CN107493154B - Channel coding and Gray mapping high-order modulation joint processing method and device - Google Patents
Channel coding and Gray mapping high-order modulation joint processing method and device Download PDFInfo
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- CN107493154B CN107493154B CN201610409866.7A CN201610409866A CN107493154B CN 107493154 B CN107493154 B CN 107493154B CN 201610409866 A CN201610409866 A CN 201610409866A CN 107493154 B CN107493154 B CN 107493154B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/004—Arrangements for detecting or preventing errors in the information received by using forward error control
- H04L1/0056—Systems characterized by the type of code used
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
- H04L1/0009—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the channel coding
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/004—Arrangements for detecting or preventing errors in the information received by using forward error control
- H04L1/0076—Distributed coding, e.g. network coding, involving channel coding
Abstract
The invention discloses a channel coding and Gray mapping high-order modulation combined processing method and a device, which relate to the technical field of communication information transmission, and the method comprises the following steps: carrying out signal coding on received information bits belonging to a low signal-to-noise ratio channel to obtain a first code word and storing the first code word; carrying out signal coding on the received information bits belonging to the next low signal-to-noise ratio to obtain a second code word and storing the second code word; storing the received information bits belonging to the high signal-to-noise ratio as a third code word; the stored first code word, the second code word and the third code word are put into a transmitting end position converter for position conversion to obtain two groups of bit streams; and the two groups of bit streams are sent into an M-QAM modulator for Gray mapping high-order modulation to be coded and modulated, and modulated symbols are sent into a channel to be sent. The invention fully utilizes the information of high-reliability bits in high-order modulation and improves the overall throughput of code modulation.
Description
Technical Field
The present invention relates to the field of communication information transmission technologies, and in particular, to a method and an apparatus for joint processing of channel coding and gray mapping high-order modulation.
Background
As the transmission speed of mobile communication is faster and faster, the utilization rate of wireless spectrum is required to be higher and higher, and as one of the necessary methods for improving the utilization rate of spectrum, high-order modulation has become a necessary technology in mobile communication, and channel coding is a necessary technology for ensuring the reliability of information transmission. For channel coding, in order to transmit information more efficiently and reliably, the reliability of bits (symbols) is often required to be known, rather than the reliability of symbols, and the reliability of bits mapped to a symbol by high-order modulation is usually different, which requires joint design of coding and modulation. Common code modulation methods are: TCM (trellis Coded Modulation) technology, which jointly designs convolutional codes and PSK (Phase Shift Key) or QAM (Quadrature Amplitude Modulation) to improve the overall minimum Euclidean distance of code Modulation; the multilayer code scheme combines block code and high-order modulation and carries out layered transmission on information. These prior art techniques suffer from the disadvantage of being only suitable for specific coding and specific modulation scenarios. In addition, for some special channel error correcting codes, such as a polar code, it is necessary to know the signal-to-noise ratio of a symbol to construct the polar code well, and therefore, it is necessary to know the signal-to-noise ratio of each bit fixedly, and if the polar code is transmitted directly using high-order modulation, the error probability of each symbol varies with the variation of the symbol, which is equivalent to that the channel experienced by each symbol is dynamic, which is not favorable for the optimal construction of the polar code.
Disclosure of Invention
The technical problem solved by the scheme provided by the embodiment of the invention is that when the polar code directly uses high-order modulation for transmission, the error probability of each code element can change along with the change of the code element, so that the channel experienced by each code element is dynamic, and the optimal construction of the polar code is not facilitated.
The channel coding and Gray mapping high-order modulation joint processing method provided by the embodiment of the invention comprises the following steps:
carrying out signal coding on received information bits belonging to a low signal-to-noise ratio channel to obtain a first code word and storing the first code word;
carrying out signal coding on the received information bits belonging to the next low signal-to-noise ratio to obtain a second code word and storing the second code word;
storing the received information bits belonging to the high signal-to-noise ratio as a third code word;
the stored first code word, the second code word and the third code word are put into a transmitting end position converter for position conversion to obtain two groups of bit streams;
and the two groups of bit streams are sent into an M-QAM modulator for Gray mapping high-order modulation to be coded and modulated, and modulated symbols are sent into a channel to be sent.
