KR101507849B1 - Digital broadcasting receiver and method for processing data - Google Patents

Abstract

Disclosed herein are a digital broadcasting system and a data processing method. A data processing method of a digital broadcast transmission system according to an embodiment of the present invention is a method of processing a broadcast signal including main service data and mobile service data, STD (Transport Stream System Target Decoder) model based on the PCR of the delayed reference time, and transmitting the T-STD model according to the authentication result of the T-STD model , And controlling transmission of the main service data.

Digital broadcasting, PCR

Description

[0001] DIGITAL BROADCASTING RECEIVER AND METHOD FOR PROCESSING DATA [0002]

The present invention relates to a digital broadcasting system, and more particularly, to a digital broadcasting transmission system, a digital broadcasting receiver, and a data processing method for the digital broadcasting transmission system and the digital broadcasting receiver.

The digital broadcasting system may include a digital broadcasting transmitter and a digital broadcasting receiver. Also, the digital broadcast transmitter processes data such as a broadcast program in a digital manner and transmits the processed data to the digital broadcast receiver. Such digital broadcasting systems are gradually replacing analog broadcasting systems due to various advantages such as efficiency of data transmission.

In recent years, studies have been made on a digital broadcast receiver capable of receiving broadcast signals even on the move. Therefore, the digital broadcasting transmission system can transmit both the broadcasting signal for the fixed digital broadcasting reception system and the broadcasting signal for the mobile digital broadcasting reception system.

However, according to the related art, when a broadcasting signal for the mobile digital broadcasting receiving system is simply added to a broadcasting signal for the fixed digital broadcasting receiving system, an unexpected buffer overflow or underflow ) And the like occur frequently.

In an exemplary embodiment of the present invention, even in the process of processing both the broadcasting signal for the fixed digital broadcasting receiving system and the broadcasting signal for the mobile digital broadcasting receiving system, the overflow or underflow of the buffer A digital broadcasting system, and a data processing method in which a problem of a digital broadcasting system and a data processing method may not occur at all.

A data processing method of a digital broadcast transmission system according to an embodiment of the present invention is a method of processing a broadcast signal including main service data and mobile service data, STD (Transport Stream System Target Decoder) model based on the PCR of the delayed reference time, and transmitting the T-STD model according to the authentication result of the T-STD model , And controlling transmission of the main service data.

Also, a data processing method of a digital broadcast receiver according to an embodiment of the present invention includes receiving a broadcast signal including a main service data packet, a mobile service data packet, and a PCR (Program Clock Reference) delayed by a reference time Demultiplexing the received broadcast signal, and decoding the demultiplexed main service data packet according to the PCR.

In addition, in the case of processing a broadcast signal including main service data and mobile service data, the digital broadcast transmission system according to an embodiment of the present invention may further include: a reference of a PCR (Program Clock Reference) based on the size of the mobile service data; An authentication unit for verifying a T-STD (Transport Stream System Target Decoder) model based on the PCR of the delayed reference time, And a control unit for controlling transmission of the main service data.

A digital broadcast receiver according to an embodiment of the present invention includes a receiver for receiving a main service data packet, a mobile service data packet, and a broadcast signal including a PCR (Program Clock Reference) delayed by a reference time, A demultiplexer for demultiplexing the broadcast signal, and a decoder for decoding the demultiplexed main service data packet according to the PCR.

According to the embodiment of the present invention, overflow and underflow of the T-STD model, which may occur by adding MH data to the TS stream satisfying the T-STD, can be prevented.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings and accompanying drawings, but the present invention is not limited to or limited by the embodiments.

As used herein, terms used in the present invention are selected from general terms that are widely used in the present invention while taking into account the functions of the present invention, but these may vary depending on the intention or custom of a person skilled in the art or the emergence of new technologies. Also, in certain cases, there may be a term chosen arbitrarily by the applicant, in which case the meaning thereof will be described in the description of the corresponding invention. Therefore, it is intended that the terminology used herein should be interpreted based on the meaning of the term rather than on the name of the term, and on the entire contents of the specification.

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.

Among the terms used in the present invention, MH is the first letter of each of a mobile and a handheld, and is a concept opposite to a fixed type. The MH service data includes at least one of mobile service data and handheld service data. For convenience of explanation, the MH service data is also referred to as mobile service data in the present invention. In this case, the mobile service data may include not only MH service data but also service data indicating movement or carrying, so that the mobile service data will not be limited to the MH 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 Advanced Video Coding (AVC), and Scalable Video Coding (SVC). Also, any kind of data can be transmitted with the mobile service data. For example, TPEG (Transport Protocol Expert Group) data for broadcasting traffic information in real time can be transmitted as mobile service data.

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.

