KR100859877B1 - Forward Error Correction Apparatus of digital broadcasting system - Google Patents

Abstract

An error correction encoding apparatus of a digital broadcasting system is disclosed. The error correction encoding apparatus includes a scrambler that removes a correlation between input data by mixing pseudo-random binary signal sequences in a TS stream, and a first RS encoder that performs block-based encoding for error correction on data from which correlation has been removed. A convolutional interleaver for rearranging the encoded data, a second RS encoder for re-encoding the rearranged data in a block unit to enable error correction, and redistributing the re-encoded data in the block unit bitwise A bit interleaver, a symbol mapper for mapping the data distributed bit by bit for the transmission of data distributed bit by bit, and a modulator for performing modulation suitable for transmission of the data on which the symbol-by-symbol mapping is performed. By applying a block code-based RS encoder as an internal encoder, a constant error correction capability is secured and stable error correction of a digital broadcast signal is possible even in a poor reception environment.

Error Correction, Coding, FM, Digital Broadcasting, Internal Encoder, RS Encoder, Block Code

Description

Forward Error Correction Apparatus of digital broadcasting system

1 is a block diagram showing a general error correction encoding apparatus applied to a transmitter of a digital broadcasting system;

2 is a block diagram showing a preferred embodiment of an error correction encoding apparatus of a digital broadcasting system according to the present invention;

3 is a block diagram showing another embodiment of an error correction encoding apparatus of a digital broadcasting system according to the present invention;

4 is a block diagram showing a preferred embodiment of the error correction decoding apparatus of the digital broadcasting system according to FIG.

5 is a flowchart illustrating an error correction method using an error correction encoding apparatus according to the present invention.

Explanation of symbols on the main parts of the drawings

100: scrambler 120: 1RS encoder

140: convolutional interleaver 160: 2RS encoder

180: bit interleaver 200: symbol mapper

220: modulator 240: block turbo encoder                 

300: demodulator 320: symbol demapper

340: bit deinterleaver 360: first RS decoder

380: convolutional deinterleaver 400: second RS decoder

420: Descrambler

The present invention relates to an error correction encoding apparatus and method of a digital broadcasting system, and more particularly, to a digital broadcasting system for performing error correction encoding on broadcast data to be transmitted so that a reception environment can be more stably received in a mobile and portable environment. An error correction coding apparatus and method.

In general, a broadcasting system of a high definition television (HDTV) can be roughly divided into an image encoder and a modulator. The video encoder compresses digital data of about 1 Gbps obtained from a high quality video source into data of 15 to 18 Mbps. The modulator transmits several tens of Mbps of digital data to the receiver through a limited band channel of 6 to 8 MHz. Digital high-definition television broadcasting adopts a terrestrial simultaneous broadcasting method using a channel of a very high frequency (VHF) / ultra high frequency (UHF) band allocated for conventional television broadcasting. Therefore, the modulation scheme used in the high definition television broadcasting system must satisfy the following conditions due to the environment of terrestrial simultaneous broadcasting.                         

First, the modulation scheme used in the high-definition television broadcasting system requires high spectrum efficiency in order to transmit digital data of several tens of Mbps to a receiver through a limited band channel of 6 to 8 MHz. Second, the modulation scheme used in the high definition television broadcasting system has multipath fading due to the surrounding buildings or structures, and therefore has a strong characteristic for fading. Third, modulation schemes used in high-definition television broadcasting systems inevitably cause co-channel interference by existing analog television signals, and thus have a strong characteristic against co-channel interference. In addition, digitally modulated signals of high-definition television systems should be able to minimize interference with existing analog television receivers.

