KR100771625B1 - System and method for digital broadcasting transmitting/receiving - Google Patents

Abstract

The present invention relates to a digital broadcasting system and method capable of transmitting additional data while being compatible with an existing broadcasting system. The system and method are characterized in that information bits of additional data are coded to generate parity bits and transmitted together with the information bits, It is possible to transmit MPEG video / audio data and additional data more reliably even in a signal and a channel with high noise. In particular, the performance of the slicer predictor and the trellis decoder in the reception system can be greatly improved.

Additional data, convolutional coding

Description

TECHNICAL FIELD The present invention relates to a system and method for transmitting / receiving digital broadcasting,

Figure 1 shows an ATSC 8T-VSB transmission system

2 shows an ATSC 8T-VSB receiving system

FIG. 3 is a block diagram of a VSB transmission system for digital television broadcasting

4 is a diagram illustrating a null sequence insertion

5 is a block diagram showing a configuration of a trellis encoder and a precoder;

6 is a block diagram of a 1/2 convolutional encoder in a general feedback form

7 is a block diagram showing the concatenated state of a 1/2 convolutional encoder and a trellis encoder in the digital VSB transmission system of the present invention

8 is a block diagram of a configuration of a selective 1/2 convolutional encoder according to the present invention

9 is a block diagram of a supplementary data symbol designation unit according to the present invention

10 is a block diagram of a configuration of a digital VSB transmission system according to the present invention

DESCRIPTION OF THE REFERENCE NUMERALS

46: Additional data processing unit 47: Multiplexer

48: first coder 49: additional data symbol indicator

50: selective 1/2 convolutional encoder 51: first decoding unit

52: ATSC 8T-VSB transmitter

The present invention relates to a system and method capable of transmitting / receiving additional data while being compatible with an existing receiving system.

In the United States, the ATSC 8T-VSB (8Trellis-Vestigial Sideband) transmission method for terrestrial digital broadcasting was adopted as the standard in 1995 and has been broadcasting since the second half of 1998. In Korea, the same ATSC 8T- The test broadcasting was started in May 1995 and the test broadcasting system was changed on August 31, 2000.

1 shows a conventional ATSC 8T-VSB transmission system.

1, the data randomizer 1 randomly outputs data to the Reed-Solomon encoder 2, and the Reed-Solomon encoder 2 performs Reed-Solomon encoding on the randomized data to generate 20 bytes And outputs the result to the data interleaver 3. The data interleaver 3 interleaves the data and outputs the interleaved data to the trellis coder 4. The trellis coder 4 converts the interleaved data from bytes to symbols and performs trellis coding. The multiplexer 5 multiplexes the trellis coded symbol stream and the synchronization signals and outputs the multiplexed signal to the pilot inserter 6, and the pilot inserter 6 adds the pilot signal to the multiplexed symbol stream. The VSB modulator 7 modulates the symbol stream output from the pilot inserter 6 into an 8T-VSB signal and outputs the 8T-VSB signal to the RF converter 8. The RF converter 8 converts the baseband signal modulated with the 8T-VSB signal into an RF band signal, which is transmitted toward the receiving system via the antenna 9.

2 shows a conventional ATSC 8T-VSB receiving system.

2, a demodulator 11 converts a signal of an RF band received through the antenna 10 into a baseband signal, and a synchronization and timing recovery unit (not shown) receives a segment synchronization signal, a field synchronization signal, Lt; / RTI > On the other hand, the comb filter 12 removes the NTSC interference signal, and the channel equalizer 13 uses the slicer predictor 14 to correct the distorted channel during transmission. The phase reconstructor 15 restores the phase of the received signal, and the trellis decoder 16 performs Viterbi decoding on the phase recovered signal and outputs the result to the data deinterleaver 17. The data deinterleaver 17 performs an inverse operation of the data interleaver 3 of the VSB transmission system and outputs the result to the Reed-Solomon decoder 18, and the Reed-Solomon decoder 18 decodes the Reed-Solomon encoded signal . Meanwhile, the data derandomizer 19 performs an inverse operation of the data randomizer 1 in the transmission system.

As described above, the conventional ATSC 8T-VSB receiver only receives MPEG data and can not receive additional data (e.g., program executable file, security information, etc.).

That is, the 8T-VSB transmission method adopted as a digital broadcasting standard in North America and domestic is a system developed for transmission of MPEG video / audio data. However, as the digital signal processing technology is rapidly developing and the Internet is widely used these days, digital home appliances, computers, and the Internet are being integrated into a single large frame. Therefore, in order to meet various demands of users, it is necessary to develop a system capable of transmitting various additional data in addition to video / audio data through a digital broadcasting channel.

