CN105356905B - A kind of direct sequence spread spectrum codes and 1/K rate convolutional code hybrid coding methods - Google Patents
A kind of direct sequence spread spectrum codes and 1/K rate convolutional code hybrid coding methods Download PDFInfo
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- CN105356905B CN105356905B CN201510672502.3A CN201510672502A CN105356905B CN 105356905 B CN105356905 B CN 105356905B CN 201510672502 A CN201510672502 A CN 201510672502A CN 105356905 B CN105356905 B CN 105356905B
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
- H04B1/707—Spread spectrum techniques using direct sequence modulation
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/69—Spread spectrum techniques
- H04B1/707—Spread spectrum techniques using direct sequence modulation
- H04B1/7073—Synchronisation aspects
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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
- H04L1/0059—Convolutional codes
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Abstract
The invention discloses a kind of method by Spread Spectrum Sequences and convolutional code assembly coding, it can to carry out the binary data that source speed is R bps after the convolution coding that code check is 1/K and the frequency expansion sequence spread spectrum that length is M, on the one hand, it is K sections that the frequency expansion sequence that length is M, which will not be convolved code division, so as to which band spread receiver can realize spread and disposal plus conveniently by the mode of coherent detection or matched filtering, to ensure receptivity；On the other hand the spreading rate after spread spectrum is ensured for M*R, rather than M*R*K, so as to save wireless bandwidth；On the other hand spreading gain is ensure that for M, rather than M/K.
Description
Technical field
Mixed the present invention relates to wireless communication field, more particularly to a kind of direct sequence spread spectrum codes with 1/K rate convolutional codes
Coding method.
Background technology
DSSS (DSSS：Direct sequence spread spectrum) it is a kind of spread spectrum communication
(spread spectrum communication) technology, starts from military communication earliest.Because spread spectrum communication is improving signal receiving quality, anti-interference, confidentiality
With increase power system capacity in terms of have the advantages that it is prominent, so at present extensively commercialization.Direct spreading sequence is one long
Spend for N (N be more than 1) pseudo-random sequence, conventional DSSS sequence has m-sequence, gold sequences, Barker sequences etc.
Deng.The DSSS for being N by length operation can obtain the spreading gain that size is N, and 10log is expressed as with db numbers
(N)。
The channel error correction coding techniques that convolutional code belongs in radio communication.Convolution coding is carried out in transmitter terminal, logical
The receiving terminal of letter can correct the error code that certain amount is caused due to the interference in communication process by convolutional code decoder.Communication system
System can obtain coding gain by using forward error correction.1 bit binary number is encoded to K bit binary system by convolutional encoding
Several cataloged procedures can introduce redundant bit, and the code check of definition in this case is 1/K.
From communication theory, when DSSS and convolutional code are used in combination communication system, it can obtain simultaneously
Size is N spreading gain and corresponding coding gain.By the possible of the convolutional code combination of DSSS and 1/K code checks
Method has：
(1) data rate is R bps binary data, and first by the Error Correction of Coding that code check is 1/K, obtaining speed is
R*K binary data stream, with code length is N to the data flow after convolution coding, spreading rate (chip rate) is N*R*
K bps frequency expansion sequence is spread.Its spreading gain obtained is N, while obtaining convolution coding gain.
(2) according to the binary data that speed is R bps, after the convolution coding for being first 1/K by code check, speed is obtained
With length it is N*K, spreading rate (chip rate) to the binary data after convolution coding for R*K binary data stream
Frequency expansion sequence for R*N*K bps is spread.Its spreading gain obtained is N*K, while also obtain convolution coding increasing
Benefit.
In the case of convolutional code coding and decoding scheme identical, the convolutional encoding gain phase of method 2 and method 1 acquisition of the above
Together.But the spreading gain that method 2 is obtained is N*K, the spreading gain of method 1 is N, and method 2 is K times of method 1.So two more than
Plant under spread spectrum and convolutional code associated methods, identical convolutional encoding gain can be obtained, method 2 obtains bigger spread spectrum and increased
Benefit.But in the case of method 2, a frequency expansion sequence is convolved code division and is segmented into K sections, this prevents in receiving terminal from by matching
Or autocorrelative mode carries out spread and disposal plus, in the case of receiver clock and transmitter clock frequency are nonsynchronous, receive
Machine can not keep spread and disposal plus for a long time, and very big limits communication performance.Therefore, the receiver of method 1 is easily realized, but
Have the disadvantage that spreading gain is limited by very large, only the 1/K of method 2；And method 2 obtains larger spreading gain, but
It is that the spread and disposal plus of receiver is restricted, influences communication performance.Therefore, those skilled in the art is directed to exploitation one
Kind of spreading code and convolutional code hybrid coding method, this assembly coding method can overcome lacking for the above method 1 and method 2 simultaneously
Point, while its advantage can also be retained.
