KR101160333B1 - Digital broadcasting transmission/reception devices capable of improving receiving performance and signal processing method thereof - Google Patents

Abstract

Disclosed are a digital broadcast transmission / reception system having improved reception performance and a signal processing method thereof. The digital broadcast transmitter includes: a randomizer for randomizing a transport stream having a stuff byte inserted at a predetermined position; A stuff byte exchange unit which replaces the stuff byte included in the data output from the randomization unit with predetermined known data; An RS encoding unit for performing RS encoding on data output from the stuff byte exchange unit; An interleaving unit performing interleaving on data output from the RS encoding unit; A trellis encoding unit for trellis encoding the data output from the interleaving unit; An RS parity generating unit generating parity based on the data output from the RS encoding unit and the data output from the trellis encoding unit and inputting the generated parity to the trellis encoding unit; And a modulation and RF unit for performing modulation on the data output from the trellis encoding unit and performing RF upconversion. Accordingly, digital broadcast reception performance can be improved in a poor multipath channel by detecting known data from a signal received at the receiving side and using the same for synchronization and equalization.

ATSC VSB, Stuff Bytes, Base Data, Digital Broadcast Transceiver System

Description

Digital broadcasting transceiver / signal processing method and improved receiving performance and signal processing method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a digital broadcast transceiver and a signal processing method thereof, and more particularly, to receiving by inserting known data (also referred to as "SRS") into a VSB (Vestigial Side Bands) data stream. A digital broadcast transceiver capable of improving the reception performance of a system and a signal processing method thereof.

ATSC (Advanced Television Systems Committee) VSB, a terrestrial digital broadcasting system for the United States, is a single carrier and a field sync signal is used in units of 312 segments.

1 is a block diagram showing a transceiver according to the ATSC DTV standard as a general US terrestrial digital broadcasting system.

The digital broadcast transmitter of FIG. 1 is a randomizer 110 that randomizes a Moving Picture Experts Group (MPEG-2) transport stream (TS), to correct bit errors caused by channel characteristics in a transmission process. Reel Solomon (Reel-Solomon: Encoder 120) for adding Reed Solomon parity bytes to the transport stream, and an interleaving unit for interleaving RS encoded data according to a predetermined pattern. 130) and a trellis encoding unit 140 that performs trellis encoding on the interleaved data at a 2/3 ratio and performs mapping into 8-level symbols, and includes error correction encoding on the MPEG-2 transport stream. Perform

In addition, the digital broadcast transmitter includes a multiplexer (MUX) 150 for inserting a segment sync signal and a field sync signal to error corrected coded data, and a segment sync signal and a field sync signal. Modulator / RF up-convertor: adds a predetermined DC value to a data symbol, inserts a pilot tone, pulses, performs VSB modulation, up-converts to a signal of an RF channel band, and transmits it. 160).

Accordingly, the digital broadcasting transmitter randomizes the data of the MPEG-2 transport stream, and externalizes the randomized data through the RS encoder 120, which is an outer coder, and the encoded data is interleaved. Distribute data through In addition, the interleaved data is internally encoded through the trellis encoding unit 140 in units of 12 symbols, the internally encoded data is mapped into 8 level symbols, and then a field synchronization signal and a segment synchronization signal are inserted, and a pilot tone is applied. It is inserted into the VSB modulation and converted to RF signal and transmitted.

Meanwhile, the digital broadcast receiver of FIG. 1 includes a tuner (Tuner / IF) 210 for converting an RF signal received through a channel into a base signal, and a demodulator 220 for performing synchronous detection and demodulation on the converted base signal. An equalizer 230 for compensating for channel distortion generated by the multipath with respect to the demodulated signal, a trellis decoder 230 for correcting an error and decoding the symbol data into symbol data, and digital The deinterleaving unit 240 rearranges the data distributed by the interleaving unit 130 of the broadcast transmitter, the RS decoder 250 correcting the error, and the data corrected through the RS decoding unit 250. And a derandomizer 260 that derandomizes and outputs an MPEG-2 transport stream.

Accordingly, the digital broadcast receiver of FIG. 1 performs down-converting of an RF signal to baseband in the reverse process of the digital broadcast transmitter, demodulates and equalizes the converted signal, and performs channel decoding to restore the original signal.

FIG. 2 shows a VSB data frame in which a segment synchronization signal and a field synchronization signal are inserted in a US-based digital broadcasting (8-VSB) system. As shown, one frame consists of two fields and one field consists of one field sync segment, which is the first segment, and 312 data segments. In addition, one segment corresponds to one MPEG-2 packet in a VSB data frame, and one segment includes four symbols of segment sync and 828 data symbols.