Some users of the supplementary data broadcasting are expected to receive supplementary data broadcasting using a PC card or a portable device with a simple indoor antenna. In the indoor environment, signal intensities The broadcast reception performance may be degraded due to the influence of the ghost and noise due to the reflected waves. However, unlike general video / audio data, additional data transmission should have a lower error rate. In the case of video / audio data, errors that can not be detected by the human eye and ears are not a problem, but in the case of additional data, a bit error may cause serious problems. Therefore, it is necessary to develop a system that is more resistant to ghost and noise in the channel.

At this time, the additional data transmission will normally be done in a time division manner over the same channel as the MPEG video / audio. However, since the start of digital broadcasting, ATSC VSB digital broadcasting receiver, which receives only MPEG video / audio, is widely available in the market. Therefore, the additional data transmitted on the same channel as the MPEG video / audio should have no influence on the existing ATSC VSB dedicated receiver which has been introduced to the market. This situation is defined as ATSC VSB compatibility, and the additional data broadcasting system should be a system compatible with the ATSC VSB system.

In order to solve such a problem, the present applicant has applied for a related patent (Application No. P01-3304, filed on January 19, 2000).

An object of the present invention is to provide a digital VSB transmission system for multiplexing and transmitting MPEG video / audio data and additional data through the same digital broadcasting channel.

It is another object of the present invention to provide a digital VSB transmission system for transmitting additional data so as to be compatible with an existing ATSC 8T-VSB reception system.

It is still another object of the present invention to provide a digital VSB transmission system that enhances the coding gain of additional data to be transmitted and has excellent performance for channel noise and ghost at the receiver side.

According to an aspect of the present invention, there is provided a digital VSB transmission system including: an additional data processing unit for encoding additional data and converting the additional data into a format of an MPEG transport packet; a multiplexing unit for multiplexing and outputting the additional data and MPEG broadcast data; A first encoder for sequentially performing data randomizing on the multiplexed data, parity addition by Reed-Solomon coding, data interleaving, and byte-symbol conversion, A second encoding unit for encoding the data output from the encoding unit with 1 / n (n is a natural number) code rate; and a second encoding unit for performing symbol-byte conversion and data deinterleaving on the output data of the second encoding unit, 1 < / RTI > encoder removes the Reed-Solomon parity added from the deinterleaved data And a first decoding unit, characterized in that the configuration including the second transmission unit that transmits the modulation after performing the parity addition, the data interleaved by the trellis encoding, Reed-Solomon coding for data output from the first decoding unit.

Preferably, the second encoder is a feedback type half convolutional encoder.

Preferably, the second encoder generates parity bits by performing ½ convolutional encoding on the information bits of the additional data, and then outputs the unencoded information bits as upper bits of the trellis encoder in the transmitter, parity And outputs a bit.

The second encoding unit may further include an additional data symbol indicating unit for determining whether the input data is additional data and outputting a control signal corresponding to the determination result to the second encoding unit.

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

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Figs. 3 to 5 are diagrams shown in patents (P01-3304, 2000.1.19) filed by the present application, which are compatible with the conventional digital broadcasting system and can transmit additional data as well as MPEG data.

3, the Reed-Solomon encoder 20, the data interleaver 21, the null sequence insertion section 22, and the MPEG header inserting section 23 are parts for processing the additional data, The same structure as the packet is made.

 That is, the Reed-Solomon encoder 20 adds Reed-Solomon coding of the additional data and adds 20 bytes of parity code. The data interleaver 21 interleaves the added data with the added parity to improve the performance against burst noise And inserts a null sequence into the additional data by outputting it to the null sequence inserting section 22. [ Here, the reason why the null sequence is inserted is that the reception can be performed well even in a poor channel environment.

FIG. 4 is a diagram for explaining a process of inserting a predetermined sequence into additional data in the null sequence inserting unit 22 of FIG. 3. When one bit of additional data is input, one bit of null bits When two bytes are input, one byte is output, and two bytes are output.

On the other hand, the MPEG header inserting unit 23 inserts the 3-byte MPEG header into the additional data into which the null sequence is inserted so as to form the same format as the MPEG transport packet. The generated additional data is time-division multiplexed with the MPEG transport packet, that is, the MPEG video / audio data, and output to the 8T-VSB transmitter 25 in the multiplexer 24. The 8T VSB transmitter 25 has the same configuration as that of FIG.