1 is a block diagram showing a configuration of a T-STD, which is one of digital broadcasting transmission systems. However, the T-STD may correspond to, for example, MPEG2 (Moving Picture Experts Group 2) T-STD.

The T-STD models a digital broadcast receiver and adjusts the encoder of the digital broadcast transmission system using the modeling result. In FIG. 1, t (i) denotes the time when the i-th byte of the transport stream is input, and the bitrate of the time is, for example, about 19.39 Mbps.

On the other hand, the path of the TS packets to be moved according to the PID is determined. In the case of the video packet, the TS packet moves to the uppermost path (e.g., TB1 in FIG. 1) shown in FIG. In the case of an audio packet, the intermediate path shown in Fig. 1 (for example, TBn in Fig. 1) is shifted to the lowest path shown in Fig. 1 (for example, TBsys.

However, although audio packets are described in the specification of the present invention, the present invention can be applied to both video packets and packets controlling the system. Accordingly, the scope of the present invention should be determined in accordance with the contents of the claims, and the scope of the present invention is not limited to audio packets.

TBn 110 shown in FIG. 1 denotes a transport buffer, Bn 120 denotes a main buffer, and Dn 130 denotes a decoder.

The TBn 110 may have a size of, for example, 512 bytes, and data input to the TBn 110 is transferred to the Bn 120 at a rate of RXn. The moving speed to the Bn 120 is a rate of 2 Mbps when there is data in the TBn 110 and a rate of 0 Mbps when there is no data in the TBn 110. In addition, an overflow should not occur in the TBn (110). However, in the case of processing both the mobile service data and the main service data, an overflow in the TBn 110 is a problem, and a method for solving the problem will be described in detail with reference to other drawings.

The size of the Bn 120 may be, for example, 3584 bytes or 2592 bytes, and a bit stream input at a rate of RXn is transmitted to the Dn 130 at a time of tdn (j) . The tdn (j) is determined by a DTS (Decoding Time Stamp) transmitted through a bitstream. In addition, the STC is recovered using PCR, and the data in the Bn 120 is transferred to the Dn 130 at a time when the restored STC coincides with the DTS. In addition, overflow and underflow should not occur in the Bn (120). However, when both the mobile service data and the main service data are processed, an overflow in the Bn 120 is particularly problematic, and a method of solving the problem will be described in detail with reference to the other drawings.

2 is a block diagram illustrating a configuration of a digital broadcasting transmission system according to an embodiment of the present invention. 2, the digital broadcast transmission system 200 according to an exemplary embodiment of the present invention includes an MH frame controller 201, a packet timing / PCR adjustment unit A packet mux 210, an MH frame encoder 205, a block processor 206, a signaling encoder 207, a group formatter A group formatter 208, a packet formatter 209, a modified data randomizer 212, a systematic / non-systematic RS encoder 213, A data interleaver 214, a parity replicator 215, a non-systematic RS encoder 217, a modulated trellis encoder 216, A Sync mux 218, a Pilot-inserter 219, a modulator 220, an RF up-converter an onverter 221, an auxiliary buffer 203, and the like.

For reference, the MH frame encoder 205, the block processor 206, the signaling encoder 207, the group formatter 208, And a packet formatter 209 may be referred to as a pre-processor 204. [

For reference, the modified data randomizer 212, the systematic / non-systematic RS encoder 213, the data interleaver 214, A module including a parity replicator 215, a non-systematic RS encoder 217, and a modified trellis encoder 216 is provided as a post-processor (211).

The packet mux 210 multiplexes the main service data packet and the 188-byte mobile service data packet output from the packet formatter 209 according to a predetermined multiplexing method and transmits the main service data packet to the mod- ude data randomizer 212 Output. The multiplexing method can be adjusted by various parameters of the system design.

Meanwhile, the MH frame encoder 205 performs at least one of an error correction encoding process and an error detection encoding process on the inputted mobile service data. In this way, robustness is given to mobile service data, and congestion errors, which may be caused by radio wave environment changes, are dissipated, so that it is possible to cope with extremely poor and rapidly changing radio waves. The MH frame encoder 205 may include a process of mixing mobile service data of a predetermined size on a row basis.

At this time, the RS is applied to the error correction coding and the CRC (Cyclic Redundancy Check) coding is applied to the 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 uses an FEC (Forward Error Correction) structure. 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.

The mobile service data encoded by the MH frame encoder 205 is input to the block processor 206 as described above. The block processor 206 encodes the input mobile service data again with G / H (where G < H) and outputs the encoded data to the group formatter 208. In addition to the MH frame encoder 205, the signaling encoder 207 may encode the signaling data and transmit the encoded signaling data to the group formatter 208.