In FIG. 2, the segment synchronization signal and the field synchronization signal, which are synchronization signals, are used for synchronization and equalization at the digital broadcast receiver. That is, the field synchronizing signal and the segment synchronizing signal are data already known between the digital broadcast transmitter and the receiver, and are used as reference signals when performing equalization at the receiver side.

The VSB scheme of the U.S. terrestrial digital broadcasting system as shown in FIG. 1 is a single carrier scheme, which is vulnerable to a multipath fading channel environment having Doppler. Thus, the performance of the receiver is highly dependent on the performance of the equalizer to eliminate this multipath.

However, according to the conventional transmission frame as shown in FIG. have.

That is, it is not easy to equalize a received signal by estimating a channel using a small amount of known data using the conventional equalizer and removing a multipath. As a result, the conventional digital broadcasting receiver has a problem in that reception performance is degraded in a poor channel environment, particularly in a Doppler fading channel environment.

Accordingly, an object of the present invention is to provide a digital broadcast transceiver and a signal processing method thereof capable of generating and transmitting a transmission signal added with known data in a digital broadcast transmitter and detecting the same in a receiver to improve reception performance. It is.

According to an aspect of the present invention, there is provided a digital broadcast transmitter, comprising: a randomizer for randomizing a transport stream having a stuff byte inserted at a predetermined position; A stuff byte exchange unit which replaces the stuff byte included in the data output from the randomization unit with predetermined known data; An RS encoding unit for performing RS encoding on data output from the stuff byte exchange unit; An interleaving unit performing interleaving on the data output from the RS encoding unit; A trellis encoding unit performing trellis encoding on the data output from the interleaving unit; An RS parity generating unit generating parity based on the data output from the RS encoding unit and the data output from the trellis encoding unit and inputting the generated parity to the trellis encoding unit; And a modulation and RF unit for performing modulation on the data output from the trellis encoding unit and performing RF upconversion.

       Preferably, the trellis encoding unit includes a memory for performing trellis encoding, and performs the memory initialization on data input at a position where the stuff byte is inserted.

       Preferably, the trellis encoding unit inputs a value for initializing the memory to the RS parity generator, receives a parity generated by the RS parity generator, and replaces the corresponding parity.

       Preferably, the control unit for generating a control signal indicating the information about the insertion position of the stuff byte to control the memory initialization of the trellis encoding unit; further comprises a.

       More preferably, the control unit sends the position information of the stuff byte and known data to be replaced at the position to the stuff byte exchange unit, and sends the position information of the initialization packet to the RS parity generation unit.

       The RS parity generation unit may further include a packet buffer that temporarily stores a packet including an initialization region output from the RS encoding unit.

       More preferably, the packet buffer receives the data changed according to the memory initialization and updates the stored data.

       Also, preferably, the RS parity generation unit maps the initialization symbol output from the trellis encoding unit to a predetermined byte and outputs the byte mapper to the packet buffer and the RS encoding RS output data from the packet buffer. The encoder further includes a symbol mapper for converting an output of the RS encoder into a predetermined symbol.

     The stuff byte is also inserted into an adaptation field of the transport stream.

      Further, information on the position and length of the stuff byte is inserted in the transport stream at a predetermined position.

      In addition, the predetermined known data has a property that an output after passing through the trellis encoding unit has a spectrum similar to pseudo noise and an average direct current (DC) value is close to zero.

      On the other hand, the transmission method of a digital broadcast transmitter according to an embodiment of the present invention includes a randomization step of randomizing a transport stream in which a stuff byte is inserted at a predetermined position; A stuff byte exchange step of replacing the stuff byte with predetermined known data for the data output in the randomization step; An encoding step of performing RS encoding on the data output in the stuff byte exchange step; an interleaving step of performing interleaving on the data output in the RS encoding step; A trellis encoding step of performing trellis encoding on the data output in the interleaving step; An RS parity generating step of generating parity based on data output in the RS encoding step and data output in the trellis encoding step and inputting the generated parity into the trellis encoding step; And performing modulation and performing RF upconversion on the data output in the trellis encoding step.

According to an embodiment of the present invention, a digital broadcast receiver includes a demodulator for receiving and demodulating an encoded signal by inserting predetermined known data into a stuff byte inserted at a predetermined position; An equalizer for equalizing the demodulated signal; A Viterbi decoding unit for correcting and decoding an error of the equalized signal; A deinterleaving unit performing deinterleaving on the output data of the Viterbi decoding unit; And an inverse randomizer for performing inverse randomization on the output data of the deinterleaving unit.

