KR20140092278A - Apparatus and Method for transmitting/receiving Digital broadcasting signal - Google Patents

Abstract

The present invention relates to a digital transmission system and a data processing method which can reduce errors in mobile service data transmission. Accordingly, the present invention performs additionally mobile service data encoding before transmitting the mobile service data. Therefore, the mobile service data acquires strong robustness and is capable of reliably coping with rapid channel variation.

Description

[0001] The present invention relates to a digital broadcasting signal transmitting and receiving apparatus and method,

The present invention relates to a digital broadcasting system, and more particularly, to an apparatus and method for transmitting and receiving digital broadcasting.

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

Accordingly, the present invention provides a digital broadcasting system and a data processing method that are robust against channel variation and noise.

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

The present invention provides a digital broadcasting system and a data processing method that can maintain compatibility with an existing system by encapsulating mobile service data in the form of a TS packet instead of a transport stream (TS) packet format.

According to an aspect of the present invention, there is provided a method of processing data in a transmission system, the method comprising: receiving mobile service data and encapsulating the mobile service data into a transport stream (TS) packet; And multiplexing the main service data packet including the main service data and the encapsulated mobile service data packet and transmitting the multiplexed main service data packet to at least one transmitter located at a remote place.

Encapsulating the input mobile service data into an addressable section if the inputted mobile service data is in the IP format; And generating a predetermined unit of mobile service data packet including mobile service data in the form of the encapsulated section.

The encapsulating step may insert a transmission parameter including service-related information of the mobile service data in a specific area in the mobile service data packet.

The encapsulation step may insert null data into a specific area in the mobile service data packet.

According to another aspect of the present invention, there is provided a data processing method of a transmission system, comprising: inputting mobile service data into at least a part of a payload area in an Operations and Maintenance (OM) packet and outputting the data; And multiplexing the main service data packet including the main service data and the OM packet and transmitting the multiplexed main service data packet to at least one transmitter located at a remote location.

The OM packet output step may insert a transmission parameter including service-related information of the mobile service data into at least a part of the payload of the OM packet.

The OM packet output step may insert null data into at least a part of the payload of the OM packet.

The service multiplexer of the transmission system according to an embodiment of the present invention may include a packet encapsulator and a transport multiplexer.

The packet encapsulator may receive the mobile service data and encapsulate it in the form of a transport stream (TS) packet and output it as a mobile service data packet.

The packet encapsulator may insert the input mobile service data into at least a part of a payload area in an operations and maintenance (OM) packet and output it as a mobile service data packet.

The transport multiplexer may multiplex the main service data packet including the main service data and the mobile service data packet and transmit the main service data packet and the mobile service data packet to at least one transmitter located at a remote place.

Other objects, features and advantages of the present invention will become apparent from the detailed description of embodiments with reference to the accompanying drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. The structure and operation of the present invention shown in the drawings and described by the drawings are described as at least one embodiment, and the technical ideas and the core structure and operation of the present invention are not limited thereby.

INDUSTRIAL APPLICABILITY As described above, the digital broadcasting system and the data processing method according to the present invention are advantageous in that they are robust against errors when transmitting mobile service data through a channel and compatible with existing receivers. In addition, there is an advantage that mobile service data can be received without error even in a channel with ghost and noise more than the existing system.

Further, the present invention can provide robustness to the mobile service data and strongly cope with fast channel change by performing error correction coding and error detection coding on the mobile service data and transmitting the same.

When multiplexing the main service data and the mobile service data with the burst structure, the relative positions of the main service data packets are re-adjusted and multiplexed, thereby allowing a packet to be generated when the multiplexed main service data packet is received in the receiving system Jitter can be reduced.

In particular, according to the present invention, if the mobile service data format input to the service multiplexer is not a TS packet format, it is encapsulated in a TS packet format and transmitted to a transmitter, thereby maintaining compatibility with the existing system.

The present invention is more effective when applied to portable and mobile receivers where channel changes are severe and robustness against noise is required.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments but should be determined by the claims.

1 is a schematic block diagram of a digital transmission system according to an embodiment of the present invention;
Fig. 2 is a block diagram showing an embodiment of the service multiplexer of Fig. 1. Fig.
3 is a diagram showing an example of a syntax structure for a mobile service data packet that is encapsulated in a TS packet in an encapsulator as a TS packet of FIG.
4 is a diagram showing an example of a syntax structure for Mobile_service_data () according to the present invention.
5 is a diagram showing an example of a syntax structure for Tx_parameter () according to the present invention.
6 and 7 are diagrams showing examples of an RS code mode in a transmission parameter according to the present invention.
8 is a diagram showing examples of turbo code modes in transmission parameters according to the present invention;
9 is a diagram showing an example of a syntax structure for an OM packet according to the present invention.
10 is a block diagram showing an embodiment of the transmitter of FIG.
11 is a block diagram showing an embodiment of the preprocessor of FIG. 10
12A and 12B are diagrams showing examples of data structures before and after data deinterleavers according to the present invention;
13 is a block diagram of a receiving system according to an embodiment of the present invention

Definitions of terms used in the present invention

The terms used in the present invention are selected from general terms that are widely used in the present invention while considering the functions of the present invention. However, the terms may vary depending on the intention or custom of the artisan or the emergence of new technology. Also, in certain cases, there may be a term selected arbitrarily by the applicant, in which case the meaning thereof will be described in detail in the description of the corresponding invention. Therefore, it is to be understood that the term used in the present invention should be defined based on the meaning of the term rather than the name of the term, and on the contents of the present invention throughout.

Among the terms used in the present invention, main service data may include audio / video (A / V) data as data that can be received by a fixed receiving system. That is, the main service data may include HD (High Definition) or SD (Standard Definition) A / V data, and various data for data broadcasting may be included. The known data is previously known data by the promise of the transmitting / receiving side.

Also, in the present invention, the mobile service data includes at least one of mobile service data, pedestrian service data, and handheld service data. For convenience of description, Service data. At this time, the mobile service data may include not only M / P / H (Mobile / Pedestrian / Handheld) service data, but also service data indicating movement or carrying, Service data.

The mobile service data defined above may be data having information such as a program executable file, stock information, etc., or A / V data. In particular, the mobile service data may be service data for a portable or mobile terminal (or broadcast receiver), and may be A / V data having a smaller resolution and smaller data rate than the main service data. For example, if the A / V codec used for the existing main service is an MPEG-2 codec, the A / V codec for mobile service may be MPEG-4 AVC (Advanced Video Coding), and SVC (Scalable Video Coding). Also, any kind of data can 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.

The data service using the mobile service data may include a weather service, a traffic service, a securities service, a viewer participation quiz program, a real-time opinion survey, an interactive education broadcast, a game service, a plot of a drama, Providing information on programs by service, media, hourly, or topic that enables information service for information, information on past competitions of sports, profiles and grades of athletes, and product information and orders Or the like, and the present invention is not limited thereto.

The transmission system according to the present invention is capable of multiplexing the main service data and the mobile service data on the same physical channel without any influence on receiving the main service data in the existing receiving system. In particular, the present invention allows mobile service data to be multiplexed using a transport multiplexer used in an existing digital broadcasting system.

The transmission system of the present invention enables mobile service data not encapsulated in a transport stream (TS) packet format to be encapsulated and transmitted in the form of a TS packet.

The transmission system of the present invention performs additional coding on the mobile service data and inserts known data, that is, known data, into both the transmitting and receiving sides.

With this transmission system, mobile service data can be received and received in the receiving system, and stable reception of mobile service data is possible even with various distortions and noises occurring in the channel.

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

Here, 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. At this time, the transmitter 200 may be located in a plurality of different areas. In one embodiment, the plurality of transmitters may share the same frequency for the same channel, in which case the plurality of transmitters all transmit the same signal. Then, in the receiving system, the channel equalizer compensates the signal distortion due to the reflected wave to restore the original signal. In another embodiment, the plurality of transmitters may have different frequencies for the same channel.

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

At this time, the service multiplexer 100 receives at least one kind of main service data and PSI (Program Specific Information) / PSIP (table and program information) for each main service and encapsulates it into a TS packet )do.

The service multiplexer 100 receives at least one kind of mobile service data and encapsulates the mobile service data into a TS packet. At this time, the service multiplexer 100 may receive a PSI / PSIP table for the mobile service according to the input data format, or may not receive the PSI / PSIP table.

 And multiplexes the TS packets according to a preset multiplexing rule and outputs the multiplexed TS packets to the transmitter 200.