Preferably, said signal encoding the received information bits belonging to the channel with low snr to obtain the first codeword and storing the first codeword comprises:
carrying out signal coding on received information bits belonging to a first low signal-to-noise ratio channel to obtain a first code word and storing the first code word;
and carrying out signal coding on the received information bits belonging to the second low signal-to-noise ratio channel to obtain a second first code word and storing the second first code word.
Preferably, the performing position conversion by putting the stored first code word, the second code word and the third code word into a transmitting end position converter comprises:
a first position of said sending end position transducer is taken from a first codeword;
determining whether the second position of the transmitter-side position transducer is taken from a second first codeword or a second codeword according to the bit value of the first position;
and sequentially determining the code words of the rest positions of the transmitter-end position converter according to the code words of the second position.
Preferably, the determining whether the second position of the transmitter-end position transducer is taken from the second first codeword or the second codeword according to the bit value of the first position comprises:
if the bit value of the first position is 1, determining that a second position of the transmitter-end position converter is taken from a second first code word;
and if the bit value of the first position is 0, determining that the second position of the transmitter-end position converter is taken from a second code word.
Preferably, the sequentially determining the code words of the remaining positions of the transmitter-end position converter according to the code word of the second position includes:
if the second position of the sending end position transducer is taken from a second first code word, the rest position of the sending end position transducer is determined to be taken from a second code word or a third code word according to the bit value placed by the previous bit;
if the second position of the transmitter end position transducer is taken from the second codeword, the remaining positions of the transmitter end position transducer are determined to be taken from the second first codeword or the third codeword according to the bit value placed by the previous bit.
Preferably, the method further comprises the following steps:
sending the received modulated symbols into an M-QAM soft demodulator for soft demodulation to obtain k rows and N columns of log-likelihood ratios, and storing the k rows and N columns of log-likelihood ratios into a receiving end position converter;
respectively recovering N code elements after the obtained N log-likelihood ratios of the ith row are processed by a decoder and an encoder, replacing the N log-likelihood ratios of the ith row in the receiving end position converter with the N code elements, and sending the N code elements to an information sink;
sending the rest symbols in the receiving end position converter to a signal sink according to the sequence of the front and the back;
wherein i < ═ k-1, and N is the code length of the code.
Preferably, the N log-likelihood ratios stored in the first row of the receiving-end position converter are sent to a decoder for decoding, and then the decoding result obtained is sent to the signal sink.
The device for processing channel coding and Gray mapping high-order modulation jointly provided by the embodiment of the invention comprises:
the coding and storing module is used for carrying out signal coding on the received information bits belonging to the low signal-to-noise ratio channel to obtain and store a first code word, carrying out signal coding on the received information bits belonging to the next low signal-to-noise ratio channel to obtain and store a second code word, and storing the received information bits belonging to the high signal-to-noise ratio channel as a third code word;
the position conversion module is used for performing position conversion by putting the stored first code word, the stored second code word and the stored third code word into a transmitting end position converter to obtain two groups of bit streams;
and the sending module is used for sending the two groups of bit streams into a Gray mapping high-order modulated M-QAM modulator for coding modulation, and sending modulated symbols into a channel for sending.
Preferably, the encoding and saving module includes:
a first coding and storing unit, configured to perform signal coding on received information bits belonging to a first low snr channel to obtain a first codeword and store the first codeword, and perform signal coding on received information bits belonging to a second low snr channel to obtain a second first codeword and store the second first codeword;
the second coding and storing unit is used for carrying out signal coding on the received information bits belonging to the second lowest signal-to-noise ratio to obtain a second code word and storing the second code word;
a third storing unit for storing the received information bits with high SNR as a third code word
Preferably, the position conversion module includes:
and the position conversion unit is used for obtaining a first code word from a first position of the transmitting end position converter, determining whether a second position of the transmitting end position converter is obtained from a second first code word or a second code word according to a bit value of the first position, and sequentially determining code words of the rest positions of the transmitting end position converter according to the code words of the second position.
