section. Therefore, the main service data section for transmitting the main service data may exist in both the burst on section and the burst off section. In this case, the number of main service data packets included in the main service data section and the burst off section in the burst on section may be different or the same.

As described above, when the mobile service data is transmitted in a burst structure, the receiving system receiving only the mobile service data turns on power only in the burst section to receive the data, and turns off the power in the section where only the main service data is transmitted. By not receiving, the power consumption of the receiving system can be reduced. This feature is particularly useful in portable receivers that require low power consumption.

11 (a) and 11 (b) illustrate an embodiment of a method of multiplexing on a burst basis in the packet multiplexer. In FIG. 11, a data group is composed of a plurality of consecutive mobile service data packets, and a plurality of data groups are gathered to form one burst on period.

For convenience of description, it is assumed that one burst-on period in FIGS. 11A and 11B includes a program according to one service.

In FIGS. 11A and 11B, TNB (Time to Next Burst) means a time until the start time of the next burst Burst2 in each data group in the current burst Burst1.

In the present invention, the next burst time (TNB) is inserted and transmitted for each data group in the current burst, and the next burst time is inserted into a predetermined area of the data group. For example, the next burst time (TNB) information may be inserted as signaling information in a fourth known data pattern region of the first known data region as shown in FIGS. 8 and 9.

As can be seen from (a) of FIG. 11, it can be seen that the next burst time TNB continues to decrease from data group G1 of the current burst 1 to G2 and G3 (TNBG1> TNBG2> TNBG3). In this case, the reason why the next burst time TNB is repeatedly inserted into each data group is to allow the receiving system to determine the next burst time through reception of another data group even when an error occurs in the reception of a specific data group.

12 (a) to 12 (c) illustrate another embodiment of a method of multiplexing on a burst basis in the packet multiplexer.

12 (a) to 12 (c) show an embodiment in which two types of mobile service data are multiplexed with a main data packet.

In FIGS. 12A to 12C, mobile service data providing a first mobile service is represented by mo1, and mobile service data providing a second mobile service is represented by mo2. That is, mo1 and mo2 denote data groups of the first mobile service and data groups of the second mobile service, respectively. As can be seen from FIG. 12, the data mo1 of the first mobile service and the data mo2 of the second mobile service are each multiplexed and transmitted in data group units, and the burst period is independently applied to each type of mobile service. Able to know. That is, among the data groups G1, G2, G3, and G4, G1 and G3 are data groups of the first mobile service, and G2 and G4 are data groups of the second mobile service, so that the burst period of the first mobile service is the start time of G1. To the end of G3 and the burst period of the second mobile service is a period from the start of G2 to the end of G4. As described above, since the burst of the first mobile service and the burst period of the second mobile service are independent of each other, the next burst time (TNB) inserted into each data group is applied differently according to the mobile service type of the data group.

In other words, the next burst times TNBG1 and TNBG3 inserted into the data groups G1 and G3 of the first mobile service mean the time until the start of the burst of the next first mobile service, and the data group G2 of the second mobile service. The next burst times TNBG2 and TNBG4 inserted into G4 mean time until the start of the burst of the next second mobile service.

The various transmission parameters such as the next burst time (TNB), the length of each data group, the time from the current group to the next group in the burst, the length of the burst, etc. may use any predetermined values and vary in real time. You can also use the value of. For example, the transmission parameter may be inserted as signaling information in the fourth known data pattern region of the first known data region as shown in FIGS. 8 and 9.

RS  Specific to frame composition and packet multiplexing Example

Next, specific embodiments of the preprocessor 230 and the packet multiplexer 240 will be described.

In an embodiment of the present invention, an N value, which is the length of one row of the RS frame configured in the RS frame encoder 302, is set to 538.

Then, the RS frame encoder 302 may receive 538 transport stream (TS) packets to configure a first RS frame having a size of 538 * 187 bytes. Then, as described above, a second RS frame having a size of 538 * 235 bytes is formed through (235,187) -RS encoding, and a third RS frame having a size of 540 * 235 bytes is formed again through a 16-bit CRC checksum generation process. do.

For example, the mobile service data to be inserted in the areas A1 to A5 in the area A is encoded by the block processor 303 at a 1/2 code rate, and the mobile service data to be inserted in the areas B1 and B2 in the area B. Suppose that the block processor 303 performs encoding at a 1/4 code rate. In addition, it is assumed that the mobile service data inserted into the A and B areas are the same type.

Then, as shown in FIG. 7A, when the number of bytes of the area A1-A5 in the area A, into which the 1 / 2-encoded mobile service data is to be inserted, is 13024 bytes (= 2428 + 2580 + 2772 + 2472). +2772 bytes). In this case, the number of bytes before 1/2 encoding is 6512 (= 13024/2) bytes.

The number of bytes in the B1 and B2 areas in the B area into which the 1 / 4-coded mobile service data is to be inserted is 2280 (= 930 + 1350) bytes. In this case, the number of bytes before 1/4 encoding is 570 (= 2280/4) bytes.

In summary, when 7082 bytes of mobile service data are input to the block processor 303, 6512 bytes of which are extended to 13024 bytes through 1/2 encoding, and 570 bytes to 2280 bytes through 1/4 encoding. To be. The group formatter 304 inserts the mobile service data extended to 13024 bytes into the areas A1 to A5 in the area A, and the mobile service data extended to 2280 bytes is inserted into the areas B1 and B2 in the B area.

In this case, the 7082 bytes of mobile service data input to the block processor 303 may be classified into an output of the RS frame encoder 302 and signaling information. According to the embodiment of the present invention, 7050 bytes of the 7082 bytes are received at the output of the RS frame encoder 302, and the remaining 32 bytes are inputted with signaling information data to perform 1/2 encoding or 1/4 encoding.

On the other hand, one RS frame that has undergone RS coding and CRC coding in the RS frame encoder 302 is composed of 540 * 235 bytes, that is, 126900 bytes. Dividing this by 7050 bytes for the time base divides it into 18 7050 bytes.

The 7050-byte mobile service data output from the RS frame encoder 302 is combined with 32-byte signaling information data and then half-coded or quarter-coded by the block processor 303 to be group-formatter 304. Is output. The group formatter 304 inserts half-coded data into the A region and inserts 1 / 4-coded data into the B region.

Next, a process of determining an N value required to form an RS frame in the RS frame encoder 302 will be described.

That is, (N + 2) * 235 bytes, which is the size of the last RS frame (that is, the third RS frame) RS-coded and CRC-coded in the RS frame encoder 302, must be allocated to an integer number of groups. At this time, since 7050 bytes are allocated to a single data group before encoding, if (N + 2) * 235 bytes are divided into 7050 (= 30 * 235), the output data of the RS frame encoder 302 is divided. It can be efficiently assigned to a data group. In an embodiment of the present invention, the value of N is determined such that N + 2 is a multiple of 30. In the present invention, 538 is determined by the N value, and N + 2 (= 540) divided by 30 gives 18. This means that mobile service data in one RS frame is divided into 18 data groups through 1/2 encoding or 1/4 encoding.

13 shows a process of dividing an RS frame in the group formatter 304 according to the present invention. That is, an RS frame having a size of (N + 2) * 235 is divided into 30 * 235 byte blocks. Each divided block is mapped to one data group. That is, data of one block having a size of 30 * 235 bytes is inserted into one data group through 1/2 encoding or 1/4 encoding.

As another example, the mobile service data to be inserted into the C region is encoded by the block processor 303 at a 1/2 code rate, and the mobile service data to be inserted into the C region is inserted into the A and B regions. Suppose it is a different kind of data than a service.

Then, as shown in FIG. 7A, when the number of bytes of the C1-C3 region in the C region, into which the 1 / 2-encoded mobile service data is to be inserted, is 4144 bytes (= 1272 + 1560 + 1312 bytes), as shown in FIG. 7A. to be. In this case, the number of bytes before 1/2 encoding is 2072 (= 4144/2) bytes.

In this case, assuming that 18 data groups are collected to form one RS frame, and the mobile service data of the RS frame is inserted into the C region, the RS frame is composed of 37296 bytes. Here, if the RS parity (P) is set to 36 and the CRC checksum is allocated to 2 bytes for each row, 165 mobile service data packets of 187 bytes can be transmitted in one RS frame.

In this case, 55 bytes remain in each C frame in the C region of the data group. If the byte remains as described above may occur while dividing the RS frame into a plurality of data groups of the same size. That is, the size of the RS frame, the size and number of data groups to be distinguished, the number of mobile service data bytes that can be inserted into each data group, the code rate of the corresponding area, the number of bytes of RS parity, whether CRC checksums are allocated, and Depending on the number of bytes of the CRC checksum, the remaining bytes may occur in a specific area per RS frame.

When a single RS frame is divided into a plurality of data groups having the same size as described above, when bytes remaining in the RS frame are generated, a plurality of dummy bytes are added after the number of bytes (K) remaining in the RS frame. Separate into three data groups.

This process is illustrated in FIG. 14.

14 illustrates an embodiment of a process in which K bytes remain when an RS frame having a size of (N + 2) * (187 + P) is divided into M data groups having the same size.

In this case, after adding K dummy bytes to the RS frame having a size of (N + 2) * (187 + P) as shown in FIG. 14A, it is read in rows and read as M as shown in FIG. 14B. Separate into three data groups. Each data group has a NoBytesPerGrp byte size.

This is represented by the following equation (3).

M * NoBytesPerGrp = (N + 2) * (187 + P) + K

Here, NoBytesPerGrp is the number of bytes allocated to one data group (NoBytesPerGrp means the Number of Bytes per a Group).

That is, the size of bytes + K bytes of one RS frame is the same as that of M data groups.

If the mobile service data is transmitted in the method and mode described so far, the data randomizer 301 of the preprocessor 230 is a first mobile service data path in which data to be allocated to the A and B areas of the data group is input. Packets, 165 packets may be input to the second mobile service data path.

To this end, a plurality of data randomizers and RS frame encoders may be provided. Then, 538 packets inputted to the first mobile service data path and 165 packets inputted to the second mobile service data path are each randomized by the plurality of data renderers, and each RS frame encoder encodes each of the RS frames. After row mixing is performed in units of and super frames, the signals are divided into RS frames and inputted to the block processor 303.

For example, the RS frame encoder encoding data input through the first mobile service data path adds 48 parity bytes in the column direction and a CRC checksum of 2 bytes in the row direction for the corresponding RS frame. The RS frame encoder for encoding data input through the second mobile service data path adds 36 parity bytes for the corresponding RS frame, and adds a 2-byte CRC checksum in the row direction.

For example, the block processor 303 performs 1/2 encoding on data to be allocated to the A and C regions, and performs 1/4 encoding on data to be allocated to the B regions and outputs the data to the group formatter 304. do.

In this case, as described above, since the C region in the data group has 55 bytes remaining for every RS frame, the block processor 303 adds a dummy byte of 55 bytes when all data of the RS frame to be allocated to the C region is input. Perform the / 2 encoding. The addition of the dummy byte may be performed by the block processor 303 or may be input from an external block (not shown).

In the group formatter 304, the mobile service data and other data inputted with 1/2 encoding or 1/4 encoding (for example, an MPEG header position holder, an unstructured RS parity position holder, a main service data position holder, a base) Data, known data position holder, initialization data position holder, etc.) are inserted (or arranged) in the corresponding area in the data group of FIG. 7A. For example, mobile service data that is input to the first mobile service data path and encoded at 1/2 code rate or 1/4 code rate is inserted into the A and B areas, and is input to the second mobile service data path to 1 / Mobile service data encoded at two code rates is inserted in the C region.

As described above, the data group in which the corresponding data and the position holder are inserted in each layered area in the group formatter 304 is input to the packet multiplexer 240 through the data deinterleaver 305 and the packet formatter 306.

15 illustrates an operation of the packet multiplexer 240 according to a specific embodiment of the present invention. That is, the packet multiplexer 240 multiplexes fields including data groups and fields including only main service data in a burst structure and outputs the data to the data randomizer 251. In the present invention, fields including the data group are transmitted in the burst on period, and fields including only the main service data are transmitted in the burst off period. In this case, the main service data may be transmitted in the burst on period.

In this case, in order to transmit one RS frame having a size of 540 * 235 bytes, 18 data groups must be transmitted. Here, each data group includes field synchronization as shown in FIG. 7A. Therefore, 18 data groups are transmitted during 18 field periods, and the period in which the 18 data groups are transmitted is a burst on period.

In each field in the burst-on period, one data group including field synchronization and main service data are multiplexed and output. In an embodiment, each field within the burst on period is multiplexed with a data group of 118 segments and main service data of 194 segments.

Referring to FIG. 15, a field including 18 data groups is transmitted during a burst on period, that is, an 18 field period, and then a field including only main service data during a burst off period, that is, a 12 field period. Will be sent. After that, 18 fields including 18 data groups are transmitted in the burst on period, and 12 fields including only main service data are transmitted in the next burst off period.

In addition, the present invention may provide the same type of data service or may transmit different data services in the burst on period including the first 18 data groups and the burst on period including the second 18 data groups.

For example, suppose that the first burst on period and the second burst on period of FIG. 15 transmit different data services, and the receiving system wants to receive only one data service. In this case, the receiving system can reduce the power consumption of the receiving system by turning on the power only in the corresponding burst on period including the desired data service and receiving 18 fields, and turning off the power for the remaining 42 field periods. Will be. In addition, the receiving system can configure one RS frame from 18 data groups received in one burst-on period, so that decoding is easy.

In the present invention, the number of data groups included in one burst on interval depends on the size of the RS frame, and the size of the RS frame depends on the value of N. That is, the number of data groups in the burst can be adjusted by adjusting the N value. In this case, the (235,187) -RS encoding adjusts the N value in a fixed state.

In addition, the size of the mobile service data that can be inserted in the data group may vary depending on the size of trellis initialization, known data, MPEG header, RS parity, etc., inserted into the data group.

Meanwhile, since the data group including the mobile service data is multiplexed between the main service data in the packet multiplexing process, the temporal position of the main service data packet is relatively moved. The system target decoder (i.e., MPEG decoder) for main service data processing of the receiving system receives and decodes only main service data and recognizes the mobile service data packet as a null data packet.

Therefore, when the system target decoder of the receiving system receives the main service data packet multiplexed with the data group, packet jitter occurs.

In this case, since there are various buffers for the video data in the system target decoder and the size thereof is quite large, the packet jitter generated by the packet multiplexer 240 is not a big problem in the case of video data. However, the size of the buffer for audio data, which the system target decoder has, can be problematic.

That is, the packet jitter may cause overflow or underflow in a buffer for main service data of the receiving system, for example, a buffer for audio data.

Accordingly, the packet jitter reducer 220 readjusts the relative position of the main service data packet so that no overflow or underflow occurs in the buffer of the system target decoder.

The present invention describes embodiments of relocating the audio data packet of the main service data in order to minimize the influence on the operation of the audio buffer. The packet jitter reducer 220 rearranges the audio data packets in the main service data section so that the audio data packets of the main service are as uniform as possible.

The criterion for relocating the audio data packet of the main service in the packet jitter reducer 220 is as follows. In this case, it is assumed that the packet jitter reducer 220 knows the multiplexing information of the packet multiplexer 240 at a later stage.

First, if there is one audio data packet in the main service data section in the burst on section, for example, the main service data section between two data groups, the audio data packet is placed in front of the main service data section. If two are present, they are placed at the front and the rear. If there are three or more, they are placed at the front and the rear and the rest are evenly spaced between them.

Second, in the main service data section before the start of the burst on section, that is, the burst off section, the audio data packet is arranged at the last position.

Third, the audio data packet is placed first in the main service data section of the burst off section after the burst on section ends.

Packets other than audio data are arranged in a space excluding the location of audio data packets in the order of input.

On the other hand, when the position of the main service data packet is relatively readjusted as described above, the PCR value must be corrected accordingly. The PCR value is a time reference value to match the time of the MPEG decoder and is inserted into a specific area of the TS packet and transmitted. In an embodiment, the packet jitter reducer 220 performs a function of PCR value correction.

The output of the packet jitter reducer 220 is input to the packet multiplexer 240. The packet multiplexer 240 multiplexes the main service data packet output from the packet jitter reducer 220 and the mobile service data packet output from the preprocessor 230 into a burst structure according to a preset multiplexing rule. And outputs the data to the data renderer 251 of the post processor 250.

If the input data is a main service data packet, the data randomizer 251 performs rendering in the same way as the existing renderer. That is, the sync byte in the main service data packet is discarded and the remaining 187 bytes are randomly generated using a pseudo random byte generated internally, and then output to the RS encoder / unstructured RS encoder 252.

However, if the input data is a mobile service data packet, only a part of the packet may be rendered. For example, assuming that the preprocessor 230 has previously performed rendering on mobile service data, the data renderer 251 may select a sync byte of a 4-byte MPEG header included in the mobile service data packet. Discard it and perform rendering for only the remaining 3 bytes to output to the RS encoder / unstructured RS encoder 252. That is, the rest of the mobile service data except the MPEG header is output to the RS encoder / unstructured RS encoder 252 without performing rendering. The data randomizer 251 may or may not perform the randomization of the known data (or known data location holder) and the initialization data location holder included in the mobile service data packet.

The RS encoder / unstructured RS encoder 252 adds 20 bytes of RS parity by performing RS encoding on the data to be rendered or bypassed by the data randomizer 251, and then the data interleaver 253. Will output In this case, the RS encoder / unstructured RS encoder 252 adds 20 bytes of RS parity to 187 bytes of data after performing systematic RS encoding in the same manner as the existing broadcasting system when the input data is a main service data packet. In case of a mobile service data packet, unsystematic RS coding is performed, and the 20-byte RS parity obtained at this time is inserted at a predetermined parity byte position in the packet.

The data interleaver 253 is a convolutional interleaver in bytes.

The output of the data interleaver 253 is input to a parity substituent 254 and an unstructured RS encoder 255.

On the other hand, in order to make the output data of the trellis encoder 256 located at the rear end of the parity substituter 254 into known data defined by appointment on the transmitting / receiving side, the memory in the trellis encoder 256 is first initialized. Is needed. That is, before the input known data string is trellis encoded, the memory of the trellis encoder 256 must be initialized.

At this time, the start of the known data stream is not the actual known data but the initialization data position holder inserted by the group formatter in the preprocessor 230. Therefore, a process of generating initialization data immediately before the input known data string is trellis encoded and replacing the corresponding trellis memory initialization data position holder is required.

The trellis memory initialization data is generated by determining a value thereof according to the memory state of the trellis encoder 256. In addition, a process of recalculating RS parity under the influence of the replaced initialization data and replacing the RS parity with the RS parity output from the data interleaver 253 is necessary.

Accordingly, the unstructured RS encoder 255 receives a mobile service data packet including an initialization data position holder to be replaced with initialization data from the data interleaver 253 and inputs initialization data from the trellis encoder 256. Receive. The initialization data position holder of the input mobile service data packet is replaced with the initialization data, and the RS parity data added to the mobile service data packet is removed, and then unstructured RS encoding is performed. The RS parity obtained by the unsystematic RS coding is output to the parity substituent 255. Then, the parity substituter 255 selects the output of the data interleaver 253 for data in the mobile service data packet, and selects the output of the unstructured RS encoder 255 for the RS parity. Will output

Meanwhile, when the main service data packet is input or the mobile service data packet including the initialization data location holder to be replaced is input, the parity substituter 254 selects data and RS parity output from the data interleaver 253 as it is. The trellis encoder 256 outputs the trellis encoder.

The trellis encoder 256 converts the data of the byte unit into the symbol unit, performs 12-way interleaving, trellis-encodes, and outputs the trellis to the synchronous multiplexer 260.

The synchronous multiplexer 260 inserts field sync and segment sync into the output of the trellis encoder 256 and outputs the field sync and segment sync to the pilot inserter 271 of the transmitter 270.

Data in which the pilot is inserted in the pilot inserter 271 is modulated by a modulator 272, for example, a VSB method, and then transmitted to each receiving system through the RF up converter 273.

Block handler

16 is a detailed block diagram of a block processor according to an embodiment of the present invention, which includes a byte-bit converter 401, a symbol encoder 402, a symbol interleaver 403, and a symbol-byte converter 404. can do.

The byte-bit converter 401 divides the mobile service data byte input from the RS frame encoder 112 into bits and outputs the bits to the symbol encoder 402.

The byte-symbol converter 401 may also receive signaling information including a transmission parameter and the like, and the signaling information bytes are also divided into bits and output to the symbol encoder 402. In this case, the signaling information including the transmission parameter may be input to the block processor 303 via the data renderer 301 and the RS frame encoder 302 in the same manner as the mobile service data processing process, or the data renderer ( It may be input directly to the block processor 303 without passing through the 301 and the RS frame encoder 302.

The symbol encoder 402 is a D / E encoder that encodes the input data D bits into E bits and outputs them (where D <E). For example, if one bit of input data is encoded into two bits and outputted, D = 1 and E = 2. If one bit of input data is encoded into four bits and outputted, D = 1 and E = 4.

According to an embodiment of the present invention, the symbol encoder 402 performs encoding at a 1/2 code rate (or sometimes referred to as 1/2 encoding) or encoding at a quarter code rate (also referred to as 1/4 encoding). Explain. That is, the symbol encoder 402 performs 1/2 encoding or 1/4 encoding on the received mobile service data and signaling information. After the encoding of the symbol encoder 402, the signaling information is also described as mobile service data.

The symbol encoder 402 may operate as an encoder having a 1/2 code rate or may operate as an encoder having a 1/4 code rate.

17A to 17C are block diagrams illustrating embodiments in which a symbol encoder according to the present invention operates as an encoder having a quarter code rate.

The symbol encoder of FIG. 17A may include a quarter outer encoder (411), and a parallel / serial converter (412).

In FIG. 17A, the 1/4 external encoder 411 encodes the input mobile service data bit U into 4 bits u0 to u3, that is, two symbols, and outputs the same to the parallel / serial converter 412. The parallel / serial converter 412 converts two symbols inputted in parallel into a series of symbol units and sequentially outputs the two symbols to the symbol interleaver 403. That is, the parallel / serial converter 412 outputs one symbol of u0, u1 bits to the symbol interleaver 403, and then outputs another symbol of u2, u3 bits to the symbol interleaver 403.

The symbol encoder of FIG. 17B may include a 1/2 external encoder 421, and a parallel / serial converter 422.

In FIG. 17B, the 1/2 external encoder 421 encodes the input mobile service data bit U into 2 bits u0, u1, that is, one symbol, and outputs the same to the repeater 422. The iterator 422 repeats a symbol encoded at a 1/2 code rate once and outputs the symbol to the symbol interleaver 403. That is, the repeater 422 outputs a symbol of u0, u1 bits to the symbol interleaver 403, and then outputs a symbol of u0, u1 bits to the symbol interleaver 403 again.

The symbol encoder of FIG. 17C may include an iterator 431 and a 1/2 outer encoder 432.

In FIG. 17C, the repeater 431 repeats the input mobile service data bit U once and outputs two bits of U and U to the 1/2 external encoder 432. The 1/2 external encoder 432 encodes the mobile service data bits U output from the iterator 431 into 2 bits u0, u1, that is, one symbol, and outputs the encoded bits to the symbol interleaver 403. In this case, since the same mobile service data bits U are sequentially input twice, the 1/2 outer encoder 432 performs 1/2 encoding twice on the mobile service data bits U input to the repeater 431. do.

That is, the symbol encoder 402 repeatedly outputs two symbols encoded at a 1/2 code rate as shown in FIG. 17B, or outputs two times encoded input data bits at 1/2 code rate as shown in FIG. 17C. The code rate is 1/4.

As described above, when the symbol encoder 402 is operated with an encoder having a 1/4 code rate, the input data bits are encoded at a 1/4 code rate and then sequentially output one symbol at a time, or at a 1/2 code rate. The coded symbols may be repeated once and sequentially output one symbol at a time, or the input data bits may be encoded twice at a 1/2 code rate and sequentially output one symbol at a time.

On the other hand, when the symbol encoder 402 is operated with an encoder having a 1/2 code rate, the input data bits may be encoded after being encoded at a 1/2 code rate by a 1/2 external coder and then output.

Alternatively, if the data bits input from the 1/4 external encoder are encoded at a 1/4 code rate and only one symbol of the two encoded symbols is selected and outputted, the symbol encoder 402 may have a 1/2 code rate. Can be operated.

The 1/2 code rate and the 1/4 code rate are one embodiment, and since the code rate may vary depending on the number of times the coded symbols are selected or repeated, the present invention will not be limited to the above-described embodiment. In this case, the smaller the code rate, the smaller the actual amount of data that can be transmitted, so the code rate is determined in consideration of two factors.

Fig. 18A is a detailed block diagram showing an embodiment of a 1/2 external encoder, which is composed of two delayers 501 and 503 and one adder 502, which encodes an input data bit U and thus two bits (u0, u1). ) At this time, the input data bit U is output as it is as the upper bit u0 and encoded and output as the lower bit u1.

That is, the input data bit U is output as it is as the upper bit u0 and to the adder 502 at the same time. The adder 502 adds the input data bit U and the output of the first delayer 501 and outputs the result to the second delayer 503, and a predetermined time (for example, one clock) in the second delayer 503. The delayed data is outputted to the lower bit u1 and fed back to the first delayer 501. The first delayer 501 delays the data fed back from the second delayer 503 by a predetermined time (for example, one clock) and outputs the delayed data to the adder 502.

At this time, if the data bit U input to the symbol encoder 402 is data to be encoded at a 1/4 code rate, the symbol consisting of u0u1 bits is repeatedly outputted twice, or the input data bit U is repeated once to indicate 1 in FIG. 18A. / 2 can be input with external encoder.

FIG. 18B is a detailed block diagram showing an embodiment of a 1/4 external coder, which is composed of two delayers 501 and 503 and three adders 502, 504 and 505, and encodes the input data bits U to four bits (u0 to u3). ) At this time, the input data bit U is output as it is as the most significant bit u0 and is encoded and output as the lower bit u1u2u3.

That is, the input data bits U are output as they are as most significant bits u0 and output to the first and third adders 502 and 505. The first adder 502 adds the input data bit U and the output of the first delayer 501 and outputs the result to the second delayer 503. The delayed data is output to the lower bit u1 and fed back to the first delay unit 501. The first delayer 501 delays the data fed back from the second delayer 503 by a predetermined time (for example, one clock) and outputs the delayed data to the first adder 502 and the second adder 504. . The second adder 504 adds the outputs of the first and second delayers 501 and 503 to output the lower bit u2. The third adder 505 adds the input data bit U and the output of the second adder 504 to output the lower bit u3.

In this case, if the data bit U input to the 1/4 external encoder is data to be encoded at a 1/2 code rate, a symbol composed of u0u1 bits among the four output bits u0u1u2u3 may be configured and output. In addition, if the data is to be encoded at a 1/4 code rate, a symbol composed of u0u1 bits may be output through a parallel / serial converter, and then another symbol of u2u3 bits may be output. In another embodiment, if the input data bit U is data to be encoded at a 1/4 code rate, a symbol composed of u0u1 bits may be repeatedly output.

In another embodiment, the symbol encoder 402 outputs all four output bits u0u1u2u3, and when the symbol interleaver 403 at the next stage has a 1/2 code rate, only a symbol consisting of u0u1 bits among the four output bits u0u1u2u3 is used. If the code rate is 1/4, the symbol may be designed to select both a symbol composed of u0u1 bits and another symbol composed of u2u3 bits. In another embodiment, when the code rate is 1/4, a symbol composed of u0u1 bits may be repeatedly selected.

The output of the symbol encoder 402 is input to the symbol interleaver 403, and the symbol interleaver 403 performs block interleaving on a symbol unit basis for the output data of the symbol encoder 402.

The symbol interleaver 403 may be applied to any interleaver as long as it is an interleaver structurally performing any order rearrangement. However, according to an embodiment of the present invention, a variable length symbol interleaver applicable even when the length of symbols to be rearranged is various will be described.

19A to 19C illustrate an embodiment of a symbol interleaver according to the present invention, and are variable length symbol interleaver applicable even when the lengths of symbols to rearrange the order vary.

Particularly, FIGS. 19A to 19C show examples of symbol interleaver in the case where BK = 6 and BL = 8. The BK is the number of symbols output for symbol interleaving in the symbol encoder 402, and the BL is the number of symbols actually interleaved in the symbol interleaver 403.

The symbol interleaver 403 of the present invention must satisfy the BL = BK condition while BL = 2 ⁿ (where n is a natural number). If the values of BK and BL are different, an interleaving pattern is created by adding null or dummy symbols by the number of differences (= BL-BK).

Therefore, the BK is a block size of actual symbols input to the symbol interleaver 403 for interleaving, and the BL is an interleaving unit in which interleaving is performed by an interleaving pattern generated by the symbol interleaver 403.

19 (a) to (c) show an example, the number of symbols (= BK) output from the symbol encoder 402 for interleaving is 6 symbols, and the actual interleaving unit BL is 8 symbols. do. Therefore, as shown in FIG. 19A, two symbols are added as null symbols to form an interleaving pattern.

BK 조건을 만족하는 BL을 찾아 인터리빙 패턴을 만들어 재배열하는 과정을 수학식으로 표현한 것이다. Equation 4 below receives BK symbols to be rearranged in the symbol interleaver 403 in order, and then BL = 2 ⁿ and BL.

It is a mathematical expression of the process of rearranging an interleaving pattern by finding a BL satisfying the BK condition.

모든 위치 0 i BL-1 에 대해서,

For all positions 0 i BL-1,

P (i) = {S x i x (i + 1) / 2} mod BL

BK , BL = 2ⁿ이고, n, S는 자연수이다. 도 12에서 S는 89, BL은 8로 가정하고, 구현한 인터리빙 패턴 및 인터리빙 예이다.Where BL

BK, BL = 2 ⁿ , and n and S are natural numbers. In FIG. 12, S is 89, and BL is 8, which is an example of an interleaving pattern and an interleaving scheme.

After rearranging the order of BK input symbols and (BL-BK) null symbols in BL symbol units as shown in Equation 4 and FIG. 19B, Equation 5 below and FIG. 19C show The positions of the null symbols are removed and rearranged, and the interleaved symbols are output to the symbol-byte converter 404 in the sorted order.

if P (i)> BK-1, then P (i) position removed and aligned

The symbol-byte converter 404 converts the mobile service data symbols outputted after the sequence rearrangement is completed in the symbol interleaver 403 into bytes and outputs them to the group formatter 304.

FIG. 20A is a detailed block diagram of a block processor according to another embodiment of the present invention, and may include an interleaving nit 610 and a block formatter 620.