FIG. 2 is a detailed block diagram illustrating an embodiment of the service multiplexer. The PSI / PSIP generator 110 for a main service, the encapsulator 120 for a transport stream (TS) packet, And a controller 140 that controls the overall operation of the service multiplexer.

The transport multiplexer 130 may include a main service multiplexer 131 and a transport stream (TS) packet multiplexer 132.

Referring to FIG. 2, at least one kind of compression-encoded main service data and PSI / PSIP table data generated by the PSI / PSIP generator 110 for the main service are transmitted to the main service multiplexer 130 of the transport multiplexer 130 131). The main service multiplexer 131 encapsulates the input main service data and the PSI / PSIP table in the form of MPEG-2 TS packets, multiplexes the TS packets and transmits them to a TS packet multiplexer 132 Output. The data packet output from the main service multiplexer 131 will be referred to as a main service data packet for convenience of explanation.

Meanwhile, since the format of data transmitted to the STL is defined as a TS packet type, when the mobile service data input to the service multiplexer 100 is not a TS packet type, the mobile service data can be transmitted using the existing STL none.

The present invention is for transmitting mobile service data, not TS packet type, to a transmitter using STL. In the present invention, for convenience of description, the mobile service data other than the TS packet type is also referred to as the non-TS packet type mobile service data.

To this end, the TS packet encapsulator 120 divides the input non-TS packet type mobile service data into a payload having a size of 184 bytes, and attaches a 4-byte TS packet header (or MPEG header) And encapsulates it into a TS packet of 188 bytes.

For example, if the non-TS packet type mobile service data is an IP type mobile service data, the TS packet encapsulator 120 converts the IP type mobile service data into an addressable section structure (e.g., ATSC T3 / S13), and encapsulates the mobile service data in the form of an encapsulated section into an MPEG-2 TS format and outputs it to the TS packet multiplexer 132 of the transport multiplexer 130. [

That is, the TS packet encapsulator 120 divides the IP-type mobile service data into IP datagrams of a predetermined size and encapsulates the IP datagrams into addressable sections. And then encapsulates the encapsulated section-type mobile service data in an MPEG-2 TS (Transport Stream) format.

An addressable section has a form in which an IP datagram is added with a section header, a checksum, and a CRC. The form of such an addressable section structure may be structured to conform to a DSMCC (Digital Storage Media Command and Control) section format for private data transmission. The TS packet has a form in which an addressable section is divided into a payload of 184 bytes, and a 4-byte MPEG header is additionally added to each payload.

The TS packet encapsulator 120 TS packetizes the non-TS packet type mobile service data and outputs the TS packet to the TS packet multiplexer 132 of the transport multiplexer 130 as described above. If the PSI / PSIP table data for the mobile service data is inputted, the mobile service data and the PSI / PSIP table data for the mobile service data are multiplexed in units of TS packets and output to the TS packet multiplexer 132 of the transport multiplexer 130.

If the mobile service data input to the encapsulator 120 is a TS packet, the mobile service data is multiplexed with the corresponding PSI / PSIP table data without encapsulating the mobile service data into a TS packet, 130 to the TS packet multiplexer 132 of the base station.

If the PSI / PSIP table data is in a section format, the PSI / PSIP table data of the section type is encapsulated into a TS packet, then multiplexed in units of TS packet and mobile service data in TS packet format, To the TS packet multiplexer 132 of FIG.

The data packet output from the encapsulator 120 as the TS packet will be referred to as a mobile service data packet for convenience of description.

The transport multiplexer 130 multiplexes the main service data packet output from the main service multiplexer 131 and the mobile service data packet output from the encapsulator 120 as a TS packet and transmits the main service data packet to the transmitter 200 at a data rate of 19.39 Mbps. Lt; / RTI >

The controller 140 controls the encapsulation of the TS packet of the TS packet encapsulator 120 and the multiplexing of the main service multiplexer 131 and the TS packet multiplexer 132.

FIG. 3 shows an example of a syntax structure for a mobile service data packet encapsulated in a TS packet by the encapsulator 120, which is a TS packet of FIG.

The mobile service data packet encapsulated in the TS packet has a fixed length of 188 bytes and is largely composed of a header and a payload. At this time, the payload has a variable length of 0 to 184 bytes depending on whether or not an adaptation field is included in the mobile service data packet. If the adaptation field is not included, the payload of the mobile service data packet is fixed to 184 bytes. The mobile service data input to the encapsulator 120, which is a TS packet, is inserted into a payload of a mobile service data packet encapsulated in a TS packet and transmitted.

3 shows an example in which a Sync_byte field, a Transport_error_indicator field, a Payload_unit_start_indicator field, a Transport_priority field, a PID field, a Transport_scrambling_control field, an Adaptation_field_control field, a Continuity_counter field, an Adaptation_field (), and / or a Mobile_service_data () field are allocated to a mobile service data packet .

At this time, the Sync_byte field, the Transport_error_indicator field, the Payload_unit_start_indicator field, the Transport_priority field, the PID field, the Adaptation_field_control field, and the Continuity_counter field correspond to a 4-byte header.

The payload of the mobile service data packet is determined according to whether or not an adaptation field is included, and a payload field is assigned a Mobile_service_data () field. In the Mobile_service_data () field, non-TS packet type mobile service data input to the encapsulator 120, which is a TS packet, is allocated.

In FIG. 3, the Sync_byte field is allocated 8 bits in one embodiment, and indicates a synchronization byte of the corresponding mobile service data packet. The Sync_byte field value may be assigned, for example, 0x47.

The Transport_error_indicator field is assigned 1 bit in one embodiment and indicates whether an error has occurred in the corresponding mobile service data packet. In an embodiment of the present invention, the value of the Transport_error_indicator field may be used as identification information for identifying a mobile service data packet. For example, the Transport_error_indicator field of the mobile service data packet may be negotiated between the service multiplexer 100 and the transmitter 200 to set to 1.

The payload_unit_start_indicator field is allocated 1 bit in one embodiment, and is used to notify the start of one packet.

The Transport_priority field is assigned 1 bit in one embodiment and indicates the priority of the packets when there are packets having the same PID in the TS transmission path. In one embodiment, if the value of the Transport_priority field is 1, it means that the packet having the same PID has higher priority than the packet having the transport_priority = 0.

The PID field is assigned 13 bits in one embodiment and indicates a unique value for recognizing each packet. In an embodiment of the present invention, the PID field value may be used as identification information for identifying a mobile service data packet.

The Transport_scrambling_control field is assigned 2 bits in one embodiment and indicates whether the corresponding mobile service data packet has been scrambled.

The Adaptation_field_control field is allocated with 2 bits in one embodiment and indicates whether an adaptation field is included in the payload portion of the corresponding mobile service data packet. The Adaptation field control field indicates whether or not an Adaptation Field is included. For example, if the value of the Adaptation_field_control field is 10 or 11, it indicates that an adaptation field is included in the mobile service data packet. At this time, if the value is 10, it indicates that no payload area exists in the corresponding mobile service data packet, and if it is 11, the length of the payload area changes according to the length of the adaptation field. Also, if the Adaptation_field_control field value is 01, it indicates that the adaptation field is not included in the corresponding mobile service data packet, and 00 is an unused value.

The Continuity_counter field is used for a packet having the same PID and is incremented by 1 for each packet but does not increase when the adaptation_field_control field value is 00 or 10. That is, it does not increase when there is no payload. And the value of the adaptation_field_control field is rotated to 0 after the maximum value of 15 is reached.

The Continuity_counter field is followed by an Adaptation_field () field and / or a Mobile_service_data () field according to an adaptation_field_control field value.

That is, if the value of the adaptation_field_control field is 10 or 11, the Adaptation_field () field is included in the corresponding mobile service data packet. For example, if the value of the adaptation_field_control field is 10, no payload is allocated to the corresponding mobile service data packet, and thus no mobile service data is transmitted through the corresponding mobile service data packet.

If the adaptation_field_control field value is 01 or 11, the mobile service data packet includes a Mobile_service_data () field, and the mobile service data is transmitted through the Mobile_service_data () field.

For example, if the value of the adaptation_field_control field is 11, the payload size of the corresponding mobile service data packet is determined according to a data length inserted in the Adaptation_field () field. If the value of the adaptation_field_control field is 01, since the adaptation field is not included in the mobile service data packet, the payload is allocated to 184 bytes.

