CN104168083A - Interleaved mapping method for coded modulation of protograph LDPC code - Google Patents
Interleaved mapping method for coded modulation of protograph LDPC code Download PDFInfo
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Abstract
An interleaved mapping method for coded modulation of a protograph LDPC code. Firstly, q bits of constellation mapping points are sequenced according to modulation reliability; p variable nodes in a P-LDPC code protograph which represent actual transmission are divided and sequenced according to weight, and the sequence is: the heaviest variable nodes; variable nodes whose weight is 1; variable nodes whose weight is 2; and variable nodes whose weight is between 2 and the weight of the heaviest nodes. np code bits output by an encoder are sequenced according to the abovementioned weight sequence of the variable nodes, thereby obtaining an interleaved sequence. The interleaved sequence is sequentially and equally divided into q bit segments, and each segment has m=np/q bits; and the divided q code bit segments are sequentially allocated to q modulating constellation bits. A bit is sequentially selected from each bit segment in sequence, thereby forming a modulation symbol including q bits, and m modulation symbols are formed in total.
Description
Technical field
The code modulated mapping method that interweaves that the present invention relates to a kind of prototype figure low-density checksum (P-LDPC) code, belongs to the chnnel coding modulation technique field in digital communication.
Background technology
The task of wireless communication system is to utilize limited bandwidth that the errorless transmission of high speed of information is provided.To the wireless communication system of typical power and Bandwidth-Constrained, Channel Coding and Modulation is the important guarantee of transmission reliability and spectrum efficiency.Advanced channel coding technology can effectively improve the reliability of system, and in the situation that air-link resources is limited, adopts high order modulation technology to improve beyond doubt one of effective means of system spectral resources utilance.
But along with the increase of order of modulation has reduced the Euclidean distance between transmission symbol, reduce the reliability of communication system, limited the further raising of order of modulation.This has just caused the separately larger defect of design existence of traditional Channel Coding and Modulation, therefore, coded modulation (Coded Modulation, CM) concept of co-design is suggested, Bit Interleave coded modulation (Bit-Interleaved Coded Modulation, BICM) is exactly a kind of like this Channel Coding and Modulation to be made to as a whole technology of carrying out combined optimization design.As shown in Figure 1, BICM introduces bit interleaver between encoder and modulator, and under desirable interwoven strips part, coding and modulation can independent design, thereby has reduced the design difficulty of CM system.
Low-density checksum (Low-Density Parity-Check, LDPC) code is the best channel coding schemes of performance of finding so far, and it can represent with a bipartite graph.BICM system based on LDPC code, with its superior performance, has obtained considerable concern and research in recent years, in various communication systems, is all widely used.The broadband wireless communications long evolving system (LTE) and European second generation digital television broadcasting (DVB) system that have represented advanced level have adopted respectively the BICM technology based on turbo code and LDPC code.
High order modulation technology mainly contains the modes such as QAM, PSK, ASK, and each constellation mapping point comprises multiple bits, and exponent number is higher, and bit is more.At present LTE system is the highest has adopted 64-QAM modulation, and DVB system has adopted 256-QAM modulation.
Difference protection degree to information bit in code modulation system comes from two aspects, that coding produces on the one hand, as inconsistent through bit convergence in iterative decoding process of LDPC coding, heavy bit (the high bit of the number of degrees in other words, the many bits of fillet number in other words) convergence rate is faster, and heavy bit has higher protection degree; Another side comes from constellation mapping, and the information bit after ovennodulation is because the different noise resisting abilities of constellation mapping bit are also different, does not modulate reliability not etc.For modulation, optimum Gray mapping has also just reduced the reliability difference of modulated bit to greatest extent.As shown in Figure 2, adopt the planisphere of the 64-QAM modulation of Gray mapping, the constellation point of each modulation symbol comprises 6 bit b
1b
2b
3b
4b
5b
6, it is λ (b that its reliability is closed
1)=λ (b
2) > λ (b
3)=λ (b
4) > λ (b
5)=λ (b
6).Along with the rising of code check and order of modulation, it is more remarkable that the difference that coding protection degree and modulation reliability cause becomes, and this makes coded-bit become more important to the mapping that interweaves of modulation constellation.