That is, the block processor 206 divides the mobile service data, which is input on a byte-by-byte basis, into bits, encodes the separated G bits into H bits, and converts the encoded data 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 208 at the subsequent stage is allocated to a region where reception performance may deteriorate, and the data encoded at the 1/2 code rate may have better performance It is possible to obtain an effect of reducing the difference in performance.

At this time, the block processor 206 may receive additional information data such as signaling including information on the system, etc. from the signaling encoder 207. This additional information data is also the same as the mobile service data processing procedure 1/2 encoding or 1/4 encoding. Then, the additional information data such as the signaling is regarded as mobile service data and processed. The signaling information is information necessary for receiving and processing data included in a data group in the receiving system, and may include data group information, multiplexing information, and the like.

Meanwhile, the group formatter 208 inserts the mobile service data output from the block processor 206 into a corresponding area in a data group formed according to a predefined rule, Data is inserted into the corresponding area in the data group, and then deinterleaving is performed.

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.

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 long consecutive known data into mobile service data, a certain length of known data is stored in an area free of interference from the main service data It is possible to insert it periodically. However, it is difficult to periodically insert the known data due to the interference of the main service data in the area where interference of the main service data exists, and it is also difficult to continuously insert the known data.

In addition, in the group formatter 208, additional information data such as signaling for informing overall transmission information is inserted into the data group separately from the mobile service data.

In addition to the encoded mobile service data output from the block processor 206, the group formatter 208 inserts an MPEG header location holder, an unstructured RS parity location holder, and a main service data location holder in association with data deinterleaving in the subsequent stage do. The reason for inserting the main service data location holder is that there is a region where the mobile service data and the main service data are mixed based on the data after the data interleaving. For example, the position holder for the MPEG header is allocated in front of each packet when viewed from the output data after the data deinterleaving.

In addition, the group formatter 208 inserts known data generated by a predetermined method, or inserts a known data location holder for inserting known data later. In addition, a position holder for initializing the modulated trellis encoder 216 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 size of the mobile service data that can be inserted into one data group may vary depending on the size of the trellis initialization, known data, MPEG header, and RS parity inserted in the corresponding data group.

The output of the group formatter 208 is transmitted to the packet formatter 209. The packet formatter 209 removes the main service data location holder and the RS parity location holder which were allocated for deinterleaving among the deinterleaved input data And the remaining parts are collected, and then the MPEG header is inserted into the 4-byte MPEG header location holder.

The packet formatter 209 may insert the known known data into the known data location holder when the known data location holder is inserted in the group formatter 208 or may insert the known data location holder It can be output without adjustment.

Then, the packet formatter 209 divides the data in the packet formatted data group into 188-byte mobile service data packets (i.e., MPEG TS packets) and provides the data to the packet mux 210.

If the input data is a main service data packet, the modified data renderer 212 performs the same rendering as the existing renderer. That is, it discards the synchronous bytes in the main service data packet, randomizes the remaining 187 bytes using internally generated pseudo random bytes, and outputs them to the system / non-system RS encoder 213.

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 Non-system RS encoder 213 without carrying out randomization.

The system / non-system RS encoder 213 RS-encodes data to be rendered or bypassed by the mod- ude data randomizer 212, adds 20 bytes of RS parity, 214. If the input data is a main service data packet, the system / non-system RE encoder 213 performs systematic RS encoding in the same manner as in the existing ATSC VSB 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 214 is a convolutional interleaver on a byte basis.

The output of the data interleaver 214 is input to a parity replicator 215 and a non-system RS encoder 217.

Meanwhile, in order to convert the output data of the modulated trellis encoder 216 located at the rear end of the parity replicators 215 into known data defined by an appointment at the transmitting / receiving end, the modulated trellis encoder 216 first Memory initialization is required. That is, the memory of the modulated trellis encoder 216 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 initialization data position holder inserted in the group formatter 208. [ 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 value of the initialization data of the trellis memory is determined according to the memory state of the modulated trellis encoder 216. Also, it is necessary to recalculate the RS parity due to the effect of the replacement initialization data and to replace the RS parity with the RS parity output from the data interleaver 214.

Therefore, the non-system RS encoder 217 receives the mobile service data packet including the initialization data position holder to be replaced with the initialization data from the data interleaver 214, and receives the initialization data from the modulated trellis encoder 216 .

Then, the initialization data location 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 replayer 215 . The parity replicators 215 select the output of the data interleaver 214 for data in the mobile service data packet and select the output of the non-system RS encoder 217 for the RS parity, And outputs it to the encoder 216.

Meanwhile, the parity replicators 215 select RS data and data output from the data interleaver 214 when a mobile service data packet including no initialization data location holder to be input or replaced is selected To the modulated trellis encoder 216 as it is.