The interleaving unit 610 may include a byte-symbol converter 611, a symbol-byte converter 612, a symbol interleaver 613, and a symbol-byte converter 614. The symbol interleaver is also called a block interleaver.

Bytes of the interleaving unit 610 The symbol converter 611 converts the mobile service data X output in the unit of byte from the RS frame encoder 302 in the unit of symbol and outputs it to the symbol-byte converter 612 and the symbol interleaver 613. That is, the byte- The symbol converter 611 outputs two bits of the input mobile service data byte (= 8 bits) as one symbol. This is because the input of the trellis encoder 256 is a symbol unit of 2 bits. The relationship between the block processor 303 and the trellis encoder 256 will be described later.

In this case, the byte-symbol converter 611 may also receive signaling information including a transmission parameter and the like. The signaling information bytes may also be divided in symbol units so that the symbol-byte converter 612 and the symbol interleaver 613 are received. )

The symbol-byte converter 612 collects four symbols output from the byte-symbol converter 611 to form a byte, and outputs the byte to the block formatter 620. In this case, since the symbol-byte converter 612 and the byte-symbol converter 611 are inverse processes, the results of the two blocks are canceled so that the input data X is bypassed to the block formatter 620 as shown in FIG. 20B. It is effective. That is, since the interleaving unit 610 of FIG. 20B has an equivalent structure to that of the interleaving unit 610 of FIG. 20A, the same reference numerals are used.

The symbol interleaver 613 performs block interleaving on a symbol-by-symbol basis for the data output from the byte-symbol converter 611 and outputs the result to the symbol-byte converter 614.

The symbol interleaver 613 may be applied to any interleaver as long as the interleaver is structurally rearranged. According to an embodiment of the present invention, a variable length interleaver may be used even when the length of symbols to be rearranged is various. For example, the symbol interleaver of FIG. 19 may also be applied to FIGS. 20A and 20B.

The symbol-byte converter 614 collects the mobile service data symbols outputted after the sequence rearrangement is completed in the symbol interleaver 613, forms a byte, and outputs the byte to the block formatter 620. That is, the symbol-byte converter 614 forms four bytes by collecting four symbols output from the symbol interleaver 613.

The block formatter 620 arranges the output of each symbol-byte converter 612 and 614 according to a predetermined criterion in the block as shown in FIG. In this case, the block formatter 620 operates in relation to the trellis encoder 256.

That is, the block formatter 620 determines the position (or order) of the remaining data except for mobile service data such as main service data, known data, RS parity data, and MPEG header data input to the trellis encoder 256. Consider the mobile service data output order of each symbol-byte converter 612,614.

The trellis encoder 256 has twelve trellis encoders as an example.

FIG. 22 is a detailed block diagram of a trellis encoder 256 according to an embodiment of the present invention, in which 12 identical trellis encoders are combined into an interleaver for noise dispersion. Each trellis encoder may include a pre coder.

FIG. 23A illustrates a state in which the block processor 303 and the trellis encoder 256 are concatenated. In practice, in the transmission system, as shown in FIG. 3, a plurality of blocks exist between the preprocessor 230 including the block processor 303 and the trellis encoder 256, but in the receiving system, the two blocks are considered to be concatenated. Decoding will be performed.

However, the data except for mobile service data such as main service data, known data, RS parity data, and MPEG header data inputted to the trellis encoder 256 are the block processor 303 and the trellis encoder 256. Data added in blocks existing in between. 23B illustrates an example in which the data processor 650 is disposed between the block processor 303 and the trellis encoder 256 in consideration of such a situation.

Here, the interleaving unit 610 of the block processor 303 may be configured as shown in FIG. 20A (or 20B) when encoding is performed at a 1/2 code rate. 3, the data processor 650 includes a group formatter 304, a data deinterleaver 305, a packet formatter 306, a packet multiplexer 240, and a data randomizer of the post processor 250. 251, an RS encoder / unstructured RS encoder 252, a data interleaver 253, a parity substituent 254, and an unstructured RS encoder 255.

At this time, the trellis encoder 256 symbolizes the input data and sends the trellis encoder to each trellis encoder according to a predefined method. At this time, one byte is converted into four symbols consisting of two bits, and symbols made from one byte are all transmitted to the same trellis encoder. Then, each trellis encoder precodes the upper bits of the input symbols and outputs them to the highest output bit C2, and the lower bits are trellis-coded and outputs the two output bits C1 and C0.

The block formatter 620 controls the output bytes of each symbol-byte converter to be transmitted to different trellis encoders.

Next, detailed operations of the block formatter 620 will be described with reference to FIGS. 16 to 20.

Referring to FIG. 20A, the output byte of the symbol-byte converter 612 and the output byte of the symbol-byte converter 614 are different from each other of the trellis encoder 256 under the control of the block formatter 620. It is input to the trellis encoder.

In the present invention, for convenience of explanation, the output byte of the symbol-byte converter 612 is referred to as X, and the output byte of the symbol-byte converter 614 is referred to as Y. In (a) of FIG. 21, each number 0-11 indicates a trellis coder from 1st to 12th of the trellis encoder 256, respectively.

The block formatter 620 inputs output bytes of the symbol-byte converter 612 to trellis encoders 0 to 5 of the trellis encoder 256. In one embodiment, the output order of each symbol-byte converter 612, 614 is arranged such that the output bytes of the symbol-byte converter 614 are inputted to the trellis encoders 6-11 of numbers 6-11. do. Here, the trellis encoders to which the output bytes of the symbol-byte converter 612 are allocated and the trellis encoders to which the output bytes of the symbol-byte converter 614 are assigned are one embodiment for understanding the present invention. It is only.

In addition, assuming that the input of the block processor 303 is a block composed of 12 bytes, the symbol-byte converter 612 outputs 12 bytes from X0 to X11, and the symbol-byte converter 614 also outputs Y0 to According to an embodiment, 12 bytes are output to Y11.

21 (b) shows an embodiment of data input to the trellis encoder 256, in which main service data and RS parity data as well as mobile service data are input to the trellis encoder 256. The example is distributed to each trellis encoder. That is, while the mobile service data output from the block processor 303 passes through the group formatter 304, the mobile service data is output in a form in which main service data and RS parity data are mixed with the mobile service data as shown in FIG. Each byte is input to 12 trellis encoders according to their position in the data group after data interleaving.

If the output bytes (X, Y) of the symbol-byte converter 612, 614 are allocated to the corresponding trellis encoder according to the aforementioned principle, the input of each trellis encoder is as shown in FIG. It can be in form.

That is, referring to (b) of FIG. 21, six mobile service data bytes X0 to X5 output from the symbol-byte converter 612 are the first to sixth tracks of the trellis encoder 256. The two mobile service data bytes (Y0, Y1) sequentially allocated (or distributed) to the release encoders 0 to 5 and output from the symbol-byte converter 614 are the seventh and eighth trellis. Assigned to the encoders 6, 7 sequentially. Four main service data bytes of the five main service data bytes are sequentially allocated to the ninth to twelfth trellis encoders 8 to 11, and the next one main service data byte is again the first trellis encoder. An example is assigned to (0).

Assume that the mobile service data, the main service data, the RS parity data, etc. are allocated to each trellis encoder as shown in FIG. 21B. As described above, the input of the block processor 303 is a block composed of 12 bytes. The symbol-byte converter 612 outputs 12 bytes from X0 to X11, and the symbol-byte converter 614 also outputs Y0. Suppose that 12 bytes are output until ~ Y11. In this case, the block formatter 620 outputs the symbol-byte converters 612 and 614 in the order of X0 to X5, Y0, Y1, X6 to X10, Y2 to Y7, X11, Y8 to Y11 as shown in FIG. Output by arranging

That is, it is determined in which trellis encoder each data byte is encoded according to which position in the transmission frame. In this case, not only the mobile service data but also main service data, MPEG header data, and RS parity data are input to the trellis encoder 256, so that the block formatter 620 performs a data group format after data interleaving. Suppose you know information about.

24 is a block diagram illustrating an embodiment of a block processor for encoding at a 1 / N code rate according to the present invention, and includes (N-1) symbol interleavers 741 to 74N-1 configured in parallel. do. That is, a block processor having a 1 / N code rate has a total of N branches, including a branch or path through which original input data is passed to the block formatter 730. Each of the symbol interleavers 741 to 74N-1 may be configured with different symbol interleavers. Corresponding (N-1) symbol-byte converters 751 to 75N-1 may be configured at the output terminals of the (N-1) symbol interleavers 741 to 74N-1. Outputs of the (N-1) symbol-byte converters 751 to 75N-1 are also input to the block formatter 730.

In the present invention, N is one embodiment less than or equal to 12.

If N is 12, the block formatter 730 may arrange the output data such that the output byte of the twelfth symbol-byte converter 75N-1 is input to the twelfth trellis encoder. If N is 3, the block formatter 730 inputs the output bytes of the symbol-byte converter 720 to the first to fourth trellis encoders of the trellis encoder 256, and the symbol-byte converter ( The output bytes of 751) may be input to the fifth to eighth trellis encoders, and the output bytes of the symbol-byte converter 752 may be input to the ninth to twelfth trellis encoders.

In this case, the output data order of each symbol-byte converter may vary according to the position in the data group of data other than the mobile service data mixed with the mobile service data output from each symbol-byte converter.

FIG. 25 illustrates a detailed block diagram of a block processor in another embodiment of the present invention, in which a block formatter is removed and a role of the block formatter is performed in a group formatter. That is, the block processor of FIG. 25 may include a byte-symbol converter 810, a symbol-byte converter 820, 840, and a symbol interleaver 830. In this case, the output of each symbol-byte converter 820, 840 is input to the group formatter 850.

In addition, the block processor may add a symbol interleaver and a symbol-byte converter to obtain a desired code rate. If encoding is desired at 1 / N code rate, the original input data is composed of N branches and N-1 branches in parallel, including branches or paths that are passed to the group formatter 850 as it is. N-1) symbol interleavers and symbol-byte converters may be provided. At this time, the group formatter 850 inserts a position holder for securing the position for the MPEG header, the unstructured RS parity, and the main service data, and places the bytes output from each branch of the block processor at a predetermined position.

The number of trellis encoders, the number of symbol-byte converters, and the number of symbol interleavers presented in the present invention are preferred embodiments or simple examples, and thus the scope of the present invention is not limited to the above numerical values. In addition, it is apparent to those skilled in the art that the byte type and position allocated to each trellis encoder of the trellis encoder 256 may vary according to the data group format. will be. Therefore, it is to be understood that the present invention is not limited to the above described embodiments.

As described above, the mobile service data encoded and output at the 1 / N code rate by the block processor 303 is input to the group formatter 304. In this embodiment, the output data order in the block formatter of the block processor 303 is arranged and output according to the byte position in the data group.

Signaling  Information processing

In the transmitter 200 according to the present invention, transmission parameters may be inserted in various methods and positions and transmitted to the receiving system.

 To facilitate understanding of the present invention, transmission parameters to be transmitted from a transmitter to a reception system will be defined. The transmission parameter includes data group information, area information in the data group, the number of RS frames constituting a super frame (Super frame size: SFS), the number of RS parities (P) per column in the RS frame, and the row direction of the RS frame. Use of checksum added to determine whether there is an error, type and size (if present, add 2 bytes as CRC) if used, number of data groups constituting one RS frame-RS frame is one burst period Is equal to the number of data groups (Burst size (BS)) in a burst-and so on, and there are a turbo code mode and an RS code mode. In addition, the transmission parameters required for burst reception are Burst Period (BP)-one burst period is a count of the number of fields from the start of one burst to the start of the next burst. The order occupied in the super frames (Permuted Frame Index (PFI)), the order of groups currently being transmitted in one RS frame (burst) (Group Index: GI), burst size, and the like. According to the burst operation method, there is the number of fields remaining until the start of the next burst (TNB), and by transmitting this information as a transmission parameter, the relative until the start of the next burst for each data group transmitted to the receiving system. You can also tell the distance (number of fields).

The information included in the transmission parameter is only one embodiment for better understanding of the present invention, and the present invention is not limited to the above embodiment because addition and deletion of information included in the transmission parameter can be easily changed by those skilled in the art. Will not.

As a first embodiment, the transmission parameter may allocate and insert a certain area of the mobile service data packet or data group. In this case, in the receiving system, once synchronization and equalization of the received signal are performed and symbol-based decoding is performed, the packet deformatter can separate and detect the mobile service data and the transmission parameter. In the case of the first embodiment, the transmission parameter may be inserted and transmitted in the group formatter 304.

As a second embodiment, a transmission parameter may be inserted by multiplexing with other data. For example, when multiplexing the known data with the mobile service data, the transmission parameter may be inserted instead of the known data at a position where the known data may be inserted, or may be mixed with the known data. In the case of the second embodiment, the transmission parameter may be inserted and transmitted in the group formatter 304 or the packet formatter 306. For example, the service ID according to the program, the RS mode of the A and B areas in the data group, the RS mode of the C area, the super frame size (SFS), and the position occupied by the RS frame in the super frame Permuted frame index (PFI), burst size (BS), data group index (GI), and time to next burst (TNB) information are shown in FIG. In the same manner, the data can be inserted into the fourth known data pattern region in the first known data region and transmitted.

As a third embodiment, the transmission parameter may allocate and insert a part of the unused area in the field sync segment of the transmission frame. In this case, since the transmission system can detect the transmission parameter before symbol-based decoding of the received signal is performed, the transmission parameter having information on the processing method of the block processor 303 and the group formatter 304 is provided. Can be inserted into the unused area of the field sync signal. That is, in the receiving system, after acquiring the field sync using the field sync segment, the transmission parameter may be detected at the promised position. In the case of the third embodiment, the transmission parameter may be inserted and transmitted by the synchronous multiplexer 260.

As a fourth embodiment, the transport parameter may be inserted and transmitted at a higher layer than a transport stream packet. In this case, the receiving system should be able to receive the signal and make it beyond the TS packet layer, and the purpose of the transmission parameter is to verify the transmission parameter of the currently received signal and to give the transmission parameter of the signal to be received later. Can be performed.

In the present invention, various transmission parameters related to a transmission signal are inserted and transmitted through the method of the above-described embodiments, wherein the transmission parameters may be inserted and transmitted only through one embodiment or may be inserted through some embodiments. It may be transmitted or may be inserted and transmitted through all embodiments. In addition, the information in the transmission parameter may be inserted in duplicate in each embodiment, or only necessary information may be inserted and transmitted in the corresponding position of the embodiment.

In addition, the transmission parameter may be inserted into a corresponding region after performing block coding of a short period to ensure robustness. Examples of the short-term block coding method include Kerdock coding, BCH coding, RS coding, repetitive coding of transmission parameters, and the like. In addition, a combination of several block encodings is also possible.

The transmission parameters may be collected to form a small block code and inserted into a byte allocated for signaling in a data group for transmission. However, in this case, since the transmission parameter value is obtained by passing through the block decoder in terms of reception, transmission parameters such as the turbo code mode and the RS code mode necessary for block decoding must be obtained first. For this reason, the transmission parameter related to the mode may insert the transmission parameter into a part of the known data region, and in this case, symbol correlation may be used for fast decoding. The receiving system determines the sign mode and the combination mode by looking at the correlation between the sequences and the currently received sequence.

On the other hand, when the transmission parameter is inserted into the field sync segment area or the known data area and is transmitted, since the reliability is lowered when the transmission parameter passes through the transmission channel, one of the predefined patterns is inserted according to the transmission parameter. It is also possible. In this case, the reception system may recognize a transmission parameter by performing a correlation operation between the received signal and predefined patterns.

For example, suppose that the number of groups in the burst is five, determined in advance by the appointment of the transmitting / receiving side in the F pattern. Then, when the number of groups in the burst is five, the transmitter inserts and transmits an F pattern. The receiving side performs a correlation operation between the received data and various reference patterns including the pre-generated F pattern. In this case, if the correlation value between the received data and the F pattern is the largest, the received data indicates a transmission parameter, in particular, the number of groups in the burst, and the number is recognized as five.

Next, a process of inserting and transmitting a transmission parameter will be described by dividing the first to third embodiments.

First Example

FIG. 26 is a schematic diagram of the present invention for receiving a transmission parameter from the group formatter 304 and inserting the transmission parameter into the A region in the data group.

In this case, the group formatter 304 receives mobile service data from the block processor 303. In contrast, the transmission parameter may be input to the group formatter 304 after at least one of data rendering, RS frame encoding, and block processing, or input to the group formatter 304 without going through all three processes. May be In addition, the transmission parameter may be provided by the service multiplexer 100 or may be generated and provided within the transmitter 200.

The transmission parameter may include information necessary for receiving and processing data included in the data group in a receiving system. For example, the transmission parameter may include data group information, multiplexing information, and the like.

The group formatter 304 inserts mobile service data and transmission parameters input to a corresponding area in the data group according to a rule for forming a data group.

According to an embodiment, the transmission parameter may be inserted in an area A of the data group after a short period of block encoding. In particular, the transmission parameter may be inserted at any position promised in the A area.

 If it is assumed that the transmission parameter has been processed by the block processor 303, the block processor 303 may also encode 1/2 or 1 / signaling information including the transmission parameter in the same manner as the mobile service data processing. 4 is encoded and then output to the group formatter 304. The signaling information is also regarded as mobile service data and processed.

FIG. 27 is a block diagram illustrating an example of a block processor that receives a transmission parameter and processes the same as the mobile service data. The signaling information provider 411 and the multiplexer 412 are further added to the component of FIG. 16. An example is shown.

That is, the signaling information provider 411 outputs the signaling information including the transmission parameter to the multiplexer 412. The multiplexer 412 multiplexes the signaling information and the output of the RS frame encoder 302 and outputs them to the byte-bit converter 401.

The byte-bit converter 401 divides the mobile service data byte or signaling information byte output from the multiplexer 412 into bits and outputs the result to the symbol encoder 402.

Since the subsequent operation may refer to FIG. 16 described above, a detailed description thereof will be omitted.

If the detailed configuration of the block processor 303 applies at least one of FIGS. 20 and 23 to 25, the signaling information providing unit 411 and the multiplexer 412 may be provided in front of the bind-symbol converter. Can be.

In addition, if the transmission parameter provided from the signaling information providing unit 411 is a symbol unit, the signaling information providing unit 411 and the multiplexer 412 may be provided after the byte-symbol converter.

2nd Example

On the other hand, when the group formatter 304 inserts the known data generated by a predetermined method into a corresponding region in the data group, a transmission parameter may be inserted in place of the known data in at least a portion of the region where the known data can be inserted. .

For example, when a long known data column is inserted at the beginning of the A region in the data group, as an example of this, a transmission parameter may be inserted in the fourth known data pattern region in the first known data region instead of the known data. have. At this time, some of the known data strings inserted in the remaining region except for the region in which the transmission parameter is inserted may be used to capture the starting point of the data group in the receiving system, as shown in FIG. Can be used.

When the transmission parameter is inserted in the known data area instead of the known data, the transmission parameter may be inserted by block coding in a short period or a predetermined pattern may be inserted according to the transmission parameter as described above.

If the group formatter 304 inserts the known data position holder instead of the known data into an area in which the known data in the data group can be inserted, the transmission parameter may be inserted in the packet formatter 306.

That is, the packet formatter 306 may insert and replace the known data in the known data position holder when the known data position holder is inserted in the group formatter 304 or insert the known data in the group formatter 304. If inserted, it can be output as is.

FIG. 28 is a block diagram illustrating an example in which the packet formatter is extended to insert a transmission parameter in the packet formatter 306. The known data generator 351 and the signaling multiplexer 352 may be arranged in the packet formatter 306. FIG. ) Is further included. The transmission parameter input to the signaling multiplexer 352 includes information on the length of the current burst, information indicating the time of the next burst, the location and length of the groups in the burst, the current group to the next group in the burst. Time, known information about the data, and the like.

The signaling multiplexer 352 selects one of a transmission parameter and known data generated from the known data generator 351 and outputs it to the packet formatter 306. The packet formatter 306 inserts and outputs known data or transmission parameters output from the signaling multiplexer 352 into a known data position holder output from the data deinterleaver 305. That is, the packet formatter 306 inserts and outputs transmission parameters instead of known data in at least a portion of the known data area.

For example, when the known data position holder is inserted at the start of the area A in the data group, a transmission parameter may be inserted in place of the known data in some of the known data position holders.

When the transmission parameter is inserted in the known data position holder instead of the known data, the transmission parameter may be inserted by block encoding in a short period or a predetermined pattern may be inserted according to the transmission parameter.

That is, the signaling multiplexer 352 multiplexes the known data and the transmission parameters (or patterns defined according to the transmission parameters) to form a new known data string and outputs the new known data string to the packet formatter 306. The packet formatter 306 removes the main service data location holder, the RS parity location holder from the output of the data deinterleaver 305, and sends 188 bytes of mobile to the output of the mobile service data, the MPEG header, and the signaling multiplexer 352. The service data packet is generated and output to the packet multiplexer 240.

In this case, the A region in each data group has a different known data pattern. Therefore, the reception system recognizes only the symbol of the promised interval in the known data sequence as a transmission parameter.

In this case, since the known data may be inserted at another location such as the packet formatter 306, the group formatter 304, or the block processor 303 according to the design method of the transmission system, the known data is transmitted instead of the known data in the block in which the known data is inserted. You can insert a parameter.

In the second embodiment, a transmission parameter including a processing method of the block processor 303 may be inserted into a part of the known data area and transmitted. In this case, the symbol processing method and its position for the transmission parameter symbol itself are determined, and it should be positioned to transmit and receive in time before other data symbols to be decoded. Then, the transmission parameter symbol may be detected before data symbol decoding by the receiving system and used for decoding for the data symbol.

The third Example

Meanwhile, the transmission parameter may be inserted into the field sync segment area and transmitted.

FIG. 29 is a block diagram illustrating an embodiment in which a synchronous multiplexer is extended to insert a transmission parameter into a field sync segment region. The synchronous multiplexer 260 further includes a signaling multiplexer 261.

In general, a VSB transmission frame includes two fields, and each field includes one field sync segment and 312 data segments. Each data segment consists of a total of 832 symbols. In this case, the first 4 symbols in one data segment are segment sync parts, and the first data segment in a field is field sync parts.

One field sync signal consists of one data segment length, and there is a data segment sync pattern in the first four symbols, followed by PN 511, PN 63, and PN, which are pseudo random sequences. 63, PN 63 is present and the next 24 symbols are VSB mode-related information. The remaining 104 symbols after the 24 symbols in which the VSB mode related information exists are reserved. The last 12 symbols of the previous segment are copied to the last 12 symbols of the unused region. Then, 92 symbols in the field sync segment become actual unused areas.

Accordingly, the signaling multiplexer 261 multiplexes with the existing field sync segment symbols and outputs them to the sync multiplexer 260 so that transmission parameters are inserted into an unused area of the field sync segment. The synchronous multiplexer 260 configures a new transmission frame by multiplexing segment sync symbols, data symbols, and new field sync segments output from the signaling multiplexer 261. The transmission frame including the field sync segment in which the transmission parameter is inserted is input to the transmitter 270.

In this case, the unused area in the field sync segment for inserting the transmission parameter may be part or all of the unused area of 92 symbols.

The transmission parameter inserted into the unused area may include, for example, information for identifying whether the main service data, the mobile service data, or another type of mobile service data.

If the information on the processing method of the block processor 303 is transmitted as part of a transmission parameter, when the decoding corresponding to the block processor 303 is performed in the receiving system, the information on the block processing method should be known. Is possible. Therefore, the information on the processing method of the block processor 303 should be known before the block decoding.

Therefore, as in the third embodiment, when a transmission parameter having information about the processing method of the block processor 303 (and / or the group formatter 304) is inserted into the unused area of the field sync signal and transmitted, the reception system In this case, the transmission parameter can be detected before block decoding is performed on a received signal.

Receiving system

30 is a block diagram showing an embodiment of a digital broadcast receiving system according to the present invention. In the digital broadcast reception system of FIG. 30, the reception performance may be improved by performing carrier synchronization recovery, frame synchronization recovery, channel equalization, etc. using known data information inserted into a mobile service data section by a transmission system and transmitted.

The digital broadcast reception system according to the present invention includes a demodulator 1002, an equalizer 1003, a known data detector 1004, a block decoder 1005, a data formatter 1006, an RS frame decoder 1007, and a decode. It includes a randomizer 1008, a data deinterleaver 1009, an RS decoder 1010, and a data derandomizer 1011. For convenience of description, the present invention refers to the data deformatter 1006, the RS frame decoder 1007, and the derandomizer 1008 as a mobile service data processing unit, the data deinterleaver 1009, the RS decoder 1010, The data derandomizer 1011 will be referred to as a main service data processing unit. For example, if the receiving system is a mobile transmission receiving system, the main service data processor may be omitted.

That is, the frequency of a specific channel tuned through the tuner is down-converted to an intermediate frequency (IF) signal, and the down-converted data 1001 is output to the demodulator 1002 and the known data detector 1004. The down-converted data 1001 includes a demodulator 1002 and a known data detector through an analog / digital converter (ADC, not shown) that converts an analog IF signal of a passband into a digital IF signal. 1004) is an embodiment.

The demodulator 1002 performs automatic gain control, carrier recovery, and timing recovery on the input IF band digital IF signal, generates a baseband signal, and outputs the same to the equalizer 1003 and the known data detector 1004. .

The equalizer 1003 compensates for the distortion on the channel included in the demodulated signal and outputs it to the block decoder 1005.

At this time, the known data detector 1004 detects the known data position inserted by the transmitting side from the input / output data of the demodulator 1002, that is, the data before demodulation or the data of which the demodulation has been partially performed, A symbol sequence of known data generated at the position is output to the demodulator 1002 and the equalizer 1003. In addition, the known data detector (1004) is a block decoder (1005) for information to enable the block decoder (1005) to distinguish between the mobile service data that has undergone additional encoding and the main service data that does not undergo additional encoding at the transmitting side. Will output Although the connection state is not illustrated in the diagram of FIG. 30, the information detected by the known data detector 1004 may be used in the reception system as a whole, and may be used in the data deformatter 1006 and the RS frame decoder 1007. have.

The demodulator 1002 can improve the demodulation performance by using the known data symbol string at the time of timing recovery or carrier recovery. The equalizer 1003 can also use the known data to improve the equalization performance. . In addition, the equalization performance may be improved by feeding back the decoding result of the block decoder 1005 to the equalizer 1003.

Demodulator and known data detector in receiving system

In this case, as shown in FIGS. 7A and 8, the transmitting side may periodically insert and transmit known data into the data frame.

31 shows an example in which the transmitting side periodically inserts and transmits a known data string between actual data. In FIG. 31, AS is the number of symbols of general data and BS is the number of symbols of known data. Therefore, known data of the BS symbol is inserted and transmitted in the period of the (AS + BS) symbol. The AS may be mobile service data, main service data, or a mixture of mobile service data and main service data. In the present invention, this AS is referred to as general data to distinguish it from known data.

In FIG. 31, each known data section in which the known data columns are periodically inserted includes the known data columns of the same pattern, and the lengths of the known data columns of the same pattern and the entire known data columns of the known data section may be the same or different. . In other cases, the entire known data column is longer than the known data columns of the same pattern, and the entire known data columns contain the same pattern of known data columns. For example, if a known data pattern of F is inserted for channel equalization, at least one F pattern is included in each known data section.

When the known data is periodically inserted between the general data, the channel equalizer of the receiving system can use the known data as a training sequence and use it as an accurate discrimination value and estimate the impulse response of the channel.

Meanwhile, when known data of the same pattern is inserted periodically, each known data section may be used as a guard interval in the channel equalizer according to the present invention. The guard interval serves to prevent interference between blocks generated by the multipath channel. This is because the known data of the known data section behind the data block of the symbol (AS + BS) in FIG. 31 can be considered copied before the data block.

This structure is also called a cyclic prefix, which allows the impulse response of data blocks and channels transmitted in the transmission system to be circular convolution in the time domain. Therefore, in the channel equalizer of the receiving system, it is easy to perform channel equalization in the frequency domain using fast fourier transform (FFT) and inverse FFT (IFFT).

That is, since the data block received from the receiving system is expressed as the product of the data block and the channel impulse response (CIR) in the frequency domain, the channel equalization is simply performed by multiplying the inverse of the channel in the frequency domain during channel equalization. It is possible.

The known data detector 1004 may detect the known data position periodically inserted and transmitted, and may estimate an initial frequency offset during the known data detection process. In this case, the demodulator 1002 can more accurately estimate and compensate carrier frequency offset from the known data position information and the initial frequency offset estimate.

32 is a flowchart illustrating an example of a known data position detection method according to the present invention when known data is transmitted in the structure shown in FIG. 8. The known data detector 1004 first detects the position of the first known data area using a plurality of first known data patterns of the first known data area (step 2001).

In this case, since the known data detector 1004 knows the structure of the data frame, when the location of the first known data area is detected, the symbol or segment is counted based on the location of the first known data area, and thus the first known data is detected. It is possible to estimate the field synchronizing position in the corresponding data group temporally ahead of the data area (step 2002). In addition, a symbol or segment may be counted based on the location of the first known data area to estimate locations of second to fifth known data areas within the corresponding data group located later in time than the first known data area (step 2003). .

The estimated field sync position and known data position information are provided to the demodulator 1002 and the channel equalizer 1003. For example, the field synchronization position and position information of the second known data pattern region to which 1424 symbols in each known data region are allocated may be provided to the channel equalizer 1003. In this case, the channel equalizer 1003 includes the field synchronization data and the second known data pattern region inserted in the field synchronization region for the estimation of the channel impulse response in the field synchronization period and the known data interval into which the second known data pattern is inserted. Assume that the second known data pattern inserted into the terminal is stored in advance.

In addition, the known data detector 1004 may estimate an initial frequency offset from the first known data pattern in the process of detecting the first known data region position. In this case, the demodulator 1002 can more accurately estimate and compensate carrier frequency offset from the known data position information and the initial frequency offset estimate.

33 is a detailed block diagram of a demodulator according to an embodiment of the present invention, which includes a phase splitter 1010, a numerically controlled oscillator NCO 1020, and a first multiplier 1030. , A resampler 1040, a second multiplier 1050, a matched filter 1060, a DC remover 1070, a timing recovery unit 1080, a carrier recovery unit 1090, and a phase compensator 1110 ) May be included.

The known data detector 1004 includes a known data detection and an initial frequency offset estimator 1004-1 to estimate known data information and an initial frequency offset.

In FIG. 33 configured as described above, the phase separator 1010 receives a passband digital signal and separates the passband digital signals of real and imaginary components whose phases are 90 degrees from each other, that is, complex signals, and then divides the first multiplier 1030. Will output Here, for convenience of description, the real component signal output from the phase separator 1010 is called an I signal, and the imaginary component signal is called a Q signal.