For the BICM of high spectrum efficiency LDPC code coding, the optimal design of interleaving scheme can make system obtain obvious performance gain.Existing interleaving scheme mainly contains following several: one is random (Rand) mapping that interweaves, and LDPC code coded-bit is random to the mapping of modulation constellation points; Be a comparatively general method, the bit mapping that coding protection degree is high is modulated the bit position that reliability is high in planisphere, is referred to as water filling (Water-filling, the WF) mapping that interweaves; Also have a kind of be bit mapping that coding protection degree is low on the high constellation point of modulation reliability, and the high bit mapping of coding protection degree is on the low constellation point of modulation reliability, can be called the anti-water filling mapping that interweaves.The design of interleaving scheme also needs to consider concrete code construction and modulation mapping mode, also should consider implementation complexity simultaneously.
Not only there is the performance of progressive shannon limit based on class LDPC (P-LDPC) code of prototype figure (Protograph) structure, and because its concrete structured constitution method makes Encoding Realization complexity low, thereby adopted by deep space communication standard.Typical P-LDPC code has ARJA code, AR4A code, ARAA code etc.The foundation structure of P-LDPC code is determined by simple prototype figure, through default expansions such as " copy-Bian exchange " (as shown in Figure 3), can obtain needing the LDPC code figure of length to prototype figure.Variable node correspondence in prototype figure coded-bit, and the limit number (or weight, or the number of degrees) connecting according to variable node can be classified variable node.At present mainly still adopt above mentioned water filling mapping or anti-water filling two kinds of the mappings that interweave that interweave for the mapping method that interweaves of P-LDPC code, and mainly for based on 4 class prototype figure node correspondences 2
4the situation of the specific like this equity of-QAM modulation, for general P-LDPC code and modulation system.
Summary of the invention
The object of this invention is to provide the code modulated mapping method that interweaves of a kind of P-LDPC code, adopt the code modulation system of this mapping method that interweaves can obtain better performance, and complexity is low, it is simple to realize.
The present invention includes following technical scheme: the code modulated mapping method that interweaves of a kind of prototype figure LDPC code, step is as follows:
(1) q of a constellation mapping point bit is sorted by modulation reliability descending;
(2) p the variable node that represents actual transmissions in P-LDPC code prototype figure divided by weight and sorted, sequentially successively: a heaviest class variable node; Weight is 1 variable node; Weight is 2 variable node; And weight between 2 and the heaviest node between a class variable node; Np coded-bit of encoder output sorted according to the weight order of above-mentioned variable node, obtain the sequence through interweaving, wherein n is prototype figure spreading factor;
(3) sequence after interweaving in step (2) is divided into q bit section in order, every section has m=np/q bit;
(4) q coded-bit section in step (3) distributed in order to q bit after sequence in step (1); Bit of selective sequential from each bit section, modulates successively, generates a modulation symbol, finally forms m modulation symbol, and each modulation symbol comprises q bit.
Sequence in described step (1), in the time that modulation constellation bit reliability equates, sequence in no particular order.
The variable node of same weight in described step (2), sequence in no particular order.
In described step (2) weight between 2 and the heaviest node between a class variable node in variable node sequence in no particular order.
The present invention's beneficial effect is compared with prior art:
This method has been utilized the unequal error protection characteristic of LDPC code coded-bit and modulation constellation points; and the effect brought into play in the time of iterative decoding of the node of the different number of degrees of LDPC code; particularly take into full account that degree is 1 and 2 the variable node feature when the iterative decoding; given more preferential protection, therefore the method is improved the error performance of system.
This method takes full advantage of the characteristic of LDPC code, therefore can obtain better performance, and complexity is low, it is simple to realize.
In addition, the method is not limited to P-LDPC code, is also applicable to the irregular LDPC codes of constructing in any way, has versatility and replicability.
Brief description of the drawings
Fig. 1 is P-LDPC code and 2
qthe BICM system block diagram of-QAM modulation.