A trellis encoder of a digital broadcast transmitter according to an embodiment of the present invention is a digital broadcast for transmitting a transport stream formed by replacing a stuff byte inserted at a predetermined position with predetermined known data. In the trellis encoder of the transmitter, a memory for performing trellis encoding is provided, and the memory initialization is performed on data inputted from a position where the stuff byte is inserted.

On the other hand, according to another embodiment of the present invention, a digital broadcast transmitter includes: a randomizer for randomizing a transport stream having a stuff byte inserted at a predetermined position; A stuff byte exchange unit which replaces the stuff byte included in the data output from the randomization unit with predetermined known data; An RS encoding unit for performing RS encoding on data output from the stuff byte exchange unit; An interleaving unit performing interleaving on the data output from the RS encoding unit; A trellis encoding unit including a memory and performing initialization of the memory and trellis encoding at a position where the stuff byte is inserted to data output from the interleaving unit; An RS parity generation unit configured to receive a value for initializing the memory, generate parity, and input the generated parity to the trellis encoding unit; And a modulation and RF unit for performing modulation on the data output from the trellis encoding unit and performing RF upconversion.

On the other hand, the signal processing method of the digital broadcast transmitter according to another embodiment of the present invention, the randomization step of randomizing the transport stream, the stuff byte (Stuff byte) is inserted at a predetermined position; A stuff byte exchange step of replacing the stuff byte with predetermined known data for the data output in the randomization step; An encoding step of performing RS encoding on the data output in the stuff byte exchange step; An interleaving step of performing interleaving on the data output in the RS encoding step; Performing memory initialization and trellis encoding on the data output in the interleaving step at the position where the stuff byte is inserted; An RS parity generating step of receiving a value for initializing the memory, generating parity, and inputting the generated parity into the trellis encoding step; And performing modulation and performing RF upconversion on the data output in the trellis encoding step.

Although the preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above, and the present invention is not limited to the specific embodiments of the present invention without departing from the spirit of the present invention as claimed in the claims. Anyone skilled in the art can make various modifications, as well as such modifications are within the scope of the claims.

According to the present invention, a digital broadcast transmitter generates and inserts a stuff byte into an MPEG-2 transport stream packet, replaces the inserted stuff byte with known data, and detects known data from a signal received from the digital broadcast receiver. By using for synchronization and equalization, digital broadcast reception performance may be improved in a poor multipath channel.

In addition, by adjusting the sequence of known data to be inserted in the appropriate amount and pattern for synchronization and equalization of the receiver, the operation performance of the equalizer can be improved and the digital broadcast reception performance can be improved.

Hereinafter, with reference to the drawings will be described the present invention in more detail.

3 is a diagram showing the structure of a typical MPEG-2 transport stream packet. Referring to FIG. 3, a typical MPEG-2 transport stream consists of a TS header portion of 4 bytes and an adaptation field or payload data of 184 bytes.

4 is a diagram illustrating a structure of an MPEG-2 transport stream packet including an adaptation field added with a stuff byte according to the present invention. Referring to FIG. 4, the MPEG-2 transport stream according to the present invention consists of a header portion of 4 bytes, an adaptation field of "n" bytes, and payload data of "184-n" bytes. Two bytes of the adaptation field are an adaptation field header (AF header) including information on the length of the adaptation field, and a stuff byte that merely occupies space without inserting information after the adaptation field header may be inserted. The presence or absence of the adaptation field is determined by the value of the adaptation field control bit in the TS header of the transport stream.

In the present invention, an MPEG-2 TS packet in which a stuff byte is inserted into an adaptation field of a transport stream as in the data format shown in FIG. 4 is used as an input of a transmitter.

5 is a diagram illustrating a structure of a transport stream into which an SRS is to be inserted to implement the transmission system of the present invention. Here, for convenience of description, three bytes after a sync byte of a transport stream are referred to as a normal header, and the first two bytes of an adaptation field are referred to as an AF (adaptation field) header.

FIG. 5A is a structure of MPEG-2 packet data of a basic form in a VSB system using SRS, and includes a normal header portion consisting of a synchronization signal, 1 byte and 3 bytes of PID (Packet Identity), and information on the location of a stuff byte. A two-byte adaptive field header (AF header) and a stuff byte consisting of bytes of a predetermined length (N) are included, and the other bytes are composed of a normal stream which is ordinary data (Payload Data) to be transmitted. Since the start position of the stuff byte is fixed, the information about the position of the byte is represented by the information about the length of the stuff byte. Stuffing bytes length N can be used from 1 to 27.

