Specific implementation mode
Inventor has found the flexibility for handling and being unfavorable for bit interleaving design of punchinging used by the prior art, systematicnessIt can be promoted limited.
In view of the above-mentioned problems, inventor provides a kind of code modulating method and decoding demodulation method, is sending out by researchPenetrate end to the code word after coding punching processing when, different processing of punchinging is used based on different constellation mapping patterns, fromAnd effectively improve the flexibility of bit interleaving design；And receiving terminal based on different constellation mapping patterns to demapping afterLog-likelihood ratio carries out zero padding processing, is then deinterleaved and decodes again to demodulate information bit, can reduce in this way and isThe threshold level of system, and improve system performance.
To make the above purposes, features and advantages of the invention more obvious and understandable, below in conjunction with the accompanying drawings to the present inventionSpecific implementation mode be described in detail.
As shown in Fig. 1 the flow diagram of the specific implementation mode of a kind of code modulating method of the present invention.With reference toFig. 1, the code modulating method include the following steps：
Step S11：Information bit is encoded to obtain the code word of the first code length；
Step S12：Based on different constellation mapping patterns to the code word of first code length using it is different punching processing andBit Interleave is to obtain the code word of the second code length；
Step S13：Constellation mapping is carried out to obtain symbol stream to the code word of second code length.
In the present embodiment, for communication system, what it is in transmitting terminal input is information bit, such as can be transmittingThe digital information bits that the analog signals such as voice, the image received are obtained by digitlization and message sink coding are terminated, can also beDigital information bits etc. of the transmitting terminal received from digital devices such as computers.
As described in step S11, information bit is encoded.Transmitting terminal will be according to preset code check（Such as 1/3,2/3 etc.）, code length（It is first code length in the present embodiment）Information bit is encoded, the mode of coding may be usedLDPC code word is encoded.In other embodiment, information bit can also be encoded using other existing coding modes,Such as outer code（BCH code）LDPC code etc. is cascaded, it is numerous to list herein.
Specifically, the check bit of each block message bit is calculated, and by information bit and the check bit being calculatedIt is stitched together, to obtain the code word of the first code length.Can be that information bit exists in preceding, check bit in splicingAfterwards；Can also be check bit in preceding, information bit rear.
For example, setting the n-th block message bit as [bn,0,bn,1,…,bn,K-1], the check bit being calculated is [pn,0,pn,1,…,pn,N-K-1], wherein K is the number of specified code check and the information bit under code length, and N is the code under specified code length and code checkWord length.It is N that information bit and check bit, which are finally combined into a length,（I.e. described first code length）Code word [b 'n,0,b′n,1,…,b′n,N-1],
As described in step S12, punchinged using different to the code word of first code length based on different constellation mapping patternsProcessing and Bit Interleave are to obtain the code word of the second code length.
Unlike the prior art, in the present embodiment, punching processing and bit friendship are carried out to the code word of first code lengthWhen knitting, it is contemplated that this factor of constellation mapping pattern used by follow-up mapping processing, in identical coding mode（It is i.e. identicalCode check and code length）Under, use different processing modes of punchinging for different constellation mapping patterns.
The constellation mapping pattern includes regular constellation mapping pattern or irregular constellation mapping pattern.Wherein, described non-Regular constellation mapping mode refers to completing bit data to constellation using a kind of planisphere and more than one constellation point mapping modesThe mapping process of symbol.The irregular constellation mapping mode may be used QAM constellation and be mapped, and can also use APSKPlanisphere is mapped.Shaping can be reduced using irregular constellation mapping to lose, principle is so that low energy in planisphereThe number of constellation points of amount is more and the number of constellation points of high-energy is few, so that output signal is closer in the case where equiprobability mapsGaussian Profile.
Specifically, this step includes：
Step S121：It is determined according to different constellation mapping patterns in the code word of first code length where bit to be deletedPosition and Bit Interleave mode；
Step S122：It deletes in all bits to be deleted in this position in the code word of first code length, and according to thisBit Interleave mode carries out Bit Interleave to obtain the code word of the second code length.
In the present embodiment, for identical code check and code length, but the code word of the first different code length of constellation mapping patternPunching processing when, the bit number dug is identical, but is specifically then not quite similar by the corresponding serial number of bit that chisel is gone.In practice, the different argument sequences punchinged with Bit Interleave can be set, to right（Subsequently mould is mapped using various constellationsFormula）The code word of first code length carries out different processing and the Bit Interleaves of punchinging to obtain the code word of the second code length.