The content of the invention
In view of the drawbacks described above of prior art, the technical problems to be solved by the invention are：
" the convolutional encoding that code check is 1/K+chip speed is carried out to the binary data that data rate is R bps existing
Under the spread spectrum assembled scheme that rate is R*K*N ", it is impossible to while reach " spreading gain for obtaining N*K " and " frequency expansion sequence will not be rolled up
Product code division is segmented into K sections, so that receiver can obtain spread and disposal plus by related and matched filtering operation " both advantages.
To achieve the above object, the invention provides a kind of direct sequence spread spectrum codes and convolutional code hybrid coding method, bag
Containing following steps：
S1, offer one are by 2KThe spreading code set that individual length constitutes for M pseudorandom spreading sequence；
S2, by 2 in the spreading code setKIndividual frequency expansion sequence is numbered in any order；The numbering is K and two entered
Number processed；
S3, be to speed R bps source data carry out code check be 1/K convolution coding；
S4, by speed after convolutional encoding for R*K bps convolution coding data successively in units of K bit be grouped；Often
K bit one pseudorandom spreading sequence of correspondence of group, and the decimal system size and pseudorandom spreading sequence of every group of K bit
K positions binary number numbering decimal system size it is identical；Every group of K bits of encoded is M chip；
The grouped data of S5, K bits is mapped as after a length of M spread-spectrum code chip, according to original packet sequencing
Arranged, form final hybrid coding data flow.
Further, the pseudo-random sequence is one kind in m-sequence, gold sequences, barker sequences.
Further, 2 in the spreading code setKIndividual pseudorandom spreading sequence has cross correlation and autocorrelation haracter
Property.
The present invention after the assembly coding method using the present invention, can make convolutional code and frequency expansion sequence assembly coding
The frequency expansion sequence spread spectrum that the convolution coding and length that the binary data progress code check that to source speed must be R bps is 1/K are M
Afterwards, on the one hand, it is K sections that the frequency expansion sequence that length is M, which will not be convolved code division, so that band spread receiver can easily lead to
The mode for crossing coherent detection or matched filtering realizes spread and disposal plus, to ensure receptivity；On the other hand ensure after spread spectrum
Spreading rate is M*R, rather than M*R*K, so as to save wireless bandwidth；On the other hand ensure that spreading gain is M, rather than
M/K。
Without loss of generality, it is assumed that binary data speed is R bps before coding, and the convolutional code code check of selection is 1/K,
Spread spectrum code sequence length is M, it is desirable to and the spreading rate after coding is R*M.
The first step is, it is necessary to design one by 2KThe spreading code set that individual length constitutes for M pseudorandom spreading sequence.It is required that
2 in the setKIndividual pseudorandom spreading sequence has good cross correlation and autocorrelation performance, conventional pseudo-random sequence
There are m-sequence, gold sequences, barker sequences etc., application person can voluntarily choose according to demand.
Second step, by 2 in pseudorandom spreading sequence setKIndividual frequency expansion sequence presses any (application person decides in its sole discretion) order
Numbering is 0,1,2,3 ..., 2K-1.The numbering of these decimal representations can be represented with K bits.
3rd step, is that R bps source data carries out the convolution coding that code check is 1/K, coding polynomial peace treaty to speed
Shu Changdu application persons can voluntarily choose as needed, and the two parameters do not interfere with the implementation of the present invention, only influence whether to obtain
The convolution coding gain obtained.
4th step, speed after convolutional encoding is divided in units of K bit successively for R*K bps convolution coding data
Group.Every group of K bit one K bit of correspondence, its magnitude range is 0 to 2K- 1, prepare in this and " second step "
Pseudorandom spreading sequence number range in pseudorandom spreading sequence set is identical.It is N by every group of the corresponding size of K bit
(span is 0 to 2K- 1) K bits are encoded to the pseudorandom spread spectrum that numbering is N in pseudorandom spreading sequence set
Sequence, so as to complete the assembly coding of convolutional code and pseudorandom spreading sequence.Every group of K bits of encoded is M chip.
