CN108055044A - A kind of cascade system based on LDPC code and polarization code - Google Patents
A kind of cascade system based on LDPC code and polarization code Download PDFInfo
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- CN108055044A CN108055044A CN201810055193.9A CN201810055193A CN108055044A CN 108055044 A CN108055044 A CN 108055044A CN 201810055193 A CN201810055193 A CN 201810055193A CN 108055044 A CN108055044 A CN 108055044A
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- polarization code
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M13/00—Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes
- H03M13/03—Error detection or forward error correction by redundancy in data representation, i.e. code words containing more digits than the source words
- H03M13/05—Error detection or forward error correction by redundancy in data representation, i.e. code words containing more digits than the source words using block codes, i.e. a predetermined number of check bits joined to a predetermined number of information bits
- H03M13/11—Error detection or forward error correction by redundancy in data representation, i.e. code words containing more digits than the source words using block codes, i.e. a predetermined number of check bits joined to a predetermined number of information bits using multiple parity bits
- H03M13/1102—Codes on graphs and decoding on graphs, e.g. low-density parity check [LDPC] codes
- H03M13/1105—Decoding
- H03M13/1111—Soft-decision decoding, e.g. by means of message passing or belief propagation algorithms
- H03M13/1117—Soft-decision decoding, e.g. by means of message passing or belief propagation algorithms using approximations for check node processing, e.g. an outgoing message is depending on the signs and the minimum over the magnitudes of all incoming messages according to the min-sum rule
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M13/00—Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes
- H03M13/03—Error detection or forward error correction by redundancy in data representation, i.e. code words containing more digits than the source words
- H03M13/05—Error detection or forward error correction by redundancy in data representation, i.e. code words containing more digits than the source words using block codes, i.e. a predetermined number of check bits joined to a predetermined number of information bits
- H03M13/13—Linear codes
Abstract
The present invention provides the designs based on LDPC and the cascade system of polarization code, it is related to signal coding/decoding system field, less hsrdware requirements reach preferably decoding effect, it is a kind of outstanding reliable complete information coding/decoding system, cascade system of the present invention includes coding module, signal transmitting module, signal receiving module and decoding module.Coding module includes polarization code coder, cover device and LDPC encoder.Decoding module includes ldpc decoder, selector and polarization code decoder, iterations and is obtained by emulating.Outer code is set to polarization code, and Internal Code is set to the becate problem of the design optimization of LDPC code LDPC code coding, therefore the two outstanding codes cascades, it is convenient to omit deinterleaving when intertexture during coding and decoding.When concatenated code decodes, two codes are decoded using BP, and decoding module periodic internal transmission soft decoding information stops calculating after reaching iterations, and output Soft Inform ation carries out hard decision, and output information completes decoding process.This cascade system can be applied to the fields such as communication, image transmitting.
Description
Technical field：
The present invention relates to communication and image code domain more particularly to concatenated codes and iterative decoding.
Background technology：
5th third-generation mobile communication (5G) needs the diversity in face of usage scenario and demand, it is necessary to superior technique supports,
Wherein coding, decoding technique are exactly one of key technology.Polarization code theoretically first time Strict Proof in binary system
Shannon capacity " can be reached " under symmetrical discrete memoryless channel(DMC), and have low coding and decoding complexity.
Polarization code is a kind of a kind of channel coding method proposed based on channel-polarization phenomenon, and channel-polarization principle is pointed out：
For one group of independent identically distributed binary discrete memoryless channel(DMC) after channel-polarization, the channel capacity of obtained binary channel will
Tend to produce a polarization, a part of channel capacity is close to 0, and another part is close to 1.Polarization code coding is exactly according to so
Basic principle, channel-polarization process is represented by matrix, the reliability of some is allowed in information sequence to level off to 1, is allowed remaining
Level off to 0.
The cascade system of polarization code and LDPC code is as a kind of serial stage of outer code, LDPC code as Internal Code by polarization code
Connection, structure are as shown in Figure 1.
Outer code Polar codes be (n, k) code, code check Rp=k/n, Internal Code LDPC code be (N, K) code, code check RL=K/N.
In this concatenated schemes, polarization code coding is first carried out, carries out LDPC code coding again to polarization code coding result, decodes end then phase
Instead, LDPC decodings are first carried out and carries out polarization code decoding again.Wherein code word size n after polarization code coding, is set equal to LDPC codings
Preceding information bit length K.Then the code check of entire concatenated code is R=RP*RL=k/N.
In our concatenated schemes, polarization code decoding and LDPC decodings are using BP decoding algorithms, wherein calculating main
It is probability calculation, therefore often using logarithmic form during realization, this large amount of multiplying can become add operation, so as to
Reduce operation time and complexity.
How under certain hardware complexity, it is to always exist in the field of communications at present to reach better decoding performance
The problem of.