The modulated trellis encoder 216 performs byte-interleaved data on a symbol-by-symbol basis, performs 12-way interleaving on the data, performs trellis encoding on the data, and outputs the data to the sync mux 218.

The sync mux 218 inserts the field sync and the segment sync into the output of the modulated trellis encoder 216 and outputs it to the pilot inserter 219.

The pilot inserted data in the pilot inserter 219 is VSB-modulated by the modulator 220 and then transmitted to the broadcasting receiving system or the digital broadcasting receiver through the RF up-converter 221.

2, the packet timing / PCR adjuster 202, the auxiliary buffer 203, the MH frame controller 202, the buffer controller 203, (201), and the like.

For example, it is assumed that the MH frame has a size of 968 msec, and the MH frame can be divided into five subframes. Each subframe is divided into 16 slots, and each slot consists of 156 consecutive TS packets. Of the 156 TS packets, 118 TS packets can be allocated to the MH data area. However, the MH data area may refer to an area to which MH service data is allocated. Of course, when there are many MH data, MH data is allocated to more slots. For reference, the MH data may correspond to the mobile service data.

On the other hand, when the MH data area is allocated and the mobile service data is transmitted as described above, the data packet can not be transmitted immediately. Accordingly, the transmission order of the main service data packet must be changed so that the main service data packet that can not be transmitted is transmitted in an area other than the area where the mobile service data is transmitted. This function is designed to be handled by the packet timing / PCR adjustment unit 202 of FIG.

The packet timing / PCR adjuster 202 is responsible for correcting the time information that is changed as the temporal location of the main service data packet including the PCR is changed. In addition, the position of the audio packet is changed in order to prevent buffer overflow. The reference time of the PCR is delayed in order to prevent an underflow of the buffer caused by the change of the position of the audio packet.

On the other hand, in order to check whether an underflow occurs in the buffers shown in FIG. 1, the following assumption is made.

When an audio packet is sampled at about 32 kHz and encoded at 384 kbps, one frame is 48 ms, and the size of the data corresponds to 13 TS packets. It is also assumed that a decoding time stamp (DTS) is set so that the audio packet is transmitted as soon as possible and decoding is performed when the transmission is completed. Assuming such a case, the size of the data included in the TBn 110 is shown in FIG.

The horizontal axis in FIG. 3 corresponds to an index of a TS packet, and the vertical axis represents the size of data included in TBn. The moment when the data starts to accumulate in the TBn 110 is a moment when one audio frame moves from TBn to Bn.

As shown in FIG. 3, after 9.91 msec after the first audio TS packet is received, the TBn 110 is again empty. From this point on, the audio decoder, such as Dn 130, can decode the audio frame. That is, if the DTS value of the audio PES packet header included in the first TS packet corresponds to the STC value after 9.91 msec, the underflow does not occur. That is, if decoding is performed in the &quot; a &quot; area shown in Fig. 3, no underflow occurs.

Hereinafter, a phenomenon that occurs when mobile service data is transmitted together with a stream in which main service data is encoded will be described. The case of transmitting the mobile service data, that is, the MH data as much as possible is shown in FIG. As described above, in the MH data, 118 TS packets are continuously transmitted. The main service data packet must be transmitted between the slots or slots in which the MH data is transmitted. In the case of such transmission, as shown in FIG. 4, the instant when the TBn rises is 34.05 msec, and the value of 34.05 msec is about 24.14 msec when compared with FIG. 3 in which the MH data does not exist do.

Even if MH data or the like is being transmitted, the MH data or the mobile service data are not considered, and at any time point among the &quot; a &quot; areas shown in FIG. 3 If decoding is performed in the same way as in the past, underflow is likely to occur. This is because the data packet is moved from the audio buffer to the audio decoder in a state in which the Bn 120 is not filled with data.

For reference, the areas "b", "c", "d", "e", "f", "g", and "h" The time can be corresponding to the time.

Therefore, according to an embodiment of the present invention, PCR is designed to adjust to prevent such an underflow phenomenon. That is, the experimentally obtained diagram of FIG. 3 is compared with the diagram of FIG. 4, and the PCR reference time is delayed so as to have a value of 24.14 msec or more, which is the time difference (34.05 msec-9.91 msec = 24.14 msec) shown in FIGS. That is, it is possible to delay the clock in which the decoder operates, so that the main buffers can be sufficiently full. Of course, the value of 24.14 msec is an experimentally obtained preferable value, and even if a value between 24 and 25 msec is applied in some cases, the underflow phenomenon can be removed to some extent.

According to another embodiment of the present invention, not only the underflow phenomenon of the buffers, for example, the TBn 110 and the Bn 120, but also the overflow phenomenon is originally eliminated.