5th, the grouped data of K bit is mapped as after a length of M spread-spectrum code chip, according to original packet sequencing
Arranged.Form final encoded data stream.
The present invention after the assembly coding method using the present invention, can make convolutional code and frequency expansion sequence assembly coding
The frequency expansion sequence spread spectrum that the convolution coding and length that the binary data progress code check that to source speed must be R bps is 1/K are M
Afterwards, have the following advantages that：
(1) it is K sections that the frequency expansion sequence that length is M, which will not be convolved code division, so that band spread receiver can be easily
Spread and disposal plus is realized by way of coherent detection or matched filtering, to ensure receptivity；
(2) spreading rate after spread spectrum is ensured for M*R, rather than M*R*K, so as to save wireless bandwidth；
(3) spreading gain is ensure that for M, rather than M/K.
The technique effect of the design of the present invention, concrete structure and generation is described further below with reference to accompanying drawing, with
It is fully understood from the purpose of the present invention, feature and effect.
Brief description of the drawings
Fig. 1 is the convolution coder structure and example of the preferred embodiment of the present invention
Fig. 2 is by convolutional code packet and Mapping implementation assembly coding process example
Embodiment
Without loss of generality, 10 (but being not limited to 10), K are equal to R are equal to 2 (but being not limited to 2) and M and (but do not limit equal to 31
Exemplified by 31).In this case, convolution coding code check is 1/2, and pseudorandom spreading sequence length is 31, and data rate is
10bps。
Hybrid coding method specific implementation process of the present invention is：
The first step, the spreading code set that design one is made up of the pseudorandom spreading sequence that 4 length are 31.Select herein
Gold sequences generate pseudorandom spreading sequence.4 pseudo-random sequences are respectively:
Sa=" 1000010101110110001111100110100 "
Sb=" 1000011010100100010111110110011 "
Sc=" 0101000111111101110100101000100 "
Sd=" 0110010011011111001010011011000 "
4 frequency expansion sequences in pseudorandom spreading sequence set are pressed any (application person decides in its sole discretion) order by second step
Numbering is 0,1,2,3.The numbering plan chosen in present embodiment is：Sa reference numerals 0；Sb reference numerals 1；Sc reference numerals
2；Sd reference numerals 3.
The source data that 3rd step is 10bps to speed carries out the convolution coding that code check is 1/2, coding polynomial peace treaty
Shu Changdu application persons can voluntarily choose as needed.The convolution coding constraint length chosen in the present embodiment is 4, coding
Multinomial is (d, f), and wherein d, f is hexadecimal values.As shown in figure 1, top half gives convolution coder knot in Fig. 1
Structure, two of which adder is binary adder；The latter half with sequence " ... 10110110 " (note：The present invention is on data
In the narration of stream, the bit of " " number on the right side is the relatively early bit sent on the time, similarly hereinafter.) to input, give coding and show
Example.In Fig. 1 examples, above adder output stream for " ... 01101 ", below adder output stream for " ...
00110”.The output of two adders by obtained after parallel-serial conversion final convolutional encoding output stream " ...
0001111001”。
4th step, 2 bits are unit point to the convolution coding data for being 10*2=20bps by speed after convolutional encoding successively
Group.Every group of two bits, one 2 bit of correspondence, its magnitude range is the puppet prepared in 0 to 3, this and " second step "
Pseudorandom spreading sequence number range in random frequency expansion sequence set is identical.By in every group of 2 bits：" 00 " is encoded to Sa
=" 1000010101110110001111100110100 "；" 01 " is encoded to
Sb=" 1000011010100100010111110110011 "；" 10 " are encoded
For Sc=" 0101000111111101110100101000100 "；" 11 " are compiled
Code is Sd=" 0110010011011111001010011011000 ".So as to
The assembly coding of convolutional code and pseudorandom spreading sequence is completed, every group of 2 bits of encoded are 31 chips.As shown in Figure 2.Group