5B-5E also illustrate a packet structure in which other information such as PCR, OPCR, splice_count, and the like are included in an adaptation field in order to effectively use SRS. Even in this case, the adaptation field is configured such that its size is always constant. Parts other than information such as AF header, PCR, OPCR, and splice_count are stuff bytes that do not contain information to be inserted with SRS.

6 is a block diagram illustrating a digital broadcast transmission system according to an embodiment of the present invention.

Referring to FIG. 6, the digital broadcast transmitter includes a randomizer 610, a stuff byte exchanger 620, an RS encoder 630, an interleaving unit 640, a trellis encoder 650, and an RS parity generator. 660, a multiplexer 670, and a controller 680.

The randomizer 610 randomizes the input MPEG-2 transport stream data to increase the utilization of the allocated channel space. The data input to the randomization unit 610 has a data format formed by inserting a stuff byte of a predetermined byte length into a predetermined position, which does not include payload data, as shown in FIG. 5.

The stuff byte exchanger 620 may generate known data, which is a specific sequence having a predetermined pattern predetermined between the transmitting side and the receiving side, and replaces the stuff byte with the known data at the stuff byte position of the randomized data. . Since the known data is distinguished from the payload data in which the pattern is transmitted and received, it can be easily detected and used for synchronization and equalization at the receiving end.

The RS encoding unit 630 adds parity of a predetermined byte by performing RS encoding on packet data in which stuff bytes are exchanged by the stuff byte exchange unit 620 to correct an error generated by a channel.

The interleaving unit 640 performs data interleaving with a predetermined pattern on the packet to which the parity output from the RS encoding unit 630 is added.

The trellis encoding unit 650 converts the data output from the interleaving unit 640 into symbols and performs symbol mapping through trellis coding at a ratio of 2/3. Here, the trellis encoding unit 650 initializes the value temporarily stored in its own memory device to a specific value at the start of the known data and performs trellis encoding. The memory device stored value is initialized, for example, by making it "00". In addition, the trellis encoder 650 inputs a value for initializing the memory to the RS parity generator 660 and receives a new parity generated by the RS parity generator to replace the existing parity with the parity. .

The RS parity generator 660 generates parity by performing RS encoding on MPEG-2 packets received from the RS encoder 630 using a value for initializing a memory received from the trellis encoder 650. Then, the generated parity is sent to the trellis encoding unit.

The control unit 680 sends the stuff byte position information and known data to be replaced at the position to the stuff byte exchange unit 620.

In addition, the control unit 680 transmits the position information of the initialization packet including the portion used for initialization among the 187 byte units input to the RS parity generation unit 660 to the RS parity generation unit, and only the initialization packet is used. To control. On the other hand, for the convenience of design, even though the stuff byte is used smaller than 27, it is assumed that 27 or 26 stuff bytes are used, and 33 or 32 initialization packets corresponding thereto may be used as an input of the RS parity generator. In this case, the problem does not occur even if there is an unchanged parity.

In addition, the controller 680 inputs a signal indicating the initialization region and the parity region to be replaced to the trellis encoding unit 650. The trellis encoder uses the signal to initialize the memory and receives the parity generated by the RS parity generator 660 to replace the existing parity.

The multiplexer 670 inserts a segment sync signal in segment units into the data converted into symbols by the trellis encoder 650 and a field sync signal in field units as shown in the data format of FIG. 2.

Meanwhile, the modulation and RF unit (not shown) performs VSB modulation such as pulse shaping a signal into which a pilot signal is inserted and loading the intermediate frequency carrier on an intermediate frequency carrier, and modulating the amplitude, and RF-modulating the modulated signal. Converts and amplifies and transmits through a channel assigned to a predetermined band.

Hereinafter, the configuration and operation of the trellis encoding unit 650 of FIG. 6 will be described in detail.

The trellis encoder 650 receives a signal indicating an initialization region and a parity region to be replaced from the controller 680, initializes the memory, and outputs a value used to initialize the memory to the RS parity generator 660. The trellis encoding section has a feedback structure, so its output is affected by previous memory values. Therefore, even if the stuff byte exchanger 620 replaces the stuff byte of the transport stream with a supplementary reference sequence (SRS), which is specific known data, the memory value of the trellis encoding unit 650 is not fixed. Can be output in various forms. To solve this problem, the memory of the trellis encoding unit 650 is initialized by changing the input value of the trellis encoding unit 650 at the beginning of the SRS by the number of stuff bytes.