The Mobile_service_data () field is allocated 8 bits in one embodiment, and N1, which is a value repeating the Mobile_service_data () field, is a payload length in bytes of the corresponding mobile service data packet (= Field length). The Mobile_service_data () field is repeatedly performed by N1 to transmit the mobile service data. The mobile service data may include transmission parameters. That is, not only the mobile service data but also a transmission parameter, which is additional information to be transmitted to the transmitter 200 and / or the receiving system, may be inserted and transmitted in the Mobile_service_data () field.

In FIG. 3, the order, location, and meaning of the fields allocated to the mobile service data packet are merely examples for facilitating understanding of the present invention, and the order, location, meaning of fields allocated to the mobile service data packet, The number of fields can be easily changed by a person skilled in the art, so the present invention is not limited to the above embodiment.

FIG. 4 shows an example of a syntax structure for the Mobile_service_data () field of FIG. 3, and may include a Mobile_service_data_length field, a Tx_parameter () field, and / or a Mobile_service_data_payloads field.

The Mobile_service_data_length field is allocated 8 bits in one embodiment and indicates the total length of the Mobile_service_data () field. Here, the value indicated in the Mobile_service_data_length field is less than or equal to the payload length of the mobile service data packet. For example, if the value of the Mobile_service_data_length field is smaller than the payload length value of the corresponding mobile service data packet, the remaining shortage of the payload is referred to as null data (also referred to as a stuffing byte or dummy data) Can be filled.

And transmit the transmission parameters necessary for processing the mobile service data in the transmitter and / or receiver system via the Tx_parameter () field.

Following the Tx_parameter () field, a Mobile_service_data_payloads field may be included according to the length of the Tx_parameter () field.

8 bits are allocated to the Mobile_service_data_payloads field, and N2, which is a value repeating the Mobile_service_data_payloads field, is determined as a value obtained by subtracting the length of the Tx_parameter () field from the total length (= Mobile_service_data_length field value) of the Mobile_service_data do. The Mobile_service_data_payloads field is repeated by N2 to transmit pure mobile service data.

The transmission parameters sent to the Tx_parameter () field are additional information needed to process the mobile service data in the transmitter and / or receiver system. For example, the transmission parameters include mobile service identification information, data group information, region information within a data group, RS frame information, super frame information, burst information, turbo code information, and RS code information, . In addition, the burst information may include burst size information, burst period information, time until the next burst, and the like. The burst period refers to a period in which a burst for transmitting a mobile service of the same type is repeated and a burst size refers to the number of data groups included in one burst. The data group includes a plurality of mobile service data packets, and a plurality of such data groups are gathered to form one burst. A burst section means the period from the start of the current burst to the start of the next burst. The burst section (or burst-on section) in which the data group is included and the section in which the data group is not included ). One burst-on period is composed of a plurality of fields, and one field may include one data group.

The transmission parameters include information on how signals in the symbol area are encoded in order to transmit the mobile service data, multiplex information on how the main service data is multiplexed with the mobile service data or various kinds of mobile service data May be included.

The information included in the transmission parameter is merely an example for facilitating understanding of the present invention. Addition and deletion of information included in the transmission parameter can be easily changed by those skilled in the art. Therefore, the present invention is not limited to the above embodiment I will not.

FIG. 5 shows an example of a syntax structure for the Tx_parameter () field of FIG. 4, and shows an example in which a tx_parameter_length field, a service_id field, a super_frame_size field, a burst_size field, a burst_period field, an RS_code_mode field, and a turbo_code_mode field are allocated. The Tx_parameter () field may further include an Additional_parameter () field.

The tx_parameter_length field is allocated 8 bits in one embodiment and indicates the total length of the corresponding Tx_parameter () field.

The service_id field is assigned 4 bits in one embodiment and indicates a mobile service identifier, i.e., a mobile service ID, which can uniquely identify each mobile service.

The super_frame_size field is allocated 4 bits in one embodiment, and indicates the size of the superframe. That is, the transmitter 200 constructs an RS frame to perform error correction coding, and constructs a super frame by combining a plurality of error correction-coded RS frames. And perform permutation or interleaving on the super frame basis. In this case, the super_frame_size field indicates the number of RS frames constituting one super frame. The super_frame_size field is one of transmission parameters that are transmitted together when the corresponding mobile service data is transmitted from the transmitter 200 to the receiving system. The Super_frame_size field may be followed by a 2-bit reserved bit.

The burst_size field is allocated 6 bits in one embodiment and indicates the size of the burst. That is, the burst_size field indicates the number of data groups constituting one burst when the transmitter 200 transmits the mobile service data to the burst structure. The burst_size field is also one of the transmission parameters that are transmitted together when the corresponding mobile service data is transmitted from the transmitter 200 to the receiving system.

The burst_period field is allocated 8 bits in one embodiment, and indicates a period of a burst. That is, the burst_period field is a period in which bursts for transmitting the mobile service of the same type are repeated in the transmitter 200 when the transmitter 200 transmits the mobile service data to the burst structure. The burst_period field indicates the number of data fields. The burst_period field is also one of the transmission parameters that are transmitted together when the corresponding mobile service data is transmitted from the transmitter 200 to the receiving system. A 1-bit reserved bit may be allocated after the burst_period field.

The RS_code_mode field is an RS code mode to which 4 bits are allocated and is applied to each region in the data group. For example, a plurality of mobile service data packets are gathered to form a data group, and a plurality of data groups are gathered to form one burst. At this time, one data group is divided into a plurality of areas, for example, areas A, B, and C as shown in FIGS. 12A and 12B. The area classification of the data group and the description of each area will be described later in detail with reference to FIGS. 12A and 12B when describing the transmitter 200. FIG.

When one data group is divided into A, B and C regions as shown in FIGS. 12A and 12B, FIG. 6 shows an example of an RS code mode applied to the A / B region, and FIG. An example of the RS code mode is shown. For example, if the value of the RS_code_mode field is 1110, the transmitter 200 performs (235, 187) -RS coding on the RS frame to be allocated to the A / B area to generate 48 parities, (223, 187) -RS coding is performed on the frame to generate 36 parities.

The Turbo_code_mode field is assigned 3 bits in one embodiment, and indicates a mode of a turbo code applied to each region in the data group. 8 is a table showing an example of the turbo code mode applied to the A / B area and the C area in the data group. For example, if the value of the Turbo_code_mode field is 001, the transmitter 200 encodes the mobile service data to be allocated to the A / B area at a 1/2 coding rate, and the mobile service data to be allocated to the C area is 1/4 .

The Additional_parameter () field is a reserved field for future use, and in one embodiment, 8 bits are allocated. The Additional_parameter () field is repeatedly executed by a value obtained by subtracting 5 bytes from the tx_parameter_length field value. This is because 5 bytes are allocated from the tx_parameter_length field to the Turbo_code_mode field in FIG. As an example, the Additional_parameter () field may be filled with null data.

In this way, the service multiplexer 100 encapsulates the non-TS packet type mobile service data into the TS packet type mobile service data, inserts the mobile service data and / or the transmission parameter into the corresponding mobile service data packet, (200). Then, the transmitter 200 can process the mobile service data using transmission parameters.

The order, position, and meaning of fields allocated to the Tx_parameter () field in FIG. 5 are merely examples for facilitating understanding of the present invention, and the order, position, and meaning of fields allocated to the Tx_parameter The number of fields can be easily changed by a person skilled in the art, so the present invention is not limited to the above embodiment.

Meanwhile, the transport multiplexer 130 may use the transport multiplexer used in the existing digital broadcasting system as it is. That is, the data rate of the main service output from the main service multiplexer 131 is limited to a data rate of (19.39-K) Mbps, and the K Mbps corresponding to the remaining data rate is output from the TS packet encapsulator 120 To the mobile service data packet. By doing so, the already used transport multiplexer can be used without modification.

The transport multiplexer 130 multiplexes the main service data packet output from the main service multiplexer 131 and the mobile service data packet output from the encapsulator 120, which is a TS packet, and transmits the multiplexed data to the transmitter 200.

When the output data rate of the TS packet encapsulator 120 is allocated to K Mbps, the data rate L Mbps of the mobile service data input to the TS packet encapsulator 120 is equal to or less than 1/2 K Mbps do. This is because a pre-processor of the transmitter performs additional encoding on the mobile service data to increase the amount of data. As a result, the data rate of the mobile service data that can be input to the encapsulator 120, which is a TS packet, becomes small.