Fig. 2 is the planisphere that adopts the 64-QAM modulation of Gray mapping.
Fig. 3 is that prototype figure carries out extended operation schematic diagrames such as " copy-Bian exchanges ".
Fig. 4 is the prototype figure schematic diagram of P-LDPC code, and Fig. 4 a is AR4A code prototype figure structure, and Fig. 4 b is AR4JA code prototype figure structure.
Fig. 5 is the flow chart of the embodiment of the present invention.
Fig. 6 is the frame error rate performance comparison diagram of the inventive method and the existing mapping method that interweaves.
Embodiment
Basic thought of the present invention is: to based on the code modulated interleaving design of P-LDPC code; according to the unequal characteristic of the coding protection degree of variable node waiting for transmission in P-LDPC code prototype figure and high-order modulation constellation bit reliability; the variable node that priority protection is the heaviest; secondly protection is heavily 1 variable node; then being to be heavily 2 variable node, is finally the variable node of other weight.
For making content of the present invention and technological means more clear and complete, below in conjunction with accompanying drawing, the present invention is done further and illustrated in detail.
This enforcement is introduced as an example of typical QAM modulation and Gray mapping mode example.
As shown in Fig. 4 a, on definition P-LDPC code prototype figure, there is p+1 variable node, be labeled as respectively { V
0, V
1..., V
p, wherein V
0represent the node that punching is not transmitted, actual transmissions bit after the corresponding coding of all the other p variable node (solid black circle represents).In the time of structure LDPC code, by certain predetermined rule, prototype figure is expanded, each node is an associated n coded-bit respectively, and physical relationship is as follows:
V
t＝{v
nt+1,v
nt+2,…,v
nt+n},t＝0,1,2,…,p
P-LDPC code total coding bit length is N=n (p+1), and actual transmissions bit number is N '=np, V
0corresponding bit section punching is not transmitted.Whole P-LDPC code is V
1, V
2..., V
pthe bit of this p section actual transmissions, provides different coding protection degree, the nodes encoding protection Du Genggao that the number of degrees are high conventionally.
Fig. 1 has provided P-LDPC code and 2
qthe BICM system block diagram of-QAM modulation.Definition coded-bit is as follows through the relation of the output that interweaves:
c
j＝v
i,j＝π(i),i,j＝1,2,3,…,np
Bit sequence after interweaving carries out 2
q-QAM modulation, the output sequence { c after coded-bit is interweaved
1, c
2..., c
npsequentially be divided into q bit section, and every section has m bit, and m=np/q, is defined as follows:
C
k＝{c
m(k-1)+1,c
m(k-1)+2,…,c
m(k-1)+m},k＝1,2,…,q
From { C
1, C
2..., C
qin respectively choose l bit, be modulated into one 2
q-qam symbol, altogether m individual 2
q-qam symbol:
There is definition and explanation above, by reference to the accompanying drawings 5, the deinterleaving method of present embodiment comprises following concrete steps:
Step S401: by the q of constellation mapping point bit b
1b
2b
qsort by modulation reliability descending.
Step S402: p the variable node that represents actual transmissions in P-LDPC code prototype figure divided by weight and sorted, sequentially successively: a heaviest class variable node; Weight is 1 variable node; Weight is 2 variable node; And weight between 2 and the heaviest node between a class variable node.Np coded-bit of encoder output sorted according to the weight order of above-mentioned variable node, obtain the sequence { c through interweaving
1, c
2..., c
np.N is prototype figure spreading factor, obtains P-LDPC code code figure after n doubly expands, and each node is an associated n coded-bit respectively, and after expansion, code length is np.
Step S403: by the sequence { c after interweaving
1, c
2..., c
npsequentially be divided into q bit section, and every section has m=np/q bit, and q bit section is expressed as C
k={ c
m (k-1)+1, c
m (k-1)+2..., c
m (k-1)+m, k=1,2 ..., q, i.e. C
1={ c
1, c
2..., c
m, C
2={ c
m+1, c
m+2..., c
m+m... C
q={ c
m (q-1)+1, c
m (q-1)+2..., c
m (q-1)+m.