Modulation techniques that meet these conditions include Quadrature Amplitude Modulation (QAM) and Residual Side Band (VSB) modulation. In terrestrial broadcasting, the multiplication of QAM and VSB is already limited. have. Here, the transmission rate is determined, and even if the symbol transmission rate is increased in the same multiple dimensions, the transmission rate of the bandwidth is improved. However, when the symbol transmission speeds of 16- / 32-inch quadrature amplitude modulation and 4-valued residual sideband modulation are increased, the interference caused by the interference between the second image and the multipath is severely generated. This is especially true in urban areas where skyscrapers are struggling.

Therefore, in order to solve these problems, Europe adopts Orthogonal Frequency Division Multiplexing (OFDM), a digital modulation method that can achieve the dual effect of improving the transmission speed per bandwidth and preventing interference, as a next-generation high-definition television terrestrial broadcasting method. Doing.                         

In general, an OPM transmitter that transmits an OFM signal using time domain synchronization re-assembles an OFM signal formed on a frequency axis that provides one service allocated to a preset frequency band along a time axis. Arrange. The OPM transmitter inserts a guard interval (GI) for suppressing interference between signals in front of the OFM signal formed along the time axis, and inserts synchronization information before the guard period and transmits it.

The part that corrects an error generated during data transmission in digital communication is called Error Correcting Coding (ECC). The error correction coding can be roughly divided into a block code and a convolutional code, that is, a convolutional code.

The block code encodes and decodes data in block units. The convolutional code uses a certain amount of memory to encode the previous data and the current data. A representative method of the block code is RS coding (Reed-Solomon coding). In particular, RS coding has a strong characteristic of continuous error. RS coding consists of a message to be sent and a search byte for error correction.

On the other hand, the representative decoding method of the convolutional code is the Viterbi algorithm. In the Viterbi algorithm, the complexity increases exponentially with the magnitude of the constraint length (K). Currently K = 7 or K = 9 is actually the most used

1 is a block diagram illustrating a general error correction encoding device applied to a transmitter of a digital broadcasting system.

The error correction encoding apparatus includes a scrambler 10, an RS encoder (Reed-Solomon encoder) 12, a convolutional interleaver 14, a convolutional encoder 16, It has a bit interleaver 18, a symbol mapper 20, and a modulator 22.

The scrambler 10 removes the correlation of the input signal by mixing a pseudo random binary sequence with a transport stream (TS) in MPEG-2 format.

The RS encoder 12 receives the data passed through the scrambler 10 and performs RS coding in units of blocks for error correction.

The convolutional interleaver 14 used as an outer interleaver rearranges data encoded in units of blocks in the RS encoder 12.

The convolutional encoder 16 encodes the data rearranged by the convolutional interleaver 14.

The bit interleaver 18 rearranges the data bit by bit in order to disperse a possible collection error.

The symbol mapper 20 performs mapping such as 64QAM, which is a kind of Quadrature Amplitude Modulation (QAM), on the data rearranged bit by bit in the bit interleaver 18.                         

The modulator 22 modulates the data mapped by the symbol mapper 20 such as a residual side band (VSB) modulation or a coded orthogonal frequency division multiplexing (COFDM) modulation.

However, when the convolutional encoder 16 is used as an internal coder, it is difficult to completely recover the received signals in a poor reception environment such as a mobile environment and a mobile environment.

That is, since the convolutional encoder 16 is very weak to the collection error, there is a problem in that it does not perform a minimum error correction function in a poor reception environment.

An object of the present invention for solving the above problems is to perform error correction encoding so that the receiving environment can more stably and accurately recover data transmitted in a poor receiving environment such as a mobile and portable receiving environment. An error correction encoding apparatus and method of a digital broadcasting system can be provided.

According to the present invention, in the error correction encoding apparatus of a digital broadcasting system for correcting an error occurring during transmission of digital broadcasting data, a similar random binary signal sequence is mixed in a TS stream to remove correlation of input data. A scrambler to perform block-wise encoding on error-resolved data, a first RS encoder, a convolutional interleaver to rearrange coded blocks, and error correction on the rearranged data. A second RS encoder that re-encodes block-wise to enable, a bit interleaver that redistributes the data re-encoded in block units bitwise, and for each symbol of data distributed in bit units for transmission of data distributed in bit units A symbol mapper for performing mapping, and a modulation suitable for transmission of data on which symbol-by-symbol mapping is performed. Is achieved by an error correction encoding apparatus of a digital broadcasting system including a modulator.