For example, the preprocessor of the transmitter increases the amount of mobile service data by performing RS frame coding and coding with at least a 1/2 coding rate on the mobile service data. For this reason, when TS packets are encapsulated only in the mobile service data input to the TS encapsulator 120, the output data rate of the TS packet encapsulator 120 becomes smaller than K Mbps.

In the present invention, in order to set the output data rate of the TS packet encapsulator 120 to K Mbps, the transmission parameter may be inserted when the mobile service data is inserted into the mobile service data packet as described above.

However, even if the transmission parameter is inserted into the mobile service data packet, the output data rate of the TS packet encapsulator 120 may be lower than K Mbps.

At this time, the TS packet encapsulator 120 can adjust the output data rate to K Mbps using at least one method.

In one embodiment, when configuring a mobile service data packet, it may be configured to insert only transmission parameters for a particular mobile service data packet and not insert mobile service data. In this case, null data may be inserted into a region where mobile service data is to be inserted in the mobile service data packet.

In another embodiment, the mobile service data packet may be configured not to include mobile service data as well as transmission parameters. In this case, null data may be inserted into the area where the transmission parameter in the mobile service data packet is inserted and the area where the mobile service data is inserted. Alternatively, the value of the tx_parameter_length field may be set to 0 in the corresponding mobile service data packet, so that the mobile service data packet may not be allocated an area for the transmission parameter.

The transmission parameter and the mobile service data packet not inserting the mobile service data may be referred to as a null data packet for convenience of explanation. At this time, identification information for distinguishing the mobile service data packet and the null data packet may be included in the corresponding packet and transmitted.

In another embodiment, the output data rate of the TS packet encapsulator 120 may be set to K Mbps by inserting null data into an area to be inserted with a transmission parameter in the mobile service data packet. In addition, identification information for identifying a mobile service data packet in which null data is inserted in the transmission parameter area may be included in the packet and transmitted. For example, in the Tx_parameter () field structure shown in FIG. 5, the Tx_parameter () field length is displayed in the tx_parameter_length field, and the service_id field includes identification information for identifying the mobile service data packet in which null data is inserted in the transmission parameter area Can be displayed. In this case, the transmission parameter area after the service_id field is filled with null data. That is, the service_id field may be used as an identifier for identifying the type of mobile service data transmitted in the corresponding mobile service data packet, or may be used as an identifier for identifying a mobile service data packet in which null data is inserted in the transmission parameter area have. The identification information for identifying the mobile service data packet in which the null data is inserted in the transmission parameter area is not limited to the above embodiment.

In another embodiment, null data may be inserted into a payload of an Operations and Maintenance (OM) packet (or an OMP) to set the output data rate of the TS packet encapsulator 120 to K Mbps .

That is, a packet called an Operations and Maintenance Packet (OMP) is defined for the purpose of operation and management of the transmission system. For example, the OMP conforms to the format of the MPEG-2 TS packet and the corresponding 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, and the remaining 183 bytes are the actual data as the OM_payload field.

According to the present invention, it is possible to distinguish the OM packet inserted to match the data rate by using a predetermined value among the unused field values of the OM_type field. In this case, the OM_payload field in the OM packet can be filled with null data. Then, the transmitter 200 can find the OMP by looking at the PID. The OM_type field in the OMP can be parsed to know whether null data is inserted in the OM_payload field of the corresponding packet. That is, when the OM packet is input in the transmitter 200, it is possible to know whether the input OM packet is a packet transmitted to match the data rate.

Meanwhile, identification information is necessary for the transmitter 200 to distinguish and process the main service data packet and the mobile service data packet. The identification information may be a predetermined value in accordance with the promise of the transmitting / receiving side, may be composed of separate data, or may be used by modifying a value of a predetermined position in the data packet.

In an embodiment, a different PID (Packet Identifier) may be assigned to the main service data packet and the mobile service data packet to distinguish the main service data packet from the mobile service data packet.

In another embodiment, the main service data packet and the mobile service data packet can be distinguished by modifying the synchronization byte in the header of the mobile service data packet. For example, the synchronous byte of the main service data packet is output without modification as it is defined in ISO / IEC13818-1 (for example, 0x47), and the synchronous byte of the mobile service data packet is transformed and output, It is possible to distinguish between the data packet and the mobile service data packet. Conversely, the main service data packet and the mobile service data packet can be distinguished by modifying the synchronization byte of the main service data packet and outputting the synchronization byte of the mobile service data packet without modification. There are various methods for modifying the sync byte. For example, the synchronization byte may be inverted bit by bit, or only some bits may be inverted.

In another embodiment, the transport_error_indicator flag in the header of the data packet may be used as identification information to distinguish the main service data packet from the mobile service data packet. As an example, the transport_error_indicator flag of the mobile service data packet may be set to 1, and the transport_error_indicator flag of all data packets other than the mobile service data packet may be reset to zero to distinguish the mobile service data packet.

As described above, any of the identification information that can distinguish the main service data packet and the mobile service data packet is possible, and thus the present invention is not limited to the above-described embodiments.

Meanwhile, in the TS packet encapsulator 120, the mobile service data input in the non-TS packet format may be inserted into the OM_payload field in the OM packet and transmitted to the transmitter 200.

FIG. 9 shows a syntax structure of an OM packet according to the present invention. In particular, FIG. 9 shows a syntax structure of 184 bytes excluding a 4-byte packet header. In FIG. 9, the Mobile_service_data field of FIG. 4 is inserted after the OM_type field to transmit mobile service data.

At this time, the OM packet needs identification information for identifying that the mobile service data is inserted and transmitted, and an OM_type field of the corresponding OM packet may be used as an identifier.

In the present invention, it is possible to distinguish the OM packet from the unused field values of the OM_type field as a packet for transmitting mobile service data. Then, the transmitter 200 can find the OMP by looking at the PID, and can know whether or not the mobile service data is inserted in the corresponding packet by parsing the OM_type field in the OMP.

That is, mobile service data having a syntax structure of Mobile_service_data () as shown in FIG. 4 may be included in the OM_payload field of the OM packet, and whether the mobile service data is included may be displayed in the OM_type field.

The Mobile_service_data () field of FIG. 4 includes a Tx_parameter () syntax structure as shown in FIG. 5, so that a transmission parameter can also be inserted into the OM packet. As described above, the null data may be inserted into the Mobile_service_data () field of the OM packet to adjust the output data rate of the TS packet encapsulator 120 to K Mbps. At this time, the OM_type field can be used as an identifier for identifying the OM packet into which null data is inserted.

As described above, the TS packet encapsulator 120 transmits the TS packet type mobile service data to the transport multiplexer 130 while setting the output data rate to K Mbps.

The transport multiplexer 130 multiplexes the main service data packet output from the main service multiplexer 131 and the mobile service data packet (or OM packet) output from the encapsulator 120, which is a TS packet, to generate 19.39 Mbps data To the transmitter (200).

FIG. 10 is a block diagram of a transmitter 200 according to an embodiment of the present invention. The transmitter 200 includes a demultiplexer 211, a packet jitter mitigator 212, a TS packet decipherer 213, A pre-processor 214, a packet multiplexer 215, a post-processor 220, a sync multiplexer 230, and a transmission unit 240 .

The data packet transmitted from the service multiplexer 100 is input to a demultiplexer 211 of the transmitter 200.

The demultiplexer 211 distinguishes whether the incoming data packet is a main service data packet or a mobile service data packet.

The main service data packet separated in the demultiplexer 211 is provided to the packet jitter separator 212 and the mobile service data packet is provided to the preprocessor 214 via the TS packet decipherer 213.

There are various methods of distinguishing whether the data packet input to the demultiplexer 211 is a main service data packet or a mobile service data packet.

In one embodiment, the mobile service data packet and the main service data packet can be distinguished according to the PID value of the input data packet. That is, the demultiplexer 211 provides the data packet having the PID assigned to the mobile service data packet to the TS packet decapsulator 213, and the data packet having the other PIDs is provided to the packet jitter separator 212, .

In another embodiment, the demultiplexer 211 can distinguish whether the data packet input according to the value of the transport_error_indicator flag in the input data packet is a mobile service data packet or a main service data packet.

In another embodiment, when mobile service data is inserted into an OM packet and then transmitted, the demultiplexer 211 can find the OMP by viewing the PID. The OM_type field in the OMP is parsed, and the OM_payload field of the corresponding mobile It is possible to know whether the service data is inserted or not. If the input data packet is an OM packet in which mobile service data is inserted, it is provided to the TS packet decapsulator 213.