According to the scheme provided by the embodiment of the invention, each binary input channel has a fixed signal-to-noise ratio, so that the targeted design of an encoder is facilitated; the complexity of the coding reduction scheme is adopted only for the low signal-to-noise ratio channel and the second low signal-to-noise ratio channel; the information of high-reliability bits in high-order modulation is fully utilized, and the overall throughput of code modulation is improved.
Drawings
Fig. 1 is a flowchart of a method for jointly processing channel coding and gray mapping high-order modulation according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a joint processing apparatus for channel coding and gray mapping high-order modulation according to an embodiment of the present invention;
fig. 3 is a schematic diagram of channel code modulation transmission and reception provided by an embodiment of the present invention;
fig. 4 is a flowchart of position conversion of a sending end position converter according to an embodiment of the present invention.
Detailed Description
The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, and it should be understood that the preferred embodiments described below are only for the purpose of illustrating and explaining the present invention, and are not to be construed as limiting the present invention.
Fig. 1 is a flowchart of a method for jointly processing channel coding and gray mapping high-order modulation according to an embodiment of the present invention, as shown in fig. 1, including:
step S101: carrying out signal coding on received information bits belonging to a low signal-to-noise ratio channel to obtain a first code word and storing the first code word;
step S102: carrying out signal coding on the received information bits belonging to the next low signal-to-noise ratio to obtain a second code word and storing the second code word;
step S103: storing the received information bits belonging to the high signal-to-noise ratio as a third code word;
step S104: the stored first code word, the second code word and the third code word are put into a transmitting end position converter for position conversion to obtain two groups of bit streams;
step S105: and the two groups of bit streams are sent into an M-QAM modulator for Gray mapping high-order modulation to be coded and modulated, and modulated symbols are sent into a channel to be sent.
Wherein, said signal coding the received information bits belonging to the low snr channel to obtain the first code word and store it includes: carrying out signal coding on received information bits belonging to a first low signal-to-noise ratio channel to obtain a first code word and storing the first code word; and carrying out signal coding on the received information bits belonging to the second low signal-to-noise ratio channel to obtain a second first code word and storing the second first code word.
Specifically, the performing position conversion by putting the stored first code word, second code word and third code word into a transmitting end position converter includes: a first position of said sending end position transducer is taken from a first codeword; determining whether the second position of the transmitter-side position transducer is taken from a second first codeword or a second codeword according to the bit value of the first position; and sequentially determining the code words of the rest positions of the transmitter-end position converter according to the code words of the second position. Wherein the remaining positions are k- (k-2), k- (k-3) … k-1, k. k is 1/2 log2And M, wherein M is the order of Gray mapping. Wherein determining whether the second position of the sender-side position transducer is taken from the second first codeword or the second codeword based on the bit value of the first position comprises: if it isIf the bit value of the first position is 1, determining that a second position of the transmitter-end position converter is taken from a second first code word; and if the bit value of the first position is 0, determining that the second position of the transmitter-end position converter is taken from a second code word. Wherein the sequentially determining the codewords of the remaining positions of the transmitter-end position converter according to the codewords of the second position comprises: if the second position of the sending end position transducer is taken from a second first code word, the rest position of the sending end position transducer is determined to be taken from a second code word or a third code word according to the bit value placed by the previous bit; if the second position of the transmitter end position transducer is taken from the second codeword, the remaining positions of the transmitter end position transducer are determined to be taken from the second first codeword or the third codeword according to the bit value placed by the previous bit.