Preferably, the second RS encoder of the present embodiment may be replaced with a block turbo encoder. The symbol-to-symbol mapping performed by the symbol mapper includes 16QAM, 64QAM, 256QAM, and QPSK. The modulation performed in the modulator is either VSB modulation or COFDM modulation.

On the other hand, the object as described above, according to the present invention, in the error correction encoding method using an error correction encoding apparatus of a digital broadcasting system for correcting an error occurring in the transmission of digital broadcast data, a pseudo-random binary signal sequence to the TS stream A scrambling step of mixing and removing correlation of input data, a first RS encoding step of performing block unit encoding for error correction on the removed correlation data, and convolutional interleaving to rearrange coded data in block units. A second RS encoding step of re-encoding the block to re-correct the rearranged data, a bit interleaving step of redistributing the re-encoded data bit by block, data distributed bit by bit Symbol mapping to perform symbol-to-symbol mapping of data distributed bit by bit for transmission of data Type, and is achieved by the error correction coding method used for the error correction encoding apparatus of a digital broadcasting system including a modulating step of performing modulation suitable for transmission of the symbols mapped by the performance data.                     

According to the present invention, by applying a block code-based RS encoder or a block turbo encoder as an internal encoder, a constant error correction capability is secured. Accordingly, even in a poor reception environment such as a mobile and portable reception environment, the reception side of the reception side can receive a stable digital broadcast signal and correct an error.

In addition, by applying a block code-based RS decoder or block turbo decoder as an internal decoder, a certain error correction capability is secured so that a stable broadcast signal can be received and error corrected even in a poor reception environment such as a mobile or portable environment. Restoration is possible.

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

2 is a block diagram showing a preferred embodiment of an error correction encoding apparatus of a digital broadcasting system according to the present invention.

The error correction encoding apparatus includes a scrambler 100, a first RS encoder (Reed-Solomon encoder) 120, a convolutional interleaver 140, and a second RS encoder (Reed-Solomon encoder). 160, a bit interleaver 180, a symbol mapper 200, and a modulator 220.

The scrambler 100 mixes a pseudo random binary sequence into a transport stream (TS) stream of an MPEG-2 format to eliminate correlation of an input signal.

The first RS encoder 120 encodes the data passing through the scrambler 100 in units of blocks for error correction.                     

The convolutional interleaver 140, which is an outer interleaver, rearranges data encoded in units of blocks in the first RS encoder 120. The data rearrangement of the convolutional interleaver 140 is a countermeasure for the occurrence of an error exceeding the maximum error that can be corrected by the decoding of the first RS encoder 120. Make corrections possible.

The second RS encoder 160, which is an internal encoder, re-encodes data in units of blocks so that error correction may be performed on the rearranged data in the convolutional interleaver 140.

The bit interleaver 180 used as an inner interleaver redistributes the data re-coded in units of blocks by the second RS encoder 160 in units of bits in order to disperse possible burst errors.

The symbol mapper 200 performs symbol mapping such as 16QAM, 64QAM 256QAM, and Quadrature Phase Shift Keying (QPSK), which are a kind of quadrature amplitude modulation (QAM) for data distributed bit by bit in the bit interleaver 180. (mapping).

The modulator 220 converts the data mapped for each symbol in the symbol mapper 200 according to digital broadcasting such as residual side band (VSB) modulation or coded orthogonal frequency division multiplexing (COFDM) modulation. Perform modulation appropriate for the transmission of data.