The TS packet decipherer 213 restores the mobile service data before encapsulation, which is a TS packet, from the input mobile service data packet (or OM packet), and outputs the restored mobile service data to the preprocessor 214. In the case where the transmission parameter is inserted in the mobile service data packet (or OM packet), the transmission parameters are also restored and necessary blocks (for example, the preprocessor 214, the packet multiplexer 215, etc.) The parameters are provided in corresponding blocks so that they can be utilized.

For example, the transmission parameters may include mobile service identification information, superframe information, burst size information, burst period information, turbo code information, RS code information, and the like.

The information included in the transmission parameter is merely an example for facilitating understanding of the present invention. Addition and deletion of information included in the transmission parameter can be easily changed by those skilled in the art. Therefore, the present invention is not limited to the above embodiment I will not.

At this time, if null data is inserted to match the output data rate of the service multiplexer 100 to the mobile service data packet input to the TS packet decapsulator 213, the TS packet decapsulator 213 transmits the null It does not process the data and does not provide it as another block. That is, the null data inserted in the mobile service data packet is discarded without being processed. For example, the null data may be inserted into the payload area of the incoming mobile service data packet, inserted only into the transmission parameter area of the payload area, or inserted only into the mobile service data area of the payload area It may be inserted. As another example, the null data may be inserted in the OM_payload field of the OM packet.

The mobile service data packet input to the TS packet decapsulator 213 may include identification information for identifying whether the packet includes data, and the TS packet decapsulator 213 may use the identification information The null data can be extracted from the input data packet.

For example, it is possible to extract null data using the PID field in the header of an input data packet, or to extract null data using the service_id field in the transmission parameter area of the payload. Also, if NULL data is inserted in the OM_payload field of the OM packet, the TS packet decipherer 213 can determine whether null data is inserted in the OM_payload field of the corresponding packet by parsing the OM_type field in the OMP.

The preprocessor 214 performs additional encoding on the mobile service data and outputs it to the packet multiplexer 215 in order to quickly and strongly respond to noise and channel changes.

11 is a block diagram showing an embodiment of the preprocessor 214 according to the present invention and includes a data renderer 401, an RS frame encoder 402, a block processor 403, a group formatter 404, A deinterleaver 405, and a packet formatter 406.

The preprocessor 214 according to the present invention performs additional encoding on the input mobile service data with reference to the transmission parameters provided by the TS packet decipherer 213 as one embodiment.

That is, the data renderer 401 randomizes the input mobile service data and outputs the data to the RS frame encoder 402. At this time, the data renderer 221 of the post-processor 220 may skip the process of rendering the mobile service data by performing the rendering of the mobile service data in the data renderer 401.

The RS frame encoder 402 forms a RS frame by combining a plurality of pieces of mobile service data, which are input after being rendered, and performs at least one of an error correction encoding process and an error detection encoding process on an RS frame basis. In addition, a plurality of RS frames may be gathered to form a super frame, and interleaving or permutation may be performed on a super frame basis. This provides robustness to mobile service data, and can cope with extremely poor and rapidly changing radio environments.

That is, when the RS frame encoder 402 performs low-mix operation for mixing the respective rows of the super frame in predetermined rules, the positions of the rows before and after the low-mix are different in the super frame. Even if an error that can not be corrected is contained in one RS frame to be decoded because a section in which a large number of errors occur is very long in the super-frame-by-super-frame blurring, these errors are distributed throughout the super frame, The decoding capability is improved.

The RS frame encoder 402 applies RS coding for error correction coding and CRC (Cyclic Redundancy Check) coding for error detection coding. When the RS coding is performed, parity data to be used for error correction is generated, and CRC coding is performed to generate CRC data to be used for error detection.

The RS encoding is one of FEC (Forward Error Correction). The FEC refers to a technique for correcting an error occurring in a transmission process. The CRC data generated by the CRC encoding can be used to indicate whether the mobile service data is transmitted through the channel and is damaged by an error. The present invention may use other error detection coding methods other than CRC coding, or may improve the overall error correction capability on the receiving side by using an error correction coding method.

Here, the RS frame encoder 402 refers to the RS frame configuration, the RS encoding, the CRC encoding, the super frame configuration, and the RS frame configuration with reference to the preset transmission parameters and / or the transmission parameters provided by the TS packet decapsulator 213. [ It is possible to perform low-level mixing on a superframe basis.

For example, if the RS code mode (see FIGS. 6 and 7) in the transmission parameter is 1110, the RS frame encoder 402 performs (235, 187) -RS encoding on the RS frame to be allocated to the A / B area 48 parities are generated, and (223, 187) -RS coding is performed on the RS frame to be allocated to the C region, thereby generating 36 parities.

The mobile service data encoded by the RS frame encoder 402 is input to the block processor 403 as described above.

The block processor 403 encodes the input mobile service data again with G / H (where G < H) and outputs the encoded data to the group formatter 404.

That is, the block processor 403 divides the mobile service data input in byte units into bits, encodes the separated G bits into H bits, and converts the converted G bits into bytes. For example, when 1 bit of input data is encoded into 2 bits, G = 1 and H = 2. If 1 bit of input data is encoded into 4 bits, G = 1 and H = 4. In the present invention, for convenience of explanation, the former is referred to as 1/2 coding rate coding (or 1/2 coding) and the latter coding to 1/4 coding rate (or 1/4 coding) do.

This is because, when 1/4 encoding is used, a higher error correction capability can be obtained because of a higher code rate than a 1/2 encoding. For this reason, the data encoded at the 1/4 code rate in the group formatter 404 at the subsequent stage is allocated to the area where reception performance may deteriorate, and the data encoded at the 1/2 code rate is allocated to the area The effect of reducing the difference in performance can be obtained.

At this time, the block processor 403 can also receive signaling information such as a transmission parameter, and this signaling information also carries out a 1/2 coding or a 1/4 coding in the same manner as the mobile service data processing. Then, the signaling information is regarded as mobile service data and processed.

Meanwhile, the group formatter 404 inserts the mobile service data output from the block processor 403 into a corresponding area in a data group formed according to a predefined rule, Data is also inserted into the corresponding area in the data group.

At this time, the data group can be divided into at least one layered area, and the type of mobile service data inserted in each area can be changed according to characteristics of each layered area. And each area can be categorized based on the reception performance in the data group as an example.

In the present invention, one data group is divided into A, B and C regions in the data structure before data deinterleaving. At this time, the group formatter 404 can allocate the mobile service data input by RS encoding and block coding to the corresponding area by referring to the transmission parameter.

FIG. 12A shows data after data interleaving, and FIG. 12B shows data in which data before data interleaving are sorted. That is, the data structure as shown in FIG. 12A is transmitted to the receiving system.

The data group formed by the structure shown in FIG. 12A is input to the data deinterleaver 405.

12A shows an example of dividing a data group into three regions, for example, a region A, a region B and a region C in the data structure before data deinterleaving have.

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

12A shows a case where the A region is divided into five sub regions A1 to A5 and the B region is divided into two sub regions B1 and B2 and the C region is divided into three sub regions C1 to C3 .

The A to C regions are classified based on regions having similar reception performance in a data group. At this time, the type of mobile service data to be inserted may be changed according to the characteristics of each area.

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

The reason why the data group is divided into a plurality of regions is to differentiate each use. That is, a region where there is no interference of the main service data or a region where there is no interference can show robust reception performance than the region where no interference occurs. In addition, when a system for inserting and transmitting known data into a data group is applied, when it is desired to periodically insert consecutive long known data into mobile service data, an area without interference of main service data (for example, ), It is possible to periodically insert known data of a predetermined length. However, it is difficult to periodically insert the known data into the areas where interference of the main service data exists (for example, areas B and C) due to the interference of the service main service data, and it is also difficult to continuously insert the known data.

A specific example in which A (A1 to A5), B (B1, B2), and C (C1 to C3) are allocated in the data group will be described with reference to FIG. 12A. The size of the data group in FIG. 12A, the number of layered areas in the data group and the size of each area, the number of mobile service data bytes insertable into each layered area, and the like are one embodiment for describing the present invention.

At this time, in the group formatter 404, a data group including a position at which a field sync is inserted is formed, so that a data group can be configured as described below.

That is, the A area is an area where a long known data sequence in the data group can be periodically inserted, and includes an area in which main service data is not mixed (for example, A2 to A5). The area A includes an area (for example, A1) between the field sync area to be inserted in the data group and the area where the first known data sequence is to be inserted. The field sync area has a segment length (i.e., 832 symbols) existing in the ATSC.