The embodiment of the invention also comprises the following steps: sending the received modulated symbols into an M-QAM soft demodulator for soft demodulation to obtain k rows and N columns of log-likelihood ratios, and storing the k rows and N columns of log-likelihood ratios into a receiving end position converter; respectively recovering N code elements after the obtained N log-likelihood ratios of the ith row are processed by a decoder and an encoder, replacing the N log-likelihood ratios of the ith row in the receiving end position converter with the N code elements, and sending the N code elements to an information sink; sending the rest symbols in the receiving end position converter to a signal sink according to the sequence of the front and the back; wherein i < ═ k-1, and N is the code length of the code.
And sending the N log-likelihood ratios of the first line stored in the receiving end position converter to a decoder for decoding to obtain a decoding result and sending the decoding result to an information sink.
Fig. 2 is a schematic diagram of a channel coding and gray mapping higher order modulation joint processing apparatus provided in an embodiment of the present invention, as shown in fig. 2, including: an encoding and storing module 201, a position conversion module 202 and a transmitting module 203. The encoding and storing module 201 is configured to perform signal encoding on the received information bits belonging to the low snr channel to obtain a first codeword and store the first codeword, perform signal encoding on the received information bits belonging to the next low snr channel to obtain a second codeword and store the second codeword, and store the received information bits belonging to the high snr channel as a third codeword; the position conversion module 202 is configured to perform position conversion by placing the stored first codeword, second codeword, and third codeword into a transmitting end position converter, so as to obtain two groups of bit streams; the sending module 203 is configured to send the two groups of bit streams into a gray-mapped high-order modulated M-QAM modulator for code modulation, and send the modulated symbols into a channel for sending.
Wherein, the encoding and storing module 201 includes: a first coding and storing unit, configured to perform signal coding on received information bits belonging to a first low snr channel to obtain a first codeword and store the first codeword, and perform signal coding on received information bits belonging to a second low snr channel to obtain a second first codeword and store the second first codeword; the second coding and storing unit is used for carrying out signal coding on the received information bits belonging to the second lowest signal-to-noise ratio to obtain a second code word and storing the second code word; and the third storage unit is used for storing the received information bits with high signal-to-noise ratio as a third code word. The position conversion module 202 includes: and the position conversion unit is used for obtaining a first code word from a first position of the transmitting end position converter, determining whether a second position of the transmitting end position converter is obtained from a second first code word or a second code word according to a bit value of the first position, and sequentially determining code words of the rest positions of the transmitting end position converter according to the code words of the second position.
The embodiment of the invention decomposes the high-order modulation symbol bearing Gray code into a plurality of channels with fixed and different transmitting power by utilizing the internal relation between the information bit and the modulation symbol, namely the condition of code element error probability, so that each channel is equivalent to a binary input channel, and for a high transmitting power channel (namely high signal-to-noise ratio), channel coding is not adopted, but for a low signal-to-noise ratio, code rate channel coding matched with the signal-to-noise ratio is adopted, so as to control the total bit error probability. In particular, the invention employs coding for the lowest signal-to-noise ratio and the next lowest signal-to-noise ratio channels, and for moreHigh snr channels do not use coding. It can be proved that, in gray-mapped M-order QAM modulation (M-QAM), when two lowest signal-to-noise ratio channels and one next lowest signal-to-noise ratio channel are fixed in each modulation symbol, the optimal system throughput can be obtained. The same coding mode is adopted for each coder, the code length is N (N is an even number), and the code rate of the lowest signal-to-noise ratio is R1，R1The code rate is set according to the equivalent noise variance as
Is set by a binary input gaussian channel of, wherein N0The code rate of the next lowest signal-to-noise ratio is R for the noise power spectrum density of the high-order modulation real Gaussian channel2，R2The code rate is set according to the equivalent noise variance as
The binary input Gaussian channel is set, the specific coding mode and the corresponding decoding method are not limited, the specific high-order modulation is Gray mapping M-QAM, and the M-QAM can be decomposed into two orthogonal ones according to real and imaginary parts
(pulse amplitude modulation).