Compiling in collaboration with the output stream after code is：“…；1 0 0 0 0 1 0 1 0 1 1 1 0 1 1 0 0 0 1 1 1 1 1 0 0
1 1 0 1 0 0；1 0 0 0 0 1 1 0 1 0 1 0 0 1 0 0 0 1 0 1 1 1 1 1 0 1 1 0 0 1 1；0 1
1 0 0 1 0 0 1 1 0 1 1 1 1 1 0 0 1 0 1 0 0 1 1 0 1 1 0 0 0；0 1 0 1 0 0 0 1 1 1
1 1 1 1 0 1 1 1 0 1 0 0 1 0 1 0 0 0 1 0 0；1 0 0 0 0 1 1 0 1 0 1 0 0 1 0 0 0 1
0 1 1 1 1 1 0 1 1 0 0 1 1”。
5th, the grouped data of 2 bits is mapped as after a length of 31 spread-spectrum code chip, according to original packet sequencing
Arranged, form final encoded data stream.With Fig. 2 example, final encoded data stream for " ...；1 0 0 0 0 1 0 1
0 1 1 1 0 1 1 0 0 0 1 1 1 1 1 0 0 1 1 0 1 0 0；1 0 0 0 0 1 1 0 1 0 1 0 0 1 0 0
0 1 0 1 1 1 1 1 0 1 1 0 0 1 1；0 1 1 0 0 1 0 0 1 1 0 1 1 1 1 1 0 0 1 0 1 0 0 1
1 0 1 1 0 0 0；0 1 0 1 0 0 0 1 1 1 1 1 1 1 0 1 1 1 0 1 0 0 1 0 1 0 0 0 1 0 0；1
0 0 0 0 1 1 0 1 0 1 0 0 1 0 0 0 1 0 1 1 1 1 1 0 1 1 0 0 1 1”。
Preferred embodiment of the invention described in detail above.It should be appreciated that the ordinary skill of this area is without wound
The property made work just can make many modifications and variations according to the design of the present invention.Therefore, all technical staff in the art
Pass through the available technology of logical analysis, reasoning, or a limited experiment on the basis of existing technology under this invention's idea
Scheme, all should be in the protection domain being defined in the patent claims.
Claims (2)
1. a kind of direct sequence spread spectrum codes and convolutional code hybrid coding method, it is characterised in that the hybrid coding method is included
Following steps：
S1, offer one are by 2KThe spreading code set that individual length constitutes for M pseudorandom spreading sequence；In the spreading code set
2KIndividual pseudorandom spreading sequence has cross correlation and autocorrelation performance；
S2, by 2 in the spreading code setKIndividual frequency expansion sequence is numbered in any order；The numbering is the binary number of K；
S3, be to speed R bps source data carry out code check be 1/K convolution coding；
S4, by speed after convolutional encoding for R*K bps convolution coding data successively in units of K bit be grouped；Every group of K
One pseudorandom spreading sequence of individual bit correspondence, and decimal system size and the K positions of pseudorandom spreading sequence of every group of K bit
Binary number numbering decimal system size it is identical；Every group of K bits of encoded is M chip；
The grouped data of S5, K bits is mapped as after a length of M spread-spectrum code chip, is carried out according to original packet sequencing
Arrangement, forms final hybrid coding data flow.
2. hybrid coding method as claimed in claim 1, it is characterised in that the pseudo-random sequence is m-sequence, gold sequences
One kind in row, barker sequences.
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| CN1771671A (en) * | 2003-04-11 | 2006-05-10 | 艾利森电话股份有限公司 | Joint multi-code detectors in CDMA communications system |
| CN101141178A (en) * | 2006-09-07 | 2008-03-12 | 中兴通讯股份有限公司 | Method of self-adaptive selecting transmission time spacing |
| CN101296021A (en) * | 2007-04-28 | 2008-10-29 | 华为技术有限公司 | Multi-channel multiplexing transmission method and device |
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| JP3590310B2 (en) * | 1999-12-07 | 2004-11-17 | シャープ株式会社 | Concatenated convolutional code decoder |
| CN100544239C (en) * | 2003-02-14 | 2009-09-23 | 华为技术有限公司 | The deinterleaving method that is used for OFDM communications |
| CN100440838C (en) * | 2005-11-10 | 2008-12-03 | 中兴通讯股份有限公司 | Terminal wireless access method and its system |
| CN102104458B (en) * | 2010-07-02 | 2013-07-31 | 电信科学技术研究院 | Method and equipment for transmitting uplink control information |
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| CN1771671A (en) * | 2003-04-11 | 2006-05-10 | 艾利森电话股份有限公司 | Joint multi-code detectors in CDMA communications system |
| CN101141178A (en) * | 2006-09-07 | 2008-03-12 | 中兴通讯股份有限公司 | Method of self-adaptive selecting transmission time spacing |
| CN101296021A (en) * | 2007-04-28 | 2008-10-29 | 华为技术有限公司 | Multi-channel multiplexing transmission method and device |
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