The first multiplier 1010 multiplies a complex signal having a frequency proportional to a constant output from the NCO 1020 by a passband digital complex signal (I, Q) output from the phase separator 1010, Transmit the passband digital complex signal (I, Q) to a baseband digital complex signal. The baseband digital signal of the first multiplier 1030 is input to the resampler 1040.

The resampler 1040 resamples the signal output from the first multiplier 1030 according to the timing clock provided by the timing recovery unit 1080 and outputs the signal to the second multiplier 1050.

For example, when the analog-to-digital converter uses a 25 MHz fixed oscillator, the baseband digital signal having the 25-MHz frequency generated through the analog-to-digital converter, the phase separator 1010, and the first multiplier 1030 may be generated. The resampler 1040 recovers the baseband digital signal having a frequency twice the symbol clock of the received signal, that is, 21.524476 MHz, through an interpolation process. If the analog / digital converter uses the timing clock of the timing recovery unit 1080 as the sampling frequency, that is, performing A / D conversion using a variable frequency, the resampler 1040 is not necessary.

The second multiplier 1050 multiplies the output frequency of the carrier recovery unit 1090 by the output of the resampler 1040 to compensate for the residual carriers included in the output signal of the resampler 1040 and then matches the filter 1060. ) And to the timing recovery unit 1080.

The signal filtered by the matched filter 1060 is input to the DC remover 1070, the known data detection and initial frequency offset estimator 1004-1, and the carrier recovery unit 1090.

The known data detection and initial frequency offset estimator 1004-1 detects the position of the known data stream transmitted periodically or aperiodically and estimates an initial frequency offset during the known data detection process. Also, the known data detection and initial frequency offset estimator 1004-1 may extract and output a group valid indicator that is group valid information and a burst valid indicator that is burst valid information.

That is, while the transmission frame as shown in FIGS. 7A and 8 is received, the known data detection and initial frequency offset estimator 1004-1 detects the position of the known data included in the transmission frame, and the position information (Known Sequence Position). Indicator is output to the timing recovery unit 1080, the carrier recovery unit 1090, the phase compensator 1110, and the equalizer 1003 of the demodulator 1002. In addition, the known data detection and initial frequency offset estimator 1004-1 estimates an initial frequency offset and outputs the initial frequency offset to the carrier recovery unit 1090.

In this case, the known data detection and initial frequency offset estimator 1004-1 may receive an output of the matched filter 1060 or an output of the resampler 1040, which is a designer's option.

The timing recovery unit 1080 detects a timing error by using the output of the second multiplier 1050 and the known data position information detected by the initial data offset and initial frequency offset estimator 1004-1, and the detected timing error. A sampling clock proportional to is output to the resampler 1040 to adjust the sampling timing of the resampler 1040. In this case, the timing recovery unit 1080 may receive the output of the matching filter 1060 instead of the output of the second multiplier 1050, which is a designer's option.

Meanwhile, the DC remover 1070 removes the pilot tone (that is, DC) inserted at the transmitting side from the matched filtered signal and outputs it to the phase compensator 1110.

The phase compensator 1110 estimates a frequency offset by using DC-removed data, known data detection, and known data position information detected by the initial frequency offset estimator 1004-1 in the DC eliminator 1070. Compensate for the phase change included in the output of the DC remover 1070. The data whose phase change is compensated for is input to the equalizer 1003. The phase compensator 1110 is optional. If the phase compensator 1110 is not provided, the output of the DC remover 1070 is input to the equalizer 1003.

FIG. 34 is an example of a detailed block diagram of the timing recovery unit 1080, the carrier recovery unit 1090, and the phase compensation unit 1110 in the demodulator.

As an example, the timing recovery unit 1080 may include a decimator 1081, a buffer 1082, a timing error detector 1083, a loop filter 1084, a holder 1085, and an NCO 1086. ) May be included.

In one embodiment, the carrier recovery unit 1090 includes a buffer 1091, a frequency offset estimator 1092, a loop filter 1093, a holder 1094, an adder 1095, and an NCO 1096. ) May be included. A decimator may be included in front of the buffer 1091.

The phase compensator 1110 may include a buffer 1111, a frequency offset estimator 1112, a maintainer 1113, an NCO 1114, and a multiplier 1115.

In addition, a decimator 1200 may be included between the phase compensator 1110 and the equalizer 1003. The decimator 1200 may be included in front of the output DC dash DC remover 1070 of the phase compensator 1110.

The decimators are necessary when the signal input to the demodulator 1002 is oversampled N times by the analog / digital converter. In other words, N represents a sampling rate of the received signal. For example, if the input signal is oversampled twice in the analog-to-digital converter (N = 2), it means that one sample contains two samples, in which case the decimators are half decimators. The decimators may be bypassed depending on whether or not the received signal is oversampled.

Meanwhile, the buffer 1091 of the carrier recovery unit 1090 receives input or output data of the matched filter 1060 and temporarily stores the received input or output data and outputs the result to the frequency offset estimator 1092. If a decimator is provided in front of the buffer 1091, the input or output data of the matched filter 1060 is decimated by 1 / N in the decimator and then output to the buffer 1091. For example, if the input or output data of the matched filter 1060 is oversampled twice, the input or output data of the matched filter 1060 is decimated in decimator 1081 in half. It is then input to the buffer 1091. That is, the carrier recovery unit 1090 operates in units of symbols when a decimator is provided in front of the buffer 1091, and operates in units of oversample when there is no decimator.

The frequency offset estimator 1092 estimates a frequency offset using data before or after the matched filtering and known data detection and known data position information output from the initial frequency offset estimator 1004-1, and then loop filter 1093. Will output That is, the frequency offset estimator 1092 estimates the frequency offset from the known data stream before or after the matched filtering and outputs the frequency offset to the loop filter 1093. Therefore, the estimated frequency offset value is obtained once for each repetition period of the known data string.

The loop filter 1093 low-pass filters the frequency offset value estimated by the frequency offset estimator 1092 and outputs it to the maintainer 1094.

The retainer 1094 maintains the low pass filtered frequency offset estimate for the period of the known data sequence and then outputs to the adder 1095. Here, the positions of the loop filter 1093 and the retainer 1094 may be interchanged. In addition, the function of the retainer 1094 may be included in the loop filter 1093, and the retainer 1094 may be omitted.

The adder 1095 adds an initial frequency offset value estimated by the known data detection and initial frequency offset estimator 1004-1 and a frequency offset value output from the loop filter 1093 (or the maintainer 1094). Output to NCO 1096. If the adder 1095 is designed to receive a constant input to the NCO 1020, the NCO 1020 and the first multiplier 1030 may be omitted. In this case, the second multiplier 1050 may simultaneously perform transition and residual carrier removal to the baseband.

The NCO 1096 generates a complex signal corresponding to the output frequency offset of the adder 1095 and outputs the complex signal to the second multiplier 1050. The NCO 1096 may comprise a ROM. In this case, the NCO 1096 generates a compensation frequency corresponding to the frequency offset output from the adder 1095, reads a complex sine wave corresponding to the compensation frequency from the ROM, and outputs the complex sine wave to the second multiplier 1050.

The second multiplier 1050 multiplies the output of the resampler 1040 by the output of the NCO 1094 of the carrier recovery unit 1090 to remove the carrier offset included in the output signal of the resampler 1040.

FIG. 35 is a detailed block diagram illustrating an embodiment of the frequency offset estimator 1092 of the carrier recovery unit 1090, according to known data detection and known data position information detected by the initial frequency offset estimator 1004-1. It works.

In this case, if the input or output data of the matched filter 1060 is input through a decimator, the frequency offset estimator 1092 operates in symbol units, and if there is no decimator, the frequency offset estimator 1062 operates in oversample units. In the present invention, operating in symbol units will be described as an embodiment.

35, a controller 1300, a first N symbol buffer 1301, a K symbol delayer 1302, a second N symbol delayer 1303, a conjugator 1304, a multiplier 1305, and an accumulator ( 1306, phase detector 1307, multiplier 1308, and multiplexer 1309.

35 configured as described above will be described as an example of operating during a known data interval.

That is, the first N symbol buffer 1301 may store up to N input symbols, and the symbol data temporarily stored in the first N symbol buffer 1301 is input to the multiplier 1305.

At the same time, the input symbol is delayed by a K symbol in the K symbol delayer 1302 and then conjugated by the conjugate 1304 to the multiplier 1305 via the second N symbol buffer 1303.

The multiplier 1305 multiplies the output of the first N symbol buffer 1301 by the output of the conjugator 1304 to output to the accumulator 1306, and the accumulator 1306 outputs the output of the multiplier 1305 to N. Accumulate during the symbol and output to the phase detector 1307. The phase detector 1307 extracts phase information from the output of the accumulator 1306 and outputs the phase information to the multiplier 1308. The multiplier 1308 divides the phase information by K, and outputs the result to the multiplexer 1309. In this case, the value obtained by dividing the phase information by K becomes a frequency offset estimation value.

That is, the frequency offset estimator 1092 is delayed by N symbols and N input data stored in the first N symbol buffer 1301 at the time when the input of the known data ends or a desired time, and thus the frequency offset estimator 1032 is transmitted to the second N symbol buffer 1303. The product of the complex conjugates of the stored N input data is accumulated for N symbols and divided by K to extract the frequency offset estimate.

The multiplexer 1309 selects the output of the multiplier 1308 or '0' according to the control signal of the controller 1300 and outputs the final frequency offset estimate.

The controller 1300 receives the known data position indicator from the known data detection and initial frequency offset estimator 1004-1 and controls the output of the multiplexer 1309. That is, the controller 1300 determines whether the frequency offset estimate output from the multiplier 1308 is valid from the known data position information. The controller 1300 selects the output of the multiplier 1308 in the multiplexer 1309 when the frequency offset estimate is valid, and selects '0' in the multiplexer 1309 when the frequency offset estimate is valid. Generate a signal.

In this case, the input signals stored in the first N symbol buffer 1301 and the second N symbol buffer 1303 may be signals received through the same channel through the same known data. Otherwise, the frequency offset estimation performance is greatly degraded by the influence of the transmission channel.

The N and K values of the frequency offset estimator 1092 of FIG. 35 may be variously determined. This is because only certain portions of known data that are repeated equally may be used. As an example, when data having a structure as shown in FIG. 31 is transmitted, N = BS and K = (AS + BS) may be set.

The estimation range of the frequency offset in the frequency offset estimator 1092 is determined by the K value. The larger the K value, the smaller the estimated range of the frequency offset. The smaller the K value, the larger the estimated range of the frequency offset. Therefore, when data having a structure as shown in FIG. 31 is transmitted, if the repetition period (AS + BS) of known data is long, the frequency offset estimation range is reduced. In this case, even though the initial frequency offset is estimated by the known data detection and initial frequency offset estimator 1004-1 and then compensated by the second multiplier 1050, the residual frequency offset after the compensation is estimated in the estimation range of the frequency offset estimator 1092. Can be exceeded.

As a way to compensate for this, the known data stream that is periodically transmitted can be configured with the same portion of repetition using cyclic extension. As an example, if the known data of FIG. 31 is composed of two identical portions of the length BS / 2, N = BS / 2 and K = BS / 2 of the frequency offset estimator 1092 of FIG. 35 may be set. In this case, it is possible to have a wider estimation range than when using repeated known data.

Meanwhile, the known data detection and initial frequency offset estimator 1004-1 detects the position of the known data stream transmitted periodically or aperiodically and estimates an initial frequency offset during the known data detection process. .

The known data position information (Known Sequence Position Indicator) detected by the known data detection and initial frequency offset estimator (1004-1), the timing recovery unit (1080), carrier recovery unit (1090), phase compensation unit of the demodulator 1002 1110, and the equalizer 1003, and the estimated initial frequency offset is output to the carrier recovery unit 1090.

In this case, the known data detection and initial frequency offset estimator 1004-1 may receive an output of the matched filter 1060 or an output of the resampler 1040, which is a designer's option.

The frequency offset estimator of FIG. 35 may be applied to the frequency offset estimator of the known data detection and initial frequency offset estimator 1004-1 or the phase compensator 1110 as it is.

36 is a detailed block diagram illustrating an example of known data detection and initial frequency offset estimator according to the present invention, and shows an example of estimating an initial frequency offset together with known data position information. FIG. 36 illustrates a case where an input signal is oversampled by N times. In other words, N represents a sampling rate of the received signal.

Referring to FIG. 36, the known data detection and initial frequency offset estimator includes N partial correlation units 1411 to 141N configured in parallel, a known data position detection and frequency offset determiner 1420, a known data extractor 1430, and a buffer. 1440, multiplier 1450, NCO 1460, frequency offset estimator 1470, and adder 1480.

The first partial correlator 1411 consists of a 1 / N decimator and a partial correlator.

The second partial correlator 1412 consists of a one sample delay, a 1 / N decimator, and a partial correlator.

The Nth partial correlator 141N includes an N-1 sample delay unit, a 1 / N decimator, and a partial correlator.

This is to match the phase of each sample in the oversampled symbol with the phase of the original symbol, decimate the samples in the remaining phases, and then perform partial correlation respectively. That is, the input signal is decimated at a ratio of 1 / N for each sampling phase and passes through each partial correlator.

For example, if the input signal is oversampled twice, that is, N = 2, it means that one symbol contains two samples. In this case, two partial correlation parts (for example, 1411 and 1412) Required, 1 / N decimator is 1/2 decimator.

At this time, the 1 / N decimator of the first partial correlator 1411 decimates (removes) a sample between the symbol position and the symbol position among the input samples and outputs the partial correlator.

The 1-sample delay of the second partial correlation unit 1412 delays the input sample by 1 sample and outputs the 1-N decimator. Subsequently, the 1 / N decimator decimates (removes) a sample between the symbol position and the symbol position among the samples input from the 1 sample delay unit and outputs the partial correlator.

Each partial correlator outputs a correlation value and an approximate frequency offset estimation value at a predetermined period of the VSB symbol to the known data position detection and frequency offset determination unit 1420.

The known data position detection and frequency offset determiner 1420 stores the output of the partial correlator for each sampling phase for a data group period or a predetermined period, and then determines a position where the correlation value is the maximum among the values as the reception position of the known data. The frequency offset estimation value of the instant is finally determined as an approximate frequency offset value of the receiving system.

The known data position information is position information of a first known data region into which a first known data pattern is inserted. From this known data position information, the field synchronizing position and the positions of the second to fifth known data regions can be estimated. In addition, the position of the second known data pattern region allocated with 1424 symbols in each known data region may be estimated.

The known sequence position indicator is provided to a known data extractor 1430, a timing recoverer 1080, a carrier recoverer 1090, a phase compensator 1110, and an equalizer 1003. The approximate frequency offset is provided to adder 1480 and NCO 1460.

The buffer 1440 temporarily stores the received data and outputs the received data to the known data extractor 1430 while the N partial correlation units 1411 to 141N estimate the known data position detection and the approximate frequency offset.

The known data extractor 1430 extracts known data from the output of the buffer 1440 by using the known data position information output from the known data position detection and frequency offset determiner 1420 and then multiplies the multiplier 1450. Output

The NCO 1460 generates a complex signal corresponding to the approximate frequency offset output from the known data position detection and frequency offset determiner 1420 and outputs the complex signal to the multiplier 1450.

The multiplier 1450 multiplies the complex data of the NCO 1460 by the complex data of the NCO 1460 by the known data output from the known data extractor 1430 and outputs the known data whose frequency offset is compensated to the frequency offset estimator 1470.

The frequency offset estimator 1470 estimates the fine frequency offset from the known data with the approximate frequency offset compensated and outputs the fine frequency offset to the adder 1480.

The adder 1480 adds an approximate frequency offset and a fine frequency offset and outputs the result as an initial frequency offset to the adder 1095 of the carrier recovery unit 1090 in the demodulator 1002. That is, the present invention can improve the estimation performance of the initial frequency offset by estimating and using the fine frequency offset as well as the coarse frequency offset when initial synchronization is acquired.

If it is assumed that the known data is inserted into the data group and transmitted as shown in FIG. 8, the known data detection and initial frequency offset estimator 1004-1 may correlate a plurality of first known data patterns in the first known data area. We can estimate the initial frequency offset using.

And field synchronization position information estimated by the known data detection and initial frequency offset estimator 1004-1 and position information of known data periodically inserted into the A region (for example, periodically inserted into each known data region). Position information of the second known data pattern region) includes a frequency offset estimator 1092 of the timing error detector 1083 of the timing recovery unit 1080, a frequency offset estimator 1092 of the carrier recovery unit 1090, and a frequency offset estimator of the phase compensator 1110. 1112, to the equalizer 1003.

FIG. 37 illustrates the structure of one of the partial correlators of FIG. 36. In the known data detection step, since the received signal includes a frequency offset, each partial correlator divides known data known by appointment on the transmitting / receiving side into K parts having an L symbol length to correlate with the corresponding part of the received signal. do.

To this end, one partial correlator may include K phase and magnitude detectors 1511 to 151K, an adder 1520, and an approximate frequency offset estimator 1530 configured in parallel.

The first phase and magnitude detector 1511 includes an L symbol buffer 1511-2, a multiplier 1511-3, an accumulator 1511-4, and a squarer 1511-5. The correlation value of the known data of the first L symbol length is obtained.

The second phase and magnitude detector 1512 includes an L symbol delay unit 1512-1, an L symbol buffer 1512-2, a multiplier 1512-3, an accumulator 1512-4, and a squarer 1512. Including -5), a correlation value of known data having a length of the second L symbol among K intervals is obtained.

The K-th phase and magnitude detector 151K includes a (K-1) L symbol delay unit (151K-1), an L symbol buffer 151K-2, a multiplier 151K-3, an accumulator 151K-4, And a squarer (151K-5) to obtain a correlation value of known data having a length of the K-th L symbol among K intervals.

In the multipliers of FIG. 37, {P0, P1, ..., PKL-1}, which are multiplied with the received signal, represent known data known to the transmitting / receiving side (i.e., reference known data generated on the receiving side). * Represents a complex conjugate.

Taking the first phase and magnitude detector 1511 as an example, the signal output from the 1 / N decimator of the first partial correlator 1411 of FIG. 36 is an L symbol buffer (1) of the first phase and magnitude detector 1511. 1511-2) is temporarily stored and then input to the multiplier 1511-3. The multiplier 1511-3 complex conjugates the output of the L symbol buffer 1511-2 and the known data P0, P1, ..., PL-1 of the first L symbol length among the K intervals already known. Multiply and output to the accumulator 1511-4. The accumulator 1511-4 accumulates the output of the multiplier 1511-3 during the L symbol and outputs the result to the squarer 1511-5 and the coarse frequency offset estimator 1530. The output of the accumulator 1511-4 is a correlation value having a phase and a magnitude. Accordingly, when the squarer 1511-5 takes an absolute value at the output of the multiplier 1511-4 and squares the absolute value, the magnitude of the correlation value is obtained, and the magnitude is input to the adder 1520.

The adder 1520 adds outputs of the squarers of the phase and magnitude detectors 1511 to 151K and outputs them to the known data position detection and frequency offset determiner 1420.

The coarse frequency offset estimator 1530 receives the outputs of the accumulators of the phase and magnitude detectors 1511 to 151K, estimates a coarse frequency offset in the corresponding sampling phase, and detects the known data position and the frequency offset determiner 1420. )

When the K inputs outputted from the accumulators of the phase and magnitude detectors 1511 to 151K are {Z ₀ , Z ₁ ,..., Z _{K -1} }, the approximate frequency offset estimator 130 is output. Can be obtained as in Equation 6 below.

The known data position detection and frequency offset determiner 1420 stores the output of the partial correlator for each sampling phase for a data group period or a predetermined period, and then determines a position where the correlation value is the maximum among the values as the reception position of the known data. The frequency offset estimate at that moment is determined as the approximate frequency offset of the receiving system. For example, when one of the outputs of the partial correlator of the second partial correlator 1412 has a maximum value, the position is determined as a known data position, and the approximate frequency estimated by the second partial correlator 1412 is determined. The offset is determined as the final coarse frequency offset and output to the demodulator 1002.

The output of the second multiplier 1050 is input to a timing error detector 1083 through the decimator 1081 and the buffer 1082 of the timing recovery unit 1080.

If the output of the second multiplier 1050 is oversampled by N times, the output of the second multiplier 1050 is decimated at decimator 1081 to 1 / N and then input to buffer 1082. do. That is, the decimator 1081 decimates the input signal in a VSB symbol period. The decimator 1081 may also receive the output of the matched filter 1060 instead of the output of the second multiplier 1050.

The timing error detector 1083 detects a timing error using data before or after the matched filtering and known data detection and known data position information output from the initial frequency offset estimator 1004-1, and then loop filter 1084. Will output That is, the timing error detector 1083 detects a timing error from a known data string before or after matched filtering and outputs the timing error to the loop filter 1084. Therefore, the detected timing error information is obtained once for every repetition period of the known data string.

As an example, the timing error detector 1083 may detect a timing error using the known data if a known data string having the same pattern is periodically inserted and transmitted as shown in FIG. 31.

There may be various methods for detecting timing errors using the known data. According to an embodiment of the present invention, a timing error is detected by using a correlation characteristic between known data and received data known by a promise of a transmitting / receiving party in a time domain, or a correlation characteristic between two known data received in a frequency domain is detected. To detect timing errors. In another embodiment, the timing error may be detected by applying a spectral line method of detecting a timing error using a sideband of a spectrum of a received signal.

The loop filter 1084 filters and outputs the timing error detected by the timing error detector 1083 to the maintainer 1085.

The retainer 1085 maintains the timing error filtered out by the loop filter 1084 for a period of a known data string and then outputs it to the NCO 1086. Here, the positions of the loop filter 1084 and the retainer 1085 may be interchanged. In addition, the function of the retainer 1085 may be included in the loop filter 1084, and the retainer 1085 may be omitted.

The NCO 1086 accumulates the timing error output from the retainer 1085, and outputs the phase component of the accumulated timing error, that is, the sampling clock to the resampler 1040 to determine the sampling timing of the resampler 1040. Adjust.

38 illustrates another embodiment of the timing recovery unit, and includes first and second timing error detectors 1611 and 1612, a mux 1613, a loop filter 1614, and an NCO 1615.

When a region having known data and a region having no known data are transmitted separately, a method of detecting a timing error may vary depending on the presence or absence of known data. And a timing error detector suitable for the presence or absence of known data can be used. Therefore, in the case of FIG. 38, this is an effective case when it is applied to a case where a predetermined length of known data is inserted into a region where a predetermined length is inserted and a region where the known data is not inserted.

For example, assume that the first timing error detector 1611 detects a timing error using the sideband of the spectrum of the received signal, and the second timing error detector 1612 detects a timing error using the known data. lets do it.

The mux 1613 then selects the output of the first timing error detector 1611 in the region where there is no known data, and selects the output of the second timing error detector 1612 in the region where the known data is present, thereby providing a loop filter 1614. Can be designed to output Alternatively, in the region where the known data exists, the output of the first timing error detector 1611 and the output of the second timing error detector 1612 may be integrated and output to the loop filter 1614. This makes it possible to restore the timing clock more stably by detecting more reliable timing errors using the known data in the region where the known data exists.

The timing error detection method using the known data may be various. Two embodiments are described here for the timing error detection method. One method is to detect a timing error by using a correlation characteristic between known data and received data known by a promise of a transmitting / receiving party in a time domain, and the other is to detect a correlation characteristic of two known data received in a frequency domain. It is a method of detecting a timing error by using.

39 and 40 show an example of detecting a timing error by obtaining a correlation value between a known signal (i.e., reference data generated at the receiving side) and a received signal known by an appointment at the transmitting / receiving side.

First, FIG. 39A illustrates an example of obtaining a received signal sequence and a correlation value while moving the entire known data sequence repeated every data block period in accordance with the received signal sequence. At this time, the correlation value between the known data string and the received signal outputs a maximum value or a peak value at the last symbol position of the known data string of the received signal as shown in FIG.

FIG. 40A illustrates an example of dividing a known data string into two or more portions to obtain a correlation value. In this case, the peaks of the correlation values of the known data occur at the last symbol position of the part where each known data is separated. The final peak value may be calculated by calculating the sum of the generated peak values as one value. 40 (b) shows a final cheek value that is the sum of the correlation values and the correlation values when the known data are correlated into three parts.

The timing error can be calculated from the peak position of the correlation value. As shown in FIG. 39, when one correlation value is obtained using one entire known data string, timing error detection may be detected once every data block period. However, by dividing the known data sequence as shown in FIG. 40 to obtain a correlation value with the received signal, a more accurate timing error can be calculated when the degree of correlation with respect to the entire known data sequence falls. The peak of the correlation value corresponding to the divided number can be obtained.

When a single peak data is obtained by dividing a single known data string, and a peak value is calculated by summing these operations, it is necessary to obtain a correlation value by dividing the known data string into parts rather than using the entire known data string. The effect of errors can be reduced. In addition, when timing errors are detected using a plurality of correlation peak values, respectively, the timing restoration speed may be increased. For example, if a known data sequence known by an appointment is divided into K parts on the transmitting / receiving side and correlated with a received signal, peaks of correlation values can be obtained by K number in the known data string. Timing error, or the number of timing errors adjusted by the combination can be obtained. Therefore, when the full known data sequence is used, the dispersion of timing error detection values is small but the application period is long. When the partial known data sequence is used, the dispersion may be slightly increased, but the adaptation period may be shortened compared to the case where the full known data sequence is used. .

The timing error can be calculated from the peak portion of the correlation value. Therefore, if one correlation value is obtained using the entire known data sequence as shown in FIG. 41, the timing error is detected once every data block period. However, by dividing the known data stream as shown in FIG. 40 to obtain a correlation value with the received signal, a peak of the correlation value corresponding to the number of known data streams can be obtained and the timing error can be detected as much as the divided number.

A method of detecting a timing error by obtaining a correlation value between the known data and the received data described with reference to FIGS. 39 and 40 will be described in detail with reference to FIG. 41. In the figure, bold points indicate correlation values between known data and received data, and solid lines indicate the flow of the points approximately. The points indicate that correlation values are obtained for samples sampled at twice the period of the symbol clock.

In FIG. 41, if the influence of the random data is excluded and there is no noise and there is no error in the timing clock, the correlation value of the known data sequence and the received data sequence is shown in a symmetrical form with respect to the peak, similar to the shape of the solid line. However, if there is a timing phase error, the symmetry of the samples immediately before and after the peak is not maintained and there is a difference. Therefore, the timing error detection using the correlation value can be calculated using a value proportional to the difference between the immediately preceding value and the subsequent value of the peak value.

FIG. 42 is a detailed block diagram illustrating an example of a timing error detector that detects a timing error in a time domain using the correlation value of the known data and the received signal. The example of FIG. 42 includes a correlator 1701, a down sampler 1702, an absolute value operator 1703, a delayer 1704, and a subtractor 1705.

The correlator 1701 receives data sampled at a clock faster than twice the symbol clock frequency, calculates a correlation with a known data symbol string, and outputs the correlation value to the down sampler 1702. The down sampler 1702 downsamples the correlation value by the sampling rate to obtain a sample of the symbol frequency. For example, if the received data input to the correlator 1701 is sampled at twice the symbol frequency, the down sampler 1701 downsamples 1/2 to obtain a sample of the symbol frequency. The correlation value of the down sampler 1701 is input to an absolute value calculator 1703, and the absolute value calculator 1703 obtains the absolute value or the square of the absolute value of the down-sampled correlation values to obtain a magnitude value having no phase component. Convert to component. The output of the absolute value calculator 1703 is provided to a delayer 1704 and a subtractor 1705. The subtractor 1705 outputs a difference between the square of the absolute value or the absolute value delayed by one symbol in the delayer 1704 and the square of the current absolute value or the absolute value as a timing error value. That is, the difference between the value that delays the output of the absolute value calculator 1703 by one symbol and the output value of the absolute value calculator 1703 becomes a value proportional to the timing phase error.

Here, the procedural relationship of each block is not absolute and can be calculated by reordering each other within a logically valid range in which the result value does not change. For example, the operation may be performed in order of the down sampler, the correlator, and the absolute value calculator, or the operation may be performed in the order of the correlator, the absolute value operator, and the down sampler.

The timing error may be detected using the frequency characteristic of the known data. When a timing frequency error occurs, the phase increases and decreases as the frequency increases within the band of the signal in the frequency domain, and the slope of the phase increases and decreases according to the frequency of the next block compared to the current block. Therefore, the slope of the phase change according to the frequency using the frequency characteristic between two known data blocks can be detected and used as a timing frequency error.

43 exemplifies an example of detecting a timing frequency error using the above-described frequency characteristic of known data. A fast Fourier transform (FFT) of the currently received known data stream is transformed into a signal in the frequency domain, and a previously received known data stream is transformed into a signal in the frequency domain by FFT. A correlation value is calculated in the frequency domain by multiplying a conjugate value of the frequency response of the previous known data stream by each frequency value of the frequency response of the current known data stream. That is, the phase change between the known data blocks can be extracted at each frequency by obtaining a correlation value between the frequency values of the previous known data stream and the frequency values of the current known data stream. In addition, the influence of the phase distortion caused by the channel can be eliminated.

Since the frequency response of the complex VSB signal is not present in the whole region but only in the half, as in the example of the frequency response of FIG. 41, the frequency response of the complex VSB signal also exists only in the half region. In order to obtain the phase slope of the correlation value in the frequency domain, the frequency domain in which the correlation value exists is divided into two, and each phase of the values of the sum of the correlation values in the corresponding region in each region is obtained. In addition, the timing frequency error may be calculated by obtaining the difference between the two phases respectively obtained in the two regions.

To calculate the phase after adding correlation values at each frequency, when the components of each correlation value are divided into magnitude and phase, the magnitude component of each correlation value is proportional to the reliability and is proportional to this magnitude. This is to allow the component to affect the final phase component.

FIG. 44 discloses an example in which timing errors can be detected by the method disclosed in FIG. 43. The timing error detector of FIG. 44 includes an FFT unit 1801, a first delayer 1802, a conjugator 1803, a multiplier 1804, an adder 1805, a phase extractor 1806, and a second delayer 1807. , And a subtractor 1808. Here, the first delayer 1802 is one data block delayer, and the second delayer 1807 is a quarter data block delayer. The one data block means one block composed of frequency responses of N known data symbol strings.

That is, when a known data area is known and a received data symbol string is input, the FFT unit 1801 converts a complex value of consecutive N known data strings among the input data symbol strings into a complex value of a frequency domain, thereby obtaining a first value. Output to delay unit 1802 and multiplier 1804. The first delayer 1802 delays the complex value in the frequency domain of the known data by one data block and outputs the result to the conjugator 1803, and the conjugator 1803 conjugates the input complex value to the multiplier 1804. ) The multiplier 1804 multiplies the known data of the current data block output from the FFT unit 1801 with the known data of the previous data block output from the conjugator 1803 in sample units and outputs the complex data to the adder 1805. . That is, the outputs of the multiplier 840 are correlation values in the frequency domain within one known data block.