The following describes the transmission process in detail with reference to fig. 3 and 4:
step 1: NR to be transmitted from a source1The bits are sent to a coder C1 for coding, a code word with the length of N is output and stored in a B1, and NR sent by a source is sent1The bits are sent to a coder C2 for coding, a code word with the length of N is output and stored in a B2, and NR sent by a source is sent2Sending one bit to encoder C3 for encoding, outputting code word with length N and storing in B3, and sending the rest N (k-3) bits from source directly to buffer B4, where k is 1/2 log2And M, wherein M is the order of Gray mapping.
Step 2: taking k bits from 4 buffers each time and sending the k bits into a position buffer with the length of k for position conversion, and the specific process is as follows:
step 2. A: the first position of the position transducer is taken from B1 and if the bit value is 1, go to step 2.B, otherwise go to step 2. C;
step 2. B: the second position of the position transducer is taken from B2, starting from the third bit of the position buffer, the next position is taken from B3 if the bit value placed by the previous bit is the first occurrence of 1, otherwise all bits from B4, if the first 2 to (k-1) bits in the position buffer are all 0, the last bit of the position buffer is taken from B3;
step 2. C: the second position of the position transducer is taken from B3, starting from the third bit of the position buffer, the next position is taken from B2 if the bit value placed by the previous bit is the first occurrence of 1, otherwise all bits from B4, if the first 2 to (k-1) bits in the position buffer are all 0, the last bit of the position buffer is taken from B2;
and step 3: each two groups of 2k bits transformed by the position transformer are sent to an M-QAM modulator of Gray mapping, each group of M-QAM modulators respectively corresponds to a QAM real part and an imaginary part to be modulated conventionally, and modulated symbols are sent to a channel;
the receiving end is described in detail below with reference to fig. 3:
the receiving end process is opposite, firstly, the received signal is processed by M-QAM soft demodulation, each symbol soft demodulation outputs two groups of log-likelihood ratios of 2k in total according to the real-imaginary part sequence, thus, the log-likelihood ratios of k in each converter of N position converters are solved in total, and are stored in a buffer with k rows and N columns, and then the following processing is carried out:
step 1: sending the N log-likelihood ratios of the first row in the buffer into a C1 decoder, decoding, sending a decoding result to a signal sink, sending the decoding result into a C1 encoder to recover N code elements, and replacing the recovered code elements with the log-likelihood ratios of the corresponding positions of the buffer;
step 2: according to the value of the recovered ith code element of C1, i is from 1 to N, the following processing is carried out: if the ith code element is 1, turning to the step 2.a, otherwise, turning to the step 2. b;
step 2. a: taking out the log-likelihood ratio from the ith row and the ith column in the second row in the buffer, and sending the log-likelihood ratio to a C2 decoder;
step 2. b: taking out the jth row from the ith column in the buffer, wherein j is more than or equal to 3 and less than or equal to k, k-2 log-likelihood ratios are obtained, taking the absolute value of the absolute value, recording the number of the corresponding absolute value of the log-likelihood ratio which is greater than 4(2j-4)/N0, if the number is greater than (k-2)/2, outputting the log-likelihood ratio which corresponds to the maximum absolute value of the k-2 log-likelihood ratios to a C2 decoder, and if the number is less than (k-2)/2, outputting the log-likelihood ratio which corresponds to the minimum absolute value of the k-2 log-likelihood ratios to a C2 decoder;
step 2. c: directly judging the residual log-likelihood ratio value which is sent to a C2 decoder from the 3 rd row in the ith row in the buffer except the step 2.b, namely outputting 0 if the log-likelihood ratio value is larger than 0, otherwise, outputting 1, and replacing the log-likelihood ratio value of the corresponding position in the original buffer by the judgment value;
and step 3: decoding the C2, coding and recovering the code element, and converting the log-likelihood ratio value of the corresponding bit of the C2 code element in the buffer into the corresponding C2 code element;
and 4, step 4: continuing to perform the following processing according to the value of the recovered ith symbol of C1, i is from 1 to N: if the ith code element is 0, turning to the step 4.a, otherwise, turning to the step 4. b;
step 4. a: taking out the log-likelihood ratio from the ith row and the ith column in the second row in the buffer, and sending the log-likelihood ratio to a C3 decoder;
step 4. b: sending the log-likelihood ratio value of the line after the line of the ith row and the line after the line of the ith row in the buffer area, wherein the line is 1 for the first time, into a C3 decoder;
step 4. c: directly judging the residual log-likelihood ratio value which is sent into a C3 decoder in the step 4.b and is divided from the 3 rd row in the ith row in the buffer area, and replacing the log-likelihood ratio value of the corresponding position in the original buffer with the judgment value;
and 5: decoding the C3, and sending the decoded information to the information sink;
step 6: the bit values of symbols other than the C1, C2, and C3 symbols in the buffer are sent to the sink in the order of the first and second columns.