7 is a diagram illustrating an example of a trellis encoding unit that operates to initialize a memory state to 0 according to an embodiment of the present invention.

When the memory initialization region is input to the trellis encoding unit 650, the memory initialization region is initialized, and initial_sel operates under the control of the controller, and MUX inputs the existing trellis encoding input (X1). Instead of outputting a new value (X1 ', X2') (zero forcing input) that makes the memory state zero. Here, since there are two memories of a convolutional encoder in the trellis encoding section, two consecutive symbols, that is, 2 * 2 = 4 bits, are required to initialize the memory. Table 1 shows the eight states of the three memories S0, S1, and S2 and the two consecutive inputs to zero the memory.

The trellis encoding unit of FIG. 7 inputs X1 'and X0' used for initialization of the memory to the RS parity generator 660. Since the new inputs X1 'and X0' are used as inputs of the trellis encoding unit 650, the parity of the MPEG-2 packet including the values X1 and X0 becomes incorrect parity. In order to form the correct parity, the trellis encoding unit 650 configures parity using new inputs X1 'and X0' instead of the existing inputs X1 and X0. The parity is generated through the RS parity generator 660. The parity newly generated by the RS parity generating unit 660 is sent to the trellis encoding unit 650, and the trellis encoding unit 650 replaces the existing parity with the newly generated parity.

8 shows an example of the configuration of an RS parity generation unit. The RS parity generator 800 may convert the symbol-byte converter 810, the data deinterleaver 820, the packet buffer 830, the RS encoder 840, the data interleaver 850, and the byte-symbol converter 860. Include.

The symbol-byte converter 810 receives an initialization symbol consisting of two bits from the trellis encoding unit 650, and a D.2 byte-symbol table of the ATSC Digital Television Standard "(document A / 53). Performs symbol to byte conversion, the reverse of to symbol table.

The data deinterleaver 820 deinterleaves the symbol-byte converted value and inputs it to the packet buffer.

The packet buffer 830 temporarily stores a packet including an output region of the data deinterleaver 820 and an initialization region in units of 187 bytes output from the RS encoding unit 630. The packet buffer replaces the value in the existing initialization area with the new value. The input that is replaced at this time is not used up, but only the upper 4 bits of the byte used for initialization are replaced. RS encoder 840 adds parity by RS encoding the output of the packet buffer. Here, the parity generated by the RS encoder passes through the data interleaver. The output is byte to symbol conversion of D.2 table of "ATSC Digital Television Standard" (document A / 53) and used as input to trellis encoding unit 650.

FIG. 9 illustrates another parity generating unit operating at a high speed, which solves a problem of delay occurring in the operation of the interleaver and the deinterleaver. The parity generator of FIG. 9 includes a byte mapper 910, a packet buffer 920, an RS encoder 930, and a symbol mapper 940.

The byte mapper 910 directly maps an initialization symbol input from the trellis encoding unit to a value obtained by performing the symbol-byte conversion and data interleaving of FIG. 8 and outputs it to the packet buffer. The packet buffer 920 temporarily stores a packet including an output region of the byte mapper and an initialization region in units of 187 bytes output from the RS encoding unit. After data replacement is performed in this packet buffer, its output is RS encoded by the RS encoder 930 and then input into the trellis encoding section at high speed via the symbol mapper 940. The symbol mapper 940 simultaneously performs operations of the interleaver and the byte-symbol converter of FIG. 8.

10 and 14 illustrate data formats for explaining the operation of the present invention.

First, FIG. 10 is a diagram for explaining a change in an SRS region of a transport stream by an interleaving operation of the interleaving unit 640.

The stuff bytes for the SRS present in the 207 packets output from the RS encoding unit 630 by interleaving repeatedly appear in 52-segment units. The stuff bytes are arranged in the horizontal direction by interleaving. Here, the first horizontal line corresponds to the first stuff byte, the second horizontal line corresponds to the second stuff byte, and the Nth horizontal line corresponds to the Nth stuff byte. As shown in FIG. 2, in the VSB frame, 312 data segments exist after field sync. That is, since 312/52 = 6, six identical SRSs appear in 52-segment units after the field sync segment.

FIG. 11 illustrates an SRS area, an initialization area, and an initialization packet RS parity of an initialization packet when the stuff byte has a length of 27. FIG. The initialization packet RS parity is a parity corresponding to an initialization area and indicates parity to be replaced with a new parity according to the initialization of the trellis encoder. As shown in Fig. 10, the lower part of the 52 bytes is the part appearing first after interleaving, and thus this part becomes an initialization region.