In this case, since the complex VSB data exists only in the half region in the frequency domain, the adder 1805 divides the meaningful data region in the known data block in half again and accumulates correlation values of the corresponding region in each region. Output to phase extractor 1806. The phase extractor 1806 extracts only phase information from the accumulated values in the two meaningful data regions and outputs the phase information to the second delayer 1807 and the subtractor 1808, respectively. Phase information delayed by a quarter block in the second delayer 1807 is input to the subtractor 1808.

The subtractor 1808 obtains the difference between the phase information delayed by the 1/4 data block in the second delayer 1807 and the phase information of the phase extractor 860, and outputs this value as a timing frequency error value.

As in the first embodiment of the present invention, a method for obtaining a correlation value between a known data and a received signal in the time domain and a timing error at its peak is performed when the received signal experiences a multipath channel with a time delay. Although the shape of V is influenced by the channel a lot, but as in the second embodiment, when the timing error is obtained by using the correlation value between the previously received known data and the subsequently received known data, the influence of the channel can be reduced. have.

In addition, the timing error detection method described above may perform timing error detection using all of the known data strings inserted by the transmitter, and in order to eliminate the influence of the multipath channel due to time delay, the influence of the random data according to the channel is less. Only part of the known data stream may be taken to perform timing error detection.

Meanwhile, the DC remover 1070 removes the pilot tone (that is, DC) inserted at the transmitting side from the matched filtered signal and outputs it to the phase compensator 1110.

45 is a detailed block diagram illustrating an embodiment of a DC remover according to the present invention. The same signal processing is performed on the real component (In-phase, I) and the imaginary component (Q) of the complex input signal. DC values in each component are estimated and then removed.

For this purpose, FIG. 45 is composed of first and second DC estimators and removers 1900 and 1950.

The first DC estimator and remover 1900 includes an R sample buffer 1901, a DC estimator 1902, an M sample maintainer 1901, a C sample delayer 1904, and a subtractor 1905. The DC of the component is estimated and removed.

The second DC estimator and remover 1950 includes an R sample buffer 1951, a DC estimator 1952, an M sample maintainer 1953, a C sample delayer 1954, and a subtractor 1955. The DC of the component is estimated and removed.

In the present invention, since only two input structures of the first and second DC estimator and cancellers 1900 and 1950 are different, the first DC estimator and canceller 1900 will be described in detail. Detailed description of 1950 is omitted.

That is, the signal of the real component matched and filtered by the matched filter 1060 is input to and stored in the R sample buffer 1901 of the first DC estimator and the remover 1900 in the DC remover 1070. The R sample buffer 1901 is a buffer having an R sample length, and an output of the R sample buffer 1901 is input to the DC estimator 1902 and the C sample delayer 1904.

The DC estimator 1902 estimates a DC value using Equation 7 below using data of the R sample length output from the buffer 1901.

In Equation 7, x [n] represents input sample data stored in the buffer 1901, and y [n] represents a DC estimated value.

That is, the DC estimator 1902 accumulates the R sample data stored in the buffer 1901 and estimates the DC value by dividing by R. At this time, the input sample data stored in the buffer 1901 is moved by M samples ( shift) to output a DC estimate once every M samples.

46 shows the movement of input sample data used for DC estimation. For example, when M = 1, the DC estimator 1902 estimates the DC value every time the sample moves to the buffer 1901 and outputs the result every sample. If M = R, the DC estimator 1902 estimates the DC value each time the R sample moves to the buffer 1901 and outputs the output for each R sample. In this case, the DC estimator 1902 is in units of blocks of the R samples. Become a working DC estimator. Wherein the M value can be any value between 1 and R.

As described above, since the output of the DC estimator 1902 is generated every M samples, the M sample maintainer 1903 maintains the DC value estimated by the DC estimator 1902 for M samples and outputs the result to the subtractor 1905. The C sample delayer 1904 delays the input sample data stored in the buffer 1901 by C samples and outputs the result to the subtractor 1905. The subtractor 1905 subtracts the output of the M sample retainer 1903 from the output of the C sample delayer 1904 and outputs a signal from which the DC of the real component is removed.

Here, the C sample delayer 1904 determines which portion of the input sample data to compensate for the output of the DC estimator 1902. In detail, the DC estimator 1900 may be divided into a DC estimator 1902 for estimating DC and a subtractor 1905 for compensating the estimated DC value with input sample data. In this case, the C sample delayer 1904 determines which part of the input sample data is compensated for. For example, if C = 0, the DC estimate using the R sample is compensated at the beginning of the R sample. If C = R, the DC estimate using the R sample is compensated at the end of the R sample. .

The DC-free data is input to the buffer 1111 and the frequency offset estimator 1112 of the phase compensator 1110 as described above.

FIG. 47 is a detailed block diagram illustrating another embodiment of the DC eliminator according to the present invention, and performs the same signal processing on the real component (In-phase, I) and the imaginary component (Q) of the complex input signal. After estimating the DC value in each component, remove it.

For this purpose, FIG. 47 is largely comprised of first and second DC estimators and removers 2100 and 2150. 47 is an Infinite Impulse Reponse (IIR) structure.

The first DC estimator and remover 2100 includes a multiplier 2101, an adder 2102, a one sample delayer 2103, a multiplier 2104, a C sample delayer 2105, and a subtractor 2106. After estimating the DC of the real component, remove it.

The second DC estimator and remover 2150 includes a multiplier 2151, an adder 2152, a one sample delayer 2153, a multiplier 2154, a C sample delayer 2155, and a subtractor 2156. After estimating the DC of the imaginary component, remove it.

In the present invention, since only two input signals of the first and second DC estimators and removers 2100 and 2150 are different, the first DC estimator and the remover 2100 will be described in detail, and the second DC estimator and the remover 2 will be described in detail. Detailed description of 2150 will be omitted.

를 곱하여 가산기(2102)로 출력한다. 상기 가산기(2102)는 상기 곱셈기(2101)의 출력과 피드백되는 곱셈기(2104)의 출력을 더하여 1 샘플 지연기(2103)와 감산기(2106)로 출력한다. 즉, 상기 가산기(2102)의 출력이 추정된 실수 성분의 DC 값이다.That is, the signal of the real component matched and filtered by the matched filter 1060 is input to the multiplier 2101 and the C sample delayer 2105 of the first DC estimator and remover 2100 in the DC remover 1070. The multiplier 2101 is a constant preset to a signal of a real component to be input.

Multiply by and output to the adder 2102. The adder 2102 adds the output of the multiplier 2101 and the output of the multiplier 2104 to be fed back and outputs it to the one sample delayer 2103 and the subtractor 2106. That is, the output of the adder 2102 is the DC value of the estimated real component.

)를 곱하여 가산기(2102)로 피드백한다.The one sample delayer 2103 delays the estimated DC value by one sample and outputs the result to the multiplier 2104. The multiplier 2104 has a constant (1-1) set to the one sample delayed DC value.

Multiply by) to feed back to adder 2102.

The C sample delayer 2105 delays the input sample data of the real component by C samples and outputs the result to the subtractor 2106. The subtractor 2106 subtracts the output of the adder 2102 from the output of the C sample delayer 2105 and outputs a signal from which the DC of the real component is removed.

The DC-free data is input to the buffer 1111 and the frequency offset estimator 1112 of the phase compensator 1110 as described above.

The frequency offset estimator 1112 is configured to remove DC from the DC remover 1070 when a known data string is input using the known data position information output from the known data detection and initial frequency offset estimator 9041. The frequency offset is estimated from the known data stream and output to the retainer 1113. Similarly, the frequency offset estimate is obtained once for each repetition period of the known data stream.

Thus, the maintainer 1113 maintains the frequency offset estimate for a period of known data sequences and then outputs it to the NCO 1114. The NCO 1114 generates a complex signal corresponding to the frequency offset maintained by the retainer 1113 and outputs the complex signal to the multiplier 1115.

The multiplier 1115 multiplies the data delayed in the buffer 1111 by a complex signal output from the NCO 1114 to compensate for the phase change included in the delayed data. The data whose phase change is compensated for in the multiplier 1115 is provided to the equalizer 903 via the decimator 1500. In this case, the frequency offset estimated by the frequency offset estimator 1112 of the phase compensator 1110 represents a phase difference, that is, a phase offset between known data streams without passing through a loop filter.

Channel equalizer in the receiving system

Data demodulated using the known data in the demodulator 1002 is input to the equalizer 1003. The demodulated data may also be input to a known data detector 1004.

The channel equalizer 1003 may perform channel equalization in various ways. In the present invention, channel equalization is performed by estimating a channel impulse response (CIR).

In particular, the present invention describes that the estimation and application of the channel impulse response (CIR) are different according to each region in the data group layered and transmitted in the transmission system. In addition, the present invention provides a more stable channel equalization by estimating the CIR using known data and field synchronization, which are known in terms of location and content, by appointment of the transmitting and receiving party.

At this time, one data group inputted for equalization is divided into areas A to C, as shown in FIG. 7A, again, A area is A1 to A5 area, B area is B1 and B2 area, and C1 area is C1 to C3 area. In one embodiment, those separated by.

In the data structure as shown in FIG. 7A, the CIR estimated from the field synchronization is called CIR_FS, and the CIRs estimated from the five known data sequences in the A region are called CIR_N0, CIR_N1, CIR_N2, CIR_N3, and CIR_N4 in order.

According to the present invention, channel equalization is performed on data in a data group using the field synchronization and the CIR estimated from the known data stream. In this case, one of the estimated CIRs may be used as it is according to the characteristics of each region of the data group. In addition, CIR generated by interpolating or extrapolating at least a plurality of CIRs may be used.

Here, interpolation is a function value at some point between Q and S when the function value F (Q) at point Q and the function value F (S) at point S are known for a function F (x). It is meant to estimate, and the simplest example of the interpolation is linear interpolation. The linear interpolation technique is the simplest of many interpolation techniques, and various other interpolation techniques may be used in addition to the above-described methods, and thus the present invention will not be limited to the examples described above.

Also, extrapolation can be used to determine the function value F (Q) at time Q and the function value F (S) at time S for a function F (x). It means to estimate the function value at the time point. The simplest example of such extrapolation is linear extrapolation. The linear extrapolation technique is the simplest of many extrapolation techniques, and various other extrapolation techniques may be used in addition to the above-described methods, and thus the present invention will not be limited to the examples described above.

48 is a flowchart illustrating an embodiment of a channel equalization method according to the present invention. After temporarily storing a received data group (step 2301), a CIR is estimated using field synchronization and known data in the data group (step 2301). Step 2302). In this case, the step 2301 may store all data in the data group or only some data. This means that the data of the B1, C1, A1 area is received before the known data of the first known data area in the corresponding data group. This is done by using

For example, in the case of the C1 region, CIR_FS estimated in the field sync interval of the current data group and CIR_N0 estimated in the first known data region may be extrapolated, and channel equalization may be performed using the extrapolated CIR (step S). 2303). Alternatively, channel equalization may be performed using one of CIR_N4 estimated in the previous data group and CIR_FS estimated in the current data group to perform channel equalization. If the extrapolated CIR is used to equalize the data of the C1 region, the data of the C1 region is data that is input before the first known data region in the current data group and should be stored until the CIR_N0 is estimated. In this case, the data storage of the C1 region may be allocated by storing a partial region of an external memory (eg, RAM) in the receiving system, or may be provided with a separate memory.

In the case of the B1 region, various methods are applicable as in the C1 region. According to an embodiment, channel equalization may be performed using CIR generated by linear extrapolation of CIR_FS and CIR_N0 estimated in the current data group (step 2303). Alternatively, channel equalization may be performed using the CIR_FS estimated from the current data group. Similarly, since the data of the B1 region is the data inputted earlier than the first known data region in the current data group, it should be stored until the CIR_N0 (or CIR_FS) is estimated. The data storage of the B1 region may be allocated and stored as a partial region of an external memory (eg, RAM) in the receiving system, or may be provided with a separate memory.

In the case of the A1 region, channel equalization may be performed using the CIR generated by interpolating CIR_FS and CIR_N0 estimated in the current data group (step 2304). Alternatively, channel equalization may be performed using any one of CIR_FS and CIR_N0 estimated by the current data group. If the data of the area A1 is equalized using the interpolated CIR, the data of the area A1 is also inputted before the first known data area in the current data group, and thus should be stored until the CIR_N0 is estimated. In this case, the data storage of the A1 region may be allocated and stored as a partial region of an external memory (eg, RAM) in the receiving system, or may be provided with a separate memory.

In the areas A2 to A5, channel equalization may be performed using CIR generated by interpolating CIR_N (i-1) and CIR_N (i) estimated in the current data group (step 2305). Alternatively, channel equalization may be performed using any one of CIR_N (i-1) and CIR_N (i) estimated in the current data group.

In the B2, C2, and C3 regions, channel equalization may be performed using CIR generated by extrapolating CIR_N3 and CIR_N4 estimated in the current data group (step 2306). Alternatively, channel equalization may be performed using CIR_N4 estimated from the current data group.

In this way, optimum performance can be obtained at the time of channel equalization for the data inserted in the data group.

49 illustrates, as an embodiment of the channel equalizer according to the present invention, by estimating the residual carrier phase error and compensating for the channel equalized signal, thereby further improving reception performance.

FIG. 49 is a block diagram illustrating an embodiment of a channel equalizer according to the present invention. The first frequency domain transform unit 3100, the channel estimator 3110, the second frequency domain transform unit 3121, and coefficient calculation are shown in FIG. 3122, Distortion Compensator 3130, Time Domain Converter 3140, Residual Carrier Phase Error Canceler 3150, Noise Canceller (NC) 3160, and Decision Unit ( 3170).

The first frequency domain transform unit 3100 includes an overlap unit 3101 that overlaps input data, and an FFT (Fast Fourier Transform) unit 3102 that converts output data of the overlap unit 3101 into a frequency domain. It is configured to include.

The channel estimator 3110 may include a CIR estimator 3111 for estimating a channel impulse response (CIR) from input data, and a phase compensator 3112 for compensating the phase of the CIR estimated by the CIR estimator 3111. , A first cleaner (Pre-CIR Cleaner) 3113, a CIR calculator 3114, a second cleaner (Post-CIR Cleaner) 3115, and a zero-padding unit 3116. .

The second frequency domain converter 3121 includes an FFT unit for converting the CIR output from the channel estimator 3110 into a frequency domain.

The time domain converter 3140 extracts only valid data from an IFFT unit 3141 for converting data whose distortion is compensated by the distortion compensator 3130 into a time domain, and output data of the IFFT unit 3141. And a save unit 3314.

The residual carrier phase error remover 3150 uses an error compensator 3151 to remove the residual carrier phase error included in the channel equalized data, and the channel equalized data and decision data of the determiner 3170. And a residual carrier phase error estimator 3152 that estimates the residual carrier phase error and outputs the residual carrier phase error to the error compensator 3151.

The distortion compensator 3130 and the error compensator 3151 may be any element that performs a complex multiplication role.

At this time, since the received data is data modulated by the VSB method, 8-level discrete data exists only in the real component. Therefore, all signals used in the noise canceling unit 3160 and the determiner 3170 in FIG. 49 are real signals. However, in order to estimate and compensate for the residual carrier phase error and phase noise, not only a real component but also an imaginary component is required, and thus the residual carrier phase error remover 3150 receives an imaginary component.

In general, the demodulator 1002 in the receiving system performs the frequency and phase recovery of the carrier before performing channel equalization. If the residual carrier phase error that is not sufficiently compensated is input to the channel equalizer, the performance of the channel equalization is degraded. Let's go. In particular, in the dynamic channel environment, the residual carrier phase error is larger than that of the static channel due to the drastic change of the channel, which is a major cause of reception performance degradation.

Also, a local oscillator (not shown) in a receiving system should ideally have a single frequency component, but in practice there is a frequency component outside the desired frequency, which is called the phase noise of the local oscillator. The phase noise is also a factor of deterioration of reception performance. Such residual carrier phase error and phase noise are difficult to compensate in a conventional channel equalizer.

Accordingly, the present invention can improve the channel equalization performance by including a carrier recovery loop, ie, the residual carrier phase error removal unit 3150, in the channel equalizer to remove the residual carrier phase error and phase noise as shown in FIG. 49.

That is, the received demodulated data in FIG. 49 is superimposed at a preset overlap ratio by the overlapping unit 3101 of the first frequency domain converter 3100 and output to the FFT unit 3102. The FFT unit 3102 converts the overlapped data of the time domain into overlapped data of the frequency domain through an FFT and outputs the overlapped data to the distortion compensator 3130.

The distortion compensator 3130 complexly multiplies the equalization coefficient calculated by the coefficient calculator 3122 with the overlapped data of the frequency domain output from the FFT unit 3102 of the first frequency domain transform unit 3100 to perform the FFT unit. After compensating for the channel distortion of the superimposed data output from 3102, the channel distortion is output to the IFFT unit 3141 of the time domain converter 3140. The IFFT unit 3141 IFFTs the overlapped data whose distortion of the channel is compensated, converts the data into a time domain, and outputs the converted data to the save unit 3314. The save unit 3322 extracts only valid data from the overlapped data of the channel equalized time domain and outputs the valid data to the error compensator 3151 of the residual carrier phase error remover 3150.

The error compensator 3151 removes the residual carrier phase error and the phase noise included in the valid data by multiplying the valid data extracted in the time domain by a signal for compensating the estimated residual carrier phase error and phase noise.

The data of which the residual carrier phase error is compensated by the error compensator 3151 is output to the residual carrier phase error estimating unit 3152 to estimate the residual carrier phase error and phase noise, and at the same time, to remove the noise ( 3160).

The residual carrier phase error estimator 3152 estimates the residual carrier phase error and phase noise by using the output data of the error compensator 3151 and the decision data of the determiner 3170, and estimates the estimated residual carrier phase error and phase noise. A signal for compensating for noise is output to the error compensator 3151. According to an embodiment of the present invention, the estimated reciprocal of the estimated residual carrier phase error and phase noise is output as a signal for compensating the residual carrier phase error and phase noise.

50 is a detailed block diagram showing an embodiment of the residual carrier phase error estimator 3152, and includes a phase error detector 3211, a loop filter 3212, and a numerically controlled oscillator (NCO) 3213. And a conjugator 3214. In Fig. 50, the decision data and the output of the phase error detector 3211 and the output of the loop filter 3212 are real signals, the output of the error compensator 3151, the output of the NCO 3213 and the output of the conjugator 3214. Is a complex signal.

The phase error detector 3211 receives the output data of the error compensator 3151 and the decision data of the determiner 3170, estimates the residual carrier phase error and the phase noise, and outputs the result to the loop filter 3212.

The loop filter 3212 filters out the residual carrier phase error and phase noise, and outputs the result to the NCO 3213. The NCO 3213 generates a sine wave corresponding to the filtered residual carrier phase error and the phase noise and outputs the sine wave to the conjugator 3214.

The conjugate 3214 obtains the conjugate value of the sinusoidal wave of the NCO 3213 and outputs the conjugate value to the error compensator 3151. At this time, the output data of the conjugator 3214 is a signal that compensates for the residual carrier phase error and phase noise, that is, the inverse of the residual carrier phase error and phase noise.

The error compensator 3151 complexes the equalized data output from the time domain converter 3140 and a signal for compensating for the residual carrier phase error and phase noise output from the conjugator 3214 and equalizes the equalized data. Eliminate residual carrier phase error and phase noise included in.

On the other hand, the phase error detector 3211 may estimate the residual carrier phase error and phase noise by various methods and structures. In one embodiment, the residual carrier phase error and phase noise are estimated in a decision-directed manner.

The decision-oriented phase error detector according to the present invention uses only a real value in the correlation value between the channel equalized data and the decision data when there is no residual carrier phase error and phase noise in the channel equalized data.

That is, when there is no residual carrier phase error and phase noise, if the input data of the phase error detector 3211 is xi + jxq, the correlation between the input data of the phase error detector 3211 and the determination data is expressed by the following equation. Equation 8

In this case, since xi and xq have no correlation, the correlation between xi and xq is 0. Therefore, the correlation value has only a real value when there is no residual carrier phase error and phase noise. However, if residual carrier phase error and phase noise exist, the imaginary component appears in the correlation value because the real component appears in the imaginary part and the imaginary component appears in the real part.

Therefore, the imaginary part of the correlation value and the residual carrier phase error and the phase noise may be considered to be proportional. The imaginary part of the correlation value may be used as the residual carrier phase error and phase noise as shown in Equation 9 below.

Fig. 51 is a block diagram showing an embodiment of the structure of the phase error detector 3211 for obtaining the above-described residual carrier phase error and phase noise, and includes a Hilbert transform part 3311, a complex number part 3312, and a conjugator ( 3313), a multiplier 3314, and a phase error output unit 3315.

를 힐버트 변환하여 허수부 결정 데이터

를 만들고, 이를 복소수 구성부(3312)로 출력한다. 상기 복소수 구성부(3312)는 결정 데이터

와

를 이용하여 복소 결정 데이터

를 구성하여 콘쥬게이터(3313)로 출력한다. 상기 콘쥬게이터(3313)는 복소수 구성부(3312)의 출력을 콘쥬게이트시켜 곱셈기(3314)로 출력한다. 상기 곱셈기(3314)는 에러 보상부(3151)의 출력 데이터

와 상기 콘쥬게이터(3313)의 출력 데이터

를 복소곱한다. 즉 상기 곱셈기(3314)의 출력이 에러 보상부(3151)의 출력 데이터와 결정기(3170)의 결정 데이터와의 상관값이 된다. 상기 곱셈기(3314)에서 구한 상관 데이터는 위상 에러 출력부(3315)로 입력된다. That is, the Hilbert transform unit 3311 determines the decision data of the determiner 3170.

The imaginary part by Hilbert transform

And output it to the complex number unit 3312. The complex number unit 3312 determines decision data.

Wow

Complex decision data using

It configures and outputs to the conjugator 3313. The conjugate 3313 conjugates the output of the complex number component 3312 and outputs the result to the multiplier 3314. The multiplier 3314 outputs data of the error compensator 3151.

And output data of the conjugator 3313

Multiply by. That is, the output of the multiplier 3314 becomes a correlation value between the output data of the error compensator 3151 and the decision data of the determiner 3170. The correlation data obtained by the multiplier 3314 is input to the phase error output unit 3315.

을 잔류 반송파 위상 에러 및 위상 잡음으로서 출력한다. The phase error output unit 3315 is an imaginary part of the correlation data output from the multiplier 3314.

Is output as residual carrier phase error and phase noise.

The phase error detector of FIG. 51 is an example of various phase error detection schemes, and various other phase error detectors may be applied, and thus the present invention will not be limited to the above-described embodiment. In another embodiment of the present invention, two or more phase error detectors may be combined to detect residual carrier phase error and phase noise.

The output of the residual carrier phase error canceling unit 3150 from which the residual carrier phase error and phase noise detected in this manner are colored by amplifying white noise during the channel equalization process and the original signal from which the channel equalization and residual carrier phase error and phase noise are removed. It consists of the sum of the noise signals.

Accordingly, the noise remover 3160 receives the output data of the residual carrier phase error remover 3150 and the decision data of the determiner 3170 to estimate colored noise. The estimated color noise is subtracted from the data from which the residual carrier phase error and the phase noise have been removed, thereby removing the amplified noise during the equalization process.

To this end, the noise removing unit 3160 may include a subtractor and a noise predictor. That is, the subtractor subtracts the noise predicted by the noise predictor from the output data of the residual carrier phase error remover 3150 and outputs a signal from which the amplified noise is removed for data recovery and simultaneously to the determinator 3170. The noise predictor calculates a noise component by subtracting the output of the determiner 3170 from the signal from which the residual carrier phase error removal unit 3150 is removed, and uses the noise predictor as a filter input in the noise predictor. The noise predictor predicts a colored noise component included in an output symbol of the residual carrier phase error remover 3150 by using the filter (not shown), and outputs the color noise component to the subtractor.

The data from which the noise is removed by the noise remover 3160 is output for data decoding and simultaneously to the determiner 3170.

The determiner 3170 selects a plurality of preset decision data, for example, decision data that is closest to the output of the noise canceller 3160, from among the plurality of decision data, for example, the residual carrier phase error estimator 3152 and the noise. Output to removal unit 3160.

Meanwhile, the demodulated received data is input to the overlapping unit 3101 of the first frequency domain converter 3100 in the channel equalizer and also to the CIR estimator 3111 of the channel estimator 3110.

The CIR estimator 3111 estimates the CIR using a training sequence, for example, known data and field synchronization data, and outputs the CIR to the phase compensator 3112. That is, the CIR estimator 3111 uses the data received during the known data interval and the known data of the known data interval known to the receiving side by the promise of the transmitting / receiving side to impulse response of the channel (CIR_N0 to CIR_N4). Estimate). To this end, the CIR estimator 3111 receives the known data position information from which the second known data pattern is transmitted from the known data detector 1004. In addition, since the second known data pattern of the known data section is data already known by an appointment of a transmitting / receiving side, the second known data pattern may be stored in the CIR estimator 3111 in advance, or a second generated by the known data detector 1004. It is also possible to receive a known data pattern.

In addition, the CIR estimator 3111 estimates the impulse response (CIR_FS) of the channel using the data received during the field sync interval and the field sync data of the field sync interval known to the receiver by the promise of the transmitter / receiver side. do. To this end, the CIR estimator 3111 is provided with field sync position information from the known data detector 1004. In addition, since the field synchronization data of the field synchronization section is already known by the appointment of the transmitting / receiving side, the field synchronization data may be stored in the CIR estimator 3111 in advance, and the field synchronization data generated by the known data detector 1004 may be stored. You can also receive input.

The CIR estimator 3111 may estimate a channel impulse response (CIR) in a least square (LS) manner.

의 행렬 연산을 하여 전송 채널의 임펄스 응답(CIR)을 추정하는 방법이다.The LS estimation method obtains a cross correlation value p between known data transmitted through a channel and known data known to a receiver during a known data interval, and obtains an autocorrelation matrix R of the known data. Then remove the autocorrelation portion that exists in p that is the cross-correlation between the received data and the original data.

It is a method of estimating the impulse response (CIR) of a transmission channel by performing a matrix operation of.

The phase compensator 3112 compensates for the phase change of the estimated CIR and outputs it to the first cleaner 3113 or the CIR calculator 3114. In this case, the phase compensator 3112 may compensate for the phase change of the CIR estimated by the Maximum likelihood method.

That is, the residual carrier phase error and phase noise included in the demodulated received data change the phase of the CIR estimated by the CIR estimator 3111 for every known data string. At this time, if the phase change rate of the input CIR used for linear interpolation is large and the phase change is not linear, the channel equalization performance is deteriorated by obtaining the equalization coefficient from the CIR estimated through linear interpolation.

Accordingly, the present invention removes the phase change of the CIR estimated by the CIR estimator 3111 so that the distortion compensator 3130 passes the residual carrier phase error and the phase noise component without compensating for them, and the residual carrier phase error remover. 3150 compensates for the residual carrier phase error and phase noise components.

To this end, the present invention allows the phase compensator 3112 to remove the phase change amount of the CIR estimated by the Maximum likelihood method.

The basic concept of the maximum likelihood phase compensation method estimates a phase component common to all CIR components, multiplies the inverse of the common phase component by an estimated CIR, and multiplies the common phase component by a channel equalizer, that is, a distortion compensator 3130. ) Is not to compensate.

라 할 때, 새로 추정한 CIR은 이전에 추정한 CIR에 비해 위상이

만큼 회전되어 있다. 상기 Maximum likelihood 위상 보상법은 t 시점에서의 CIR을 h_i(t)라 할 때, h_i(t)를

만큼 회전시켰을 때 t+1 시점에서의 CIR인 h_i(t+1)과의 차의 제곱값이 최소가 되는 위상

를 찾는다. 여기서 i는 추정된 CIR의 탭(tap)을 나타내며, CIR 추정기(3111)에서 추정하는 CIR의 탭 수를 N으로 하였다면, 0이상 N-1이하의 값을 가진다. That is, the common phase component

In this case, the newly estimated CIR is out of phase with the previously estimated CIR.

Rotated by. In the maximum likelihood phase compensation method, when the CIR at time t is h _i (t), h _i (t) is calculated.

Phase that minimizes the square of the difference between h _i (t + 1) and CIR at time t + 1.

Find it. I denotes a tap of the estimated CIR, and if the number of taps of the CIR estimated by the CIR estimator 3111 is N, it has a value of 0 or more and N-1 or less.

This can be summarized as Equation 10 below.

에 대해 미분한 값이 0이 되는 조건을 만족하는

가 하기의 수학식 11과 같이 maximum likelihood 관점에서 공통 위상 성분

이 된다.The right side of the equation (10)

Satisfies the condition that the derivative is 0 for

Is a common phase component in terms of maximum likelihood, as shown in Equation 11 below.

Becomes

Equation 11 is summarized as in Equation 12 below.

가 된다. That is, the argument of the correlation between h _i (t) and h _i (t + 1) is to be estimated.

Becomes

을 구하고, 추정된 위상 성분을 추정된 CIR에서 보상하는 위상 보상기의 일 실시예를 보이고 있다. 52 shows the common phase component as above.

And an embodiment of a phase compensator for compensating the estimated phase component in the estimated CIR.

Referring to FIG. 52, the phase compensator includes a correlation operator 3410, a phase change estimator 3420, a compensation signal generator 3430, and a multiplier 3440.

The correlation operator 3410 includes a first N symbol buffer 3411, an N symbol delayer 3412, a second N symbol buffer 3413, a conjugator 3414, and a multiplier 3415.

That is, the first N symbol buffer 3411 in the correlation calculator 3410 may store up to N symbols of data input from the CIR estimator 3111 in symbol units and temporarily store the data in the first N symbol buffer 3411. The stored symbol data is input to a multiplier 3415 and a multiplier 3440 in the correlation operator 3410.

At the same time, the symbol data output from the CIR estimator 3111 is delayed by N symbols in the N symbol delayer 3412 and then conjugated in the conjugate 3414 via the second N symbol buffer 3413. And input to the multiplier 3415.

The multiplier 3415 multiplies the output of the first N symbol buffer 3411 and the output of the conjugator 3414 and outputs the multiplier 341 in the phase change estimator 3420.

That is, the accumulator of the correlation computing unit 3410 is current CIR of h _i (t + 1) and before CIR of h _i (t) the phase shift estimator 3420, obtain a correlation value having a N length having a N length ( 3421).