The case described above is designed to transmit an audio packet as soon as possible and to decode the audio packet as quickly as possible. In such a case, underflow is a problem. On the other hand, if the audio packet is designed to be transmitted as fast as possible and to stack as many data packets as possible in the audio main buffer (Bn) 120, an overflow problem will occur.

FIG. 5 shows a graph for the main buffer of audio, unlike FIG. 3 and FIG. The horizontal axis in FIG. 5 corresponds to the index of the TS packet, and the vertical axis represents the size of data included in Bn. FIG. 5 illustrates a case where as much data as possible is stored in the audio main buffer and decoding is performed, and mobile service data (or MH data) is also transmitted along with main service data.

5, when audio packet data is transmitted, audio packet data is accumulated in Bn 120, and when audio packet data accumulated at DTS (i) time point is passed to audio decoder 130, Bn (i) 120), only very small amounts of data remain. If another frame is input continuously, audio packet data is accumulated in Bn again after DTS (i). However, if the reference time of the PCR is delayed in order to prevent the underflow of the TBn 110 as described above, more data is accumulated in the Bn as shown in FIG. That is, since the reference time of the PCR is delayed, the actual decoding time is also delayed, thereby causing the Bn 120 to accumulate more data unexpectedly. This phenomenon is an overflow phenomenon of Bn (120).

2, the MH frame controller 201, the packet timing / PCR adjusting unit 202, and the auxiliary buffer 220 are connected to each other in order to eliminate the overflow phenomenon of the Bn 120. In this case, (203) and the like are newly defined.

When the digital broadcasting transmission system 200 processes a broadcasting signal including main service data and mobile service data, the packet timing / PCR adjusting unit 202 performs PCR (Program Clock Reference) is delayed.

More specifically, for example, the packet timing / PCR adjustment unit 202 compares the case of processing a broadcast signal including main service data and the case of processing a broadcast signal including both main service data and mobile service data , And the reference time of the PCR is delayed by a time between 24 and 25 milliseconds (ms). Therefore, when transmitting the TS packet satisfying the T-STD model 100 of FIG. 1 through the process of delaying the PCR reference time by the packet timing / PCR adjusting unit 202, It is possible to prevent a flow phenomenon from occurring. For reference, the T-STD model 100 shown in FIG. 1 may correspond to MPEG2 (Moving Picture Experts Group 2) T-STD.

In addition, the packet timing / PCR adjusting unit 202 or a separate module may be configured to perform a T-STD (Transport Stream System Target Decoder) shown in FIG. 1 based on the PCR of the delayed reference time, And verifies the model 100. Further, it is determined whether the overflow is predicted in the main buffer 120 of the T-STD model 100 as a result of the authentication of the T-STD model 100.

The packet timing / PCR adjusting unit 202 or another module controls the main buffer 120 to prevent an overflow from occurring using the determination result. This operation is a process for preventing an overflow phenomenon that may occur in the Bn 120 of FIG. 1 as the PCR reference time is delayed.

The control process of the packet timing / PCR adjuster 202 or another module will be described in more detail as follows.

The packet timing / PCR adjuster 202 or another module stores the packet received in the main buffer 120 in an auxiliary buffer 203 when an overflow is predicted as a result of the determination. Further, the received packet is replaced with a null packet, and a broadcast signal including the replaced null packet is transmitted.

In addition, the packet timing / PCR adjuster 202 or the separate module may be configured to control the order of replacement to be stored in the replacement process, and to change the order of the packets to be transmitted Correct the order to the original order.

On the other hand, if the overflow is not predicted as a result of the determination, the packet timing / PCR adjuster 202 or another module identifies whether the packet received in the main buffer 120 is a null packet. Further, when the identification result is a null packet, the null packet is replaced with a packet stored in the auxiliary buffer 203, and control is returned to the authentication process.

7 is a flowchart illustrating a data processing method of a digital broadcast transmission system according to an embodiment of the present invention.

First, the digital broadcasting transmission system determines whether the packet corresponds to a PCR packet including PCR information (S700). If it is determined in step S700 that the packet is a PCR packet, the reference time of the PCR is delayed in step S701. However, the degree of the delay can be determined in proportion to the size of the mobile service data, for example, a time delay belonging to the range of 24 to 25 ms. More specifically, the time delay may be 24.14 ms.

The digital broadcasting transmission system verifies the T-STD model based on the PCR of the delayed reference time before transmitting the broadcasting signal (S702). Also, the digital broadcasting transmission system determines whether the main buffer of the T-STD model is full (S703), the authentication result of the T-STD model (S702), and the main buffer of the T-STD model is full. However, the full state may mean that the main buffer is completely empty, or may be almost full state.

The digital broadcasting transmission system controls the main buffer to prevent an overflow from occurring using the determination result. However, such a control process can be implemented by using some or all of steps S704 to S711 shown in Fig.