The stuff bytes may be used for 1 to 27 SRSs, and when N stuff bytes are used for SRS, parity corresponding to the N initialization areas in FIG. 11 is initialized to RS packet parity. do.

For example, if one stuff byte is used, as shown in FIG. 11, the initialization area of the first stuffing byte has a size of 7 bytes, and 7 packets including the initialization area are included. (52,1,2,3,4,5,6) are used for initialization. The initialization area of the second stuff byte has a size of 8 bytes and 52,1,2,3,4,5,6,7 packets are used for initialization.

As shown, 52,1,2,3, ..., N + 4, N + 5 packets are initialized when N stuff strings are used to form the SRS, from the first stuff byte to the Nth stuff byte. Corresponds to a packet including (Initialization Area). That is, parity of N + 6 packets includes an initialization area, and the parity becomes an initialization packet RS parity and is replaced later. When N = 27, parity of 52,1,2,3, ..., 31,32 packets, that is, 33 parity becomes initialization packet RS parity.

On the other hand, since TCM encoders used in ATSC perform trellis encoding in units of 12 symbols, 12 TCM encoders must be initialized to completely initialize the TCM encoder. However, due to casuality, only 7,8,9,10,11 TCM encoders can be initialized in order from the first to fifth stuff bytes. In addition, the stuff byte used as the SRS can be used to initialize all 12 encoders. This number is equal to the size of the initialization area of each stuff byte in FIG. In FIG. 11, since four symbols (two bits are used to configure one symbol) of each byte pass through the same TCM encoder, one byte may initialize one TCM encoder. As mentioned above, since only two symbols, 2 * 2 = 4 bits, can be initialized, only MSB 4 bits are used for initialization and LSB 4 bits are used to configure SRS.

FIG. 12 illustrates a data format after the output of the RS encoding unit of FIG. 11 passes through the data interleaving unit. Only the 52nd, 1st, 2nd, ..., 31st, 32nd packets, i.e., 33 packets, have a parity corresponding to the packet after the initialization area of the stuff byte of length 27.

Meanwhile, as described above, the trellis encoding unit is affected by the output and the next memory state by the previous memory value. In other words, if the previous input is changed, the input to be used for initialization is changed. If the parity of the packet corresponding to the initialization region comes earlier than the initialization region, the input value used to initialize the memory of the trellis encoding unit 650 is changed by the newly generated parity. In this case, the initialization is not performed or the correct parity cannot be generated using the initialization correction value. Accordingly, in order to prevent the parity of the initialization packet from appearing before the initialization region as shown in FIG. 12, the maximum number of used stuff bytes is 27.

For the same reason as above, the trellis encoding unit 650 may initialize up to seven first stuff bytes. The remaining five stuff bytes are present in the 47th, 48th, 49th, 50th, and 51st packets. They cannot be used for initialization because the parity, which must be replaced, comes first.

13 is a diagram illustrating a structure of a TS packet repeated in 52 segment units. FIG. 13 shows the output form of the RS encoding unit when 27 stuff bytes are used for SRS. If fewer than 27 stuff bytes are used, the initialization packet RS parity is also reduced by the amount corresponding to the reduced area. The part that is not initialized is not used as SRS, so it can be used for other purposes. In this figure, if the PCR is delivered through the 15th packet, the PCR occupies 6 bytes of space as shown in FIG. In this case, the position is not used as SRS, but 6 bytes together with the previous 5 bytes are used for PCR transmission.

14 shows an example of byte values of an SRS pattern input to a stuff byte exchange to generate an SRS. The pattern byte value of FIG. 14 is stored in an SRS pattern memory (not shown), and these values have a spectrum similar to pseudo noise after passing through the trellis encoding unit, and have an average direct current value of zero. It has a property of being close. If less than 27 stuff bytes are used, the number is replaced and inserted. For example, if 10 stuff bytes are used, the SRS is generated in such a way that only up to 10 parts of the figure are replaced. In the initialization area, the lower 4 bits are used for the SRS. The upper 4 bits can contain any value. In addition, any value can be entered in the uninitialized part. However, if PCR is used, no other value can be entered at the PCR position so that the PCR is delivered as it is.

15 is a block diagram of a digital broadcast receiver of the present invention.

The digital broadcast receiver of FIG. 15 includes a demodulator 1510, an equalizer 1520, a Viterbi decoding unit 1530, a deinterleaving unit 1540, an RS decoding unit 1550, an inverse randomizer 1560, and a controller ( 1570, and operates in a reverse process of the digital broadcast transmitter of FIG. 6 to decode the received signal.