를 구하여 보상 신호 생성기(3430)로 출력한다. The accumulator 341 accumulates the correlation value output from the multiplier 3415 for N symbols and outputs the result to the phase detector 3422. The phase detector 3342 is a common phase component as shown in Equation 11 from the output of the accumulator 3421.

To obtain the output to the compensation signal generator 3430.

를 위상 보상 신호로서 곱셈기(3440)로 출력한다. 상기 곱셈기(3440)는 상기 제1 N 심볼 버퍼(3411)에서 출력되는 현재 CIR인 h_i(t+1)에 위상 보상 신호

를 곱하여 추정된 CIR의 위상 변화량을 제거한다.The compensation signal generator 3430 has a complex signal having a phase opposite to that of the detected phase.

Is output to the multiplier 3440 as a phase compensation signal. The multiplier 3440 has a phase compensation signal at h _i (t + 1) which is the current CIR output from the first N symbol buffer 3411.

Multiply by to remove the estimated amount of phase change in CIR.

As such, the phase compensator 3112 of the Maximum likelihood method obtains a phase component of a correlation value between an input CIR and a previous CIR delayed by N symbols, generates a phase compensation signal having a phase opposite to the obtained phase, and is estimated. By multiplying the CIR, the estimated amount of phase change in the CIR is removed.

The CIR compensated for the phase change as described above is input to the CIR calculator 3114 through the first cleaner 3113 or bypasses the first cleaner 3113. The CIR calculator 3114 interpolates or extrapolates the estimated CIR to the second cleaner 3115. The estimated CIR is the CIR whose phase change is compensated for.

Depending on whether the CIR calculator 3114 interpolates or extrapolates the estimated CIR, the first cleaner 3113 may or may not operate. For example, when the interpolation is performed on the estimated CIR, the first cleaner 3113 is not operated. When the extrapolation is performed on the estimated CIR, the first cleaner 3113 is operated.

That is, the CIR estimated from the known data includes not only the channel component to be obtained but also the jitter component due to noise. Since this jitter component is a factor that degrades the equalizer performance, it is preferable to remove the jitter component before using the CIR in the coefficient calculator 3122. Accordingly, in the embodiment, the first and second cleaners 3113 and 3115 remove a portion of the input CIR component whose power is less than or equal to a predetermined threshold (ie, make it '0'). do. This removal process is called CIR cleaning.

That is, CIR interpolation in the CIR calculator 3114 is estimated by the CIR estimator 3112 and multiplies and adds coefficients to two CIRs whose phase change is compensated in the phase compensator 3112, respectively. At this time, some of the noise components of the CIR are added to each other to cancel. Accordingly, when CIR interpolation is performed in the CIR calculator 3114, the original CIR in which the noise component remains is used. That is, when CIR interpolation is performed by the CIR calculator 3114, the estimated CIR whose phase change is compensated by the phase compensator 3112 is input to the CIR calculator 3114 by bypassing the first cleaner 3113. The CIR interpolated by the CIR calculator 3114 is cleaned by the second cleaner 3115.

On the other hand, the CIR extrapolation in the CIR calculator 3114 is performed by estimating the CIR located outside the two CIRs by using a difference between two CIRs whose phase change is compensated in the phase compensator 3112. Therefore, the noise component of the CIR is amplified at this time. Therefore, when CIR extrapolation is performed in the CIR calculator 3114, the CIR cleaned by the first cleaner 3113 is used. That is, when the CIR extrapolation is performed by the CIR calculator 3114, the extrapolated CIR is input to the zero padding unit 3116 via the second cleaner 3115.

Meanwhile, when the CIR cleaned and output from the second cleaner 3115 is converted into the frequency domain by the second frequency domain converter 3121, the length of the input CIR and the FFT size do not match. Can be. That is, a case where the length of the CIR is smaller than the FFT size may occur. In this case, the zero padding unit 3116 adds '0' to the CIR by the difference between the FFT size and the input CIR length and outputs the same to the second frequency domain converter 3121. The zero-padded CIR may be one of interpolated CIRs, extrapolated CIRs, and CIRs estimated from known data intervals.

The second frequency domain transforming unit 3121 converts the input CIR of the time domain into a CIR of the frequency domain and outputs the CIR to the coefficient calculating unit 3122.

The coefficient calculator 3122 calculates an equalization coefficient by using the CIR of the frequency domain output from the second frequency domain converter 3121 and outputs the equalization coefficient to the distortion compensator 3130. In this example, the coefficient calculator 3122 obtains an equalization coefficient of a frequency domain that minimizes a mean square error (MMSE) from the CIR of the frequency domain and outputs the equalization coefficient to the distortion compensator 3130. .

The distortion compensator 3130 complexly multiplies the equalization coefficient calculated by the coefficient calculator 3122 with the overlapped data of the frequency domain output from the FFT unit 3102 of the first frequency domain transform unit 3100 to perform the FFT unit. Compensate for the channel distortion of the overlapping data output at 3102.

FIG. 53 illustrates another embodiment in which channel impulse response (CIR) is differently estimated and applied according to areas A, B, and C when data groups are divided into the structures shown in FIGS. 7A and 8.

That is, as shown in FIG. 7A, indirect equalization using CIR can be used because long enough known data is periodically transmitted in region A. However, in B and C regions, not only the known data can be transmitted long enough but also periodically. Since it is not possible to transmit constantly, it is not suitable for estimating CIR using known data. Therefore, in the B and C areas, the direct equalization method should be used to obtain the error from the output of the equalizer and update the coefficients.

For example, indirect equalization channel equalization using cyclic prefix and CIR is performed on the data in the area A, and the overlap & save method is used on the data in the B and C areas. The channel equalization of the direct equalization method of updating the coefficients may be performed.

For this purpose, the frequency domain channel equalizer of FIG. 53 includes a frequency domain converter 3510, a distortion compensator 3520, a time domain converter 3530, a first coefficient calculator 3540, a second coefficient calculator 3550, and Coefficient selection unit 3560 may be included.

The frequency domain converter 3510 may include an overlapping unit 3511, a selecting unit 3512, and a first FFT unit 3513.

The time domain converter 3530 may include an IFFT unit 3531, a save unit 3532, and a selector 3535.

The first coefficient calculating unit 3540 may include a CIR estimator 3551, an average calculating unit 3542, a second FFT unit 3543, and a coefficient calculating unit 3444.

The second coefficient calculator 3550 includes a determiner 3551, a selector 3652, a subtractor 3553, a zero padding unit 3554, a third FFT unit 3555, a coefficient updater 3556, and a delay unit. (3557).

In this case, the selector 3512 of the frequency domain converter 3510, the selector 3535 of the time domain converter 3530, and the coefficient selector 3560 may determine whether the current input data is data of the A region, It can be configured as a multiplexer (ie, mux) that selects input data depending on whether the data is in the C region.

If the data input in FIG. 53 configured as described above is the data of the A region, the selecting unit 3512 of the frequency domain converting unit 3510 selects the input data among the input data and the output data of the overlapping unit 3511, and converts the time domain. The selecting unit 3535 of the unit 3530 selects the output data of the IFFT unit 3531 from among the output data of the IFFT unit 3531 and the output data of the save unit 3532. The coefficient selector 3560 selects an equalization coefficient output from the first coefficient calculator 3540.

On the other hand, if the input data is data of the B and C areas, the selection unit 3512 of the frequency domain conversion unit 3510 selects the output data of the overlap unit 3511 among the input data and the output data of the overlap unit 3511, The selector 3533 of the time domain converter 3530 selects the output data of the save unit 3532 from the output data of the IFFT unit 3531 and the output data of the save unit 3532. The coefficient selector 3560 selects an equalization coefficient output from the second coefficient calculator 3550.

That is, the received data is input to the overlapping unit 3511, the selecting unit 3512, and the first coefficient calculating unit 3540 of the frequency domain converter 3510. If the input data is data in the area A, the selector 3512 selects the received data and outputs the received data to the first FFT unit 3513, and in the case of data in the B and C areas, the selector 3512 selects the overlapped data. Output to the first FFT unit 3513. The first FFT unit 3513 transforms the time domain data output from the selector 3512 into a frequency domain by converting the data in the time domain into a frequency domain, and then delays 3575 of the distortion compensator 3520 and the second coefficient calculator 3550. )

The distortion compensator 3520 complexes the equalization coefficient output from the coefficient selector 3560 to the data in the frequency domain output from the first FFT unit 3513 to output the data from the first FFT unit 3513. The channel distortion is compensated for and output to the IFFT unit 3531 of the time domain converter 3530.

The IFFT unit 3531 of the time domain converter 3530 converts the distortion-compensated data into the time domain by IFFT-converting the data, and outputs the data to the save unit 3532 and the selector 3535. The selector 3535 selects output data of the IFFT unit 3531 if the input data is data of the A region, and selects valid data extracted from the save unit 3532 if data of the B and C regions is used to decode the data. Output to the second coefficient calculating unit 3550 at the same time.

The CIR estimator 3551 of the first coefficient calculating unit 3540 performs the data received during the known data section and the known data of the known data section known by the receiving side by the promise of the transmitting / receiving side (the reference generated on the receiving side). CIR is estimated using the data) and output to the average calculating unit 3542. In addition, the CIR estimator 3551 estimates a CIR using data received during the field synchronization period and field synchronization data (reference data generated at the receiving side) of the field synchronization period, and outputs the CIR to the average operation unit 3542.

The average calculating unit 3542 obtains an average value of successive CIRs which are input, and outputs the average value to the second FFT unit 3543.

The second FFT unit 3543 converts the input CIR of the time domain into the frequency domain and outputs the FIR to the coefficient calculator 3504.

The coefficient calculator 3504 calculates an equalization coefficient satisfying a condition for minimizing the mean square error using the CIR in the frequency domain and outputs the equalization coefficient to the coefficient selector 3560.

The determiner 3551 of the second coefficient calculator 3550 selects a decision value closest to the equalized data among the eight decision values and outputs the selected decision value to the selector 3652. The selector 3652 selects the determined value of the determiner 3551 in the general data section, and selects the known data in the known data section and outputs the known data to the subtractor 3553. The subtractor 3553 subtracts the output of the selector 3535 of the time domain converter 3530 from the output of the selector 3552 to obtain an error and outputs the error value to the zero padding unit 3554.

The zero padding unit 3554 adds a zero corresponding to an amount of overlapping received data to an input error and outputs the zero padding unit 3555 to the third FFT unit 3555. The third FFT unit 3555 converts an error in the time domain to which zero is added to an error in the frequency domain, and outputs the error to the coefficient updater 3556. The coefficient updater 3556 updates the previous equalization coefficient using the data of the frequency domain delayed by the delayer 3575 and the error of the frequency domain, and then outputs the previous equalization coefficient to the coefficient selector 3560. The updated equalization coefficient is then stored for use as a previous equalization coefficient.

The coefficient selecting unit 3560 selects the equalization coefficient calculated by the first coefficient calculating unit 3540 when the input data is data of the A region, and the equalization updated by the second coefficient calculating unit 3550 when the data of the B and C regions is selected. The coefficient is selected and output to the distortion compensator 3520.

FIG. 54 illustrates another embodiment of a channel equalizer for differentiating and applying a channel impulse response (CIR) according to areas A, B, and C when data groups are divided into the same structure as in FIG. 7A.

For example, indirect equalization channel equalization using superimposed & save CIR is performed on data in area A, and direct equalization channel equalization is performed using superimposed & save method on data in B and C areas. can do.

For this purpose, the channel equalizer of FIG. 54 includes a frequency domain transformer 3610, a distortion compensator 3620, a time domain transformer 3630, a first coefficient calculator 3640, a second coefficient calculator 3650, and coefficient selection. A portion 3660 may be included.

The frequency domain transform unit 3610 may include an overlap unit 3611 and a first FFT unit 3612.

The time domain converter 3630 may include an IFFT unit 3611 and a save unit 3632.

The first coefficient calculator 3640 may include a CIR estimator 3641, an interpolator 3542, a second FFT unit 3643, and a coefficient calculator 3644.

The second coefficient calculator 3650 includes a determiner 3701, a selector 3652, a subtractor 3653, a zero padding unit 3654, a third FFT unit 3655, a coefficient updater 3656, and a delay unit. (3657).

In this case, the coefficient selector 3660 may be configured as a multiplexer (ie, mux) that selects input data according to whether the current input data is data of the A region or the data of the B and C regions. That is, the coefficient selector 3660 selects an equalization coefficient of the first coefficient calculator 3640 when the input data is data of the A region, and selects an equalization coefficient of the second coefficient calculator 3650 if the data of the B and C regions is data. Choose.

In FIG. 54 configured as described above, the received data is input to the overlapping part 3611 and the first coefficient calculating part 3640 of the frequency domain converter 3610. The overlap unit 3611 overlaps the input data according to a preset overlap ratio and outputs the input data to the first FFT unit 3612. The first FFT unit 3612 converts overlapped data in the time domain into overlapped data in the frequency domain through an FFT and is output to the distortion compensator 3620 and the delay unit 3635 of the second coefficient calculator 3650.

The distortion compensator 3620 complex-multiplies the equalization coefficient output from the coefficient selector 3660 with the overlapping data of the frequency domain output from the first FFT unit 3612 and outputs from the first FFT unit 3612. The channel distortion of the overlapped data is compensated and then output to the IFFT unit 3611 of the time domain converter 3630. The IFFT unit 3611 IFFTs the overlapped data whose distortion of the channel is compensated, converts the data into a time domain, and outputs the converted data to the save unit 3632. The save unit 3632 extracts only valid data from the overlapped data of the channel equalized time domain and outputs the data for data decoding and outputs the second coefficient calculator 3650 to update the coefficients.

The CIR estimator 3641 of the first coefficient calculator 3640 estimates the CIR by using the data received during the known data interval and the reference known data generated at the receiver, and outputs the CIR to the interpolator 3642. In addition, the CIR estimator 3641 estimates the CIR using data received during the field synchronization period and reference field synchronization data generated at the receiving side, and outputs the CIR to the interpolator 3642.

The interpolator 3642 estimates the CIRs at the time points located between the CIRs estimated using the input CIRs, that is, the CIRs of the section without known data, by using a preset interpolation method, and calculates the result of the second FFT unit ( 3643). The second FFT unit 3643 converts the input CIR into a frequency domain and outputs the converted CIR to the coefficient calculator 3644. The coefficient calculator 3644 calculates a frequency domain equalization coefficient that satisfies the condition of minimizing the mean square error using the CIR of the frequency domain and outputs the same to the coefficient selector 3660.

Since the configuration and operation of the second coefficient calculator 3650 are the same as those of the second coefficient calculator 3550 of FIG. 53, a detailed description thereof will be omitted.

The coefficient selector 3660 selects the equalization coefficient calculated by the first coefficient calculator 3640 when the input data is data of the A region, and updates the equalization coefficient updated by the second coefficient calculator 3650 when the data of the B and C regions is data. The coefficient is selected and output to the distortion compensator 3620.

FIG. 55 illustrates another embodiment of a channel equalizer for differentiating and applying a channel impulse response (CIR) according to areas A, B, and C when data groups are divided into the same structure as in FIG. 7A.

For example, in region A where known data are arranged at regular intervals, channel equalization is estimated using the known data, and channel equalization is performed. In the region B and C, the equalized data is performed. The channel equalization may be performed after estimating the CIR using the determined value of.

In an embodiment of the present invention, in the region A, a channel impulse response (CIR) is estimated using a least square method using the known data, and channel equalization is performed. In the C region, the channel equalization is performed after estimating the CIR using a least mean square (LMS) method. That is, in the B and C regions where periodic known data do not exist as in the A region, channel equalization cannot be performed in the same manner as the A region. Therefore, in the B and C regions, channel equalization is performed by estimating the CIR using the LMS method. To perform.

Referring to FIG. 55, an overlapping part 3701, a first fast fourier transform part 3702, a distortion compensating part 3703, an IFFT part 3704, a save part 3705, and a first CIR estimator 3706 , CIR interpolator 3707, determiner 3708, selector 3709, second CIR estimator 3710, selector 3711, second FFT unit 3712, and coefficient calculator 3713 It is composed. The distortion compensator 3703 may be any element that performs a complex multiplication role.

In FIG. 55 configured as described above, the equalizer input data is superimposed at a preset overlap ratio in the overlap unit 3701 and output to the first FFT unit 3702. The first FFT unit 3702 converts overlapping data in the time domain into overlapping data in the frequency domain through an FFT and is output to the distortion compensator 3703.

The distortion compensator 3703 complexly multiplies the equalization coefficient calculated by the coefficient operator 3713 to the overlapping data of the frequency domain output from the first FFT unit 3702, and outputs the overlapped output from the first FFT unit 3702. The channel distortion of the data is compensated and then output to the IFFT unit 3704. The IFFT unit 3704 IFFTs the overlapped data whose distortion of the channel is compensated, converts the data into a time domain, and outputs the converted data to the save unit 3705. The save unit 3705 extracts only valid data from the superimposed data in the channel equalized time domain, outputs the data for decoding, and outputs the same to the determiner 3708 for channel estimation.

The determiner 3708 selects a decision value closest to the equalized data among a plurality of decision values, for example, and outputs the selected decision value to the selector 3709. The selector 3709 may be configured as a multiplexer. The selector 3709 selects the determined value of the determiner 3708 in the general data section, and selects the known data in the known data section and outputs the known data to the second CIR estimator 3710.

Meanwhile, the first CIR estimator 3706 estimates the CIR using the data input during the known data interval and the known data and outputs the CIR to the CIR interpolator 3707. Here, the known data is reference known data generated during the known data section at the receiving side by an appointment of the transmitting / receiving side. In addition, the first CIR estimator 3706 estimates the CIR using data input during the field synchronization period and reference field synchronization data, and outputs the CIR to the CIR interpolator 3707. Here, the reference field synchronization data is reference field synchronization data generated on the receiving side by an appointment on the transmitting / receiving side.

의 행렬 연산을 하여 전송 채널의 임펄스 응답을 추정하는 방법이다.In this case, the first CIR estimator 3706 estimates the CIR by the LS method according to an embodiment. The LS estimation method obtains a cross correlation value p between known data transmitted through a channel and known data known to a receiver during a known data interval, and obtains an autocorrelation matrix R of the known data. Then remove the autocorrelation portion that exists in p that is the cross-correlation between the received data and the original data.

It is a method of estimating the impulse response of a transmission channel by performing a matrix operation of.

The CIR interpolator 3707 receives the CIR from the first CIR estimator 3706, outputs an estimated CIR in the known data section, and interpolates the CIR by a predetermined interpolation method in the section between the known data and the known data. Then output the interpolated CIR. In this case, the preset interpolation method is a method of estimating data at an unknown point using known data in a function. The simplest example is a linear interpolation method, which is the simplest of many interpolation methods. The present invention is not limited to the examples described above since the present invention may employ various other interpolation techniques in addition to the above methods.

That is, the CIR interpolator 3707 estimates the CIR of the section without known data by using a preset CIR by using a preset interpolation method and outputs the CIR to the selector 3711.

The second CIR estimator 3710 estimates the CIR using the equalizer input data and the output data of the selector 3709 and outputs the CIR to the selector 3711. At this time, the CIR is estimated by the LMS method according to an embodiment. The LMS estimation method will be described in detail later.

The selector 3711 selects the CIR output from the CIR interpolator 3707 in the area A, and selects the CIR output from the second CIR estimator 3710 in the B and C areas, thereby selecting a second FFT unit ( 3712). The second FFT unit 3712 converts the input CIR into a frequency domain and outputs the converted CIR to the coefficient calculator 3713. The coefficient calculator 3713 calculates an equalization coefficient by using the CIR of the input frequency domain and outputs the equalization coefficient to the distortion compensator 3703. In this embodiment, the coefficient calculator 3713 obtains an equalization coefficient of a frequency domain that minimizes a mean square error (MMSE) from the CIR of the frequency domain.

In this case, the second CIR estimator 3710 may use the CIR obtained in the A region as the initial CIR of the B and C regions. For example, the last CIR value of the A region may be used as the initial CIR value of the C region. This can shorten the convergence speed in the B and C areas.

The basic principle of estimating the CIR by the LMS method in the second CIR estimator 3710 is an adaptive filter to receive an output of an unknown transmission channel and minimize the difference between the output value of the channel and the output value of the adaptive filter. It is to update the coefficient value of. That is, the coefficient value of the adaptive filter is updated so that the equalizer input data and the output value of the adaptive filter (not shown) in the second CIR estimator 3710 are the same, and the filter coefficient is output to the CIR every FFT period.

를 순차적으로 지연시키는 지연기(T), 상기 각 지연기(T)의 해당 출력 데이터와 에러 데이터 e(n)를 곱하는 곱셈기, 및 상기 각 곱셈기의 해당 출력에 의해 계수가 갱신되는 계수 갱신부가 탭 수만큼 구비되어 구성된다. 설명의 편의를 위해 상기 탭 수만큼 구비되는 곱셈기들을 제1 곱셈부라 한다. 또한 상기 선택부(3709)의 출력 데이터 및 각 지연기(T)의 출력 데이터(마지막 지연기의 출력 데이터는 제외됨)를 각 계수 갱신부의 해당 출력 데이터와 곱하는 곱셈기가 탭 수만큼 더 구비되어 구성되며, 설명의 편의를 위해 상기 곱셈기들을 제2 곱셈부라 한다. 또한 상기 제2 곱셈부의 각 곱셈기의 출력 데이터를 모두 더하여 등화기 입력의 추정값

으로 출력하는 가산기와, 상기 가산기의 출력

과 등화기 입력 데이터 y(n)와의 차를 에러 데이터 e(n)로 출력하는 감산기를 더 포함하여 구성된다. Referring to FIG. 56, the second CIR estimator 3710 may output data of the selector 3709.

Delay delay T for sequentially delaying, a multiplier for multiplying the corresponding output data of the respective delayers T and the error data e (n), and a coefficient updating unit for updating coefficients by corresponding outputs of the respective multipliers. It is provided with a number. For convenience of description, multipliers provided by the number of taps are referred to as first multipliers. In addition, a multiplier for multiplying the output data of the selector 3709 and the output data of each delayer T (except the output data of the last delayer) with the corresponding output data of each coefficient updater is further provided by the number of taps. For convenience of description, the multipliers are called second multipliers. In addition, the estimated value of the equalizer input by adding up the output data of each multiplier of the second multiplier.

An adder for outputting the output of the adder

And a subtractor for outputting the difference from the equalizer input data y (n) as the error data e (n).

Referring to FIG. 56 configured as described above, the determined value of the equalized data is input to the first delay unit and the first multiplier of the second multiplier in the second CIR estimator 3710 in the known data section.

는 탭 수만큼 직렬 연결된 지연기(T)를 통해 순차적으로 지연된다. 상기 각 지연기의 출력 데이터와 에러 데이터 e(n)는 제1 곱셈부의 해당 곱셈기에서 곱해져 해당 계수 갱신부 내 계수를 갱신한다. 각 계수 갱신부에서 갱신된 계수는 제2 곱셈부의 해당 곱셈기에서 입력 데이터

및 마지막 지연기를 제외한 각 지연기의 출력 데이터와 곱해져 가산기로 입력된다. 상기 가산기는 상기 제2 곱셈부의 각 곱셈기의 출력 데이터를 모두 더하여 등화기 입력의 추정값

으로 감산기에 출력한다. 상기 감산기는 상기 추정값

과 등화기 입력 데이터 y(n)와의 차를 에러 데이터 e(n)로 하여 제1 곱셈부의 각 곱셈기로 출력한다. 이때 에러 데이터 e(n)는 지연기(T)를 통해 제1 곱셈부의 각 곱셈기로 출력된다.The input data

Delay is sequentially delayed through the serially connected retarder T by the number of taps. The output data of each delay unit and the error data e (n) are multiplied in the corresponding multiplier of the first multiplier to update the coefficients in the coefficient update unit. The coefficient updated in each coefficient updating unit is input data in the corresponding multiplier of the second multiplication unit.

And multiplied by the output data of each delayer except the last delayer and input to the adder. The adder adds all output data of each multiplier of the second multiplier to estimate an equalizer input value.

Output to the subtractor. The subtractor is the estimated value

The difference from the equalizer input data y (n) is used as the error data e (n) and output to each multiplier of the first multiplier. At this time, the error data e (n) is output to each multiplier of the first multiplier through the delay T.

The coefficient of the filter is continuously updated through the above-described process, and the output of each coefficient updating unit becomes the CIR output of the second CIR estimator 3710 for each FFT period.

Until now, the methods for obtaining CIR for channel equalization in each region in the data group described in the present invention are embodiments to aid the understanding of the present invention. It will not be limited to what is presented.

Block Decoder in Receiving System

On the other hand, data obtained by channel equalization in the equalizer 1003 and then input to the block decoder 1005 is data in which both block coding and trellis coding are performed on the transmitting side (for example, data in RS frames and signaling information data). ), The trellis decoding and the block decoding are performed in the reverse side of the transmitting side. If the trellis decoding is performed without the block encoding (for example, main service data), only the trellis decoding is performed.

The trellis decoded and block decoded data by the block decoder 1005 is output to the data deformatter 1006. That is, the block decoder 1005 removes known data, trellis initialization data, MPEG headers, and RS parity data added from an RS encoder / unstructured RS encoder or an unstructured RS encoder among data in the data group. The data is output to the data deformatter 1006. Here, data removal may be performed before block decoding, or may be performed during or after block decoding. If the transmitting side includes signaling information in the data group and transmits the signaling information, the signaling information is output to the data deformatter 1006.

Meanwhile, the trellis decoded data by the block decoder 1005 is output to the data deinterleaver 1009. In this case, the data that is trellis-decoded by the block decoder 1005 and output to the data deinterleaver 1009 may include not only main service data but also data in RS frames and signaling information. In addition, RS parity data added after the preprocessor 230 may be included in the data output to the data deinterleaver 1009.

In another embodiment, the block encoding is not performed at the transmitting side, and the data having only trellis encoding may be bypassed in the block decoder 1005 and output to the data deinterleaver 1009. In this case, a trellis decoder must be provided in front of the data deinterleaver 1009.

The block decoder 1005 outputs a hard decision value by performing Viterbi decoding on the input data, or outputting a hard decision value if the input data is data in which only the trellis encoding is performed without block encoding at the transmitting side. You can also hard determine the value and output the result.

The block decoder 1005 outputs a soft decision value with respect to the input data if the input data is data in which both block coding and trellis coding are performed at the transmitting side.

That is, if the input data is block encoding performed by the block processor 303 at the transmitting side and trellis encoding is performed by the trellis coding unit 256, the block decoder 1005 is configured to transmit the data. Conversely, trellis decoding and block decoding are performed. At this time, the block processor on the transmitting side can be seen as an external encoder, and the trellis encoder can be seen as an internal encoder.

In order to maximize the decoding performance of the outer code at the time of decoding the concatenated code, it is preferable to output the soft decision value from the decoder of the inner code.

FIG. 57 is a detailed block diagram illustrating an embodiment of a block decoder 1005 according to the present invention, and includes a feedback controller 4010, an input buffer 4011, a trellis decoder 4012, and a symbol-byte converter 4013. ), Outer block extractor 4014, feedback deformatter 4015, symbol deinterleaver 4016, outer symbol mapper 4017, symbol decoder 4018, internal symbol mapper ( An inner symbol mapper 4019, a symbol interleaver 4020, a feedback formatter 4021, and an output buffer 4022 may be included. Like the transmitting side, the trellis decoder 4012 can be viewed as an internal decoder, and the symbol decoder 4018 can be viewed as an external decoder.

The input buffer 4011 is a block coded mobile service data symbol (a symbol corresponding to signaling information, an RS parity data symbol added at the time of RS frame encoding, and CRC data) among symbol values that are channel equalized and output from the equalizer 1003. The symbol values are temporarily stored, and the stored symbol values are repeatedly output M times to the trellis decoder 4012 at the turbo block size TBL for turbo decoding.

The size of the input buffer 4011 is greater than or equal to the block size TBL for turbo decoding. The turbo block size TBL is greater than or equal to the block length BK of the symbol interleaver in the block processor. The input buffer 4011 may store and output the same for convenience when there is a symbol value in which some encoding is not performed among the block encoded symbol values.

In this case, since the input data of the input buffer 4011 should include symbol values of the block length BK interleaved in the symbol interleaver 403 at one time, the length of the TBL is greater than or equal to BK. M is a repetition number of turbo decoding predetermined by the feedback controller 4010. That is, the input buffer 4011 stores at least a symbol value of a block size TBL for turbo decoding, and the symbol values of the block size TBL for turbo decoding are repeated as many times as the turbo decoding process is performed. It is repeatedly output to the trellis decoder 4012.

In addition, the input buffer 4011 includes a mobile service data symbol (a symbol corresponding to signaling information, an RS parity data symbol added during RS frame encoding, and a CRC data symbol) among symbol values output by channel equalization from the equalizer 1003. Bypass does not store input that does not contain any value. That is, since the trellis decoding is performed only on the input symbol value of the section in which the repetitive turbo decoding is not performed, the input buffer 4011 does not perform the storing and repetitive output process on the input. 4012).

The storage, repetition, and output of the input buffer 4011 is controlled by the feedback controller 4010.

The trellis decoder 4012 includes a 12-way Trellis Coded Modulation (TCM) decoder to correspond to the 12-way trellis encoder of FIG. 22. The 12-way trellis decoding is performed on the input symbol value in a reverse process of the 12-way trellis encoder.

That is, the trellis decoder 4012 receives the output symbol value of the input buffer 4011 and the soft-decision value of the feedback formatter 4021 by TBL to perform TCM decoding of each symbol. do.

In this case, the soft determination values output from the feedback formatter 4021 are matched one-to-one with symbol positions corresponding to the TBL output from the input buffer 4011 by the control of the feedback controller 4010, and thus the trellis decoder ( 4012). That is, the symbol value output from the input buffer 4011 and the data decoded by turbo decoding are matched to the same position in the corresponding turbo block and output to the trellis decoder 4012. For example, if the turbo decoded data is the third symbol value in the turbo block, the turbo decoded data is matched with the third symbol value in the turbo block output from the input buffer 4011 and outputted to the trellis decoder 4012.

To this end, the feedback controller 4010 controls to store the corresponding turbo block data in the input buffer 4011 during recursive turbo decoding, and delays the soft decision value of the output symbol of the symbol interleaver 4020 (delay). For example, the LLR and the symbol value of the input buffer 4011 corresponding to the same position in the block of the output symbol are matched one-to-one so as to be input to the TCM decoder of the corresponding path. In this case, if the symbol value is not a block coded symbol, since it is not turbo decoded, null is input to a matching output position in the feedback formatter 4021.