For example, the code word of the second code length set is [b "n,0,b″n,1,…,b″n,N-P-1], wherein P is in identical code lengthAnd code check, but the bit number of removal is punctured under various constellations mapped mode.Sequence can be used with the parameter of Bit Interleave by punchinging[k0,k1,…,kN-P-1] indicate, i.e., forWherein, [k0,k1,…,kN-P-1] all it is integer in [0, N-1] range, and it is different two-by-two.Obviously, set K={ k0,k1,…,kN-P-1Be set I=0,1 ..., N-1 } subset, the supplementary set for defining K isIncluding P element be exactly the bit dug serial number.
That is, for identical code check and code length（I.e. N is identical）, but the first different code length of constellation mapping patternCode word punching processing when, P is identical, but set K can difference, that is, identical coding mode is in different constellation mapping mouldsThe position of the lower bit dug of formula can be different, and the parameter of the Bit Interleave used certainly is also different.
As described in step S13, constellation mapping is carried out to obtain symbol stream to the code word of second code length.
Specifically, according to different constellation mapping patterns, the code word of second code length is divided into multiple bit groups, and will be everyOne bit group is mapped as a symbol, to obtain symbol stream.For example, for the constellation mapping mould using 4-QAM planispheresFormula is grouped to obtain multiple bit groups according to 2 one group of bits, then these bit groups is respectively mapped to a plural number symbolNumber, to obtain symbol stream.
And for the constellation mapping pattern using planispheres such as 16-QAM, 64-QAM, 256-QAM and 1024-QAM, thenCorrespondingly it is grouped to obtain multiple bit groups according to 4,6,8 and 10 one group of bits, then by these bit componentsIt is not mapped to a complex symbol, to obtain symbol stream.
The embodiment of the present invention additionally provides a kind of decoding demodulation method.As shown in Fig. 2 a kind of decoding solution of the inventionThe flow diagram of the specific implementation mode of tune method.With reference to figure 2, the decoding demodulation method includes the following steps：
Step S21：Symbol stream is received, the wherein symbol stream is handled information bit by above-mentioned code modulating methodAfter obtain；
Step S22：Demapping is carried out to obtain log-likelihood ratio to the symbol stream according to the constellation mapping pattern of transmitting terminalStream；
Step S23：The log-likelihood ratio stream is carried out at zero padding processing and deinterleaving based on different constellation mapping patternsReason is with the log-likelihood ratio stream after being deinterleaved；
Step S24：Row decoding is flowed into obtain information bit to the log-likelihood ratio after the deinterleaving.
In the present embodiment, the prior art may be used to realize in the step S21 and step S22.It should be noted thatReceiving terminal can pass through signaling（It is carried when sending information by transmitting terminal）Or other modes obtain code length, code check and constellation mappingThe information such as pattern.
As described in the step S23, zero padding processing is carried out to the log-likelihood ratio stream based on different constellation mapping patternsReconciliation interleaving treatment is with the log-likelihood ratio stream after being deinterleaved.
Specifically, this step includes：
Step S231：Determine that the code word of the first code length of transmitting terminal pair carries out processing of punchinging according to different constellation mapping patternsThe location of bit deleted in the process and deinterleaving mode；
Step S232：The zero padding on the bit location of all deletions, and carry out solution friendship according to the deinterleaving modeProcessing is knitted with the log-likelihood ratio stream after being deinterleaved.
Correspond to the n-th block codewords [b " in symbol stream for example, settingn,0,b″n,1,…,b″n,N-P-1] log-likelihood ratio（Loglikelihood Ratio, LLR）For [ln,0,ln,1,…,ln,N-P-1].According to different constellation mapping patterns, allZero padding on the bit location of deletion, and obtain [l ' after being deinterleaved processing according to corresponding deinterleaving moden,0,l′n,1,…,l′n,N-1], wherein
Then, as described in step S24, row decoding is flowed into obtain information bit to the log-likelihood ratio after deinterleaving., can be according to information such as code length and code checks in practice, and pass through [l 'n,0,l′n,1,…,l′n,N-1] information bit is calculated.ThisIn embodiment, the specific algorithm of decoding is not limited, receiving terminal can be right according to the institute of coding method used by transmitting terminalThe decoded mode answered is handled into row decoding.
An example is set forth below and further describes technical scheme of the present invention.