Step S404: by q the coded-bit section { C after interweaving
1, C
2..., C
qorder-assigned gives by q modulation constellation bit of reliability descending.
The corresponding modulation constellation bit of each bit section, successively from each bit section C
1, C
2..., C
qmiddle order is chosen l bit, is modulated into one 2
q-qam symbol, altogether m individual 2
q-qam symbol:
Below by the interweave process of mapping of object lesson explanation.
As shown in Figure 2, be the planisphere that adopts the 64-QAM modulation of Gray mapping.Each constellation point comprises 6 mapped bits, i.e. q=6, and the modulation reliability of each mapped bits is not etc.Coded-bit after 6 of each 64-QAM symbol associations interweave.According to planisphere, can divide easily the decision area of each bit-detection, then from the division of decision area can release each bit q=6 bit section modulation reliability close be: λ (b
1)=λ (b
2) > λ (b
3)=λ (b
4) > λ (b
5)=λ (b
6).Therefore, sorted as { b by reliability descending in 6 mapped bits positions in 64-QAM constellation point
1, b
2, b
3, b
4, b
5, b
6.
Fig. 4 a is an AR4A code prototype figure, will in prototype figure, represent the variable node { V of actual transmissions
1, V
2..., V
6divide by weight: the variable node that weight is 4, also a heaviest class variable node is { V
2, V
3, V
4; Be heavily 1 variable node { V
1; Be heavily 2 variable node { V
5, V
6.In the example of Fig. 4 a, do not have weight between 2 and the heaviest node between a class variable node, the process of classification and ordination is carried out so far; And in the example of Fig. 4 b, exist weight between 2 and the heaviest node between a category node, the node that weight is 3, requires to divide sequence according to inventive method.Carrying out after variable node classification and ordination according to the prototype figure of Fig. 4 a is { V
2, V
3, V
4, V
1, V
5, V
6.6n the coded-bit that encoder is exported is according to the weight order { V of variable node
2, V
3, V
4, V
1, V
5, V
6sort, obtain the sequence { c through interweaving
1, c
2..., c
6n.
Then sequence { c
1, c
2..., c
6psequentially be divided into 6 bit section, every section has m=n bit, i.e. C
1={ c
1, c
2..., c
n, C
2={ c
n+1, c
n+2..., c
n+n... C
6={ c
5n+1, c
5n+2..., c
5n+n.
Coded-bit section { C by 6 after interweaving
1, C
2..., C
6order-assigned gives by 6 modulation constellation bits of reliability descending.The corresponding modulation constellation bit of each bit section, that is, and C
1corresponding b
1, C
2corresponding b
2... C
6corresponding b
6.Successively from C
1, C
2..., C
6middle order is chosen a bit, is modulated into one 2
6-qam symbol, altogether n individual 2
6-qam symbol.In the time of first modulation symbol of composition, respectively select C
1, C
2..., C
6in first bit c
1c
n+1c
5n+1, corresponding b
1b
2b
3b
4b
5b
6one group of value, generate a modulation symbol.In the time of second modulation symbol of composition, respectively select C
1, C
2..., C
6in second bit c
2c
n+2c
5n+2, corresponding b
1b
2b
3b
4b
5b
6one group of value, generate a modulation symbol.The like, until generate n individual 2
6-qam symbol.
Fig. 6 is the AR4A code of code length 4096 bits, code check 2/3 and the BICM system frame error rate simulation result of 64-QAM modulation, and the performance of multiple interleaving scheme and random interleaving scheme compares.Can find out the present invention program π
oPTwith the interleaving scheme π based on water filling
wFcompare, have the performance gain of 0.1dB, with respect to random interleaving scheme π
randthe nearly performance gain that exceedes 0.2dB, is better than anti-water filling interleaving scheme π more
rWFwith other the mapping scheme that interweaves.
The above is only the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the premise without departing from the principles of the invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.