After this process is performed for a predetermined number of iterations of turbo decoding, data of the next turbo block is output from the input buffer 4011 to repeat the turbo decoding process.

The output of the trellis decoder 4012 means the reliability of the transmission bits constituting each symbol. For example, since the input of the trellis encoder 256 on the transmitting side has two bits as one symbol, the log bit between the probability that the bit is '1' and the probability that the bit is '0' is higher than the log likelihood ratio (LLR). Output (bitwise output) can be done for and low bit respectively. The Log Likelihood Ratio (LLR) refers to a log value of a ratio between a probability value of 1 and a probability value of 0. Or outputs the logarithm ratio (LLR) of the probability values that two bits, i.e., a symbol is "00", "01", "10", or "11", for all four combinations (00,01,10,11) Symbol unit output). This is, after all, a soft decision indicating the reliability of the transmission bits of each symbol. As a decoding algorithm of each TCM decoder in the trellis decoder 4012, MAP (Maximum A posteriori Probability), SOVA (Soft-Out Viterbi Algorithm), and the like may be used.

The output of the trellis decoder 4012 is output to a symbol-byte converter 4013 and an external block extractor 4014.

The symbol-byte converter 4013 hard-decisions the soft decision value output by trellis decoding by the trellis decoder 4012, and then combines four symbols into one byte unit to decode the data. Output to interleaver 1009. That is, the symbol-byte converter 4013 performs a hard decision in bits on the soft decision value of the output symbol of the trellis decoder 4012. Therefore, data hard-determined by the symbol-byte converter 4013 and output in byte units include not only main service data but also mobile service data, known data, RS parity data, and MPEG header.

The outer block extractor 4014 may extract a mobile service data symbol (a symbol corresponding to signaling information, RS parity data added during RS frame encoding, and CRC data symbols) among soft determination values of the trellis decoder 4012. And the soft decision values corresponding to the control unit are output to the feedback deformatter 4015.

The feedback deformatter 4015 may perform an intermediate process (eg, a group formatter, a data deinterleaver, a packet formatter, and a packet multiplexing) in which an output symbol of the transmitting block processor 303 is input to the trellis encoder 256. The processing order of the soft decision value of the mobile service data symbol is reversed as a reverse process of the processing order change of the mobile service data symbol generated by the encoder, the RS encoder, and the data interleaver, and then output to the symbol deinterleaver 4016.

The symbol deinterleaver 4016 is a reverse process of symbol interleaving of the symbol interleaver 403 on the transmitting side. The symbol deinterleaver 4016 deinterleaves the soft decision value of the data symbols outputted after the order is changed by the feedback deformatter 4015. The block size used for deinterleaving in the symbol deinterleaver 4016 is equal to the interleaving size (ie, BK) of the actual symbol of the symbol interleaver (see FIG. 19) of the transmitting side, which is a turbo decoder trellis decoder. This is because it is made between the 4012 and the symbol decoder 4018.

Both the input and output of the symbol deinterleaver 4016 are soft decision values, and the deinterleaved soft decision values are output to an external symbol mapper 4017.

The operation of the external symbol mapper 4017 may vary depending on the configuration and code rate of the symbol encoder 402 on the transmitting side. For example, the external symbol mapper 4017 outputs the input data to the symbol decoder 4018 as it is data transmitted by being encoded by 1/2 of the symbol encoder 402. As another example, if the data is coded by the symbol encoder 402 and transmitted, the input data is converted to the symbol decoder 4018 according to the input format of the symbol decoder 4018.

The symbol decoder 4018 (that is, the external decoder) performs a symbol decoding on the output of the external symbol mapper 4017 as a reverse process of the symbol encoder 402 on the transmitting side. At this time, the symbol decoder 4018 outputs two soft determination values. One is a soft decision value (hereinafter referred to as a first soft decision value) that matches the output symbol of the symbol encoder 402 and the other is a soft decision value (hereinafter referred to as a second soft decision value) that matches the input bit of the symbol encoder 402. Soft judgment value). The first soft decision value represents an output symbol of the symbol encoder 402, that is, reliability of two bits, and constitutes a log ratio (LLR) between a probability of '1' and a probability of '0' of one bit. Outputs the log ratio (LLR) of the probability value for each of the upper and lower bits (bitwise output), or the probability that two bits will be "00", "01", "10", or "11". Symbol unit output). The first soft decision value is fed back to the trellis decoder 4012 through an internal symbol mapper 4019, a symbol interleaver 4020, and a feedback formatter 4021. The second soft decision value represents the reliability of the input bit of the symbol encoder 402 on the transmitting side, and is expressed as a log ratio (LLR) between a probability of '1' and a probability of '0' of one bit, thereby representing an external buffer ( 4022). As a decoding algorithm of the symbol decoder 4018, MAP (Maximum A posteriori Probability), SOVA (Soft-Out Viterbi Algorithm), and the like may be used.

The first soft decision value output from the symbol decoder 4018 is input to an internal symbol mapper 4019. The internal symbol mapper 4019 converts the first soft decision value according to the input format of the trellis decoder 4012 and outputs the converted soft signal to the symbol interleaver 4020. The operation of the internal symbol mapper 4019 may vary according to the structure and code rate of the symbol encoder 402 on the transmitting side.

Next, detailed operations of the outer symbol mapper 4017 and the inner symbol mapper 4019 when the transmitting symbol encoder 402 operates as a quarter encoder will be described with reference to FIGS. 17A to 17C.

In an embodiment, the symbol encoder is configured as shown in FIG. 17A, and the fourth outer encoder 411 encodes one bit U to output four bits u0, u1, u2, and u3. Assume that 4 bits, that is, 2 symbols, are transmitted twice by one symbol through the parallel / serial converter 412. For convenience of explanation, the first output symbol will be called an odd symbol, and the second output symbol will be called an even symbol.

In this case, if the input / output unit of the external symbol mapper 4017 and the internal symbol mapper 4019 is a symbol unit, there are 16 soft decision values to be output in symbol units in the external symbol mapper 4017 (2 ⁴ = 16). to be. Of the 16 soft decision values (2 ⁴ = 16) to be output from the external symbol mapper 4017, for example, s = (1, 0, 0, 1) soft decision value is the input odd symbol m _0. The soft decision value of = (1, 0) and the soft decision value of even symbol m ₁ = (0, 1) are calculated and added to the symbol decoder 4018.

In addition, the soft decision values to be output in symbol units are 4 ((2 ² = 4) in the internal symbol mapper 4019. Of the four outputs of the internal symbol mapper 4019, for example, an odd symbol m ₀ = The soft decision value of (1, 1) is obtained by taking the largest value of the soft decision values of the output symbols s = (1, 1, X, X) of the symbol decoder 4018. The even symbol m ₀ = ( The soft decision value of 0, 0) is obtained by taking the largest value among the soft decision values of the output symbols s = (X, X, 0, 0) of the symbol decoder 4018. Here, 'X' is 1, Any one of 0. The output of the inner symbol mapper 4019 is provided to a symbol interleaver 4020.

On the other hand, if the input / output units of the external symbol mapper 4017 and the internal symbol mapper 4019 are in bit units, there are four soft decision values to be output in bit units in the external symbol mapper 4017.

That is, in the external symbol mapper 4017, a soft decision value of two odd input bits (that is, each soft decision value for the upper and lower bits constituting the odd input symbol) and two even input bits are soft decision. A value (that is, each soft decision value for the upper and lower bits constituting the even input symbol) is simultaneously output to the symbol decoder 4018. In addition, in the internal symbol mapper 4019, soft decision values of two odd output bits (that is, high order bits constituting the odd output symbols of the symbol decoder 4018) for four inputs provided by the symbol decoder 4018. And each soft decision value for the lower bit) and the soft decision value for the two even output bits (i.e., each soft decision value for the upper and lower bits constituting the even output symbol of the symbol decoder 4018). The code is divided and output to the symbol interleaver 4020.

That is, when symbol encoding is performed as shown in FIG. 17A, the LLRs for the 16 symbols may be output as the first soft decision value after receiving the LLRs for the 16 symbols. Alternatively, the LLR for 4 bits may be output as the first soft decision value after receiving the LLR for 4 bits.

In another embodiment, the symbol encoder is configured as shown in FIG. 17B, and the half outer encoder 421 is encoded for one bit U to output two bits u0 and u1, and the repeater 422 is used. Let's say that we transmit two bits, i.e., a symbol twice, over and over. For convenience of explanation, the first output symbol will be called an odd symbol, and the second output symbol will be called an even symbol.

In this case, if the input / output unit of the external symbol mapper 4017 and the internal symbol mapper 4019 is a symbol unit, there are four soft decision values to be output in symbol units in the external symbol mapper 4017 (2 ² = 4). to be. Of the four soft decision values, for example, the soft decision value of s = (1, 0) is equal to the soft decision value of the input odd symbol m ₀ = (1, 0) and the even symbol m ₁ = (1, 0). Is calculated by summing up the soft decision value of &lt; RTI ID = 0.0 &gt;,&lt; / RTI &gt; There are also four soft determination values (2 ² = 4) to be output from the internal symbol mapper 4019. Among the four soft determination values, for example, odd symbols m ₀ = (1, 1) and even symbols m The soft decision value of ₁ = (1, 1) becomes the soft decision value of the input symbol s = (1, 1) of the symbol decoder 4018, and this soft decision value is output to the symbol interleaver 4020.

On the other hand, if the input / output units of the external symbol mapper 4017 and the internal symbol mapper 4019 are in bit units, the soft decision values to be output by the external symbol mapper 4017 are two, that is, high and low bits. Each soft determination value. The soft decision value for the upper bits is obtained by adding the soft decision value for the upper bits of the odd input and the soft decision value for the upper bits of the even input. The soft decision value for the lower bits is obtained by adding the soft decision value for the lower bits of the odd input and the soft decision value for the lower bits of the even input.

The internal symbol mapper 4019 receives the soft decision value for the upper bits and the soft decision value for the lower bits from the symbol decoder 4018, so that the soft decision value of the two odd output bits (ie, the symbol decoder 4018) is input. Each of the soft decision values for the upper bits and the lower bits to be output, and the soft decision values of the two odd output bits are repeated and output as the soft decision values of the two even output bits.

In another embodiment, the symbol encoder is configured as shown in FIG. 17C, and the repeater 431 repeats the input bit once, and the 1/2 outer encoder 432 repeats the 1/2 encoding for each input bit. Assume that two bits (u0, u1), that is, one symbol is transmitted twice. This case is a case where 1/2 encoding is repeatedly performed for one bit in the symbol encoder. For convenience of explanation, the first output symbol will be called an odd symbol, and the second output symbol will be called an even symbol.

In this case, if the input / output unit of the external symbol mapper 4017 and the internal symbol mapper 4019 is a symbol unit, the external symbol mapper 4017 transfers the output of the symbol deinterleaver 4016 to the symbol decoder 4018 as it is. The internal symbol buffer 4019 transfers the output of the symbol decoder 4018 to the symbol deinterleaver 4020 as it is.

In addition, even when the input / output unit of the external symbol mapper 4017 and the internal symbol mapper 4019 is a bit unit, the external symbol mapper 4017 uses the symbol decoder 4018 as it is. The internal symbol buffer 4019 transfers the output of the symbol decoder 4018 to the symbol deinterleaver 4020 as it is. In the case of FIG. 17C, since the input of the 1/2 external encoder 432 is repeated by the repeater 431, the soft decision value for the two symbols should be determined and output from the output of the block decoder.

That is, when symbol encoding is performed as shown in FIGS. 17B and 17C, the LLRs for the four symbols may be output as the first soft decision value after receiving the LLRs for the four symbols. Alternatively, the LLR for 2 bits may be output as a first soft decision value after receiving the LLR for 2 bits.

The symbol interleaver 4020 performs symbol interleaving on the first soft decision value output from the internal symbol mapper 4019 and outputs the result to the feedback formatter 4021. The output of the symbol interleaver 4020 also becomes a soft determination value.

The feedback formatter 4021 is an intermediate process (eg, a group formatter, a data deinterleaver, a packet formatter, and a packet multiplexer) in which an output symbol of the transmitting block processor 303 is input to the trellis encoder 256. And an order of the output values of the symbol interleaver 4020 according to a change in the order of processing of symbols generated by the RS encoder and the data interleaver, and outputs them to the trellis encoder 4012. The soft decision values output from the symbol interleaver 4020 are matched one-to-one with the positions of the mobile service data symbols corresponding to the TBLs output from the input buffer 4011 and input to the trellis encoder 4012. In this case, since the main service data symbol, the RS parity symbol of the main service data, the known data symbol, etc. are not the mobile service data symbols, the feedback formatter 4021 inserts null data at the corresponding position, and thus the trellis encoder 4012. Will output In addition, since every time the TBL-sized symbols are turbo decoded, the feedback formatter 4021 is controlled by the feedback controller 4010 since there is no value returned from the symbol interleaver 4020 at the first decoding start. Null data is inserted at all symbol positions including the data symbol and output to the trellis decoder 4012.

The output buffer 4022 receives the second soft decision value from the symbol decoder 4018 under the control of the feedback controller 4010, temporarily stores the second soft decision value, and outputs the second soft decision value to the data deformatter 1006. For example, the output buffer 4022 is overwriting the second soft decision value of the symbol decoder 4018 until M turbo decoding is performed, and then M turbo decoding is performed on one TBL. If so, the second soft decision value at that time is output to the data formatter 1006.

The feedback controller 4010 controls the number of times of turbo decoding and turbo decoding repetition of the entire block decoder as shown in FIG. 57.

That is, after turbo decoding is performed for a preset number of repetitions, the second soft decision value of the symbol decoder 4018 is output to the data formatter 1006 through the output buffer 4022, and block decoding for one turbo block is performed. The process is complete. This is referred to as a regressive turbo decoding process for convenience of description in the present invention.

At this time, the number of recursive turbo decoding between the trellis decoder 4012 and the symbol decoder 4018 may be defined in consideration of hardware complexity and error correction performance. It has the disadvantage of being complicated.

Meanwhile, the data deinterleaver 1009, the RS decoder 1010, and the derandomizer 1011 are blocks necessary for receiving main service data, and may not be necessary in a reception system structure for receiving only mobile service data. have.

The data deinterleaver 1009 deinterleaves the data output from the block decoder 1005 as an inverse process of the data interleaver on the transmitting side and outputs the data to the RS decoder 1010. The data input to the data deinterleaver 1009 includes not only main service data but also mobile service data, known data, RS parity, MPEG header, and the like.

The RS decoder 1010 performs systematic RS decoding on the deinterleaved data and outputs the deserializer 1011.

The derandomizer 1011 receives the output of the RS decoder 1010, generates pseudo random bytes that are identical to the transmitter's renderer, bitwise XORs them, and then converts the MPEG sync bytes to every packet. Insert it before and output 188 bytes by packet.

On the other hand, the data output from the block decoder 1005 to the data deformatter 1006 is in the form of a data group. In this case, since the configuration of the input data group is known in the data deformatter 1006, the signaling information having system information and the mobile service data are distinguished from each other in the data group. The divided signaling information is transmitted to a block that processes the signaling information (to be described in FIG. 60), and the mobile service data is output to the RS frame decoder 1007.

Within the receiving system RS  Frame decoder

That is, the RS frame decoder 1007 receives only RS coded and / or CRC coded mobile service data from the data deformatter 1006.

The RS frame decoder 1007 performs an inverse process in the RS frame encoder of the transmission system to correct errors in the RS frame, and then removes one byte of MPEG synchronization from the RS frame encoding process in the error corrected mobile service data packet. The bytes are added and output to the derandomizer 1008.

58 illustrates a process of collecting a plurality of data groups, for example, 18 data groups to form an RS frame and an RS frame reliability map, and inverse row mixing in units of super frames as a reverse process of a transmission system. After performing the process, the process is further divided into an inverse row-mixed RS frame and an RS frame credit map.

That is, the RS frame decoder 1007 collects the received mobile service data to form an RS frame. The mobile service data is RS-coded in units of RS frames in a transmission system and rawly mixed in units of super frames. In this case, for example, CRC encoding may be performed or may be omitted.

If it is assumed that an RS frame having a size of (N + 2) * (187 + P) bytes in the transmission system is divided into M (for example, 18) data groups and transmitted, the receiver system also has a diagram of FIG. 58 (a). Mobile service data of each data group is gathered as follows to form an RS frame of size (N + 2) * (187 + P) bytes.

At this time, if a dummy byte is added and transmitted to at least one data group constituting the RS frame, the dummy byte is removed and an RS frame and an RS frame credit map are configured. For example, if K dummy bytes are added as shown in FIG. 14, the RS frames and the RS frame credit map are configured after the K dummy bytes are removed.

In addition, assuming that the RS frames are divided into 18 data groups and transmitted in one burst on period, the receiving system also configures an RS frame by collecting mobile service data of 18 data groups in the burst on period.

In this case, assuming that the block decoder 1005 outputs a decoding result as a soft decision value, the RS frame decoder 1007 may determine 0 and 1 of a corresponding bit as a sign of the soft decision value. The eight are gathered together to form one byte. Performing this process on all of the soft decision values of the 18 data groups in one burst, it is possible to construct an RS frame of size (N + 2) * (187 + P) bytes.

In addition, the present invention not only uses the soft decision value to construct an RS frame, but also to construct a reliability map.

The credit map indicates whether or not the corresponding byte formed by collecting eight bits determined by the sign of the soft decision value is reliable.

In an embodiment, when the absolute value of the soft determination value exceeds a preset threshold, the corresponding bit value determined by the sign of the soft determination value is determined to be reliable, and when it is not exceeded, it is determined to be unreliable. Then, in the case where it is determined that even one bit in one byte composed of eight bits determined by the sign of the soft decision value is unreliable, the credit map indicates that the byte is unreliable. Here, one bit is an embodiment, and when a plurality of, for example, four or more bits are determined to be unreliable, it may indicate that the corresponding byte is not reliable in the credit map.

On the contrary, when all bits in one byte are determined to be reliable, that is, when the absolute value of the soft decision value of all bits of one byte exceeds a preset threshold, the corresponding map is marked as reliable. Similarly, if a plurality of bits in one byte, for example, four or more bits are determined to be reliable, the credit map indicates that the bytes are reliable.

The above-described numerical values are merely examples, and the scope of the present invention is not limited to the numerical values.

The configuration of the RS frame and the configuration of the credit map using the soft decision value can be performed simultaneously. At this time, the credit information in the credit map corresponds 1: 1 to each byte in the RS frame. For example, if one RS frame has a (N + 2) * (187 + P) byte size, the credit map has a (N + 2) * (187 + P) bit size. 58 (a ') and (b') show a process of forming a credit map according to the present invention.

At this time, the RS frame of FIG. 58 (b) and the RS frame credit map of (b ') are row-mixed in units of super frames (see FIG. 6). Accordingly, after collecting the RS frame and the RS frame credit map to configure the super frame and the super frame credit map, as shown in (c) and (c ') of FIG. De-permutation is performed in units of frames.

When inverse row mixing in the super frame unit is performed as described above, RS frames having a size of (N + 2) * (187 + P) bytes and (N + 2) * as shown in (d) and (d ') of FIG. Separated by a (187 + P) bit size RS frame credit map.

Subsequently, error correction is performed on the divided RS frames using RS frame credit map information.

59 shows an embodiment of an error correction decoding process according to the present invention.

59 is a diagram illustrating an error correction process when both RS encoding and CRC encoding are performed on an RS frame in a transmission system.

Next, the error correction process illustrated in FIG. 59 will be described in detail.

That is, as shown in (a) and (a ') of FIG. 59, an RS frame having a (N + 2) * (187 + P) byte size and an RS frame credit map having a (N + 2) * (187 + P) bit size If configured, CRC syndrome check is performed on this RS frame to check whether an error occurs in each row. Subsequently, as shown in (b) of FIG. 59, an RS frame having a size of N * (187 + P) bytes is formed by removing the 2-byte CRC checksum, and an error flag corresponding to each row indicates whether an error occurs. Similarly, since the portion of the credit map corresponding to the CRC checksum is not utilized, this portion is removed, leaving only N * (187 + P) credit information as shown in FIG. 59 (b ').

After the CRC syndrome check is performed as described above, RS decoding is performed in the column direction. In this case, RS erasure correction may be performed according to the number of CRC error flags. That is, as shown in (c) of FIG. 59, the CRC error flag corresponding to each row in the RS frame is checked, so that the maximum number of RS erasure corrections can be performed when the number of rows having an error is performed in the RS direction column decoding. Determine if it is less than or equal to the number of errors. The maximum error number is a parity number P inserted during RS encoding.

In an embodiment of the present invention, it is assumed that the parity number P added to each column is 48.

In this case, if the number of rows having a CRC error is less than or equal to the maximum number of errors that can be corrected by RS erasure decoding (48 according to the embodiment), as shown in (d) of FIG. (235,187) -RS erasure decoding is performed in the column direction on an RS frame having 235 N byte rows, and as shown in (e) of FIG. 59, 48 bytes of parity data added to the end of each column are removed.

However, if the number of rows having a CRC error is larger than the maximum number of errors that can be corrected by RS erasure decoding (that is, 48), RS erasure decoding cannot be performed.

In this case, error correction may be performed through general RS decoding. In addition, the present invention can further improve error correction capability by using a credit map generated when constructing an RS frame from the soft decision value.

That is, in the RS frame decoder, the absolute value of the soft decision value of the block decoder 1005 is compared with a preset threshold to determine the credit of the bit value determined by the sign of the soft decision value. Credit information for the corresponding byte formed by collecting eight bits determined by the sign of the soft decision value was displayed on the credit map.

Accordingly, the present invention does not assume that all bytes of a row have an error even if it is determined that there is a CRC error in the CRC syndrome check of a specific row as shown in (c) of FIG. Set the error to only those bytes that are considered unreliable. That is, only the bytes determined to be unreliable in the credit information of the credit map regardless of the CRC error of the corresponding row are set as erasure points.

Alternatively, the CRC syndrome check determines that there is a CRC error in the row, and sets an error only for bytes determined that the credit information of the credit map is unreliable. That is, only a byte having a CRC error in a corresponding row and determined to be unreliable in credit information of a credit map is set as an erasure point.

Then, if the number of error points in each column is less than or equal to the maximum number of errors that can be corrected by RS erasure decoding (that is, 48), RS erasure decoding is performed on the column. On the contrary, if the number of error points is larger than the maximum number that can be modified by RS erasure decoding (that is, 48), general RS decoding is performed on the column.

In other words, if the number of rows with CRC errors is greater than the maximum number of errors that can be corrected by RS erasure decoding (for example, 48), then the corresponding columns in accordance with the number of erasure points in the column determined by the credit information of the credit map RS erasure decoding is performed or general RS decoding is performed.

For example, the number of rows having a CRC error in the RS frame is greater than 48, and the number of erasure points determined by the credit information of the credit map is 40 in the first column and 50 in the second column. Suppose Then, (235,187) -RS erasure decoding is performed on the first column, and (235,187) -RS decoding is performed on the second column.

When error correction decoding is performed in all column directions in the RS frame by performing the above process, as shown in (e) of FIG. 59, 48 bytes of parity data added to the end of each column are removed.

As described above, in the present invention, even if the total number of CRC errors corresponding to each row in the RS frame is larger than the maximum error number that can be corrected by RS erasure decoding, the credit information of the corresponding credit map of the corresponding column is determined when the error correction decoding of the specific column is performed. Therefore, if the number of bytes with low credibility is equal to or smaller than the maximum error number correctable by RS erasure decoding, RS erasure decoding may be performed on the column.

Here, the difference between general RS decoding and RS erasure decoding is the number of correctable errors. That is, if general RS decoding is performed, errors can be corrected by the number (for example, 24) corresponding to (number of parity) / 2 inserted in the RS encoding process. If RS erasure decoding is performed, RS encoding process is performed. An error may be corrected by the number of parities inserted (e.g., 48).

After the error correction decoding is performed as described above, as shown in (e) of FIG. 59, an RS frame having 187 N-byte rows (ie, packets) can be obtained. RS frames of size N * 187 bytes are output in the order of N 187 bytes in size, and in this case, as shown in (f) of FIG. In addition, the mobile service data packet in units of 188 bytes is output.

The RS frame-decoded mobile service data as described above is output to the data derandomizer 1008. The de-randomizer 1008 performs de-randomization corresponding to the reverse process of the renderer of the transmission system and outputs the received mobile service data, thereby obtaining mobile service data transmitted from the transmission system.

SCCC mode  Detect and Burst On / off  Control

60 is a view showing another example of a receiving system of the present invention. Referring to FIG. 60, the operation of the illustrated reception system will be described. 60 includes the block illustrated in FIG. 30, and a detailed description of the block function described in FIG. 30 will be omitted. The field synchronization area, the known data area and the mobile service data area illustrated in FIGS. 8 and 9 may include signaling information, and the signaling information may convey various transmission parameters.

The demodulator 1002 outputs known data including the field sync area or the transmission parameter to the transmission parameter decoder (Tx parameter detecter / parser) 1013. The equalizer 1003 may output the channel compensated value of the known data including the field sync area or the transmission parameter to the transmission parameter decoder 1013. The transmission parameter decoder 1013 may detect the SCCC mode information from the data output by the equalizer 1003. When the transmission parameter decoder 1013 outputs the SCCC mode information to the block decoder 1005 and the RS frame decoder 1007, the block decoder 1005 performs block decoding on the mobile service data according to the detected SCCC mode. Can be done. The data deformatter 1006 may distinguish RS-coded signaling information and RS frame-coded mobile service data from the output of the block decoder 1005 and output them to the transmission parameter decoder 1013 and the RS frame decoder 1007, respectively. have.

The transmission parameter decoder 1013 may receive and decode transmission parameters from the demodulator 1002, the equalizer 1003, the known data detector 1004, and the data deformatter 1006, respectively. For example, the transmission parameter decoder 1013 may obtain the known data position information from the known data detector 1004 and detect the SCCC mode from the demodulator 1002 or the equalizer 1003 output signal, which may be used as a block decoder ( 1005) and the RS frame decoder 1007. An example in which the transmission parameter decoder 1013 detects the SCCC mode is described in detail with reference to FIG. 62.

The block decoder 1005 may perform an error correction decoding process of the received data according to the SCCC mode. The data deformatter 1006 divides the data constituting the RS frame and the data including the transmission parameters from the output of the block decoder 1005 and outputs the data to the RS frame decoder 1007 and the transmission parameter decoder 1013, respectively. The RS frame decoder 1007 error corrects and decodes the data received from the block decoder 1005 in units of RS frames, and outputs mobile service data to the derandomizer 1008. The transmission parameter decoding unit 1013 may error correct decoding (for example, RS decoding) data received from the block decoder 1005 to detect transmission parameters other than the SCCC mode. The transmission parameter detected by the transmission parameter decoder 1013 from the output of the block decoder 1005 includes a service identifier, an RS mode for the A / B area of the frame, an RS mode for the C area, a size of a super frame, and an RS frame. At least one of location information (PFI) occupied in the super frame, burst size (BS), index of data group (GI), and time to next burst (TNB) information may be included.

The transmission parameter decoding unit 1013 stores information about the burst (for example, information about the burst size (BS), the index of the data group (GI), the time until the next burst (TNB), etc.) of the detected transmission parameter. It can output to the known data detector 1004. On the other hand, the known data detector 1004 may output the information on the burst section to the burst control unit 5000 using the information on the burst. That is, the known data detector 1004 detects the position of the known data in the transmission frame while the transmission frame is received, and outputs the known sequence position indicator to the demodulator 1002 and the equalizer 1003. Can be. In addition, the known data detector 1004 may estimate the initial frequency offset and output the estimated frequency offset to the carrier recovery unit in the demodulator 1002. The known data detector 1004 acquires frame synchronization and transmits group valid indicators and burst valid indicators to the burst control unit 5000. Then, the burst control unit 5000 may control all the powers of the function blocks included in the dotted lines among the function blocks. Accordingly, the broadcast receiving system can reduce power consumption even when receiving a broadcast signal while moving.

There can be multiple data groups in one burst period. For data groups in the same burst period, various transmission parameters (for example, RS mode for the A / B area of a frame, RS mode for the C area, and super The size of the frame, the location information (PFI) occupied by the RS frame in the super frame, and the burst size (BS) may have the same value. When taking data having the same value, when there are a plurality of data groups in the same burst, there may be a variety of ways to decode and use the transmission parameters of the groups in the burst. For example, there may be a scheme of decoding the transmission parameters of all data groups in one burst period and using the decoded transmission parameters only when each transmission parameter is successfully decoded. Or, if the decoding of the transmission parameter included in one data group of one burst period is successful, it is determined that the transmission parameter having the same value is transmitted for all data groups of the burst and uses the decoded transmission parameter. There may be a way. When using a transmission parameter, a temporary error may occur in the transmission parameter due to channel distortion, etc., and if the error count of the transmission parameter for each data group exceeds the set reference value, the previously decoded transmission parameter is used. It may be. Alternatively, when the number of errors for the transmission parameter detection exceeds the set reference value, if a new transmission parameter is successfully detected, there may be a way to use it.

FIG. 61 is a diagram illustrating a transmission parameter detection process by the transmission parameter decoder 1013 of the broadcast reception system described with reference to FIG. 60. In the example of Fig. 61, the mode detector 5011 in the transmission parameter is detected by the equalizer and the SCCC mode is detected and output to the block decoder and the RS frame decoder. An example in which the mode detector 5011 detects the SCCC mode will be described in detail with reference to FIG. 62. Meanwhile, the signaling RS decoder 5013 may perform RS decoding on RS coded data received from a block decoder (or from a data deformatter) to obtain a transmission parameter. The transmission parameters include a service identifier, an RS mode of an A / B area, an RS mode of an area C, a super frame size, position information (PFI) in a super frame of an RS frame, a burst size, a group index (GI), and a next burst. Information of at least one of the time TNB (or burst period) can be obtained. The transmission parameter detected by the signaling RS decoder 5013 includes information on a data group unit to which the transmission parameter belongs. The information on the group index GI of the data group to which the parameter belongs among the transmission parameters and the time TNB (or burst period BP) until the next burst may be updated and transmitted for each data group. In addition, the RS mode obtained by the signaling RS decoder 5013 may be output to the RS frame decoder so that error correction decoding may be performed on the RS frame of the mobile service data.

62 discloses an example in which the transmission parameter decoder detects the SCCC mode. The transmission parameter decoder may receive known data in which the SCCC mode is set from the demodulator and the equalizer. The data point controller determines a known data position and controls a symbol for a section in which signaling information is set to be output to the pattern correlators 5120a, b,..., N. Each pattern correlator 5120 may calculate and output a correlation value in a set data section. The maximum value determiner 5130 receives the output of each pattern correlator 5120 and determines the signal pattern of the pattern correlator 5120 having the maximum correlation value as known data for the SCCC mode set by the transmitter. The SCCC mode determined by the maximum value determiner 5130 may be output to the block decoder 1005 or the RS frame decoder 1007.