Example 1：
In this example, system is by transmitting terminal and receiving terminal, and as shown in table 1, transmitting terminal and receiving terminal include 4 kinds of patterns.
Table 1：4 kinds of patterns of example 1
| Code check | Code length after punchinging | Constellation mapping pattern |
| Pattern 1 | 1/3 | 64800 | 4-QAM |
| Pattern 2 | 1/3 | 64800 | 16-QAM |
| Pattern 3 | 2/3 | 64800 | 4-QAM |
| Pattern 4 | 2/3 | 64800 | 16-QAM |
In this example, since the processing procedure of receiving terminal is the inverse process of transmitting terminal, detailed description is sent out hereThe processing procedure at end is penetrated, the specific implementation process of receiving terminal repeats no more.
In transmitting terminal, LDPC encoder is under pattern 1 and pattern 2, all according to check matrix H1, pass through 21600 information48960 bit check bits are calculated in bit, then splice to obtain in such a way that information bit is posterior in preceding, check bitThe code word of 70560 bits, i.e. N=70560, K=21600.
LDPC encoder is under pattern 3 and pattern 4, all according to check matrix H2, calculated by 43200 information bitsTo 23040 bit check bits, then splice to obtain the code of 66240 bits in such a way that information bit is posterior in preceding, check bitWord, i.e. N=66240, K=43200.
The present embodiment is to H1With H2Detail be not described.
For pattern 1 and pattern 3, [the k that punchinges with Bit interleaving block0,k1,…,k64799] can pass through it is following publicFormula obtains：
Wherein, t is the integer in [0,360] range, and m is the integer in [0,89] range.
For pattern 2 and pattern 4, [the k that punchinges with Bit interleaving block0,k1,…,k64799] can pass through it is following publicFormula obtains：
Wherein, t is the integer in [0,360] range, and m is the integer in [0,44] range.
It punchinges and Bit Interleave parameter [π0,π1,…,π179] definition it is as shown in table 2.
Table 2：It punchinges in example 1 and Bit Interleave parameter
| [π0,π1,…,π179] |
| Pattern 1 | [16,18,20,…,194,17,19,…,195] |
| Pattern 2 | [0,1,2,3,20,21,22,…,195] |
| Pattern 3 | [4,6,8,…,182,5,7,…,183] |
| Pattern 4 | [0,1,2,3,8,9,10,…,183] |
For pattern 1 and pattern 3, constellation point module will be by punchinging with the code word of Bit Interleave by two bits oneGroup grouping, then by table 3 by it is each include that the bit groups of two bits is mapped to a complex symbol.
Table 3：4-QAM mapping modes in example 1
| Bit group | Symbol |
| 00 | 1+1i |
| 01 | 1-1i |
| 10 | -1+1i |
| 11 | -1-1i |
For pattern 2 and pattern 4, constellation point module will be by punchinging with the code word of Bit Interleave by four bits oneGroup grouping, then by table 4 by it is each include that the bit groups of four bits is mapped to a complex symbol.
Table 4：16-QAM mapping modes in example 1
| Bit group | Symbol | Bit group | Symbol |
| 0000 | 3+3i | 1000 | -3+3i |
| 0001 | 3+1i | 1001 | -3+1i |
| 0010 | 1+3i | 1010 | -1+3i |
| 0011 | 1+1i | 1011 | -1+1i |
| 0100 | 3-3i | 1100 | -3-3i |
| 0101 | 3-1i | 1101 | -3-1i |
| 0110 | 1-3i | 1110 | -1-3i |
| 0111 | 1-1i | 1111 | -1-1i |
In receiving terminal, determine which kind of pattern is the symbol stream correspond to according to the signaling received first, then according to the mouldThe information such as corresponding code length, code check and constellation mapping pattern demodulate symbol stream according to the decoding described in above-described embodiment under formulaMethod carries out corresponding processing to obtain information bit, is not described in detail herein.
In conclusion the flexibility of bit interleaving design can be effectively improved using the technical program, system is reducedThreshold level, and improve system performance.
Although the invention has been described by way of example and in terms of the preferred embodiments, but it is not for limiting the present invention, any this fieldTechnical staff without departing from the spirit and scope of the present invention, may be by the methods and technical content of the disclosure above to this hairBright technical solution makes possible variation and modification, therefore, every content without departing from technical solution of the present invention, and according to the present inventionTechnical spirit to any simple modifications, equivalents, and modifications made by above example, belong to technical solution of the present inventionProtection domain.