And all three codes adopt polarization codes with the code length of 1024, wherein the code rates of the encoders C1 and C2 are set to be 0.275, and the code rate of the encoder C3 is set to be 0.85. The high-order modulation is gray mapping 256-QAM, and its real imaginary part is composed of two 16-PAM modulations respectively as an embodiment, which specifically includes:
step 1: 282 bits sent by a source are sent to an encoder C1 to be encoded, a code word with the length of 1024 is output and stored in a B1, 282 bits sent by the source are sent to an encoder C2 to be encoded, a code word with the length of 1024 is output and stored in a B2, 871 bits sent by the source are sent to an encoder C3 to be encoded, a code word with the length of 1024 is output and stored in a B3, and the rest 1024 bits sent by the source are directly sent to a buffer B3;
step 2: taking out 4 bits from 4 buffers each time and sending the 4 bits into a position buffer with the length of 4 for position conversion, the specific process is as follows:
step 2. A: the first position of the position transducer is taken from B1 and if the bit value is 1, go to step 2.B, otherwise go to step 2. C;
step 2. B: the second position of the position converter is taken from B2, starting from the third position of the position buffer, if the bit value placed by the previous position is 1 appearing for the first time, the next position is placed with B3, otherwise all the bits from B4 are taken, if the 2 nd and 3 rd bits in the position buffer are 0, the last position of the position buffer is taken from B3;
step 2. C: the second position of the position converter is taken from B3, starting from the third position of the position buffer, if the bit value placed by the previous position is 1 appearing for the first time, the next position is placed with B2, otherwise all the bits from B4 are taken, if the 2 nd and 3 rd bits in the position buffer are 0, the last position of the position buffer is taken from B2;
and step 3: each two groups of the 256-QAM modulators which are transformed by the position transformer and have 8 bits are sent to Gray mapping, each group of the 256-QAM modulators respectively corresponds to a QAM real part and an imaginary part to carry out conventional modulation, and modulated symbols are sent to a channel;
the receiving end process is opposite, firstly, 256-QAM soft demodulation is carried out on the received signal, each symbol soft demodulation outputs two groups of 8 log-likelihood ratios according to real-imaginary parts sequence, thus 4 log-likelihood ratios of each converter of 1024 position converters are solved out and stored in a buffer with 4 rows and 1024 columns, and then the following processing is carried out:
step 1: sending 1024 log-likelihood ratios of the first row in the buffer into a C1 decoder, decoding, sending a decoding result to a signal sink, sending the decoding result into a C1 encoder to recover N code elements, and replacing the recovered code elements with the log-likelihood ratios of corresponding positions of the buffer;
step 2: according to the value of the recovered ith code element of C1, i is from 1 to 1024, and the following processing is carried out: if the ith code element is 1, turning to the step 2.a, otherwise, turning to the step 2. b;
step 2. a: taking out the log-likelihood ratio from the ith row and the ith column in the second row in the buffer, and sending the log-likelihood ratio to a C2 decoder;
step 2. b: taking out the jth row from the ith column in the buffer, wherein j is more than or equal to 3 and less than or equal to 4, taking 2 log-likelihood ratios, taking the absolute value of the log-likelihood ratios, and recording the corresponding absolute value ratio of 4(2j-4)/N0And if the number is less than 1, outputting the log-likelihood ratio value corresponding to the maximum absolute value of the 2 log-likelihood ratio values to a C2 decoder, and if the number is greater than 1, outputting the log-likelihood ratio value corresponding to the minimum absolute value of the 2 log-likelihood ratio values to a C2 decoder. Wherein N is0Modulating the noise power spectral density of a real Gaussian channel for a high order;