63 shows an example in which the known data detector 1004 outputs group valid information, that is, group valid identifier. In FIG. 63, when a partial correlation value of a broadcast signal is checked at a cycle of a counter, a peak value of the partial correlation value may appear at a position (denoted as a group) of a data group including known data among broadcast signals. The known data detector 1004 may output a group valid indicator for the location where the partial correlation value occurs.

64 shows an example in which the known data detector 1004 outputs burst valid information, that is, burst valid identifier. The known data detector 1004 can obtain burst information, for example, burst information (30 fields in the example of FIG. 64) and burst length information (18 fields in the example of FIG. 64) from the signaling information. . In the data group that is the data section including the mobile service data, partial correlation values are periodically generated as illustrated in FIG. 63. Accordingly, the known data detector 1004 may output burst valid information according to the position information at which the peak value of the partial correlation value is generated and the position information at the end.

The burst control unit 5000 may receive the group valid information and the burst valid information and control the power of the broadcast receiving system on / off so that only the signal of the mobile service data section including the program desired by the user can be processed. When the broadcast reception system intends to receive only mobile service data, only the data group of the mobile service included in the burst may be regarded as valid data, and other data may not be received. The burst control unit 5000 may turn the power on / off using a group valid indicator generated while the data of the mobile service data group is processed, even within the burst period.

65 is a diagram illustrating a comparison of an actual on / off time and a burst period. In FIG. 65, (a) indicates a data reception interval according to a burst valid indicator and a group valid indicator. The broadcast receiving system is powered on at any time (set-up time) before the burst start time or before the start of the data group, and after a certain time (hold time; at the end of the burst or at the end of the data group). power off at hold time). The setup time and hold time can be arbitrarily adjusted as the case may be.

66 is a block diagram illustrating a reception system according to an embodiment of the present invention, and the demodulation unit of FIG. 30 may be applied.

The receiving system of FIG. 66 includes a tuner 6001, a demodulating unit 6002, a demultiplexer 6003, an audio decoder 6004, a video decoder 6005, a native TV application manager 6006, and a channel manager. 6007, channel map 6008, first storage 6009, SI and / or data decoder 6010, second storage 6011, system manager 6012, data broadcast application manager 6013, storage The controller may include a storage controller 6014, a third storage unit 6015, and a GPS module 6020. The first storage portion 6009 is a nonvolatile memory (NVRAM) (or flash memory). The third storage unit 6015 is a mass storage device such as a hard disk drive (HDD) and a memory chip.

The tuner 6001 tunes the frequency of a specific channel through any one of an antenna, a cable, and a satellite to down-convert to an intermediate frequency (IF) signal and outputs the demodulator 6002. At this time, the tuner 6001 is controlled by the channel manager 6007, and also reports the result and strength of the broadcast signal of the channel being tuned to the channel manager 6007. The data received at the frequency of the specific channel includes main data, mobile service data, table data for decoding of the main data and mobile service data.

In the present embodiment, audio data and video data for mobile broadcasting may be applied as mobile service data. Such audio data and video data may be compressed by various encoders and transmitted from broadcasting stations. In this case, video and audio decoders 6004 and 6005 will be provided in the receiver to correspond to the corresponding encoders used for compression, and decoding in each decoder 6004 and 6005 is performed to provide video and audio to the user. will be. Examples of code / decoding schemes for audio data include AC 3, MPEG 2 AUDIO, MPEG 4 AUDIO, AAC, AAC +, HE AAC, AAC SBR, MPEG-Surround, BSAC, and code / decoding for video data. Schemes include MPEG 2 VIDEO, MPEG 4 VIDEO, H.264, SVC, VC-1 and the like.

According to the exemplary embodiment, data for a data service, for example, data for a Java application, data for an HTML application, and data for XML, may be used as mobile service data. The data for this data service can be a Java class file for a Java application or a directory file indicating the location of these files. It can also be an audio file or a video file used in each application.

The data services include weather services, transportation services, securities services, viewer participation quiz program, real-time polls, interactive educational broadcasts, game services, drama plots, characters, background music, shooting locations, information services, sports, etc. It may be a service for providing information on the past game history of the player, the profile and the performance of the player, product information and orders for this, information providing service for the program by medium, time, or subject, but the present invention Is not limited to this.

In some embodiments, the mobile service data may be meta data. For example, the metadata is described in XML and transmitted through the DSM-CC protocol.

The demodulator 6002 performs VSB demodulation, channel equalization, etc. on the signal output from the tuner 6001, divides the data into main data and mobile service data, and outputs the data in TS packet units. The demodulator 6002 will be an example of FIG. 30 described above. However, this is only one embodiment and the scope of the present invention is not limited thereto.

In the present invention, only the mobile service data packet output from the demodulator 6002 is input to the demultiplexer 6003 according to an embodiment. In this case the main data packet is input to another demultiplexer (not shown) which processes the main data packet. At this time, the storage control unit 6014 is also connected to the demultiplexer for processing the main data packet to store the main data. In addition, one demultiplexer may be designed to perform demultiplexing not only for mobile service data packets but also for main data packets.

The storage controller 6014 interfaces with the demultiplexer 6003 to control instant recording, scheduled recording, time shift, and the like of the mobile service data and / or main data. For example, when any one of instant recording, scheduled recording, and time shift is set in the reception system of FIG. 66, the corresponding mobile service data and / or main data input to the demultiplexer 6003 are controlled by the storage controller 6014. By the third storage unit 6015. The third storage unit 6015 may be divided into a temporary storage area for a time shift function and / or a permanent storage area for permanently storing data according to a user selection.

When the data stored in the third storage unit 6015 is required to be reproduced, the storage control unit 6014 reads out the data stored in the third storage unit 6015 to decode the corresponding demultiplexer (eg, a mobile service). Data is output to the demultiplexer 6003 of FIG.

In this case, since the storage capacity of the third storage unit 6015 is limited, storing the mobile service data and / or main data compressed and encoded and input in the third storage unit 6015 as it is for the efficiency of the storage capacity. An embodiment of the present invention. In this case, the data read from the third storage unit 6015 according to the reproduction command is input to the corresponding decoder through the demultiplexer and restored to the original state.

In addition, the storage control unit 6014 may play, fast forward, rewind, slow motion, slow motion of data stored in the third storage unit 6015 or currently buffered. Instant replay can be controlled. Here, the instant replay is a function for repeatedly watching a scene to be watched again, and instant replay may be performed in association with a time shift function as well as stored data.

The storage control unit 6014 may compress and encode the input data in the third storage unit 6015 when the input data is an analog form, for example, a transmission scheme is NTSC, PAL, or the like.

To this end, the storage controller 6014 may include an encoder, and the encoder may be implemented by at least one of software, middleware, and hardware. The encoder may use an MPEG encoder in one embodiment. The encoder may be provided outside the storage controller 6014.

Meanwhile, the storage control unit 6014 scrambles the input data to prevent illegal copying when the input data is stored in the third storage unit 6015 so that the third storage unit 6015 is scrambled. You can also save to). In this case, the storage controller 6014 may refer to a scramble algorithm for scrambled data stored in the third storage unit 6015 and data read out from the third storage unit 6015 as descramble (or decryption). May include a descramble algorithm. As the method of scramble, a method of modifying data to be scrambled using an arbitrary key (for example, a control word) or mixing a signal itself may be used.

The demultiplexer 6003 receives real time data output from the demodulator 6002 or data read from the third storage unit 6015 and performs demultiplexing. According to an embodiment of the present invention, the demultiplexer 6003 performs demultiplexing on a mobile service data packet.

However, according to the exemplary embodiment, the main data as well as the mobile service data may be demultiplexer 6003, audio decoder 6004, video decoder 6005, native TV application manager 6006, channel manager 6007, channel map ( 6008, the first storage unit 6009, the SI and / or data decoder 6010, the second storage unit 6011, the system manager 6012, the data transmission application manager 6013, and the storage controller. 6014, the third storage unit 6015, and the GPS module 6020 may be used to provide various services to the user.

The demultiplexer 6003 demultiplexes a mobile service data and a system information (SI) table from mobile service data packets input by the control of the SI and / or data decoder 6010. do. The demultiplexed mobile service data and the SI tables are output to the SI and / or data decoder 6010 in the form of sections. In this case, the mobile service data input to the SI and / or data decoder 6010 may be preferably data for data service.

System information is required to extract and decode mobile service data in a channel through which the mobile service data is transmitted. Such system information is sometimes called service information in some cases. The system information may include channel information, event information, and the like.

In the embodiment of the present invention, PSI / PSIP (Program Specific Information / Program and System Information Protocol) is applied as the system information, but the present invention is not limited thereto. That is, a protocol for transmitting system information in a table format may be applicable to the present invention regardless of its name.

The PSI is a system standard of MPEG-2 defined for classifying channels and programs, and the PSIP is an Advanced Television Systems Committee (ATSC) standard for classifying channels and programs.

The PSI may include, as an embodiment, a Program Association Table (PAT), a Conditional Access Table (CAT), a Program Map Table (PMT), and a Network Information Table (NIT).

The PAT is special information transmitted by a packet having a PID of '0', and transmits PID information of a corresponding PMT and PID information of a NIT for each program. The CAT transmits information about the pay broadcasting system used on the transmitting side. The PMT transmits PID information of a transport stream packet to which a program identification number, individual bit strings such as video and audio constituting the program are transmitted, and PID information to which a PCR is delivered. The NIT transmits information of an actual transmission network.

The PSIP is, according to an embodiment, a virtual channel table (VCT), a system time table (STT), a rating region table (RTT), an extended text table (ETT), a direct channel change table (DCCT), and a direct channel change selection (DCCSCT). A code table, an event information table (EIT), and a master guide table (MGT) may be included.

The VCT transmits information about a virtual channel, for example, channel information for channel selection and packet identifier (PID) for receiving audio and / or video. In other words, when the VCT is parsed, the PID of the audio and video of the broadcast program loaded in the channel can be known along with the channel name and the channel number.

67 shows an embodiment of a VCT according to the present invention.

The VCT syntax of FIG. 67 includes at least one of a table_id field, a section_syntax_indicator field, a private_indicator field, a section_length field, a transport_stream_id field, a version_number field, a current_next_indicator field, a section_number field, a last_section_number field, a protocol_version field, and a num_channels_in_section field.

The VCT syntax further includes a first loop of a 'for' loop repeated by the value of the num_channels_in_section field, in which the short_name field, major_channel_number field, minor_channel_number field, minor_channel_number field, modulation_mode field, carrier_frequency field, channel_TSID field, and program_number field are included in the first loop. , At least one of an ETM_location field, an access_controlled field, a hidden field, a service_type field, a source_id field, a descriptor_length field, and a second loop in a 'for' loop that is repeated by the number of descriptors included in the first loop. In the present invention, the second loop is referred to as a first descriptor loop for convenience of description. Descriptor descriptors () included in the first descriptor loop are descriptors individually applied to each virtual channel.

The VCT syntax may further include an additional_descriptor_length field and a third loop that is a 'for' loop that is repeated by the number of descriptors added to the VCT. In the present invention, for convenience of description, the third loop is called a second descriptor loop. The descriptor additional_descriptors () included in the second descriptor loop is a descriptor commonly applied to all virtual channels described in the VCT.

In FIG. 67 configured as described above, the table_id field indicates a unique identifier (ID) for recognizing that information transmitted to the table is a VCT. That is, the table_id field indicates a value indicating that the table to which this section belongs is a VCT. For example, 0xC8 may be assigned.

The version_number field indicates a version value of the VCT, the section_number field indicates a number of this section, and the last_section_number field indicates a number of the last section of the complete VCT. The num_channels_in_section field designates the number of all virtual channels existing in the VCT section.

The short_name field in the first loop of the 'for' loop indicates a virtual channel name, the major_channel_number field indicates a 'major' channel number associated with a virtual channel defined in the first loop, and the minor_channel_number field is' Minor 'channel number. That is, each virtual channel number should be connected to major and minor channel numbers, and the major and minor channel numbers serve as a user reference number for the corresponding virtual channel.

The program_number field indicates to connect a virtual channel in which an MPEG-2 Program Association Table (PAT) and a Program Map Table (PMT) are defined, and corresponds to a program number in the PAT / PMT. Here, the PAT describes the components of the program for each program number, and indicates the PID of the transport packet for transmitting the PMT. The PMT describes a PID list and accessory information of a transport packet to which a program identification number and individual bit strings such as video and audio constituting the program are transmitted.

68 illustrates an embodiment of a service_type field according to the present invention.

The service_type field is a field indicating a service type in a corresponding virtual channel. As shown in the figure, the service_type field is defined to refer to analog television, digital television, digital audio only, and digital data only. In addition, according to the present invention, a mobile broadcast may be referred to as a service_type field. The service_type field parsed through the SI and / or data decoder 6010 may be provided and used in the receiving system as shown in FIG. 66. According to an embodiment, the parsed service_type field may be provided to the audio / video decoders 6004 and 6005, respectively, and used for decoding.

The source_id field represents a program source connected to the corresponding virtual channel.

Here, the source refers to one specific source such as image, text, data or sound. The source_id field value has a unique value in the transport stream for transmitting the VCT.

Meanwhile, a service loop descriptor may be included in a descriptor loop (descriptor {}) in a next loop of a 'for' loop.

This service location descriptor may include a stream type, PID, and language code for each elementary stream.

69 illustrates an embodiment of a service location descriptor according to the present invention.

As shown in FIG. 69, the service location descriptor may include a descriptor_tag field, a descriptor_length field, and a PCR_PID field.

Here, PCR_PID represents the PID of the transport stream packet including the PCR field valid in the program specified by the program_number field.

On the other hand, the service location descriptor includes the number_elements field to indicate the number of PIDs used for the corresponding program. The number of iterations of the descriptor 'for' loop statement described next is determined according to the value of this number_elements field.

As shown in FIG. 69, in the 'for' loop loop, a stream_type field indicating a stream type of the corresponding elementary stream (video, audio, data), an elementary_PID field indicating the PID of the corresponding elementary stream, and a language code of the corresponding elementary stream are shown. An ISO_639_language_code field indicating is included.

70 illustrates an embodiment that can be allocated to a stream_type field according to the present invention. As shown in FIG. 70, as a stream type, ISO / IEC 11172 Video, ITU-T Rec. H.262 | ISO / IEC 13818-2 Video or ISO / IEC 11172-2 constrained parameter video stream, ISO / IEC 11172 Audio, ISO / IEC 13818-3 Audio, ITU-T Rec. H.222.0 | ISO / IEC 13818-1 private_sections, ITU-T Rec. H.222.0 | ISO / IEC 13818-1 PES packets containing private data, ISO / IEC 13522 MHEG, ITU-T Rec. H.222.0 | ISO / IEC 13818-1 Annex A DSM CC, ITU-T Rec. H.222.1, ISO / IEC 13818-6 type A, ISO / IEC 13818-6 type B, ISO / IEC 13818-6 type C, ISO / IEC 13818-6 type D, ISO / IEC 13818-1 auxiliary, etc. Can be.

Meanwhile, according to the present invention, MPH video stream: Non-hierarchical mode, MPH audio stream: Non-hierarchical mode, MPH Non-A / V stream: Non-hierarchical mode, MPH High Priority video stream: Hierarchical mode, MPH High Priority audio stream: Hierarchical mode, MPH Low Priority video stream: Hierarchical mode, MPH Low priority audio stream: Hierarchical mode may be further applied.

MPH is the first letter of mobile, pedestrian and handheld, as opposed to fixed form. MPH video stream: Non-hierarchical mode, MPH audio stream: Non-hierarchical mode, MPH Non-A / V stream: Non-hierarchical mode, MPH High Priority video stream: Hierarchical mode, MPH High Priority audio stream: Hierarchical mode, MPH Low Priority video stream: Hierarchical mode, MPH Low priority audio stream: Hierarchical mode, etc. define the stream type to be applied when transmitting and receiving mobile broadcast. In addition, the hierarchical mode and the non-hierarchical mode are values used when there is a stream to which priority is applied by applying a hierarchical structure to any one code / decoding method. Therefore, when a codec of Hierarchical structure is used, each stream is distinguished by specifying the field value including Hierarchical mode and Non-hierarchical mode in the stream type field. This stream type information is parsed by the SI and / data decoder 6010 and provided to the video / audio decoders 6004 and 6005. The video / audio decoders 6004 and 6005 use the stream type information to perform decoding operations. To perform.

Other stream types that can be applied include MPEG 4 AUDIO, AC 3, AAC, AAC +, BSAC, HE AAC, AAC SBR, MPEG-S, etc. for audio data, MPEG 2 VIDEO, MPEG 4 VIDEO for video data. , H.264, SVC, VC-1, etc. may be added.

In addition, in the field where the hierarchical mode and the non-hierarchical mode, such as the MPH video stream: non-hierarchical mode and the MPH audio stream: non-hierarchical mode, are used in FIG. For MPEG 4 AUDIO, AC 3, AAC, AAC +, BSAC, HE AAC, AAC SBR, MPEG-S, MPEG 2 VIDEO, MPEG 4 VIDEO, H.264, SVC, VC-1, etc. Embodiments may be considered, which is included in the technical scope of the present invention.

Meanwhile, the stream_type field may be defined as one field in the PMT. In this case, the stream_type field may have the above syntax.

The STT transmits current date and time information, and the RRT transmits information about a region and a review institution for a program grade. The ETT transmits an additional description of a channel and a broadcast program, and the EIT transmits information (eg, title, start time, etc.) about an event of a virtual channel.

71 illustrates an embodiment of bit stream syntax for an EIT according to the present invention.

An embodiment of the EIT (Event Information Table) of FIG. 71 is a table of PSIP including information on a title, start time, duration, etc. of an event of a virtual channel. Is one of. As shown in FIG. 71, the EIT is composed of a plurality of fields.

The table ID (table_id) field is composed of 8 bits and has a value of '0xCB', which means that the corresponding section belongs to the EIT.

The section_syntax_indicator field consists of 1 bit and has a value of '1', which means that the section follows the generic section syntax after passing through the "section_length" field.

The private_indicator field consists of 1 bit and may have a value of '1'.

source_ID is an ID for identifying a virtual channel carrying an event indicated in this table.

The version_numbers_in_section field represents the version of an object of the event information table. In the present invention, the event change information included in the event information table having a new version number with respect to the conventional version number is recognized as the latest change information.

The current_next_indicator field represents whether event information included in the corresponding EIT is current information or future information.

The num_event field represents the number of events belonging to a channel having the source ID. In other words, the lower event loop is repeated as many as the number of events.

The field of the EIT described above is a field commonly applied to at least one or more events included in one EIT syntax.

A loop that contains "for (j = 0; j <num_events_in_section; j ++) {}" describes the characteristics of each event. The following fields are fields representing detailed information on individual events. Therefore, the fields described below are fields individually applied to the corresponding event described by the EIT syntax.

The event_ID in the event loop is an identifier that identifies each individual event. The number of event IDs is part of the event identifier for event extended text message (ETM_ID).

The start_time field is a field indicating the start time of an event.

Therefore, the start time information of the program provided by the electronic program information is collected in this field.

The length_in_seconds field indicates the duration of an event. Therefore, end time information, which is the end time of the program provided by the electronic program information, is collected in this field. That is, the end time information is collected by adding the start time field value and the length in seconds field value.

The title_text () field may be used for displaying a title of a broadcast program.

Meanwhile, a descriptor applied to each event may be included in the EIT. The descriptors_length field represents the length of a descriptor.

Meanwhile, a descriptor loop (descriptor loop) in a loop of a 'for' loop may include an AC-3 audio descriptor, an MPEG 2 audio descriptor, an MPEG 4 audio descriptor, an AAC descriptor, an AAC + descriptor, an HE AAC descriptor, and an AAC. It may include at least one of an SBR descriptor, an MPEG surround descriptor, a BSAC descriptor, an MPEG 2 video descriptor, an MPEG 4 video descriptor, an H.264 descriptor, an SVC descriptor, and a VC-1 descriptor. Here, each descriptor describes information about an audio / video codec applied to each event. Information about the codec may be provided to the audio / video decoders 6004 and 6005 to be used for decoding.

The DCCT / DCCSCT transmits information related to automatic channel change, and the MGT transmits version and PID information of respective tables in the PSIP.

The tables in the PSI / PSIP all have a basic unit called a section, and one or more sections are combined to form a table. For example, the VCT may be divided into 256 sections. And, one section may carry a plurality of virtual channel information, but information about one virtual channel is not divided into two or more sections.

In this case, the receiving system can parse and decode mobile service data transmitted using only tables in PSI, only tables in PSIP, or a combination of tables in PSI and PSIP.

In order to parse and decode the mobile service data, at least PAT and PMT are required for PSI and VCT is required for PSIP.

For example, the PAT may include system information for transmitting the mobile service data and a PID of a PMT corresponding to data (or program number) for the data service, and the PMT transmits the mobile service data. It may include the PID of the TS packet.

The VCT may include information of a virtual channel for transmitting the mobile service data and a PID of a TS packet for transmitting the mobile service data.

In some embodiments, DVB-SI may be applied instead of PSIP. Such DVB-SI may include NIT, SDT, EIT, TDT, and the like. Such DVB-SI may be used together with the above-mentioned PSI.

The network information table (NIT) classifies services belonging to a specific network provider into groups. This table contains all the tuning information used during IRD setup. This table can be used to inform the change of tuning information. The Service description table (SDT) contains a name and other parameters related to each service of a particular MPEG multiplex. The event information table (EIT) is used to transmit information related to all events occurring in the MPEG multiplex. This table contains information about the current transport and optionally covers other transport streams that the IRD can receive. The time and date table (TDT) is used for IRD internal clock update.

In addition, there are three optional SI tables:

That is, a bouquet associate table (BAT) provides a service grouping method that an IRD can use as a method of providing a service to a viewer. A particular service can belong to more than one `buque`. The Running Status Table (RST) section is used to quickly update one or more event execution states. The execution state section is transmitted only once at the time when the state of the event changes. Other SI tables are usually sent repeatedly. The stuffing table (ST) may be used to replace or discard the dependent table or the entire SI table.

According to an embodiment of the present invention, when the mobile service data is audio or video data, the mobile service data carried in the payload in the TS packet is preferably of the PES type.

As another embodiment of the present invention, when the mobile service data is data for data service, it will be described as an embodiment that the mobile service data carried in the payload in the TS packet is in the form of a DSM-CC section.

However, a TS packet carrying data for the data service may be a packetized elementary stream (PES) type or a section type. That is, the data for the PES type data service is composed of TS packets, or the data for the section type data service is composed of TS packets.

According to an embodiment of the present invention, data for the data service is transmitted in a section type. In this case, the data for the data service is included in a Digital Storage Media-Command and Control (DSM-CC) section, and the DSM-CC section is configured as TS packets in units of 188 bytes.

The identifier of the TS packet constituting the DSM-CC section is included in a data service table (DST). If the DST is transmitted, 0x95 is allocated as the stream_type field value in the PMT or the service location descriptor of the VCT. That is, when the stream_type field value of the PMT or VCT is 0x95, the reception system may know that data broadcasting including mobile service data, that is, mobile service data, is received. In this case, the mobile service data may be transmitted in a data / object carousel manner. The data / object carousel method means transmitting the same data periodically.

At this time, the demultiplexer 6003 performs section filtering under the control of the SI and / or data decoder 6010 to discard overlapping sections, and output only the non-overlapping sections to the SI and / or data decoder 6010. .

In addition, the demultiplexer 6003 may output only a section constituting a desired table, for example, a VCT or an EIT, to the SI and / or data decoder 6010 through section filtering. The VCT or EIT may include a specific descriptor for mobile service data. However, the mobile service data is not excluded from being included in another table such as PMT.

As the method of section filtering, there is a table defined in MGT, for example, a method of applying section filtering by checking PID of a VCT, or MGT when the VCT has a fixed PID, in other words, a base PID. There is a way to filter the section without checking it. In this case, the demultiplexer 6003 performs section filtering by referring to a PID, a table_id field, a version_number field, a section_number field, and the like.

In detail, there are two methods for defining the PID of the VCT according to the present invention.

Here, the PID of the VCT is a packet identifier required to distinguish the VCT from other tables.

In the first method, the PID of the VCT according to the present invention can be set to be dependent on the MGT. In this case, the receiving system cannot immediately check the VCT among numerous tables of the PSIP or PSI, and can read the VCT only by checking the PID defined in the MGT. The MGT is a table defining PIDs, sizes, version numbers, etc. of various tables.

As a second method, the PID of the VCT according to the present invention may be set to have a base PID value independent of the MGT, that is, a fixed PID value. In this case, unlike the first method, it is possible to identify the VCT according to the present invention without checking the PID of the MGT. Of course, the promise of the base PID must be preceded between the transmitting system and the receiving system.

According to an embodiment, the demultiplexer 6003 may output only an application information table (AIT) to the SI and / or data decoder 6010 through section filtering. The AIT refers to a table including information on an application running in a receiver for data service. In some cases, the AIT is also called XAIT or AMT. Therefore, any table containing information about the application will apply to the description below. When such AIT is transmitted, 0x05 may be allocated to the stream_type field of the PMT.

These AITs provide information about the application, such as the name of the application, the version of the application, the priority of the application, the ID of the application, the state of the application (auto-start, user operable, kill, etc.), and the type of application. (Java or HTML), the location of the stream containing the classes and data files of the application, the base directory of the application, the location of the icon of the application, and the like.

As a method of detecting application information for a data service using the AIT, component_tag, original_network_id, transport_stream_id, and service_id may be detected. The component_tag refers to an elementary stream carrying DSI of the corresponding Object Carousel, and the original_network_id refers to the DVB-SI original_network_id of the TS providing the transport connection. In addition, the transport_stream_id refers to the MPEG TS of the TS providing the transport connection, and the service_id refers to the DVB-SI of the service providing the transport connection. The original_network_id, transport_stream_id, and service_id may be used to obtain information on a specific channel. Data for a data service detected using the above information, for example, data about an application, may be stored in the second storage unit 6011 by the SI and / or data decoder 6010.

The SI and / or data decoder 6010 parses the DSM-CC section constituting the demultiplexed mobile service data and databases the mobile service data as a result of the parsing in the second storage unit 6011.

The SI and / or data decoder 6010 collects sections having the same table identifier (table_id) to form and parse a table, and database the system information as a result of the parsing in the second storage unit 6011.

In this case, the SI and / or data decoder 6010 parses the second multiplexer by reading all remaining sections of the actual section data that are not filtered or sectioned by the demultiplexer 6003. (6011). The second storage unit 6011 is a table and data / object carousel database storing system information parsed from a table and mobile service data parsed from a DSM-CC section.

Here, whether a table consists of one section or a plurality of sections can be known through a table_id field, a section_number field, a last_section_number field, and the like. For example, collecting only TS packets having a PID of a VCT results in a section, and gathering sections having a table identifier assigned to a VCT results in a VCT.

By parsing the VCT, information about a virtual channel through which mobile service data is transmitted can be obtained.

In addition, according to the present invention, the SI and / or data decoder 6010 parses the SLD of the VCT and transmits stream type information of the corresponding elementary stream to the audio or video decoders 6004 and 6005. In this case, the corresponding audio or video decoders 6004 and 6005 perform audio or video decoding using the transmitted stream type information.

In addition, according to the present invention, the SI and / or data decoder 6010 may include an AC-3 audio descriptor, an MPEG 2 audio descriptor, an MPEG 4 audio descriptor, an AAC descriptor, an AAC + descriptor, an HE AAC descriptor, an AAC SBR descriptor, and an MPEG. Parses surround descriptor, BSAC descriptor, MPEG 2 video descriptor, MPEG 4 video descriptor, H.264 descriptor, SVC descriptor, VC-1 descriptor and etc. To transmit. In this case, the corresponding audio or video decoders 6004 and 6005 perform audio or video decoding using the transmitted audio or video codec information.

The obtained application identification information, service component identification information, and service information of the data service may be stored in the second storage unit 6011 or may be output to the data broadcast application manager 6013.

The application identification information, service component identification information, and service information may be referred to for decoding data for the data service, or may be prepared to drive an application program for a data service in advance.

In addition, the SI and / or data decoder 6010 may control demultiplexing of the system information table, which is a channel and event related information table, and transmit the A / V PID list to the channel manager 6007.

The channel manager 6007 may make a request for receiving a system related information table to the SI and / or data decoder 6010 with reference to a channel map 6008 and receive the result. The channel manager 6007 may control channel tuning of the tuner 6001.

In addition, the channel manager 6007 may directly control the demultiplexer 6003 and directly control the audio / video decoders 6004 and 6005 by directly setting the A / V PID.

The audio / video decoders 6004 and 6005 may decode and output demultiplexed audio and video from the main service data packet, respectively, or decode and output demultiplexed audio and video from the mobile service data packet, respectively. . Meanwhile, according to the exemplary embodiment, when the mobile service data includes not only data for data service but also audio data and video data, the demultiplexer 6003 demultiplexes the audio data and the video data into the audio decoder 6004 and the video decoder ( Of course, each can be decoded at 6005). For example, the audio decoder 6004 may include an AC-3 decoding algorithm, an MPEG 2 audio decoding algorithm, an MPEG 4 audio decoding algorithm, an AAC decoding algorithm, an AAC + decoding algorithm, a HE AAC decoding algorithm, an AAC SBR decoding algorithm, an MPEG surround decoding algorithm, The BSAC decoding algorithm is applied, and the video decoder 6005 can decode by applying the MPEG 2 video decoding algorithm, the MPEG 4 video decoding algorithm, the H.264 decoding algorithm, the SVC decoding algorithm, and the VC-1 decoding algorithm.

Meanwhile, the native TV application manager 6006 drives a native application program stored in the first storage unit 6009 to perform general functions such as channel switching. The native application program refers to software embedded at the time of shipment of the receiving system.

That is, the native TV application manager 6006 responds to the user's request by displaying a graphical user interface (GUI) on the screen when a user request is made to the receiving system through a user interface (UI). .

The user interface receives a user request through an input device such as a remote controller, a keypad, a jog dial, a touch screen provided on the screen, and outputs the user request to the native TV application manager 6006, the data broadcasting application manager 6013, and the like.

In addition, the native TV application manager 6006 controls the channel manager 6007 to control channel related operations, that is, the management of the channel map 6008 and the SI and / or data decoder 6010. The native TV application manager 6006 stores and restores the GUI control of the entire receiving system, the user request, and the state of the receiving system in the first storage unit 6009.