That is, an additional data packet of 164 bytes is subjected to Reed-Solomon coding in the Reed-Solomon encoder 20 and converted into a packet of 184 bytes. After this is interleaved in the data interleaver 21 and the order is changed, When the sequence is inserted, two 184-byte packets are output. When a 3-byte MPEG transport header is added to each packet in the MPEG header inserting unit 23, two 187-byte packets are output to the multiplexer 24, And is transmitted through the 8T VSB transmission unit 25. The 8T VSB transmission unit 25 transmits the MPEG transport packet to the 8T VSB transmission unit 25 through the MPEG transport packet.

At this time, the null bits inserted in the additional data are reordered in the 8T-VSB transmitter 25 and then reed-solomon encoded. This encoded null bit is interleaved and then applied to an input d0 of a trellis encoder (not shown). Here, the input signal d0 corresponds to a lower bit of two bits input to the trellis encoder. The sequence of bits in which the null bits are input to the lower bits of the trellis encoder through the processing as described above is referred to as a predefined sequence for convenience of explanation.

FIG. 5 is a diagram showing a configuration of a trellis encoder and a precoder used in the ATSC 8T-VSB transmitter 25 of FIG. 3. The trellis encoder 28 and the precoder 27 have two input bits (c0) (c1) (c2) for the output signal (d0) (d1). Reference numeral 29 denotes an 8T-VSB modulator which demultiplexes the three output bits c0, c1, and c2 output from the trellis encoder 28 and the precoder 27 by a corresponding modulation value z ). In Fig. 5, 27a and 28b denote adders, and 27b, 28a and 28c denote registers.

5, the input bit d1 is precoded by the precoder 27 to become an output bit c2, and the input bit d0 is replaced with an output bit c1 as it is . On the other hand, the output bit c0 is determined by the value stored in the register 28c of the trellis encoder 28. [ The signal level z of the 8T-VSB modulator 29 is determined according to the output bit streams c0, c1, and c2 of the trellis encoder 28 and the precoder 27. [

In the conventional 8T VSB receiver which can not receive the additional data, only the existing MPEG transport packet is selected through the PID (Packet Identification) given in the header of the transport packet to receive the digital broadcast, and the additional data packet is discarded do. Meanwhile, the receiver capable of receiving up to the additional data demultiplexes the MPEG transport data and the additional data packet using the multiplexing information, and then processes the additional data packet.

In the meantime, instead of transmitting a predefined sequence, the present invention also receives additional data input to the upper bit (d1) of the trellis encoder and transmits the lower bit (d0) at a 1/2 coding rate . This provides additional coding gain.

That is, in the case of the additional data symbol, the upper bits among the two bits input to the trellis encoder are used as information bits, and the lower bits are used as predefined bits. Instead of the predefined bits, And outputs the obtained bits to the lower bit (d0) of the trellis encoder. Herein, the information bits can be coded using an encoder having a 1/2 coding rate, that is, a ½ encoder, and bits varying according to the coding are referred to as parity bits in the present invention. By transmitting the parity bits of the information bits obtained by coding with the 1/2 partial rate to the trellis encoder instead of the predefined sequence, a further coding gain can be obtained.

At this time, since the output of the 1/2 encoder is re-encoded by the existing trellis encoder, a convolutional encoder is preferably used as the 1/2 encoder.

Particularly, since the parity bits of the 1/2 coded symbols can not be used as a training sequence in an 8T-VSB receiver, it is desirable to use a feedback type convolutional encoder such as a conventional trellis coder in order to compensate for this Do. That is, in the conventional ATSC 8T-VSB receiver, the performance of the slicer in the channel equalizer is improved by predicting the value (s0) of the register 28c of the trellis encoder shown in FIG. 4, This is because the register value of the trellis encoder is directly outputted.

Therefore, the 1/2 coder of the present invention can also predict the register value of the 1/2 encoder in the ATSC 8T-VSB receiver by using the feedback type convolutional encoder, thereby further improving the prediction performance of the slicer.

FIG. 6 is a block diagram of a 1/2 convolutional encoder having a feedback type M-number of registers, in which the information bit u is directly output as an output bit d1, and the parity bit d0 obtained by coding the maintenance bit u is a value of the register r1 Is output.

FIG. 7 shows an example in which the 1/2 convolutional encoder and the trellis coder are concatenated in one embodiment in which the number of registers is two.