step 2. c: directly judging the residual log-likelihood ratio value which is sent to a C2 decoder from the 3 rd row in the ith row in the buffer except the step 2.b, namely outputting 0 if the log-likelihood ratio value is larger than 0, otherwise, outputting 1, and replacing the log-likelihood ratio value of the corresponding position in the original buffer by the judgment value;
and step 3: decoding the C2, coding and recovering the code element, and converting the log-likelihood ratio value of the corresponding bit of the C2 code element in the buffer into the corresponding C2 code element;
and 4, step 4: continuing to perform the following processing according to the value of the recovered ith symbol of C1, i is from 1 to N: if the ith code element is 0, turning to the step 4.a, otherwise, turning to the step 4. b;
step 4. a: taking out the log-likelihood ratio from the ith row and the ith column in the second row in the buffer, and sending the log-likelihood ratio to a C3 decoder;
step 4. b: sending the log-likelihood ratio value of the line after the line of the ith row and the line after the line of the ith row in the buffer area, wherein the line is 1 for the first time, into a C3 decoder;
step 4. c: directly judging the residual log-likelihood ratio value which is sent into a C3 decoder in the step 4.b and is divided from the 3 rd row in the ith row in the buffer area, and replacing the log-likelihood ratio value of the corresponding position in the original buffer with the judgment value;
and 5: decoding the C3, and sending the decoded information to the information sink;
step 6: the bit values of symbols other than the C1, C2, and C3 symbols in the buffer are sent to the sink in the order of the first and second columns.
According to the scheme provided by the embodiment of the invention, each binary input channel has a fixed signal-to-noise ratio, so that the targeted design of an encoder is facilitated; the complexity of the coding reduction scheme is adopted only for the low signal-to-noise ratio channel and the second low signal-to-noise ratio channel; the information of high-reliability bits in high-order modulation is fully utilized, and the overall throughput of code modulation is improved.
Although the present invention has been described in detail hereinabove, the present invention is not limited thereto, and various modifications can be made by those skilled in the art in light of the principle of the present invention. Thus, modifications made in accordance with the principles of the present invention should be understood to fall within the scope of the present invention.
Claims (10)
1. A channel coding and Gray mapping high-order modulation joint processing method comprises the following steps:
carrying out signal coding on received information bits belonging to a low signal-to-noise ratio channel to obtain a first code word and storing the first code word;
carrying out signal coding on the received information bits belonging to the next low signal-to-noise ratio to obtain a second code word and storing the second code word;
storing the received information bits belonging to the high signal-to-noise ratio as a third code word;
the stored first code word, the stored second code word and the stored third code word are put into a transmitting end position converter for position conversion, so that two groups of bit streams are obtained;
and the two groups of bit streams are sent into an M-QAM modulator for Gray mapping high-order modulation to be coded and modulated, and modulated symbols are sent into a channel to be sent.
2. The method of claim 1, wherein the signal-coding the received information bits belonging to the channel with low snr to obtain the first codeword and storing the first codeword comprises:
carrying out signal coding on received information bits belonging to a first low signal-to-noise ratio channel to obtain a first code word and storing the first code word;
and carrying out signal coding on the received information bits belonging to the second low signal-to-noise ratio channel to obtain a second first code word and storing the second first code word.