In step S703, the digital broadcasting transmission system stores the packet received in the main buffer in an auxiliary buffer of the main buffer in step S704, and transmits the received packet to the null buffer null) packet (S705).

In addition, the digital broadcasting transmission system determines whether a new packet corresponds to a PCR packet including PCR information (S706). If it is determined that the packet does not correspond to the PCR packet (S706), the broadcast signal including the replaced null packet is transmitted (S708). On the other hand, if the determination result (S706) corresponds to the PCR packet, the PCR is restored according to the change order of the packet (S707).

Yet another embodiment of the steps S707 and S708 may include storing the packet replacement order in the steps S704 and S705 described above, and transmitting the replacement order of the broadcast signal, And correcting the order of the packets to be transmitted by using the packets in the original order.

If the determination result in step S703 is NO, the digital broadcast transmission system determines whether the packet received in the main buffer is a null packet in step S709. If the result of the identification (S709) is a null packet, it is determined whether another packet is already stored in the auxiliary buffer (S710).

If it is determined in step S710 that another packet is stored, the null packet is replaced with the packet stored in the auxiliary buffer in step S711, and the process returns to step S702.

FIG. 8 is a block diagram of a digital broadcast receiver according to an embodiment of the present invention. Referring to FIG. In the digital broadcast receiver of FIG. 8, 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 digital broadcast receiver according to the present invention includes a tuner 801, a demodulator 802, an equalizer 803, a known data detector 804, a block decoder 805, an RS frame decoder 807, An interleaver 808, a data deinterleaver 809, an RS decoder 810, and a data derandomizer 811. The RS frame decoder 807 and the derandomizer 808 are referred to as a mobile service data processing section and a data deinterleaver 809, an RS decoder 810, and a data derandomizer 811 ) Will be referred to as a main service data processing section.

That is, the tuner 801 tunes the frequency of a specific channel and downconverts it to an intermediate frequency (IF) signal, and outputs it to the demodulation unit 802 and the known data detection unit 804.

The demodulator 802 performs automatic gain control, carrier recovery, and timing recovery on the input IF signal to generate a baseband signal, and outputs the baseband signal to an equalizer 803 and a known data detector 804.

The equalizer 803 compensates for the distortion on the channel included in the demodulated signal and outputs the compensated signal to the block decoder 805.

At this time, the known data detecting unit 804 detects the known data position inserted from the transmitting side, based on the input / output data of the demodulating unit 802, that is, the data before demodulation or the demodulated data, And outputs a symbol sequence of known data generated at the position to the demodulator 802 and the equalizer 803. Also, the known data detector 804 transmits information for further coding the mobile service data and the main service data, which have not been further encoded, to the block decoder 805 so that the block decoder 805 can distinguish the mobile service data, . Although not shown in FIG. 8, information detected by the known data detector 804 can be used in the receiving system as a whole, and may be used in the RS frame decoder 807 or the like.

The demodulator 802 can improve the demodulation performance by using the known data symbol sequence in timing recovery or carrier recovery, and the equalizer 803 can likewise improve the equalization performance using the known data have. Also, the decoding result of the block decoder 805 may be fed back to the equalizer 803 to improve the equalization performance.

If the data input to the block decoder 805 after channel equalization in the equalizer 803 is data in which both block coding and trellis coding are performed on the transmitting side (for example, data in the RS frame) Trellis decoding and block decoding are performed inversely to the transmitting side, and block coding is not performed, and only trellis decoding is performed if the data is only Trellis-coded data (for example, main service data).

The trellis-decoded and block-decoded data in the block decoder 805 are output to the RS frame decoder 807. That is, the block decoder 805 receives the known data among the data in the data group, the data used for initializing the trellis, the signaling information data, the MPEG header, and the RS encoder / unstructured RS encoder of the transmission system or the non- Removes the RS parity data added by the encoder, and outputs the RS parity data to the RS frame decoder 807. Further, the data removal may be performed before the block decoding, or during the block decoding or after the block decoding.

On the other hand, the trellis-decoded data in the block decoder 805 is output to the main service data processing unit. In this case, data that is trellis-decoded in the block decoder 805 and output to the main data processing unit may include not only the main service data, but also data in the RS frame and signaling information. Also, RS parity data added after the preprocessor on the transmission side may be included in data output to the main service data processing unit.

In another embodiment, the block coding is not performed on the transmitting side, and the data on which only the trellis coding has been performed may be bypassed as it is in the block decoder 805 and output to the main service data processing unit. In this case, a trellis decoder should be further provided in front of the main service data processing unit. Meanwhile, the main service data processing unit can be designed to be located at a position where it can receive a signal from the block decoder 805 of FIG.