3 is a block diagram showing another embodiment of an error correction encoding apparatus of a digital broadcasting system according to the present invention. In the illustrated error correction encoding apparatus, the same member number as that of FIG. 2 performs the same function as that of FIG. 2. Therefore, description of the member number which overlaps with FIG. 2 is abbreviate | omitted.

As shown, the RS encoder 120 of the error correction encoding apparatus performs the same function as the first RS encoder 120 of FIG. 2.

The error correction encoding apparatus of FIG. 3 may recognize that the block turbo encoder 240 is replaced with the second RS encoder 160 of FIG. 2. That is, the same effect as the embodiment of FIG. 2 may be obtained even if the block turbo encoder 240 based on the block code is replaced as shown in FIG. 3 instead of the second RS encoder 160 of FIG. 2. Can be.

Accordingly, by applying the block code-based second RS encoder 160 or the block turbo encoder 240 as an internal encoder, a constant error correction capability is secured. Accordingly, stable digital broadcast signal reception and error correction are possible even in poor reception environments such as mobile and portable reception environments.

FIG. 4 is a block diagram illustrating an exemplary embodiment of an error correction decoding apparatus of the digital broadcasting system according to FIG. 2.

The error correction decoding apparatus may include a demodulator 300, a symbol demapper 320, a bit deinterleaver 340, a first RS decoder (Reed-Solomon decoder) 360, It has a convolutional deinterleaver 380, a second RS decoder (Reed-Solomon decoder) 400, and a descrambler 420.                     

The demodulator 300 demodulates the signal transmitted by demodulating the signal modulated by the modulator 220 of FIG. 2.

The symbol demapper 320 restores the signal mapped in symbol units in the symbol mapper 200 of FIG. 2 to data in bit units.

The bit deinterleaver 340 performs a reverse operation of rearrangement of data performed by the bit interleaver 180 of FIG. 2 to restore the signal sequence before the operation of the bit interleaver 180. At this time, there is an effect that the scattering error mixed in the received signal is dispersed.

The first RS decoder 360 decodes the data encoded by the second RS encoder 160 of FIG. 2. In this process, any errors that fall within the correctability range of the decoder mixed with the received signal are corrected. In addition, errors that occur beyond the correction capability are not corrected and are passed to the next block. The same effect as that of the present embodiment can be obtained by replacing the block turbo decoder with the internal decoder of the present embodiment instead of the first RS decoder 360 based on the block decoder.

The convolutional deinterleaver 380 performs an inverse operation of rearrangement of data performed by the convolutional interleaver 140 of FIG. 2. In this process, the first RS decoder 360 distributes the uncorrected errors.

The second RS decoder 400 decodes the data encoded by the first RS encoder 120 of FIG. 2.

The descrambler 420 restores the original TS stream by removing a pseudo random binary signal string mixed with the TS stream performed by the scrambler 100 of FIG. 2.                     

Therefore, by applying a block code-based RS decoder or block turbo decoder as an internal decoder, a certain error correction capability is secured, so that a stable broadcast signal reception and error correction can be performed even in a poor reception environment such as a mobile and portable environment. Restoration is possible.

5 is a flowchart illustrating an error correction method using an error correction encoding apparatus according to the present invention.

First, the scrambler 100 removes the correlation of the input signal by mixing pseudo random binary signal strings with the input TS-2 stream of the MPEG-2 format (S100).

The first RS encoder 120 encodes the data passing through the scrambler 100 in order to perform error correction, that is, encoding in units of blocks (S120).

The convolutional interleaver 140 performs convolutional interleaving in which the first RS encoder 120 rearranges data encoded in units of blocks (S140). Convolutional interleaving of the convolutional interleaver 140 is a countermeasure for the occurrence of an error exceeding the maximum error that can be corrected by the decoding of the first RS encoder 120. Make this possible.

The second RS encoder 160 performs RS encoding, that is, re-encoding in block units, to enable error correction on convolutional interleaved data in the convolutional interleaver 140 (S160).