A tuner / IF (not shown) converts an RF signal received through a channel into a baseband signal, and the demodulator 1510 performs synchronization detection and demodulation on the converted baseband signal.

The equalizer 1520 compensates for channel distortion caused by the multipath of the channel from the demodulated signal. The equalizer 1520 receives the known data from the controller and uses the received data to compensate for the channel distortion.

The Viterbi decoder 1530 corrects an error from the equalized signal by the equalizer 1520 and performs decoding.

The data deinterleaver 1540 rearranges data distributed by the interleaving unit of the transmitter.

The deinterleaved data is error corrected through the RS decoding unit 1550, and the data corrected through the RS decoding unit 1550 is derandomized through the derandomization unit 1560 to decode the MPEG-2 transport stream. Data is restored.

On the other hand, the control unit 1570 transmits the value of the SRS interval and the SRS to the equalizer to use for performance improvement. The SRS interval and the value of the SRS are determined depending on the mode. The mode may be defined or the transmitter may send a mode signal. When the transmitter sends the mode signal, the controller detects the mode signal and sends the SRS section corresponding to the mode and the value of the SRS to the equalizer. In order to configure an SRS having a predetermined value, its input should be determined as a specific value as shown in FIG. 14. To improve performance, the Viterbi decoder or RS decoder uses the SRS part with the correct value from the controller instead of the decoding output.

16 shows another embodiment of the digital transmitter of the present invention.

The transmitter of FIG. 16 is a system using a linear coding characteristic of the RS encoder, and the RS parity generator 1660 uses only an initialization symbol as an input. For 187 bytes other than initialization, the input is assumed to be 0 and the parity is output.

17 illustrates a trellis encoding unit 1650 of a type for performing such an operation. The new input bit necessary for initializing the memory and the input bit used as the original input in the initialization area are exclusive ORed and sent to the RS parity generator 1660. The RS parity generator generates parity using only this value, and uses the value by exclusive OR with the parity coming into the original input to be replaced with the generated parity. In this operation, the same parity input as the parity used to replace the parity changed according to the above-described initialization may be performed to perform the same operation.

18 is a flowchart illustrating a digital broadcast transmission method according to the present invention.

First, the randomization unit 610 receives a transport stream and performs randomization (S100).

Under the control of the controller 680, the stuff byte exchanger 620 inserts known data into the stuff byte area included in the transport stream randomized by the randomizer 610 (S110).

When the transport stream into which the known data is inserted is input from the encoding unit 630, RS encoding is performed to add parity to the parity region included in the packet of the transport stream (S120).

The interleaving unit 640 performs data interleaving with a predetermined pattern on the packet to which the parity output from the RS encoding unit 630 is added (S130).

The trellis encoding unit 650 initializes a value temporarily stored in its own memory device to a specific value at the start of the known data and performs trellis encoding (S140).

The RS parity generator 660 performs RS encoding on the MPEG-2 packet received from the RS encoder 630 using a value used to initialize a memory received from the trellis encoder 650 to perform parity. Generates and sends the generated parity to the trellis encoding unit (S150).

In the multiplexer 670, the segment synchronization signal is inserted into the data converted into the symbol by the trellis encoding unit 650 in the unit of segments as in the data format of FIG. .

Meanwhile, the modulation and RF unit (not shown) performs VSB modulation such as pulse shaping a signal into which a pilot signal is inserted and loading the intermediate frequency carrier on an intermediate frequency carrier to modulate amplitude, and RF the modulated signal. The signal is converted and amplified and transmitted through a channel allocated to a predetermined band (S170).

19 is a flowchart illustrating a digital broadcast reception method according to the present invention.

A tuner / IF (not shown) converts an RF signal received through a channel into a baseband signal, and the demodulator 1510 performs synchronization detection and demodulation on the converted baseband signal (S200). .

The equalization unit 1520 performs channel equalization by compensating for channel distortion from the demodulated signal and removes mutual interference of the received symbol (S210).

The Viterbi decoder 1530 corrects an error from the equalized signal and performs decoding (S220).

The data deinterleaver 1540 rearranges data distributed by the interleaving unit of the transmitter (S230).

The deinterleaved data is error corrected through the RS decoding unit 1550 (S240), and the data corrected through the RS decoding unit 1550 is derandomized through the derandomization unit 1560 to be MPEG- Data of the two transport streams is restored (S250).