In one embodiment, mobile service data of 2428 bytes in the area A1, 2580 bytes in the area A2, 2772 bytes in the area A3, 2472 bytes in the area A4, and 2772 bytes in the area A5 can be inserted in the area A1. In the mobile service data, the trellis initialization, the known data, the MPEG header, and the RS parity are excluded.

In the case of the A region having the known data streams as described above, the receiving system can perform equalization using channel information obtained from the known data or the field synchronization, so that robust equalization performance can be obtained.

(For example, B1 area) located in the front 8 segments of the field sync area in the data group (in the front of the A1 area in time) and the 8th segment after the last known data row inserted in the data group (Located temporally behind the area A) (e.g., area B2) located in the segment. For example, mobile service data of 930 bytes in the B1 area and 1350 bytes in the B2 area can be inserted. Similarly, in the mobile service data, the trellis initialization, the known data, the MPEG header, and the RS parity are excluded.

In the case of the B region, since the receiving system can perform equalization using the channel information obtained in the field synchronization period and perform equalization using the channel information obtained from the last known data stream, You can respond to changes.

The C region includes a preceding 9th segment of the field sync area and is located within 30 segments ahead of it (temporally located in front of the A region) (e.g., C1 region) (E.g., C2 region) located within 12 segments including the ninth segment (temporally behind the A region), and an area located within the 32 segments following the C2 region (e.g., the C3 region) .

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

At this time, since the C region (for example, the C1 region) located temporally before the A region is considerably far away from the field synchronization which is the nearest known data, the channel information obtained from the field synchronization at the time of channel equalization in the receiving system may be used, Or the latest channel information of the previous data group may be used. The C region (for example, the C2 and the C3 region) located temporally behind the A region is used for equalization when the channel is equalized using the channel information obtained from the last known data sequence at the time of channel equalization in the receiving system It may not be perfect. Therefore, the C region may have less equalization performance than the B region.

Assuming that the data group is allocated as a plurality of layered regions as described above, the block processor 403 may encode the mobile service data to be inserted in each region at a different code rate according to the turbo code mode in the transmission parameter .

For example, if the turbo code mode (see FIG. 8) is 011, the mobile service data to be inserted in the area A1 to A5 in the area A is encoded by the block processor 403 at a 1/2 coding rate, And the encoded mobile service data may be inserted into the area A1 to A5 in the group formatter 404.

The mobile service data to be inserted in the areas B1 and B2 in the B area is encoded by the block processor 403 at a coding rate of 1/4 that has a higher error correction capability than the 1/2 coding rate, May be inserted into the areas B1 and B2 in the group formatter 404.

The mobile service data to be inserted in the C1 to C3 area in the C area is encoded by the block processor 403 at a 1/4 coding rate and the encoded data is divided into the C1 to C3 area Or may be left as an unused area for future use.

In addition, in the group formatter 404, signaling information including transmission parameters and the like are inserted into the data group separately from the mobile service data.

The transmission parameters to be transmitted from the transmitter 200 to the reception system include, for example, data group information, intra-data group area information, the number of superframe sizes (SFS) constituting a superframe, The number of RS parities per column (P), whether or not checksums are added to determine whether there is an error in the row direction of the RS frame, if so, its type and size (currently 2 bytes are added by CRC) The RS frame is transmitted in one burst period, so it is equal to the number of data groups (Burst size: BS) in one burst, and there are a turbo code mode and an RS code mode. The transmission parameters required for burst reception are a burst period (BP) - a burst period counted from the start of one burst to the start of the next burst. (PFI) in a superframe, a group index (GI) currently being transmitted in one RS frame (burst), and a burst size. Depending on the burst operation method, there is a remaining number of fields (Time to Next Burst: TNB) remaining until the start of the next burst. By transmitting such information as a transmission parameter, You can also tell the distance (number of fields).

The information included in the transmission parameter is merely an example for facilitating understanding of the present invention. Addition and deletion of information included in the transmission parameter can be easily changed by those skilled in the art. Therefore, the present invention is not limited to the above embodiment I will not.

In the group formatter 404, for example, the turbo code mode information as shown in FIG. 8 is inserted into a part of an area where the first known data sequence in the A area can be inserted. The data group information, the super frame information, the burst information, and the like are inserted into a part of the area where the mobile service data in the area A can be inserted.

In addition, in the group formatter 404, in addition to the encoded mobile service data output from the block processor 403, an MPEG header position holder, an unstructured RS parity position holder, a main 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 in the areas B and C based on the input of the data deinterleaver as shown in FIG. 12A. For example, the position holder for the MPEG header may be allocated in front of each packet when viewed from the output data after the data deinterleaving.

In addition, the group formatter 404 inserts known data location holders for inserting known data generated by a predetermined method or inserting known data later. In addition, a position holder for initializing the Trellis Encoding Module 226 is inserted into the corresponding area. In one embodiment, the initialization data location holder may be inserted before the known data sequence.

At this time, 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 location holder), MPEG header location holder, RS parity location holder, It can be different.

The output of the group formatter 404 is input to the data deinterleaver 405. The data deinterleaver 405 receives data in the data group and the position holder output from the group formatter 404 as an inverse process of data interleaving Deinterleaves the packet and outputs it to the packet formatter 406. That is, when the data in the data group and the location holder configured as shown in FIG. 12A are deinterleaved in the data deinterleaver 405, the data group output to the packet formatter 406 has a structure as shown in FIG. 12B.

The packet formatter 406 removes the main service data position holder and the RS parity position holder, which are allocated for deinterleaving from the deinterleaved data, collects the remaining parts, PID (or a PID not used in the main service data packet).

The packet formatter 406 may insert the known known data into the known data location holder when the known data location holder is inserted in the group formatter 404 or may insert the known data location holder It can be output without adjustment.

Then, the packet formatter 406 divides the data in the packet formatted data group into 188-byte mobile service data packets (i.e., MPEG TS packets) and provides them to the packet multiplexer 215.

The packet multiplexer 215 multiplexes the mobile service data packet output from the preprocessor 214 and the main service data packet output from the packet jitter separator 212 according to a predefined multiplexing method, To the data renderer 221 of the processor 220. The multiplexing method can be adjusted by various parameters of the system design.

As one of the multiplexing methods of the packet multiplexer 215, a burst period may be allocated on the time axis, a plurality of data groups may be transmitted in a burst period, and only main service data may be transmitted in a non-burst period. In this case, the main service data may be transmitted in the burst period. In addition, the packet multiplexer 215 can know the number and period of data groups included in one burst by referring to information on transmission parameters, for example, burst size and burst period.

In this case, the mobile service data and the main service data may be mixed in one burst period, and only the main service data exists in the burst period. Therefore, the main service data interval for transmitting the main service data exists in both the burst period and the non-burst period. In this case, the number of main data packets included in the main service data interval in the burst interval and the interval in the non-burst interval may be different from each other or may be the same.

When the mobile service data is transmitted in the burst structure as described above, the receiving system that receives only the mobile service data receives the data by turning on the power only in the burst period and turns off the power in the period in which only the main service data is transmitted, The power consumption of the receiving system can be reduced.

However, since the mobile service data group is multiplexed between the main service data in the packet multiplexing process, the temporal location of the main service data packet is relatively moved. In the system target decoder (i.e., MPEG decoder) for main service data processing of the receiving system, only the main service data is received and decoded, and the mobile service data packet is recognized as a null packet.

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

At this time, in the system target decoder, packet buffers generated by the packet multiplexer 215 are not a big problem in the case of video data, because buffers of various stages for video data exist and their sizes are considerably large. However, the size of the buffer for audio data of the system target decoder can be a problem because it is small.

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

Accordingly, the packet jitter canceller 212 re-adjusts the relative position of the main service data packet so that overflow or underflow does not occur in the buffer of the system target decoder.

Embodiments for rearranging the positions of the audio data packets of the main service data in order to minimize the influence on the operation of the audio buffer will be described. The packet jitter decimator 212 rearranges the audio data packet in the main service data interval so that the audio data packet of the main service can be located as uniformly as possible.

The reference for rearranging the audio data packet of the main service in the packet jitter decimator 212 is as follows. At this time, it is assumed that the packet jitter separator 212 knows the multiplexing information of the packet multiplexer 215 of the subsequent stage.