7, the information bit u of the additional data is input to the 1/2 convolutional encoder 31 and coded to generate a parity bit, and the information bit u is converted into an upper bit d1 of the trellis encoder , And the parity bit is input to the lower bit (d0) of the trellis encoder.

At this time, the convolutional encoder 31 should perform convolutional coding only on the additional data symbols into which null bits are inserted. Accordingly, the 1/2 convolutional encoder added to the front end of the trellis encoder is an optional convolutional encoder selectively operating according to the input as shown in FIG.

That is, when the input symbol is a supplementary data symbol including a predefined sequence, the input bit is directly output as the upper bit d1, and the parity bit obtained by convolutional encoding the upper bit d1 instead of the predefined sequence is used as the lower bit d0 . On the other hand, in the case other than the additional data symbol, the two input bits are directly output as upper and lower bits d1 and d0. A total of twelve selectively used convolutional encoders are used for one trellis encoder.

8, each of the convolutional encoders includes a multiplexer 36 for selectively outputting a value fed back from a register 37 immediately downstream or a value fed back from a register 40 at the final stage, an output of the multiplexer 36 An adder 38 for adding the value inputted to the upper bit d1 and the output of the register 37 and a register 37 for storing a value fed back from the register 40 or the output of the adder 38, A register 40 for storing the output of the multiplexer 39 for a predetermined period of time and a multiplexer 41 for selectively outputting the output of the register 40 or a value input to the lower bit d0, .

If the input symbol is not the additional data, the value stored in the registers 37 and 40 should not be changed by the value input to the upper bit d1. That is, when the input symbol is not the additional data, each register must keep its current state by feedback on its output value. At this time, the control signal input to the multiplexers 36, 39, and 41 informs whether or not the input symbol is an additional data symbol. For example, when the input symbol is the additional data, the control signal input to the multiplexers 36, 39, and 41 is '1', and when it is not the additional data, it is assumed to be '0'.

Therefore, when the input symbol is the additional data, that is, when the control signal is '1', the multiplexer 36 selects a value fed back from the final register 40 and outputs the selected value to the register 37, When the control signal is '0', the selector 37 selects the value fed back from the register 37 and outputs the selected value to the register 37. When the control signal is '1', the multiplexer 39 selects and outputs the value output from the adder 38 to the register 40. When the control signal is '0', the multiplexer 39 selects the register 40, And outputs the selected value to the register 40. [0050] FIG. When the control signal is '1', the multiplexer 41 selects the value stored in the register 40 and outputs the selected value to the lower bit d0 of the trellis encoder. When the control signal is '0', the multiplexer 41 outputs the lower bit d0 And outputs the selected value to the lower bit d0 of the trellis encoder.

FIG. 9 is a block diagram showing an embodiment of the control signal generation process, and is referred to as an additional data symbol indicator for convenience of explanation.

At this time, the additional data symbol instruction unit allocates a flag of one bit per byte, and sets the flag value differently when it is not the additional data. For example, when the input data is an appended data packet, the 3-bit flag corresponding to the MPEG header is set to '0', and each flag is set to '1' for the byte to which the remaining null bits are inserted. On the other hand, when the input data is an MPEG transport packet, all the flags allocated to each byte are set to '0'. Therefore, in the case of the additional data flag, it has 3 '0' and 184 '1'. In the case of the MPEG data flag, it has 187 '0'.

Then, appropriate signal processing is performed on the thus-set flag value to generate a control signal.

In one embodiment, the multiplexer 24 of FIG. 3 can determine whether the incoming data is an ancillary data packet or an MPEG data packet, so that it generates the control signal in the operations from byte-to-symbol conversion in the multiplexer 24 of FIG. You can give.

That is, as shown in FIG. 9, the additional data flag and the MPEG data flag multiplexed by the multiplexer 42 bypass the data randomizer and are output to the Reed-Solomon encoder 43. The Reed-Solomon encoder 43 sets the flag value of the parity 20 bytes to be added to '0' and outputs it to the data interleaver 44. According to the data interleaving operation in the data interleaver 44, the flag is changed in order with the data, and the byte-to-symbol converter 45 converts the flag into a symbol, and a control signal corresponding to the symbol is generated.

Meanwhile, since a predefined sequence of additional data symbols is changed to a parity bit through a 1/2 convolutional coding after the ATSC 8T-VSB Reed Solomon encoder, an error in an additional data packet Lt; / RTI > In order to prevent such an influence, the Reed-Solomon parity byte corresponding to the data converted by the selective 1/2 convolutional encoder must be calculated again. That is, the Reed-Solomon parity byte added to the first additional data (i.e., the additional data before the 1/2 convolutional encoding) is removed and the Reed-Solomon parity byte is added to the 1/2 convolutional encoded additional data.