The content of the invention
The present invention proposes a kind of improved cascade system based on LDPC code and polarization code, which is outer using polarization code
Code, LDPC code carry out serially concatenated for Internal Code, and LDPC code and polarization code are using BP algorithm in decoding module, and using decoder
Between Soft Inform ation iteration strengthen its decoding capability, detailed process is as follows：
The first step, by information sequenceAccording to polarization code coding rule, information bit is first inserted, multiplied by with generator matrix GN,
Obtain information sequence
Second step, will be by the information sequence of polarization code codingIncoming LDPC encoder, obtains information sequenceRoot
End zero padding can be carried out according to required LDPC code standard to operate to obtainAnd it transmits and is transmitted into channel into row information；
3rd step, from channel receiving information sequenceLdpc decoder is passed to, with BP decoding algorithms into row decoding,
Obtain Soft Inform ation sequence
4th step, the information sequence obtained after LDPC code is decodedSelection work is carried out on demand to obtainTransmit again into
Enter the code decoder that polarizes, still calculated, judged into row decoding with BP decoding algorithms, if reaching concatenated code greatest iteration time
Number, if then exporting decoding as a result, not up to maximum iteration, the BP of output polarization code are decoded in maximum iteration
The zero padding on demand of input value Soft Inform ation, then transfer back to ldpc code decoder continue iterative decoding；
Wherein polarization code BP decodings total transmission process is shown in Fig. 3, first analyzes its elementary cell Fig. 4：
Two nodes are judgement layer direction on the left of Fig. 4, and to receive extreme direction, calculation is as follows on right side：
Wherein function g (x, y)=ln (1+xy/ (x+y)) (2)
5th step carries out hard decision for final output valve, exports result.
There are many kinds of, it is necessary to reference to two kinds of respective advantage and disadvantage of encoding scheme in concatenated schemes for concatenated schemes.Polarization code
Advantage of the generator matrix on becate can allow LDPC to obtain better decoding performance.In addition, cascade advantage is to decode mould
Iteration in block between decoder, and if to complete iteration between decoder, the coding mode pair of used two kinds of codings
Last codeword structure has certain requirement：Code word needs include or equal to information sequence, therefore we are decoded using BP
Algorithm, and LDPC code coding causes information sequence using system codingCode word is after codingPolarization code uses
Be butterfly structure decoding, Soft Inform ation transfers back and forth, improves confidence level, right end may be employed and start the mode that right end terminates, allow
Polarization code decoder output value is to improve the information sequence of confidence level in itself, can pass ldpc decoder back again and be changed next time
The decoding in generation.Entire iterative process is exactly to promote confidence level to allow its convergent process.
Description of the drawings：
Fig. 1 is the schematic diagram of the embodiment of the present invention.
Fig. 2 is to have document polarization code combining channel schematic diagram.
Fig. 3 is to have document polarization code BP to decode factor graph, N=8.
Fig. 4 is to have document polarization code BP to decode elementary cell.
Specific embodiment
The example of the present invention is described in further detail below in conjunction with description of the drawings, but this example is not used exclusively for limiting
The present invention, every similar structure using the present invention and its similar variation, should all be included in protection scope of the present invention.
May be referred to the Tanner figures of polarization code, arbitrary code length carry out coding can have it is minimum for 12 most becate and
This be LDPC code obtain pole dominance can a guarantee, therefore the application choose that polarization code and LDPC code cascaded not only can be with
The advantage of concatenated code is played, the presence of interleaver is also eliminated in structure.
Core operation is in Fig. 1：Decoding module is made of the iterative decoding of two decoders.With reference to the detailed stream of Fig. 1
Journey can be seen that information is exported from into cascade system to conclusive judgement, and the variation of information sequence is：
Iterative decoding, i represent iterations between decoder in bracket.By the iteration of decoder decoding result is allowed to stablize
Converge on the decoding capability scope of our needs.
Polarizing in Fig. 2, there are one operations for code coder：RN, this is a bit reversal effector, is accomplished that a row
Sequence function, with R4Exemplified by, pass through R for sequence (1,2,3,4)4Sequence (1,3,2,4) can be obtained afterwards.It ensure that simulation letter
The polarizability in road allows polarization code to reach shannon limit in BSC channels.
In conclusion can obtain the cascade structure proposed by the present invention based on LDPC and polarization code has superior translate
Code performance.
Claims (3)
1. a kind of cascade system based on LDPC and polarization code, the serial concatenation system are made of coding and decoding module, mould is decoded
Block is related to iterative decoding process.