First, if there is one audio data packet in the main service data section in the burst section, for example, in the main service data section located between the two mobile service data groups, the audio data packet is placed in front of the main service data section If two or more exist, they are placed at the beginning and the end. If three or more exist, the first and the last are arranged, and the remaining are arranged at equal intervals therebetween.

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

Third, after the burst period ends, the audio data packet is arranged first in the main service data section.

The packets which are not audio data are arranged in a space excluding the positions of the audio data packets in the input order.

Meanwhile, if the position of the main service data packet is relocated as described above, the corresponding PCR (Program Clock Reference) value should be modified accordingly. The PCR value is inserted into a specific area of the TS packet as a time reference value for matching the time of the MPEG decoder and transmitted. The packet jitter canceller 212 also performs the function of correcting the PCR value.

The output of the packet jitter separator 212 is input to a packet multiplexer 215. The packet multiplexer 215 multiplexes the main service data output from the packet jitter decimator 212 and the mobile service data output from the preprocessor 214 into a burst structure according to a predetermined multiplexing rule, And outputs it to the data renderer 221 of the processor 220.

If the input data is a main service data packet, the data renderer 221 performs rendering in the same manner as a conventional renderer. In other words, the synchronous bytes in the main service data packet are discarded and the remaining 187 bytes are randomly generated using internally generated pseudo random bytes, and then output to the RS encoder / unscrambler RS encoder 222.

However, if the input data is a mobile service data packet, the synchronization byte of the 4-byte MPEG header included in the mobile service data packet is discarded and the remaining 3 bytes are subjected to rendering, and the remaining mobile service data excluding the MPEG header And outputs it to the RS encoder / unscrambler RS encoder 222 without performing randomization. This is because the data renderer 401 has previously performed the randomization on the mobile service data. Randomization may or may not be performed on known data (or known data location holders) and initialization data location holders included in the mobile service data packet.

The RS encoder / unscrambler RS encoder 222 performs RS encoding on the data to be rendered or bypassed by the data randomizer 221, adds 20 bytes of RS parity, and then transmits the data to the data interleaver 223, . If the input data is a main service data packet, the RS encoder / unscrambler RS encoder 222 performs systematic RS coding in the same manner as in the existing broadcasting system to add 20 bytes of RS parity after 187 bytes of data. If the packet is a mobile service data packet, 20 bytes of RS parity obtained by performing unstructured RS coding on the parity byte location defined in the packet is inserted.

The data interleaver 223 is a convolutional interleaver on a byte basis.

The output of the data interleaver 223 is input to a parity substitution unit 224 and an unstructured RS encoder 225.

On the other hand, in order to convert the output data of the trellis encoder 226 located at the rear end of the parity substitution unit 224 into known data defined by an appointment at the transmitting / receiving end, initialization of the memory in the trellis encoder 226 . That is, the memory of the trellis encoder 226 must be initialized before the inputted known data sequence is Trellis encoded.

At this time, the beginning of the inputted known data sequence is not an actual known data but an initialized data position holder inserted in the group formatter 404. Therefore, it is necessary to generate the initialization data immediately before the input known-data sequence is Trellis-coded and to replace it with the corresponding Trellis-memory initialization data location holder.

The trellis memory initialization data is determined based on the memory state of the trellis encoder 226 and is generated. Also, it is necessary to recalculate the RS parity due to the influence of the replaced initialization data and to replace it with the RS parity output from the data interleaver 223.

Therefore, in the non-systematic RS encoder 225, the mobile service data packet including the initialization data location holder to be replaced with the initialization data is input from the data interleaver 223, and the initialization data is input from the trellis encoder 226 Receive. Then, the initialization data position holder of the input mobile service data packet is replaced with the initialization data, the RS parity data added to the mobile service data packet is removed, and the new unstructured RS parity is calculated and output to the parity substitution unit 225. The parity substitution unit 225 selects the output of the data interleaver 223 in the mobile service data packet and the output of the unstructured RS encoder 225 in the RS parity and outputs it to the trellis encoding unit 226. [ .

Meanwhile, the parity substitution unit 224 selects RS data and RS data output from the data interleaver 223 when a mobile service data packet including no initialization data location holder to be input or replaced is input, And outputs it to the trellis encoder 226.

The trellis encoder 226 performs 12-way interleaving on the data of each byte unit in units of symbols, performs trellis encoding on the data, and outputs the resultant data to the synchronous multiplexer 230.

The synchronous multiplexer 230 inserts the field sync and the segment sync into the output of the trellis encoder 226 and outputs it to the pilot inserter 241 of the transmitter 240.

The pilot inserted data in the pilot inserter 241 is modulated by a modulator 242 in a predetermined modulation scheme, for example, a VSB scheme, and then transmitted to each reception system via an RF up-converter 243.

13 shows a block diagram of a receiving system according to an embodiment of the present invention. In the receiving system of FIG. 13, the reception performance can be improved by performing carrier synchronization recovery, frame synchronization recovery, and channel equalization using the known data information inserted in the mobile service data interval in the transmission system.

The receiving system according to the present invention includes a tuner 901, a demodulator 902, an equalizer 903, a known data detector 904, a block decoder 905, a data deformatter 906, an RS frame decoder 907 , And a data derandomizer 908. [ The receiving system may further include a data deinterleaver 909, an RS decoder 910, and a data derandomizer 911. The data de-formater 906, the RS frame decoder 907 and the derandomizer 908 are referred to as a mobile service data processing section and the data deinterleaver 909, the RS decoder 910, And the data derandomizer 911 will be referred to as a main service data processing unit.

That is, the tuner 901 tunes the frequency of a specific channel and downconverts it to an intermediate frequency (IF) signal, and outputs it to the demodulator 902 and the known data detector 904.

The demodulator 902 performs automatic gain control, carrier recovery, and timing recovery on the IF signal to generate a baseband signal, and outputs the baseband signal to an equalizer 903 and a known data detector 904.

The equalizer 903 compensates for the distortion on the channel included in the demodulated signal and outputs the compensated signal to the block decoder 905.

At this time, the known data detector 904 detects the known data position inserted at the transmitting side from the input / output data of the demodulator 902, that is, the data before demodulation or the demodulated data, To the demodulator 902 and the equalizer 903, a symbol sequence of the known data generated at the position. Also, the known data detector 904 transmits information to the block decoder 905 so that the mobile service data that has been further encoded at the transmitting end and the main service data that has not undergo further coding can be distinguished by the block decoder 905, . 23, the information detected by the known data detector 904 may be used in a general manner in the receiving system, and may be used in the data deformatter 906 and the RS frame decoder 907 or the like have.

The demodulator 902 can improve demodulation performance by using the known data symbol sequence in timing recovery or carrier recovery, and the equalizer 903 can similarly improve the equalization performance using the known data . The decoding result of the block decoder 905 may be fed back to the equalizer 903 to improve the equalization performance.

The equalizer 903 can perform channel equalization in various ways. In the present invention, channel equalization is performed by estimating a channel impulse response (CIR) in a field synchronization period and a known data interval. For example.

Particularly, in the present invention, the estimation and the 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 estimates the CIR using known data and field synchronization, which are known to the location and contents according to the promise of the transmitting / receiving side, so as to perform channel equalization more stably.

12A, a region A is divided into regions A1 to A5, a region B is divided into regions B1 and B2, a region C1 is divided into regions C1 to C3 As shown in FIG.

Let CIR_FS be a CIR estimated from field synchronization in the data structure as shown in FIG. 12A, and let CIR_N0, CIR_N1, CIR_N2, CIR_N3, and CIR_N4 be CIRs estimated from five known data sequences in the A region.

The present invention performs channel equalization on data in a data group using the CIR estimated from the field sync and known data streams. At this time, one of the estimated CIRs is used as it is according to the characteristics of each region of the data group And CIRs generated by interpolation of at least a plurality of CIRs or extrapolation are used.

Here, interpolation is a function value at a certain point between Q and S when a function value F (Q) at a point Q and a function value F (S) at a point S are known for a certain function F (x) And the most simple example of the interpolation is linear interpolation. The linear interpolation technique is the simplest example of a number of interpolation techniques, and various other interpolation techniques may be used in addition to the above-mentioned method. Therefore, the present invention is not limited to the above example.

Also, extrapolation is a process that determines the function value F (Q) at time Q and the function value F (S) at time S for a certain 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 example of a number of extrapolation techniques, and various extrapolation techniques can be used in addition to the above-described method, so that the present invention is not limited to the above example.