The block decoder 805 performs Viterbi (or trellis) decoding on the input data if the input data is data in which only the trellis coding is performed without performing block coding on the transmission side, Or a hard decision of the soft decision value, and output the result.

The block decoder 805 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-coded by the block processor on the transmission side and the data is Trellis-coded by the trellis encoder, the block decoder 805 decodes the trellis And performs decoding and block decoding. In this case, the block processor on the transmitting side may be an external encoder, and the trellis encoder may be an internal encoder.

In order to maximize the performance of the outer code at the time of decoding the concatenated code, a soft decision value should be outputted from the inner code decoder.

Accordingly, the block decoder 805 may output a hard decision value for the mobile service data, but it may be preferable to output a soft decision value if necessary.

The data deinterleaver 809, the RS decoder 810, and the derandomizer 811 are blocks required to receive the main service data. The data deinterleaver 809, the RS decoder 810, and the derandomizer 811 may be unnecessary in a receiving system structure for receiving only mobile service data have.

The data deinterleaver 809 deinterleaves the main service data output from the block decoder 805 and outputs the deinterleaved data to the RS decoder 810 in the reverse process of the data interleaver on the transmitting side.

The RS decoder 810 performs systematic RS decoding on the deinterleaved data and outputs it to the derandomizer 811.

The derandomizer 811 receives the output of the RS decoder 810 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.

The RS frame decoder 807 receives only RS-encoded and / or CRC-encoded mobile service data from the block decoder 805.

The RS frame decoder 807 corrects the errors in the RS frame by performing an inverse process in the RS frame encoder of the transmission system and then outputs a 1-byte MPEG synchronous Adds the byte and outputs it to the derandomizer 808.

The derandomizer 808 performs derandering corresponding to the inverse process of the randomizer of the transmission system and outputs the received mobile service data to obtain the mobile service data transmitted from the transmission system.

In particular, according to an embodiment of the present invention, the digital broadcast receiver can process a broadcast signal including a packet in which an underflow or an overflow does not occur.

The tuner 801 receives a main service data packet, a mobile service data packet, and a broadcast signal including a PCR (Program Clock Reference) whose reference time is delayed. Of course, a module that is responsible for the function of the tuner may be referred to as a receiver.

In accordance with an embodiment of the present invention, the tuner 801 receives, from the digital broadcasting transmission system, null data (not shown) instead of the main service data packet in accordance with the authentication process result of the transport stream system target decoder (T-STD) And receives a broadcast signal including a packet.

The block decoder 805 may demultiplex the received broadcast signals and may be referred to as a demultiplexer.

The data interleaver 809, the RS decoder 810, and the data derandomizer 811 decode the demultiplexed main service data packet using the demultiplexing result, that is, according to the PCR . Of course, a module responsible for such a function may also be called a decoder.

Therefore, according to an embodiment of the present invention, it is possible to solve all the underflow and overflow problems expected by adding mobile service data to existing main service data. For example, it is possible to originally eliminate the occurrence of an underflow phenomenon in the buffer of the T-STD model by first delaying the PCR reference time within a certain range, and additionally, an auxiliary buffer is added to the T-STD model, Through the verification process for the model, it is possible to essentially eliminate the occurrence of an overflow phenomenon in the main buffer of the T-STD model.

Furthermore, according to an embodiment of the present invention, overflow and underflow of the T-STD model that can occur by adding MH data to a TS stream that satisfies T-STD can be prevented.

According to an embodiment of the present invention, the digital broadcast transmission system checks the underflow and the overflow of the buffer in advance, so that the underflow and the overflow phenomenon do not occur in the buffer of the digital broadcast receiver.

On the other hand, in this specification, both the article invention and the method invention are described, and since the article invention and the method invention described above all include similar technical ideas, description of the article invention may be applied to the method invention, May be applied to the invention.

The method inventions according to the present invention can all be implemented in the form of program instructions that can be executed through various computer means and recorded on a computer readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the medium may be those specially designed and constructed for the present invention or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magnetic media such as floppy disks; Magneto-optical media, and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those produced by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims. This is possible.

Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined by the equivalents of the claims, as well as the claims.

1 is a block diagram showing a configuration of a T-STD, which is one of digital broadcasting transmission systems.

2 is a block diagram illustrating a configuration of a digital broadcasting transmission system according to an embodiment of the present invention.

FIG. 3 is a diagram showing fullness of data stored in the transport buffer of the T-STD of FIG. 1 when there is no mobile service data and only main service data is processed.

FIG. 4 is a diagram showing fullness of data stored in the transport buffer of the T-STD of FIG. 1 when both mobile service data and main service data are processed.

FIG. 5 is a diagram showing fullness of data stored in the main buffer of the T-STD of FIG. 1 before PCR is corrected when both mobile service data and main service data are processed.