3. The method of claim 2, wherein the performing position transformation by placing the saved first, second, and third codewords into a sender position transformer comprises:
a first position of said sending end position transducer is taken from a first codeword;
determining whether the second position of the transmitter-side position transducer is taken from a second first codeword or a second codeword according to the bit value of the first position;
and sequentially determining the code words of the rest positions of the transmitter-end position converter according to the code words of the second position.
4. The method of claim 3, wherein determining whether the second position of the sender-side position transducer is taken from the second first codeword or the second codeword based on the bit value of the first position comprises:
if the bit value of the first position is 1, determining that a second position of the transmitter-end position converter is taken from a second first code word;
and if the bit value of the first position is 0, determining that the second position of the transmitter-end position converter is taken from a second code word.
5. The method of claim 4, wherein sequentially determining the codewords of the remaining positions of the sender-side position transducer according to the codewords of the second position comprises:
if the second position of the sending end position transducer is taken from a second first code word, the rest position of the sending end position transducer is determined to be taken from a second code word or a third code word according to the bit value placed by the previous bit;
if the second position of the transmitter end position transducer is taken from the second codeword, the remaining positions of the transmitter end position transducer are determined to be taken from the second first codeword or the third codeword according to the bit value placed by the previous bit.
6. The method of any of claims 1-5, further comprising:
sending the received modulated symbols into an M-QAM soft demodulator for soft demodulation to obtain k rows and N columns of log-likelihood ratios, and storing the k rows and N columns of log-likelihood ratios into a receiving end position converter;
respectively recovering N code elements after the obtained N log-likelihood ratios of the ith row are processed by a decoder and an encoder, replacing the N log-likelihood ratios of the ith row in the receiving end position converter with the N code elements, and sending the N code elements to an information sink;
sending the rest symbols in the receiving end position converter to a signal sink according to the sequence of the front and the back;
wherein i < ═ k-1, k is the number of code words, and N is the code length of the code words.
7. The method as claimed in claim 6, wherein the decoding result obtained by sending the N log-likelihood ratios stored in the first row of the receiver-side position converter to the decoder for decoding is sent to the sink.
8. A channel coding and Gray mapping high-order modulation joint processing device comprises:
the coding and storing module is used for carrying out signal coding on the received information bits belonging to the low signal-to-noise ratio channel to obtain and store a first code word, carrying out signal coding on the received information bits belonging to the next low signal-to-noise ratio channel to obtain and store a second code word, and storing the received information bits belonging to the high signal-to-noise ratio channel as a third code word;
the position conversion module is used for performing position conversion by putting the stored first code word, the stored second code word and the stored third code word into a transmitting end position converter to obtain two groups of bit streams;
and the sending module is used for sending the two groups of bit streams into a Gray mapping high-order modulated M-QAM modulator for coding modulation, and sending modulated symbols into a channel for sending.
9. The device of claim 8, the encoding and saving module comprising:
a first coding and storing unit, configured to perform signal coding on received information bits belonging to a first low snr channel to obtain a first codeword and store the first codeword, and perform signal coding on received information bits belonging to a second low snr channel to obtain a second first codeword and store the second first codeword;
the second coding and storing unit is used for carrying out signal coding on the received information bits belonging to the second lowest signal-to-noise ratio to obtain a second code word and storing the second code word;
and the third storage unit is used for storing the received information bits with high signal-to-noise ratio as a third code word.
10. The apparatus of claim 9, the position transformation module comprising:
and the position conversion unit is used for obtaining a first code word from a first position of the transmitting end position converter, determining whether a second position of the transmitting end position converter is obtained from a second first code word or a second code word according to a bit value of the first position, and sequentially determining code words of the rest positions of the transmitting end position converter according to the code words of the second position.
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