That is, in the case of the C1 region, CIR_N4 estimated from the previous data group, CIR_FS estimated from the current data group to be channelized, or CIR generated by extrapolating CIR_FS and CIR_N0 of the current data group, Can be performed.

In the case of the B1 region, various methods such as the C1 region are applicable. In one embodiment, channel equalization may be performed using a CIR generated by linear extrapolation of CIR_FS and CIR_N0 estimated in the current data group. Alternatively, channel equalization may be performed using CIR_FS estimated in the current data group.

In the case of the area A1, channel equalization can be performed using the CIR generated by interpolating CIR_FS and CIR_N0 estimated in the current data group. Alternatively, channel equalization may be performed using one of CIR_FS and CIR_N0 estimated in the current data group.

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

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

By doing so, optimum performance can be obtained at the time of channel equalization with respect to the data inserted in the data group.

The methods for obtaining CIRs for channel equalization in each region of the data group described in the present invention are embodiments for facilitating understanding of the present invention. Since these methods can be applied to a wide variety of applications, It will not be limited to the one presented.

On the other hand, when the data input to the block decoder 905 after channel equalization in the equalizer 903 is subjected to both block coding and trellis coding on the transmitting side (for example, data in the RS frame, signaling information data , The trellis decoding and the block decoding are performed inversely to the transmitting side, and only the trellis decoding is performed if the data is the data in which only the trellis coding is performed without performing the block coding (for example, the main service data).

The trellis-decoded and block-decoded data in the block decoder 905 are output to a data deformatter 906. That is, the block decoder 905 removes RS data, RS initialization data, Trellis initialization data, and RS parity data added in the RS encoder / non-systematic RS encoder or non-systematic RS encoder of the transmission system, And outputs it to the data deformatter 906. Here, the data removal may be performed before the block decoding, or may be performed during the block decoding or after the block decoding. If the transmitting side includes signaling information in the data group, the signaling information is output to the data deformatter 906.

On the other hand, the data subjected to the trellis decoding by the block decoder 905 is output to the data deinterleaver 909. In this case, the data that is Trellis-decoded in the block decoder 905 and output to the data deinterleaver 909 may include not only the main service data but also data in the RS frame and signaling information. Also, the RS parity data added after the preprocessor 230 on the transmission side may be included in the data output to the data deinterleaver 909.

In another embodiment, block coding is not performed on the transmission side, and data subjected to only trellis coding may be bypassed as it is in the block decoder 905 and output to the data deinterleaver 909. In this case, a trellis decoder should be provided in front of the data deinterleaver 909.

The block decoder 905 outputs a hard decision value by performing Viterbi decoding on the input data if the input data is data in which only block coding is not performed on the transmission side and only Trellis coding is performed, The value may be determined hard and the result may be output.

The block decoder 905 outputs a soft decision value to the input data if the input data is data in which both block coding and trellis coding are performed on the transmission side.

That is, if the input data is block-encoded in the block processor 303 on the transmission side and Trellis-coded in the trellis encoder 256, the block decoder 905 outputs Conversely, trellis decoding and block decoding are performed. At this time, the block processor on the transmission side can be regarded as an external encoder, and the trellis encoder can be regarded as an internal encoder.

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

The data deinterleaver 909, the RS decoder 910, and the derandomizer 911 are blocks necessary for receiving main service data, and may be unnecessary in a receiving system structure for receiving only mobile service data have.

The data deinterleaver 909 deinterleaves the data output from the block decoder 905 and outputs the deinterleaved data to the RS decoder 910 in the reverse process of the data interleaver on the transmitting side. The data input to the data deinterleaver 909 may include not only the main service data but also mobile service data, known data, RS parity, MPEG header, and the like. At this time, only the RS parity data added to the main service data and the main service data packet among the input data may be output to the RS decoder 910, and after the data derandomizer 911, May be removed. In the present invention, only the RS parity added to the main service data and the main service data packet is input to the RS decoder 910.

The RS decoder 910 performs systematic RS decoding on the deinterleaved data and outputs the decoded data to the derandomizer 911.

The derandomizer 911 receives the output of the RS decoder 910 and generates pseudo random bytes that are the same as the renderer of the transmitter and performs bitwise XOR (exclusive OR) And output in units of 188 bytes of main service data packet.

On the other hand, the type of data output from the block decoder 905 to the data deformatter 906 is a data group type. At this time, since the configuration of the input data group is already known in the data deformatter 906, signaling information including transmission parameters and the like are distinguished in the data group from the mobile service data. The demodulated signaling information is transmitted to a block (not shown) for processing the signaling information, and the mobile service data is output to the RS frame decoder 907.

That is, the RS frame decoder 907 receives only RS-encoded and CRC-encoded mobile service data from the data deformatter 906.

The RS frame decoder 907 corrects the errors in the RS frame by performing an inverse process in the RS frame encoder of the transmission system, and then performs error correction on the error corrected mobile service data packet using the 1-byte MPEG synchronous Adds the byte and outputs it to the derandomizer 908.

The derandomizer 908 performs de-randomization corresponding to the inverse process of the randomizer of the transmission system with respect to the received mobile service data and outputs the mobile service data, thereby obtaining the mobile service data transmitted from the transmission system.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, .

100: service multiplexer 110: PSI / PSIP generator
120: TS packet encapsulator 130: Transport multiplexer
131: main service multiplexer 132: transport packet multiplexer
200: transmitter 211: demultiplexer
212: packet jitter rewinder 213: TS packet decapsulator
214: preprocessor 215: packet multiplexer
220: Post processor 230: Synchronous multiplexer
240:

Claims (10)

A packet formatter for outputting transport stream (TS) packets for mobile service data for each data group; And
And a data interleaver interleaving data bytes in the data group,
Wherein the packets in the first data group before interleaving have a length of 207 bytes each, the second interleaved data group includes a plurality of segments, and the interleaver is operable to transmit the data of the packets in the first data group to the second data Wherein the Nth segment included in the second data group includes M bytes of mobile service data bytes and the (N + 1) th segment included in the second data group is divided into L (N + 2) th segment comprises K bytes of mobile service data bytes, M, L and K comprise M <L <K N, M, L and K are all natural numbers; A digital broadcast signal transmitting apparatus. 3. The method of claim 2,
Wherein the data group further comprises signaling information. The method of claim 3,
Wherein the signaling information further includes transmission parameter channel (TPC) data. 5. The method of claim 4,
Wherein the data group is divided into at least three areas. Outputting transport stream (TS) packets for mobile service data for each data group; And
The data interleaver interleaving the data bytes in the data group,
Wherein the packets in the first data group before interleaving have a length of 207 bytes each, the second interleaved data group includes a plurality of segments, and the data interleaver transmits data of the packets in the first data group to the second The Nth segment included in the second data group includes M bytes of mobile service data bytes, and the (N + 1) th segment included in the second data group is distributed to the plurality of segments of the data group, (N + 2) th segment comprises K bytes of mobile service data bytes, M, L and K comprise M <L <K , N, M, L and K are all natural numbers; A digital broadcast signal transmission method. The method according to claim 6,
Wherein the data group further comprises signaling information. 8. The method of claim 7,
Wherein the signaling information further includes transmission parameter channel (TPC) data. 9. The method of claim 8,
Wherein the data group is divided into at least three areas. A tuner for receiving a digital television (DTV) signal including mobile service data,
Wherein the mobile service data is included in a data group, wherein the first data group includes a plurality of segments, and deinterleaves the plurality of segments in the first data group to provide a second Wherein the Nth segment included in the first data group includes M bytes of mobile service data bytes and the (N + 1) th segment included in the first data group includes L bytes of mobile service data (N + 2) th segment included in the first data group includes K bytes of mobile service data bytes, M, L and K satisfy M <L <K, and N , M, L, and K are all natural numbers;
A demodulator for demodulating the DTV signal including the mobile service data; And
And a decoder for decoding the demodulated DTV signal. Receiving a digital television (DTV) signal including mobile service data,
Wherein the mobile service data is included in a data group, wherein the first data group includes a plurality of segments, and deinterleaves the plurality of segments in the first data group to provide a second Wherein the Nth segment included in the first data group includes M bytes of mobile service data bytes and the (N + 1) th segment included in the first data group includes L bytes of mobile service data (N + 2) th segment included in the first data group includes K bytes of mobile service data bytes, M, L and K satisfy M <L <K, and N , M, L, and K are all natural numbers;
Performing demodulation on the DTV signal including the mobile service data; And
And performing decoding on the demodulated DTV signal.

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