To this end, the output of the selective 1/2 convolutional encoder is converted into symbol-bytes and the Reed-Solomon parity that was first calculated after the operation of the data deinterleaver is removed. Then, Reed-Solomon coding is performed again by the ATSC 8T-VSB transmitter on the data from which the Reed-Solomon parity is removed, and Reed-Solomon parity is added. Then, since the Reed-Solomon parity corresponding to the 1/2 convolutional coded data is added, an error does not occur in the additional data packet at the time of the Reed Solomon decoding in the ATSC 8T-VSB receiver.

This process is shown in Fig.

FIG. 10 is an overall block diagram of a digital VSB transmission system according to the present invention, which includes an additional data processing unit 46 for inserting Reed-Solomon coding, null sequence insertion, and MPEG header into the additional data, A multiplexer 47 for selectively outputting an additional data packet or an MPEG data packet to be output, and a multiplexer 47 for sequentially performing data randomizing, reed-solomon coding, data interleaving, and byte-to-symbol conversion on the data packet output from the multiplexer 47 An additional data symbol instruction unit 49 for indicating whether the symbol output from the first encoder 48 is an additional data symbol or not, a control unit 50 for controlling the output of the additional data symbol instruction unit 49, If the signal indicates that it is an additional data symbol, it performs 1/2 convolutional coding on the symbol output from the first encoder 48 A first decoding unit 51 for sequentially performing conversion to byte, data deinterleaving, and Reed-Solomon parity removing operations on the symbols output through the selective convolutional encoder 50, And an 8T-VSB transmitter 52 for sequentially performing Reed-Solomon coding, data interleaving, trellis encoding, and the like on the data from which the Reed-Solomon parity has been removed by the 1-decoding unit 51. The 8T-VSB transmitter 52 omits the data randomizer in the configuration of FIG.

That is, the additional data is sequentially transmitted through the Reed-Solomon encoder 46a, the data interleaver 46b (not shown), the null sequence inserting unit 46c, and the MPEG header inserting unit 46d of the additional data processing unit 46 20 bytes of Reed-Solomon parity, a null sequence, and an MPEG header.

Then, the multiplexer 47 selects the additional data packet or the MPEG video / audio data packet and outputs it to the first encoding unit 48. Here, the first encoding unit 48 and the first decoding unit 51 are for removing the reed solomon parity inserted into the additional data before convolutional encoding.

That is, the data randomizer 48a of the first encoder 48 performs randomization on the data output from the multiplexer 47, and the Reed-Solomon encoder 48b performs Reed-Solomon encoding, And parity is added. The data interleaver 48c performs interleaving on the data to which the parity is added and outputs it to the byte-symbol converter 48d. The byte-to-symbol converter 48d converts the interleaved data output in units of bytes into 2-bit symbols and outputs the 2-bit symbols to the optional convolutional encoder 50. [

In this case, the selective convolutional encoder 50 selectively performs 1/2 convolutional coding in accordance with the control signal output from the additional data symbol instruction unit 49, and the detailed operation thereof will be described in detail with reference to FIGS. 6 to 9 I have omitted it, so I will omit it.

The data output from the selective 1/2 convolutional encoder 50 is input to the symbol-to-byte conversion unit 51a of the first decoding unit 51 and is then converted into a byte unit and then output to the data deinterleaver 51b . The data deinterleaver 51b performs inverse operation of the data interleaver 48c on the byte unit data and outputs it to the Reed-Solomon parity removing unit 51c. The Reed-Solomon parity removing unit 51c removes the reed- Solomon encoder 48b and outputs it to the ATSC 8T-VSB transmitter 52. The ATSC 8T- The 8T-VSB transmitter 52 sequentially transmits the additional data by performing the Reed-Solomon coding on the parity-removed data and adding the Reed-Solomon parity.

The multiplexer, the Reed-Solomon encoder, the data interleaver, and the byte-symbol converting unit, which are components of the additional data symbol indicating unit 49, may be separately configured in the additional data symbol indicating unit 49 as shown in FIG. 47 and the first encoding unit 48 may be used as they are. In this case, the bit line for the flag may be added for each block of the multiplexer 47 and the first encoding unit 48.

Meanwhile, the ATSC 8T-VSB receiver can receive and process both the additional data and the MPEG data by performing the reverse operation of the transmission process described above.