FIG. 6 is a diagram showing fullness of data stored in the main buffer of the T-STD of FIG. 1 after correcting PCR when both mobile service data and main service data are processed.

7 is a flowchart illustrating a data processing method of a digital broadcast transmission system according to an embodiment of the present invention.

FIG. 8 is a block diagram illustrating a digital broadcast receiver according to an embodiment of the present invention. Referring to FIG.

Claims (15)

A data processing method for a digital broadcast transmission system, When processing a broadcast signal including main service data and mobile service data, delaying a reference time of a PCR (Program Clock Reference) based on the size of the mobile service data; Verifying a Transport Stream System Target Decoder (T-STD) model based on the PCR of the delayed reference time; And Storing the packet of the main service data in an auxiliary buffer when an overflow of a buffer in the T-STD model is estimated as an authentication result of the T-STD model; And transmitting the data to the digital broadcast transmission system. 2. The method of claim 1, Replacing the packet of the main service data with a null packet; And transmitting the data to the digital broadcast transmission system. 3. The method of claim 2, Storing a sequence of replacement in said replacing step; And Correcting the order of packets to be transmitted in an original order by using the stored replacement order; Further comprising the steps of: The method according to claim 1, Wherein the storing step comprises: Identifying whether a packet of the main service data is a null packet if an overflow of a buffer in the T-STD model is not predicted as a result of authentication of the T-STD model; Replacing the null packet with a packet stored in the auxiliary buffer if the identification result is a null packet; And Returning to the authenticating step And transmitting the data to the digital broadcast transmission system. The method according to claim 1, Wherein the delaying comprises: A case of processing a broadcast signal including main service data and a case of processing a broadcast signal including both main service data and mobile service data are compared and a reference time of PCR is set to a time between 24 and 25 milliseconds Of the digital broadcasting transmission system. The method according to claim 1, In the T-STD model, A data processing method of a digital broadcasting transmission system corresponding to MPEG2 (Moving Picture Experts Group 2) T-STD. A data processing method for a digital broadcast receiver, Receiving a broadcast signal including a main service data packet, a mobile service data packet, and a program clock reference (PCR) delayed by a reference time, the broadcast signal including a Transport Stream System Target Decoder (T-STD) ) &Lt; / RTI &gt; model, if the overflow of the buffer in the T-STD model is estimated, a null data packet is included instead of the packet of the main service data; Demultiplexing the received broadcast signal; And Decoding the demultiplexed main service data packet according to the PCR; And transmitting the data to the digital broadcasting receiver. 8. The method of claim 7, In the PCR in which the reference time is delayed, Wherein the delayed PCR is delayed by a time between 24 and 25 milliseconds (ms). A digital broadcast transmission system comprising: A delay unit for delaying a reference time of a PCR (Program Clock Reference) based on the size of the mobile service data when processing a broadcast signal including main service data and mobile service data; An authentication unit for verifying a Transport Stream System Target Decoder (T-STD) model based on the PCR of the delayed reference time; And When an overflow of a buffer in the T-STD model is estimated as a result of authentication of the T-STD model, an auxiliary buffer And a digital broadcast transmission system. 10. The method of claim 9, When an overflow of a buffer in the T-STD model is estimated as an authentication result of the T-STD model, a packet of the main service data is stored in the auxiliary buffer, To a null packet; The digital broadcast transmission system further comprising: 11. The method of claim 10, Wherein, STD model, if the buffer of the T-STD model is not predicted as an overflow of the buffer in the T-STD model, identifies whether the packet of the main service data is a null packet, If the identification result is a null packet, replacing the null packet with a packet stored in the auxiliary buffer, and And controls the function of the authentication unit to be performed again. 10. The method of claim 9, Wherein the delay unit comprises: A case of processing a broadcast signal including main service data and a case of processing a broadcast signal including both main service data and mobile service data are compared and a reference time of PCR is set to a time between 24 and 25 milliseconds Delay of the digital broadcast transmission system. 10. The method of claim 9, In the T-STD model, MPEG2 (Moving Picture Experts Group 2) Digital broadcasting transmission system supporting T-STD. A digital broadcast receiver comprising: A main service data packet, a mobile service data packet, and a program clock reference (PCR) delayed by a reference time, the broadcast signal being a result of an authentication process of a T-STD model of a digital broadcast transmission system, When a buffer overflow in the T-STD model is estimated, a null data packet is included instead of the main service packet; A demultiplexer for demultiplexing the received broadcast signal; And A decoder for decoding the demultiplexed main service data packet according to the PCR; And a digital broadcast receiver. 15. The method of claim 14, In the PCR in which the reference time is delayed, Corresponding to a PCR delayed by a time between 24 and 25 milliseconds (ms).

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