The bit interleaver 180 performs bit interleaving to redistribute RS-encoded data in units of bits in the second RS encoder 160 in order to disperse possible aggregation errors (S180).

The symbol mapper 200 performs symbol mapping on the bit interleaved data in the bit interleaver 180 such as 16QAM, 64QAM, 256QAM, and QPSK, which is a kind of quadrature amplitude modulation (QAM) (S200).

The modulator 220 performs modulation suitable for transmission of data according to digital broadcasting such as residual sideband (VSB) modulation or coded orthogonal frequency division multiplexing (COFDM) modulation on the data mapped for each symbol in the symbol mapper 200 ( S220).

Therefore, by applying a block code-based second RS encoder 160 or a block turbo encoder 240 as an internal encoder, stable digital broadcast signal reception and error correction are possible even in a poor reception environment such as a mobile and portable reception environment. Do

According to the present invention, by applying a block code-based RS encoder or a block turbo encoder as an internal encoder, a constant error correction capability is secured. Accordingly, even in a poor reception environment such as a mobile and portable reception environment, the reception side of the reception side can receive a stable digital broadcast signal and correct an error.

In addition, by applying a block code-based RS decoder or block turbo decoder as an internal decoder, a certain error correction capability is secured so that a stable broadcast signal can be received and error corrected even in a poor reception environment such as a mobile or portable environment. Restoration is possible.

In the above described and illustrated with respect to the preferred embodiment of the present invention, the present invention is not limited to the specific preferred embodiment described above, without departing from the gist of the invention claimed in the claims in the art Various modifications can be made by those skilled in the art, and such changes are within the scope of the claims.

Claims (9)

An error correction encoding apparatus of a digital broadcasting system for correcting an error occurring during transmission of digital broadcasting data in the form of a TS stream, A scrambler that removes correlation of input data by mixing pseudo-random binary signal strings with the digital broadcasting data of the TS stream type; A first RS encoder to perform block unit encoding for error correction on the data whose correlation is removed; A convolutional interleaver for rearranging the coded data in block units; A second RS encoder for re-encoding the rearranged data in block units to enable error correction; And And a bit interleaver for redistributing the data re-coded in the block unit in units of bits. The method of claim 1, And a symbol mapper configured to perform symbol-to-symbol mapping of the data distributed in the bit unit to transmit the data distributed in the bit unit. The method of claim 2,  And a modulator configured to perform modulation suitable for transmission of the data on which the symbol-by-symbol mapping is performed. The method of claim 3, wherein And the second RS encoder can be replaced with a block turbo encoder. The method of claim 3, wherein The modulation performed in the modulator is error correction encoding apparatus of the digital broadcasting system, characterized in that it comprises any one of the VSB modulation and COFDM modulation. The method of claim 2, The symbol-to-symbol mapping performed by the symbol mapper is any one of 16QAM, 64QAM, 256QAM, and QPSK. An error correction encoding method using an error correction encoding apparatus of a digital broadcasting system for correcting an error occurring during transmission of digital broadcasting data in the form of a TS stream, A scrambling step of removing a correlation between input data by mixing pseudo-random binary signal sequences with the digital broadcasting data in the TS stream form; A first RS encoding step of performing block unit encoding for error correction on the data whose correlation is removed; A convolutional interleaving step of rearranging the coded data in block units; A second RS encoding step of re-encoding the rearranged data in units of blocks so as to enable error correction; And And a bit interleaving step of redistributing the data re-coded in units of blocks in units of bits. The method of claim 7, wherein And a symbol mapping step of performing symbol-to-symbol mapping of the data distributed in the bit unit to transmit the data distributed in the bit unit. Encoding method. The method of claim 8,  And performing a modulation suitable for transmission of the data on which the symbol-by-symbol mapping is performed. 2. The error correction encoding method using an error correction encoding apparatus of a digital broadcasting system.

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