It is characterized in that：
A, information sequencePolarization code coder is input to, is multiplied to obtain information sequence with generator matrix
B, by the sequence of polarization code encoder outputEnd adds spot patch position to be then inputted into LDPC encoder, obtains final code wordAnd incoming channel；
C, from channel receiver receiving sequenceHe is inputted into ldpc decoder and carries out BP decodings, soft information value is exported, removes end
Sequence is obtained after tail redundancy
D, again by sequenceIncoming polarization code decoder, carries out BP decodings, and is judged, whether iterations reaches, if
Reach hard decision output decoding resultOtherwise Soft Inform ation is returned to ldpc decoder to continue to decode.
Using BP decoding algorithms, 2. the BP decoding algorithms of wherein polarization code are specially decoder according to claim 1：
BP decodings are a kind of decoded modes that left and right calculating is carried out based on a factor graph, now make first to be classified as judgement layer, with consolidating
Positioning is related with information bit, last is classified as channel receiving layer, related with the information sequence of reception, and normal decoding output is judgement
The soft information value of layer, what the present invention polarized code decoder output before the maximum iteration of decoding module is reached is polarization
The soft information value of channel receiving layer during code BP decoding last time iteration rather than the information for adjudicating layer.
3. decoding module construction according to claim 1, polarize the defeated of code decoder before maximum iteration is reached
Going out needs to pass ldpc decoder back again, and decoding capability is improved by the iteration between decoding algorithm；Due to polarization code judgement layer output
Sequence and LDPC list entries without directly contacting, and the channel receiving layer of polarization code has with LDPC and directly contacts, therefore translates every time
In iteration between code device, by the right column of last time iteration of the polarization code BP decoding algorithms before maximum iteration is reached
Sequence exports, and passes to ldpc decoder, is iterated decoding.
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Cited By (7)
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|---|---|---|---|---|
| CN109547156A (en) * | 2018-10-18 | 2019-03-29 | 北京理工大学 | Non-coherent detection methods, device and the electronic equipment of polar short code |
| CN110890896A (en) * | 2018-09-11 | 2020-03-17 | 上海大学 | Reconfigurable polar code and low density parity check code joint decoding unit |
| CN111900999A (en) * | 2020-07-16 | 2020-11-06 | 北京航空航天大学 | High-performance polarization coding method and coder for satellite discontinuous communication |
| CN112104412A (en) * | 2020-11-17 | 2020-12-18 | 四川九洲电器集团有限责任公司 | Accelerator suitable for low-orbit satellite broadband communication |
| CN112584144A (en) * | 2019-09-30 | 2021-03-30 | 华为技术有限公司 | Image signal processing method and device |
| CN113196671A (en) * | 2018-12-13 | 2021-07-30 | 华为技术有限公司 | Apparatus and method for obtaining concatenated code structures and computer program product thereof |
| WO2023125061A1 (en) * | 2021-12-29 | 2023-07-06 | 华为技术有限公司 | Method for encoding concatenated code, method for decoding concatenated code, and communication apparatus |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110890896A (en) * | 2018-09-11 | 2020-03-17 | 上海大学 | Reconfigurable polar code and low density parity check code joint decoding unit |
| CN110890896B (en) * | 2018-09-11 | 2023-04-07 | 上海大学 | Reconfigurable polar code and low density parity check code joint decoding unit |
| CN109547156A (en) * | 2018-10-18 | 2019-03-29 | 北京理工大学 | Non-coherent detection methods, device and the electronic equipment of polar short code |
| CN113196671A (en) * | 2018-12-13 | 2021-07-30 | 华为技术有限公司 | Apparatus and method for obtaining concatenated code structures and computer program product thereof |
| CN113196671B (en) * | 2018-12-13 | 2023-10-13 | 华为技术有限公司 | Apparatus and method for obtaining concatenated code structure and computer program product therefor |
| CN112584144A (en) * | 2019-09-30 | 2021-03-30 | 华为技术有限公司 | Image signal processing method and device |
| CN112584144B (en) * | 2019-09-30 | 2022-04-12 | 华为技术有限公司 | Image signal processing method and device |
| CN111900999A (en) * | 2020-07-16 | 2020-11-06 | 北京航空航天大学 | High-performance polarization coding method and coder for satellite discontinuous communication |
| CN111900999B (en) * | 2020-07-16 | 2022-11-18 | 北京航空航天大学 | High-performance polarization coding method and coder for satellite discontinuous communication |
| CN112104412A (en) * | 2020-11-17 | 2020-12-18 | 四川九洲电器集团有限责任公司 | Accelerator suitable for low-orbit satellite broadband communication |
| CN112104412B (en) * | 2020-11-17 | 2021-02-02 | 四川九洲电器集团有限责任公司 | Accelerator suitable for low-orbit satellite broadband communication |
| WO2023125061A1 (en) * | 2021-12-29 | 2023-07-06 | 华为技术有限公司 | Method for encoding concatenated code, method for decoding concatenated code, and communication apparatus |
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