The channel manager 6007 manages the channel map 6008 to control the tuner 6001 and the SI and / or data decoder 6010 so as to respond to the channel request of the user.

That is, the channel manager 6007 requests the SI and / or data decoder 6010 to parse a table related to the channel to be tuned, and from the SI and / or data decoder 6010 the table Report the result of parsing. The channel manager 6007 updates the channel map 6008 according to the reported parsing result, and demultiplexes a PID for demultiplexing data for a data service and a related table from mobile service data. (6003).

The system manager 6012 controls booting of the receiving system by powering on and off, and stores the ROM image (including the downloaded software image) in the first storage unit 6009.

That is, the first storage unit 6009 stores an operating program such as an operating system (OS) required for operation of the reception system and an application program performing a data service function.

The application program is a program for providing a data service to a user by processing data for a data service stored in the second storage unit 6011. If data for a data service is stored in the second storage unit 6011, the data is processed by the application program or another application program and provided to the user.

The operating program and the application program stored in the first storage unit 6009 may be updated or modified with a new program downloaded. In addition, since the stored operating program and the application program are continuously stored without being erased even when the supply of the operating power is cut off, when the operating power is applied, the stored operating program and the application program can be executed without downloading a new one.

The application program for providing a data service according to the present invention may be embedded in the first storage unit 6009 at the time of shipment of the receiving system, or may be stored in the first storage unit 6009 through download. In addition, an application program for a data service, that is, a data service providing application program stored in the first storage unit 6009 may be deleted, updated, or modified. In addition, the data service providing application program may be downloaded and executed together with the data for the data service whenever data for the data service is received.

When there is a data service request through a user interface (UI), the data broadcasting application manager 6013 drives a corresponding application program stored in the first storage unit 6009 to process the requested data. Provide data services. The data broadcast application manager 6013 supports a GUI for such a data service. Here, the data service is provided in the form of text, voice, graphics, still images, video, and the like.

The data broadcasting application manager may include a platform for executing an application program stored in the first storage unit 6009. The platform may be, for example, a Java virtual machine for executing a Java program.

Next, the data broadcasting application manager 6013 executes a data service providing application program stored in the first storage unit 6009 to process data for the data service stored in the second storage unit 6011. An example of providing a service will be described.

For example, assuming that the data service is a traffic information service, the data service of the present invention is a text, voice, graphic, still image in a receiver which is not equipped with an electronic map or GPS, or is not equipped with both an electronic map and GPS. , Provided to users via at least one of the videos. In this case, if the GPS module 6020 is installed in the receiving system as shown in FIG. 66, the GPS module 6020 extracts current location information (longitude, latitude, and altitude) by receiving satellite signals transmitted from a plurality of low-orbit satellites. The data is then output to the data broadcast application manager 6013. In this case, it is assumed that an electronic map including information on each link and node and various graphic information are stored in the second storage unit 6011 or the first storage unit 6009 or another storage unit not shown.

That is, at the request of the data broadcasting application manager 6013, data for the data service stored in the second storage unit 6011 is read and input to the data broadcasting application manager 6013.

The data broadcasting application manager 6013 analyzes data for a data service read from the second storage unit 6011 and extracts necessary information and / or control signals according to the message contents. That is, the data broadcasting application manager 6013 processes to provide the current location information to the user graphically using the current location information and the graphic information.

72 is a block diagram illustrating a digital broadcast reception system according to another embodiment of the present invention.

The receiving system of FIG. 72 includes a tuner 7001, a demodulator 7002, a demultiplexer 7003, a first descrambler 7004, an audio decoder 7005, a video decoder 7006, and a second descrambler 7007. , Authentication means 7008, native TV application manager 7009, channel manager 7010, channel map 7011, first storage 7072, SI and / or data decoder 7013, second storage ( 7014, a system manager 7015, a data broadcast application manager 7016, a storage controller 7017, a third storage unit 7018, a communication module 7019, and a GPS module 7020. Can be. The first storage part 7022 is a nonvolatile memory (NVRAM) (or flash memory). The third storage unit 7018 is a mass storage device such as a hard disk drive (HDD) and a memory chip. In addition, the description overlapping with FIG. 66 in the description of each part constituting the FIG. 72 uses the contents of FIG. 66 described above and will be omitted herein.

Meanwhile, the transmitter may scramble and transmit broadcast content to provide a service for preventing illegal copying or illegal viewing of a mobile service and / or main data transmitted through a broadcasting network or a paid broadcasting service.

In this case, the reception system can provide proper broadcast content to the user only by descrambled the scrambled broadcast content. In addition, the receiving system may undergo an authentication procedure by an authentication means before the descramble.

Hereinafter, a reception system including an authentication means and a descramble means according to an embodiment of the present invention will be described.

The receiving system according to the present invention may include means for receiving and descrambled scrambled broadcast content, and means for authenticating whether the corresponding receiving system is a legitimate receiving system entitled to receive in relation to the descramble.

Hereinafter, for the convenience of description, the means for descrambling are referred to as descramblers 7004 and 7007, and the means for authenticating are referred to as authentication means 7008. Such a name is just one embodiment and may be called another name, for example, a decrypter.

At this time, the receiving system of FIG. 72 is provided with the descramblers 7004 and 7007 and the authentication means 7008 therein in one embodiment, but may be provided separately in an external module. In addition, the descramblers 7004 and 7007 and the authentication means 7008 may be provided separately in the internal or external modules. The module may be a slot type such as SD or CF memory, a memory stick type, a USB type, or the like, and may be attached to or detached from the receiving system.

As described above, when the authentication is successful through the authentication means 7008, the receiving system may descramble the scrambled broadcast content in the descramblers 7004 and 7007 and provide the same to the user. In this case, the authentication method and the descramble method may use various methods. In that case, however, it must be based on a pre-determined appointment between sending and receiving.

Hereinafter, some embodiments of the authentication method and the descramble method will be described for convenience of description, and redundant description will be omitted. However, the present invention is not limited to the above-described exemplary embodiments, and it is to be understood that the present invention is included in the technical spirit apparent to those skilled in the art.

First, a description will be given of the case where the receiving unit 7008 and the descramblers 7004 and 7007 are provided in the receiving system.

The receiving system receives scrambled broadcast content through the tuner 7001 and the demodulator 7002, and the system manager 7015 determines whether the received broadcast content is scrambled. If the broadcast content is scrambled as a result of the determination, the authentication means 7008 is controlled to operate.

As described above, the authentication means 7008 undergoes an authentication procedure to determine whether the corresponding receiving system is a legitimate host who is entitled to receive the pay broadcasting service. At this time, the authentication procedure will be different according to various authentication methods.

In one embodiment, the authentication means 7008 may authenticate by comparing the IP address of the IP datagram in the received broadcast content with the unique address of the host. In this case, the unique address of the corresponding receiving system may be a MAC address. That is, the authentication means 7008 extracts an IP address from the decapsulated IP datagram and obtains reception system information mapped to the address. At this time, the receiving system should be provided with information (for example, a table format) which can map an IP address and receiving system information in advance.

Therefore, the authentication means 7008 determines the identity of the address of the corresponding receiving system and the receiving system information mapped to the IP address and performs the authentication procedure. That is, the authentication means 7008 may determine that the corresponding receiving system is a legitimate receiving system that is eligible to receive if the two pieces of information are identical.

In another embodiment, the transmitting and receiving side defines the standardized identification information in advance, and transmits the identification information of the receiving system applying for the pay broadcasting service at the transmitting side, and the receiving system performs the authentication procedure after determining the identity with its own identification number. There is a way. That is, the transmitting side generates and stores a database with unique identification information (number) of the corresponding receiving system that has applied for the paid broadcasting service, and transmits the identification information in the EMM (Entitlement Management Message) when scrambled broadcasting content. do.

When the broadcast content is scrambled, a message (for example, ECM, EMM) such as conditional access system (CAS) information, mode information, and message location information applied to the scramble is transmitted through a corresponding data header or another packet. . The Entitlement Control Message (ECM) may include a control word (CW) used for scramble. In this case, the control word may be encrypted with an authentication key. The EMM may include an authentication key and entitlement information of the corresponding data. The authentication key may be encrypted with a distribution key unique to the receiver. That is, assume that mobile service data is scrambled using the control word CW, and information for authentication and information for descrambling are transmitted at the transmitting side. Then, the transmitting side encrypts the CW with an authentication key and then transmits the CW in an entitlement control message (ECM). In addition, the transmitting side transmits the authentication key used to encrypt the CW and the receiving credentials of the receiving system (eg, a standardized serial number of the receiving system having the receiving qualification) in the EMM.

Therefore, the authentication means 7008 of the receiving system extracts identification information unique to the corresponding reception system, extracts identification information included in the EMM of the receiving broadcast service, determines whether the two identification information are identical, and performs an authentication procedure. . That is, the authentication means 7008 may determine that the corresponding receiving system is a legitimate receiving system that is eligible to receive if the two pieces of information are identical.

In another embodiment, the receiving system may be provided with the authentication means 7008 in a removable external module. In this case, the receiving system and the external module interface through a common interface (CI). That is, the external module may perform descrambling by receiving scrambled data from the receiving system through a common interface, and may transmit only information necessary for descrambling to the receiving system.

In addition, the common interface includes a physical layer and one or more protocol layers, and the protocol layer may have a structure including one or more layers that provide independent functions in consideration of scalability in the future.

The external module may be a memory or a card that stores key information and authentication information used for scramble and does not have a descramble function, or a card including a descramble function. That is, the module may include a descrambling function in the form of hardware, middleware or software.

At this time, the receiving system and the external module must be authenticated to provide the user with the pay broadcasting service provided by the transmitter. Therefore, the transmitting side may provide the pay broadcasting service only to the receiving system and the module pair which have been authenticated.

In addition, the receiving system and the external module need to mutually authenticate each other through a common interface. That is, the module may authenticate the receiving system by communicating with the system manager 7015 in the receiving system through the common interface, and the receiving system may authenticate the module through the common interface. The module may extract a unique ID and a unique ID of a receiving system and transmit the unique ID of the receiving system to the transmitting side during the mutual authentication process, and the transmitting side may use the value as service start or charging information. The system manager 7015 may transmit the charging information to the transmitting side of the remote place through the communication module 7019 if necessary.

The authentication means 7008 authenticates the corresponding receiving system and / or external module, and if the authentication is successful, recognizes the receiving system as a legitimate receiving system that is entitled to receive the pay broadcasting service. In addition, the authentication means 7008 may receive authentication-related data from a mobile communication company subscribed to by a receiving system user other than the transmitting side providing the broadcast content. In this case, the authentication-related data may be scrambled by the transmitting side providing the broadcast content through the mobile communication company or scrambled by the mobile communication company.

If authentication is successful by the authentication means 7008, the receiving system may scramble and descramble the received broadcast content. At this time, the descrambler is made in the descrambler (7004, 7007), the descrambler (7004, 7007) may be provided in an internal or external module of the receiving system.

The receiving system also has a common interface and can descramble in communication with an external module including descramblers 7004 and 7007. That is, the descramblers 7004 and 7007 may be included in the module in the form of hardware, middleware or software, or may be included in the receiving system, or may include both the module and the receiving system or only one of them.

If the descramblers 7004 and 7007 are provided inside the reception system, it is advantageous when the transmitting side (including at least one of a service provider and a broadcasting station) scrambles and transmits data using the same scramble method.

On the other hand, if the descrambler (7004, 7007) is included in an external module, it is advantageous when the scrambler to transmit data by a different scramble method for each transmitting side. In this case, the receiving system does not need to have a descramble algorithm of each transmitting end, so that the receiving system can be further simplified and downsized. Therefore, in this case, the external module may be a subject that provides CA functions exclusively provided by each transmitting party and functions for various services to be provided to the user.

The common interface communicates in a single manner between various types of external modules and the system manager 7015 in the receiving system. In addition, the receiving system has a structure in which a plurality of modules and the system manager 7015 can be connected because at least one or more modules providing different services can be connected and operated at the same time.

In addition, the common interface protocol between the receiving system and the external module includes a function of periodically checking the state of the other party to maintain normal communication with each other. The receiving system and the module use this function to manage the state of the other party, and if one malfunctions, it includes a function to report to the user or the sender and try to recover.

In another embodiment, the authentication procedure may be performed in software without being dependent on hardware.

That is, when the memory card, which is stored in advance by downloading the CAS software, is inserted, the receiving system receives and loads the CAS software from the memory card and performs an authentication procedure. According to an embodiment of the present invention, the CAS software read from the memory card is mounted in the first storage unit 7022 in the receiving system and driven in one application form. In particular, according to the present invention, the CAS software is mounted and executed on a middleware base. In addition, the middleware will be described using JAVA middleware as an example.

To this end, the receiving system may include a common interface for connecting to a memory card, and the first storage unit 7022 may be a volatile memory, a nonvolatile memory, and a flash memory (also called a flash ROM). In this case, the memory card mainly uses a flash memory or a small hard drive. The memory card may be used in at least one or more receiving systems according to the contents, authentication, scramble, billing method, etc. of the stored CAS software.

However, the CAS software must include at least information necessary for authentication and information required for descramble.

Thus, the authentication means 7008 performs an authentication procedure between the transmitting side, the receiving system, and the receiving system and the memory card. In this case, similarly to the above description, the memory card may include information on a normal receiving system that can be authenticated as being entitled to receive. For example, the information about the receiving system may include unique information such as a serial number standardized for the receiving system. Thus, the authentication means 7008 can perform authentication between the memory card and the receiving system by comparing the unique information such as the standardized serial number included in the memory card with the unique information of the corresponding receiving system.

The CAS software first performs authentication between a receiving system and a memory card when operating on a Java middleware base. For example, if the unique number of the receiving system included in the CAS software and the unique number of the receiving system read from the system manager 7015 of the receiving system are identical to each other, and the same, the memory card can be used normally in the receiving system. Confirmed by memory card. In this case, the CAS software may be embedded in the first storage unit 7015 at the time of shipment of the receiving system, or may be downloaded to the first storage unit 7015 from the transmitting side or the module or the memory card as described above. Then, the descramble function may be operated by the data broadcast application manager 7009 in the form of one application.

Thereafter, the CAS software parses the EMM / ECM packet output from the demultiplexer 7003, checks whether the corresponding receiver is eligible to receive, obtains information (i.e., CW) necessary for descramble, and descrambles the descramblers 7004 and 7007. to provide. That is, CAS software operating on the Java middleware first reads the unique number of the corresponding receiving system from the receiving system and compares the unique number of the receiving system transmitted to the EMM to check the receiving qualification of the current receiving system.

When the reception qualification of the reception system is confirmed, the reception system checks whether the reception system is entitled to receive the broadcast service by using the broadcast service information transmitted to the ECM and the reception qualification of the broadcast service. When the qualification to receive the broadcast service is confirmed, the encrypted CW transmitted to the ECM is decrypted using the authentication key transmitted to the EMM and then output to the descramblers 7004 and 7007. The descramblers 7004 and 7007 descramble a broadcast service using the CW.

On the other hand, CAS software stored in the memory card can be extended according to the pay service to be provided by the broadcasting station. In addition, the CAS software may include other additional information as well as information related to authentication and descrambling.

The receiving system may download CAS software from the transmitting side and upgrade the CAS software stored in the memory card.

As described above, the present invention implements a CAS system in a manner that satisfies all memory cards detachable to a receiving system, provided that any type of broadcast receiver is provided with only an external memory interface, so that the receiving system can receive paid broadcast contents such as broadcast. Maximum functionality can be implemented at a minimum cost and the diversity of the receiving system can be respected.

In addition, since only a minimum application program interface (API) needs to be implemented in the implementation method, the burden on the receiving system manufacturer can be minimized, and the part that has to be dependent on the CAS company can be removed. This also minimizes the cost for the CAS equipment building and operating system on the sending side.

The descramblers 7004 and 7007 may be included in the module in the form of hardware or software. In this case, the scrambled and received data may be descrambled in the module and then decoded.

When the scrambled and received data are stored in the third storage unit 7018, the scrambled data may be descrambled and stored, or the scrambled data may be stored as it is and then descrambled during playback. If the storage control unit 7017 is provided with a scramble / descramble algorithm, the storage control unit 7017 may scramble the received data once again and store the data in the third storage unit 7018.

In another embodiment, the descrambled (receive limited) broadcast content is transmitted through a broadcasting network, and the authentication, descrambling related information, etc. for solving the reception restriction are transmitted and received through the communication module 7019, thereby bidirectionally receiving in the receiving system. Enable communication.

The receiving system transmits unique information (ID) such as serial number or MAC address of the corresponding receiving system so that the transmitting side can recognize the broadcasting data desired to be transmitted and received and the receiving system transmitting the broadcasting data with the remotely located transmitter. It is delivered to the communication module in the side or provided by the communication module in the transmitting side.

The communication module 7019 in the receiving system provides a protocol required for performing bidirectional communication with the communication module in the transmitting side in a receiving system that does not support the bidirectional communication function.

The receiving system configures a Protocol Data Unit (PDU) using a Tag-Length-Value (TLV) coding method including data to be transmitted and unique information (ID). The tag field contains the indexing of the corresponding PDU, the length field contains the length of the Value field, and the Value field contains the actual data to be transmitted and the ID number of the receiving system.

If the receiving system is equipped with a Java platform and configures a platform that operates after downloading the sending Java application to the receiving system through the network, the PDU includes a tag field arbitrarily defined by the sending side. It is also possible to download the data from a storage medium in the receiving system and the like and transmit the communication module 7019.

In this case, the PDU may configure a PDU in a Java application in the receiving system and output the PDU to the communication module 7019. Alternatively, the Java application may transmit a tag value, actual data to be transmitted, and unique information of the corresponding receiving system, and configure a PDU through TLV coding in the receiving system.

The advantage of this structure is that the firmware of the receiving system does not need to be changed even if the data (or application) desired by the sender is added.

At this time, the communication module in the transmitting side transmits the PDU received from the receiving system through a wireless data network or configures the data received through the network as a PDU to the receiving system. In this case, the communication module in the transmitting end may include a transmitter-side unique information (for example, an IP address) of a remote place when configuring a PDU to be transmitted to the receiving system.

At this time, the receiving system is a WAP, a CDMA 1x EV-DO, a wireless LAN that can be connected through an access point, which has a common interface and can be connected through a mobile communication base station such as CDMA, GSM, etc. Portable Internet, WiBro, WiMAX, etc. can be provided. The above-described receiving system corresponds to a case where there is no communication function, but in the case of a receiving system having a communication function, the communication module 7019 is not necessary.

The broadcast data transmitted and received through the above-described wireless data network may include data necessary to perform a CA.

Meanwhile, the demultiplexer 7003 receives real time data output from the demodulator 7002 or data read from the third storage unit 7018 and performs demultiplexing. According to an embodiment of the present invention, the demultiplexer 7003 performs demultiplexing on a mobile service data packet. Detailed description thereof is used herein and the description is omitted herein.

The first descrambler 7004 receives and descrambles the demultiplexed signal from the demultiplexer 7003. In this case, the first descrambler 7004 may receive the authentication result or data necessary for descramble from the authentication means 7008 and use it for descramble.

The audio decoder 7005 and the video decoder 7006 receive and decode the descrambled signal from the first descrambler 7004 or output the descrambled signal without outputting it from the first descrambler 7004. Is decoded as is and output. In this case, the decoded signal is received and descrambled by the second descrambler 7007 to be processed.

The present invention described so far is not limited to the above-described embodiments, and can be modified by those skilled in the art as can be seen from the appended claims, and such modifications are the scope of the present invention. Belongs to.

1 is a schematic structural block diagram of a digital broadcasting system according to an embodiment of the present invention;

2 is a block diagram showing an embodiment of the service multiplexer of FIG.

3 is a block diagram illustrating an embodiment of the transmitter of FIG.

4 is a block diagram illustrating an embodiment of the preprocessor of FIG. 3.

5A to 5E illustrate error correction encoding and error detection encoding processes according to an embodiment of the present invention.

6 (a) to (d) is a view showing a row mixing process of a super frame unit according to an embodiment of the present invention

7A and 7B are diagrams showing an example of data configuration before and after the data deinterleaver in the digital broadcast transmission system according to the present invention.

FIG. 8 shows a part of the data group illustrated in FIG. 7A

9 (a) to (c) are diagrams of the present invention illustrating the arrangement of a signal of a transmission parameter when the transmission parameter is transmitted as signaling information;

FIG. 10 illustrates an example in which the signaling information illustrated in FIG. 9 is arranged in a data group in a transmission frame.

11 (a) and 11 (b) conceptually illustrate an embodiment of obtaining mobile service data included in a specific data group among bursts;

12 (a) to 12 (c) conceptually illustrate another embodiment of obtaining mobile service data included in a specific data group among bursts;

13 illustrates an embodiment of a process of dividing an RS frame to form a data group according to the present invention.

14 (a) and 14 (b) illustrate another embodiment of a process of dividing an RS frame to form a data group according to the present invention.

15 illustrates an example of an operation of a packet multiplexer for transmitting a data group according to the present invention.

16 is a block diagram illustrating an embodiment of a block processor according to the present invention.

17A to 17C are block diagrams illustrating embodiments in a case where a symbol encoder according to the present invention is operated as an encoder having a quarter code rate.

18A is a detailed block diagram of one embodiment of a 1/2 external encoder in accordance with the present invention.

18B is a detailed block diagram of one embodiment of a quarter external encoder in accordance with the present invention.

19 (a) to (c) illustrate an embodiment of a variable length interleaving process of the symbol interleaver of FIG. 16.

20A and 20B are block diagrams illustrating another embodiment of a block processor according to the present invention.

21 (a) to 21 (c) show examples of a block encoding and trellis encoding process according to the present invention.

22 is a block diagram showing an embodiment of a trellis encoder according to the present invention.

23A and 23B are diagrams illustrating a state in which a block processor and a trellis encoder are connected according to the present invention.

24 illustrates another embodiment of a block processor according to the present invention.

25 is a view showing another embodiment of another block processor in the present invention.

26 illustrates an embodiment for inserting and transmitting a transmission parameter in a group formatter according to the present invention.

27 illustrates an embodiment for inserting and transmitting a transmission parameter in a block processor according to the present invention.

28 illustrates an embodiment for inserting and transmitting a transmission parameter in a packet formatter according to the present invention.

29 illustrates an embodiment for inserting and transmitting a transmission parameter into a field sync segment region according to the present invention

30 is a block diagram showing an embodiment of a receiving system according to the present invention;

31 is a data structure diagram showing an example in which known data is periodically inserted into general data according to the present invention.

32 is a flowchart showing an embodiment of a known data detection process according to the present invention.

FIG. 33 is a block diagram showing an embodiment of a demodulator according to the present invention of FIG.

34 is a detailed block diagram showing an embodiment of a demodulator according to the present invention.

35 is a block diagram illustrating an embodiment of a frequency offset estimator in accordance with the present invention.

36 is a block diagram showing an embodiment of a known data detection and initial frequency offset estimator in accordance with the present invention.

FIG. 37 is a block diagram illustrating an embodiment of the partial correlator of FIG. 36; FIG.

38 is a view showing another embodiment of a timing recovery unit according to the present invention;

39A and 39B illustrate an embodiment of detecting a timing error by obtaining a correlation value between known data and a received signal.

40 (a) and 40 (b) show another embodiment of detecting a timing error by obtaining a correlation value between known data and a received signal.

41 illustrates a correlation value when there is a timing error

42 is a detailed block diagram illustrating one embodiment of a timing error detector for detecting timing errors in the time domain.

Figure 43 is a detailed block diagram illustrating one embodiment of a timing error detector for detecting timing frequency errors.

44 is a detailed block diagram illustrating another embodiment of a timing error detector for detecting timing frequency errors.

45 is a block diagram illustrating an embodiment of a DC remover according to the present invention.

46 illustrates an example of moving input sample data of the DC estimator of FIG.

47 is a block diagram illustrating another embodiment of the DC remover according to the present invention.

48 is a flowchart illustrating an embodiment of a channel equalization process according to the present invention.

49 is a block diagram illustrating an embodiment of a channel equalizer according to the present invention.

50 is a block diagram illustrating an embodiment of a residual carrier phase error estimator of FIG. 49;

51 is a block diagram illustrating an embodiment of the phase error detector of FIG. 49.

52 is a block diagram illustrating an embodiment of the phase compensator of FIG. 49.

53 is a block diagram illustrating another embodiment of a channel equalizer according to the present invention.

54 is a block diagram illustrating another embodiment of a channel equalizer according to the present invention.

55 is a block diagram illustrating another embodiment of a channel equalizer according to the present invention.

56 is a detailed block diagram illustrating one embodiment of a CIR estimator in accordance with the present invention.

57 is a detailed block diagram showing an embodiment of a block decoder according to the present invention.

58 and 59 illustrate an embodiment of an error correction decoding process according to the present invention.

60 is a block diagram showing another embodiment of a receiving system according to the present invention;

FIG. 61 is a diagram illustrating a process of detecting a transmission parameter in the transmission parameter decoder of FIG. 60.

62 is a diagram illustrating an example in which a transmission parameter decoder detects an SCCC mode according to the present invention.

63 is a diagram illustrating an example of extracting and outputting a group valid identifier according to the present invention;

64 illustrates an example of extracting and outputting a burst valid identifier according to the present invention;

65 is a diagram illustrating an actual on / off time in comparison with a burst period according to the present invention;

66 is a block diagram showing the overall configuration of a receiving system according to an embodiment of the present invention.

67 is a view showing an embodiment of a syntax structure for a virtual channel table according to the present invention

68 is a view showing an embodiment of a service_type field according to the present invention.

69 illustrates an embodiment of a syntax structure for a service location descriptor according to the present invention.

70 shows examples of values that can be assigned to a stream_type field and definitions thereof according to the present invention.

71 illustrates an embodiment of a syntax structure for an event information table according to the present invention.

72 is a block diagram showing the overall configuration of a receiving system according to another embodiment of the present invention.

Claims (22)

A data group comprising a mobile service data and a plurality of known data columns, at least two of the plurality of known data columns having different lengths, wherein one of the known data columns of the plurality of known data columns has a first pattern The remaining known data stream may include: a signal receiving unit configured to receive a broadcast signal having a second pattern different from the first pattern; A known data detector for detecting a known data stream from the data group; And And an equalizer for compensating for channel distortion generated in the data of the data group by using the detected known data sequence. The method of claim 1, And a transmission parameter is inserted between the plurality of known data streams. The method of claim 2, A block decoder for turbo decoding the mobile service data in the data group in which the channel distortion is compensated on a block basis based on the block encoding information included in the transmission parameter; And And a power control unit controlling power to receive a data group including mobile service data desired to be received based on the transmission parameter. 4. The block decoder of claim 3, wherein the block decoder A first decoder configured to perform trellis decoding by matching the mobile service data of the data group input with the block size for turbo decoding with the mobile service data that is symbol-decoded and fed back; And And a second decoder which performs symbol decoding on the trellis decoded mobile service data and feeds back to the first decoder. The method of claim 1, At least one data packet for mobile service data from a plurality of data groups, an RS parity generated based on the at least one data packet, and a CRC checksum generated based on the at least one data packet and the RS parity And an RS frame decoder configured to correct an error generated in mobile service data by performing CRC decoding and RS decoding on the RS frame. The method of claim 5, wherein the RS frame decoder A credit map indicating credit information of each mobile service data in the RS frame is generated, and CRC decoding is performed on the RS frame to refer to the number of errors generated and credit information of the credit map. A receiving system, characterized in that for correcting the error occurred. 7. The RS frame decoder of claim 6, wherein the RS frame decoder If the number of errors indicated in the error flag corresponding to each row in the RS frame is less than or equal to the number of parities added to the column direction of the RS frame, RS erasure decoding is performed in the column direction for all columns of the RS frame. A receiving system, characterized in that performing. 7. The RS frame decoder of claim 6, wherein the RS frame decoder If the number of errors indicated in the error flag corresponding to each row in the RS frame is greater than the number of parity added in the column direction of the RS frame, RS decoding and RS are performed for each column by referring to the credit information of the credit map. Determining one of the laser decoding and performing error correction with the determined error correction decoding method for the column. The method of claim 5, wherein And a derandomizer for derandomizing the error corrected mobile service data. delete The method of claim 1, At least one known data string of the plurality of known data strings is configured in the same pattern repeated two or more times. A data group comprising a mobile service data and a plurality of known data columns, at least two of the plurality of known data columns having different lengths, wherein one of the known data columns of the plurality of known data columns has a first pattern The remaining known data stream receives a broadcast signal composed of a second pattern different from the first pattern. Detecting a known data stream from the data group; And Compensating for channel distortion generated in the data of the data group by using the detected known data sequence. The method of claim 12, And a transmission parameter is inserted between the plurality of known data streams and received. The method of claim 13, Turbo decoding the mobile service data in the data group in which the channel distortion is compensated on a block basis based on the block encoding information included in the transmission parameter; And And controlling a power source to receive a data group including mobile service data desired to be received based on the transmission parameter. 15. The method of claim 14, wherein the decoding step A first decoding step of performing trellis decoding by matching the mobile service data of the data group input with the block size for turbo decoding with the mobile service data which is symbol-decoded and fed back; And And a second decoding step of performing symbol decoding on the trellis-decoded mobile service data and feeding back to the first decoding step. The method of claim 12, At least one data packet for mobile service data from a plurality of data groups, RS parity generated based on the at least one data packet, and the CRC checksum generated based on the at least one data packet and the RS parity. Comprising a RS frame comprising, and performing the CRC decoding and RS decoding for the RS frame to correct the error generated in the mobile service data. 17. The method of claim 16 wherein the error correction step is A credit map indicating credit information of each mobile service data in the RS frame is generated, and CRC decoding is performed on the RS frame to refer to the number of errors generated and credit information of the credit map. A data processing method of a receiving system, characterized in that for correcting the generated error. 18. The method of claim 17, wherein the error correction step is If the number of errors indicated in the error flag corresponding to each row in the RS frame is less than or equal to the number of parities added to the column direction of the RS frame, RS erasure decoding is performed in the column direction for all columns of the RS frame. A data processing method of a receiving system, characterized in that performing. 18. The method of claim 17, wherein the error correction step is If the number of errors indicated in the error flag corresponding to each row in the RS frame is greater than the number of parity added in the column direction of the RS frame, RS decoding and RS are performed for each column by referring to the credit information of the credit map. A method of processing data in a receiving system, characterized in that one of laser decoding is determined, and error correction is performed with the error correction decoding method determined for the column. The method of claim 16, And de-randing the error corrected mobile service data. delete The method of claim 12, And at least one known data column of the plurality of known data columns is configured in the same pattern repeated two or more times.

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