The content that the present invention is not described in detail belongs to general knowledge as well known to those skilled in the art.
Claims (4)
1. the code modulated mapping method that interweaves of prototype figure LDPC code, is characterized in that step is as follows:
(1) q of a constellation mapping point bit is sorted by modulation reliability descending;
(2) p the variable node that represents actual transmissions in P-LDPC code prototype figure divided by weight and sorted, sequentially successively: a heaviest class variable node; Weight is 1 variable node; Weight is 2 variable node; And weight between 2 and the heaviest node between a class variable node; Np coded-bit of encoder output sorted according to the weight order of above-mentioned variable node, obtain the sequence through interweaving, wherein n is prototype figure spreading factor;
(3) sequence after interweaving in step (2) is divided into q bit section in order, every section has m=np/q bit;
(4) q coded-bit section in step (3) distributed in order to q bit after sequence in step (1); Bit of selective sequential from each bit section, modulates successively, generates a modulation symbol that comprises q bit, finally forms m modulation symbol.
2. the code modulated mapping method that interweaves of a kind of prototype figure LDPC code according to claim 1, is characterized in that: the sequence in described step (1), in the time that modulation constellation bit reliability equates, sequence in no particular order.
3. the code modulated mapping method that interweaves of a kind of prototype figure LDPC code according to claim 1, is characterized in that: the variable node of same weight in described step (2), sequence in no particular order.
4. the code modulated mapping method that interweaves of a kind of prototype figure LDPC code according to claim 1, is characterized in that: in described step (2) weight between 2 and the heaviest node between a class variable node in variable node sequence in no particular order.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2017011946A1 (en) * | 2015-07-17 | 2017-01-26 | 华为技术有限公司 | Unequal error protection-based data transmission method, apparatus and device |
| CN110445582A (en) * | 2019-08-12 | 2019-11-12 | 广东工业大学 | A kind of code interleaving method, system, device and computer readable storage medium |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007108471A1 (en) * | 2006-03-20 | 2007-09-27 | Matsushita Electric Industrial Co., Ltd. | Modulation device, demodulation device, and modulating method |
| CN101127581A (en) * | 2007-09-07 | 2008-02-20 | 普天信息技术研究院有限公司 | A mapping and reverse mapping method and device for LDPC coding modulation |
| CN103580807A (en) * | 2013-11-05 | 2014-02-12 | 上海数字电视国家工程研究中心有限公司 | BICM transmission method and system for LDPC code words in specific degree distribution |
-
2014
- 2014-05-22 CN CN201410220046.4A patent/CN104168083A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2007108471A1 (en) * | 2006-03-20 | 2007-09-27 | Matsushita Electric Industrial Co., Ltd. | Modulation device, demodulation device, and modulating method |
| CN101127581A (en) * | 2007-09-07 | 2008-02-20 | 普天信息技术研究院有限公司 | A mapping and reverse mapping method and device for LDPC coding modulation |
| CN103580807A (en) * | 2013-11-05 | 2014-02-12 | 上海数字电视国家工程研究中心有限公司 | BICM transmission method and system for LDPC code words in specific degree distribution |
Non-Patent Citations (2)
| Title |
|---|
| 窦金芳 等: "LDPC码在深空通信中的应用", 《遥控遥测》 * |
| 窦金芳，何善宝，姜明: ""原型图LDPC码编码的高谱效率BICM交织器优化"", 《应用科学学报》 * |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2017011946A1 (en) * | 2015-07-17 | 2017-01-26 | 华为技术有限公司 | Unequal error protection-based data transmission method, apparatus and device |
| CN107615691A (en) * | 2015-07-17 | 2018-01-19 | 华为技术有限公司 | Data transmission method, device and equipment based on unequal error protection |
| CN107615691B (en) * | 2015-07-17 | 2020-02-14 | 华为技术有限公司 | Data transmission method, device and equipment based on unequal error protection |
| CN110445582A (en) * | 2019-08-12 | 2019-11-12 | 广东工业大学 | A kind of code interleaving method, system, device and computer readable storage medium |
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Application publication date: 20141126 |