Particularly, on the ATSC 8T-VSB receiver side, the register value in the convolutional encoder for determining c1 and the register value in the trellis encoder for determining c0 can be predicted. Therefore, the channel equalizer uses the prediction information to replace the ordinary 8- Level slicer having a level-to-level distance can be used.

Therefore, the reception performance of the reception system can be further improved with respect to the ghost signal and the noise signal of the channel, and in particular, the performance performance of the slicer predictor and the trellis decoder in the reception system is greatly improved.

That is, it is possible to use slicers (e.g., two-level slicers) that are farther apart from each other to minimize errors in signal determination. This is because the farther the determined signal interval is, the less affected by ghost or noise.

Meanwhile, the VSB transmission system of the present invention can be used for transmission of another MPEG video / audio data instead of additional data transmission. In this case, reception is possible even in a poor reception environment (for example, receiving indoor antenna) than MPEG video / audio data transmitted in the conventional ATSC 8T-VSB transmission method. This application is suitable for receiving the MPEG video / audio with the minimum quality in a harsh environment and dividing the channel into time division so as to receive MPEG video / audio of better quality in a good reception environment.

As described above, according to the digital VSB transmission system of the present invention, the following effects can be obtained.

First, MPEG data and additional data can be multiplexed and transmitted through the same digital broadcasting channel while maintaining compatibility with the existing ATSC 8T-VSB receiver.

Second, parity bits are generated by encoding the information bits of the additional data at a coding rate of 1/2, and transmitted together with the information bits. Thus, MPEG video / audio data and additional data can be transmitted even in a channel with a ghost signal and a noisy channel. It can be transmitted more reliably.

Thirdly, a larger coding gain can be obtained by encoding the information bits of the additional data at a 1/2 coding rate to generate parity bits. In particular, the performance of the slicer predictor and the trellis decoder in the receiving system is greatly improved .

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

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

Claims (16)

A first error correction coding unit for performing first error correction coding on data input through a first path; A multiplexer for multiplexing the MPEG data input through the second path and the first error correction-coded data in the first error correction coding unit; A second error correction coding unit for performing a second error correction coding on the data multiplexed by the multiplexing unit; And And a transmitter for modulating and transmitting the second error correction coded data in the second error correction coding unit. The apparatus of claim 1, wherein the first error correction encoding unit And a Reed-Solomon encoder for performing Reed-Solomon coding on data input through the first path and adding parity. The apparatus of claim 1, wherein the second error correction encoding unit And a Reed-Solomon encoder for performing Reed-Solomon coding on the multiplexed data to add parity. delete Performing a first error correction encoding on data input through a first path; Multiplexing the MPEG data input through the second path and the first error correction-coded data in the step; Performing a second error correction encoding on the multiplexed data; And And modulating and transmitting the second error correction coded data. 6. The method of claim 5, wherein the first error correction encoding step Wherein a parity is added by performing Reed-Solomon coding on data input through a first path. 6. The method of claim 5, wherein the second error correction coding step Wherein the parity is added by performing Reed-Solomon coding on the multiplexed data. delete A demodulator for receiving the first error correction coded data after the first error correction coded data is multiplexed with the MPEG data and then transmitting the second error correction coded data and performing demodulation; A first error correction decoding unit for performing a first error correction decoding on data demodulated by the demodulation unit; A demultiplexer for separating the first and second error correction-coded data received from the first error correction-decoded data by the first error correction decoding unit; And And a second error correction decoding unit for performing a second error correction decoding on data separated by the demultiplexing unit. The apparatus of claim 9, wherein the first error correction decoding unit And a Reed-Solomon decoder for performing Reed-Solomon decoding on the demodulated data to correct errors generated during transmission. The apparatus of claim 9, wherein the second error correction decoding unit And a Reed-Solomon decoder for performing Reed-Solomon decoding on data separated by the demultiplexer to correct an error generated during transmission. delete A first error correction coded data is multiplexed with the MPEG data, and the second error correction coded data is transmitted and then demodulated; Performing a first error correction decoding on the demodulated data; Separating first and second error correction-coded received data from the first error correction decoded data; And And performing a second error correction decoding on the separated data in the step (c). 14. The method of claim 13, wherein the first error correction decoding step And performing Reed-Solomon decoding on the demodulated data to correct errors generated during transmission. 14. The method of claim 13, wherein the second error correction decoding step And performing Reed-Solomon decoding on the data separated in the step to correct errors generated during transmission. delete

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