1 is a block diagram showing a transmission and reception system of a typical US digital broadcasting (ATSC VSB) system,

2 shows an ATSC VSB data frame structure;

3 is a diagram showing the structure of a typical MPEG-2 transport stream packet;

4 illustrates the structure of an MPEG-2 transport stream packet including an adaptation field according to the present invention;

5 illustrates various data formats of an MPEG-2 transport stream packet including an adaptation field added with a stuff byte according to the present invention;

6 is a block diagram showing a digital broadcast transmitter according to an embodiment of the present invention;

7 is a structural diagram of a trellis coding unit of a digital broadcast transmitter according to an embodiment of the present invention;

8 is a structural diagram of an RS packet generator of a digital broadcast transmitter according to an embodiment of the present invention;

9 is an embodiment of an RS packet generation unit of a digital broadcast transmitter according to an embodiment of the present invention;

10 is a view for explaining the SRS interval operation of the interleaving unit according to the present invention;

11 is a view showing an input frame of an interleaving unit according to the present invention;

12 is a view showing an output frame of the interleaving unit according to the present invention;

13 is a view showing an input frame of a repeating structure of an interleaving unit according to the present invention;

14 is a view showing an input frame of a stuff byte exchange unit of the present invention;

15 is a block diagram illustrating a digital broadcast receiver according to an embodiment of the present invention;

16 is a block diagram illustrating a digital broadcast transmitter according to another embodiment of the present invention;

17 is a structural diagram of a trellis coding unit used for the transmission system of FIG. 16;

18 is a flowchart provided to explain an operation of a digital broadcast transmitter according to an embodiment of the present invention; and

19 is a flowchart provided to explain an operation of a digital broadcast receiver according to an embodiment of the present invention.

Description of the Related Art [0002]

620: randomization unit 620: stuff byte exchange unit

630: RS encoding unit 640: interleaving unit

650: trellis encoding unit 660: RS parity generation unit

670: the multiplexer 680: the control unit

Claims (10)

In a digital broadcast receiver, A tuner unit for receiving a stream from a digital broadcast transmitter; A demodulator for demodulating the stream; And And an equalizer for equalizing the demodulated stream by using known data disposed at a predetermined position other than a header area in the demodulated stream. The stream, And an initialization byte used for initialization of the trellis encoding unit including a plurality of trellis encoders included in the digital broadcast transmitter. The first 4 bits of the initialization byte are input to one of the plurality of trellis encoders to be used for initialization of at least two memories in the trellis encoder, and the remaining 4 bits constitute known data. receiving set. The method of claim 1, A decoding unit for decoding the equalized stream; A deinterleaving unit for rearranging the decoded stream; And And an RS decoding unit for RS decoding the stream rearranged by the deinterleaving unit. The method of claim 1, The trellis encoding unit includes 12 trellis encoders, And the first 4 bits of the initialization byte are input to one of the 12 trellis encoders to be used for the initialization, and the remaining 4 bits constitute known data. delete In the stream processing method of a digital broadcast receiver, Receiving a stream from a digital broadcast transmitter; Demodulating the stream; And Equalizing the demodulated stream by using known data arranged at a predetermined position other than a header area in the demodulated stream. The stream, And an initialization byte used to initialize a trellis encoding unit including a plurality of trellis encoders included in the digital broadcast transmitter, wherein the first 4 bits of the initialization bytes are input to one of the plurality of trellis encoders. And the remaining 4 bits constitute known data used for initializing at least two memories in the trellis encoder. The method of claim 5, Decoding the equalized stream; Reordering the decoded stream; And RS decoding the RS decoded rearranged stream. The method of claim 5, The trellis encoding unit includes 12 trellis encoders, The first 4 bits of the initialization byte is input to one of the 12 trellis encoders and used for the initialization, and the remaining 4 bits constitute known data. delete The method of claim 1, The trellis encoder, A first mux connected to a first memory and the first memory and outputting one of an existing input signal and a value stored in the first memory according to a control signal, an output of the first mux and a value stored in the first memory Is added to the first adder, the second memory, the third memory connected to the second memory, the value of the second memory is shifted, a value stored in the existing input signal and the third memory according to the control signal And a second adder for outputting one of the second mux and a second adder for adding the output of the second mux and the value stored in the third memory to the second memory. The method of claim 5, The trellis encoder, A first mux connected to a first memory and the first memory and outputting one of an existing input signal and a value stored in the first memory according to a control signal, an output of the first mux and a value stored in the first memory Is added to the first adder, the second memory, the third memory connected to the second memory, the value of the second memory is shifted, a value stored in the existing input signal and the third memory according to the control signal And a second adder for outputting one of the second mux and a second adder for adding the output of the second mux and the value stored in the third memory to the second memory. .

Images