CN113037298B - System and method for filling interference information based on low-code-rate LDPC code - Google Patents

System and method for filling interference information based on low-code-rate LDPC code Download PDF

Info

Publication number
CN113037298B
CN113037298B CN202110223043.6A CN202110223043A CN113037298B CN 113037298 B CN113037298 B CN 113037298B CN 202110223043 A CN202110223043 A CN 202110223043A CN 113037298 B CN113037298 B CN 113037298B
Authority
CN
China
Prior art keywords
information
unit
decoding
interference
ldpc code
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202110223043.6A
Other languages
Chinese (zh)
Other versions
CN113037298A (en
Inventor
安建平
王帅
蒙艳松
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Beijing Institute of Technology BIT
Original Assignee
Beijing Institute of Technology BIT
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Beijing Institute of Technology BIT filed Critical Beijing Institute of Technology BIT
Publication of CN113037298A publication Critical patent/CN113037298A/en
Application granted granted Critical
Publication of CN113037298B publication Critical patent/CN113037298B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • H03M13/1148—Structural properties of the code parity-check or generator matrix
    • H03M13/1154—Low-density parity-check convolutional codes [LDPC-CC]

Landscapes

  • Physics & Mathematics (AREA)
  • Mathematical Physics (AREA)
  • Probability & Statistics with Applications (AREA)
  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Radio Transmission System (AREA)

Abstract

The invention relates to a system and a method for filling interference information based on a low code rate LDPC code, in particular to a system and a method for realizing anti-interference in a strong interference system in a diversity mode by the LDPC code-assisted interference information filling, belonging to the field of digital signal processing. The anti-interference communication system comprises a repeat diversity unit, a modulation unit, a demodulation unit, a diversity receiving unit, an LDPC code decoding unit and an information replacement unit. The invention reduces the interference of high-power narrow-band noise by repeatedly sending at the sending end and diversity receiving at the receiving end, finally realizes the replacement of interference information in decoding soft information by iterative updating among the LDPC code decoding unit, the information replacing unit and the diversity receiving unit to improve the decoding performance, realizes anti-interference covert communication under the influence of high-power strong interference noise, and improves the reliability of a communication system. The method has the advantages of strong anti-interference performance and good concealment.

Description

System and method for filling interference information based on low-code-rate LDPC (Low Density parity check) code
Technical Field
The invention relates to a system and a method for filling interference information based on a low-code-rate LDPC code, in particular to a system and a method for realizing anti-interference in a strong interference system in a form of LDPC code auxiliary interference information filling and diversity, belonging to the field of digital signal processing.
Background
In practical applications, a low density parity check code (LDPC) is a code pattern that is greatly affected after being subjected to strong interference, and when a transmission signal is transmitted through a channel in a communication system and is subjected to strong interference, decoding performance of the LDPC code is drastically deteriorated. In order to counter strong interference in a channel and realize error-free decoding, how to reduce the influence caused by high-power strong interference narrowband noise in the channel becomes a very important problem in the application of the LDPC code. In the prior art, a frequency hopping spread spectrum system is generally adopted to reduce narrowband interference; the frequency hopping system enables the frequency to be repeatedly converted in the process of transmitting radio signals, the influence of electronic countermeasure is reduced, spread spectrum modulation enables the signals to be transmitted through a frequency band which is much wider than the minimum bandwidth required by information signals, and spread spectrum communication can reduce narrow-band interference; however, in the conventional hop-spread communication system, the high-power strong-interference narrow-band noise still causes a part of soft information required for decoding to be greatly affected, and a large amount of errors occur in the subsequent decoding result. The LDPC code with low code rate not only has spread spectrum gain but also coding gain, realizes the purpose of anti-interference by transmitting terminal repetition and receiving terminal diversity reception, and provides a scheme of utilizing code to assist interference information filling in the decoding iteration process of the LDPC code to further improve the anti-interference performance.
Disclosure of Invention
The invention aims to solve the problem of communication system performance deterioration caused by high-power narrow-band noise in a strong interference environment, and provides a system and a method for filling interference information based on a low-code-rate LDPC code.
The purpose of the invention is realized by the following technical scheme.
The invention repeatedly sends the coded code group at the sending end and uniformly distributes the influence of the strong power narrow-band noise in the channel on the bandwidth of the whole signal at the receiving end in a diversity reception mode, so that the influence on the soft information received by the LDPC code decoding unit is reduced, and the deterioration of the strong interference signal in the channel on the performance of a communication system is improved. In addition, the invention also provides a method for filling and updating the interference information, which updates the interference information after each iterative decoding through the LDPC code decoding unit, the information replacing unit and the diversity receiving unit, thereby improving the accuracy of the decoding, finally realizing the correct decoding, improving the problem of the performance deterioration of the communication system caused by the existence of high-power narrow-band noise in the strong interference environment and improving the anti-interference performance of the communication system.
A system for interference information padding based on low code rate LDPC codes, comprising: an LDPC code encoding unit, a repetition diversity unit, a modulation unit, a demodulation unit, a diversity reception unit, an LDPC code decoding unit, and an information replacement unit.
The LDPC code encoding unit is used for performing LDPC code encoding on the information bits and transmitting the encoded signals to the repetition diversity unit.
The repetition diversity unit is configured to repeat a plurality of encoded copies of the signal and to pass the same plurality of signals to the modulation unit.
And the modulation unit is used for modulating a plurality of same signals to obtain modulated signals and sending the modulated signals to a receiving end through a channel.
The demodulation unit is used for sensing the signal frequency band interfered by the narrow-band noise on the frequency spectrum, demodulating the received signal to obtain a demodulated signal, and then transmitting the demodulated signal to the diversity receiving unit.
The diversity receiving unit is used for combining (including selecting and combining) the received multiple statistically independent demodulated fading signals, and then transmitting the combined signals as channel initial information to the LDPC code decoding unit and the information replacing unit.
The LDPC code decoding unit is used for finishing the LDPC decoding function of the receiving system and outputting the final decoding result. And meanwhile, the hard decision information of the variable node is transmitted to the information replacement unit during each decoding iteration.
And the information replacement unit is used for processing the hard decision information and the channel initial information of the variable node transmitted by the LDPC code decoding unit to replace and update the interference information after each decoding iteration is finished, so as to obtain new channel initial information and transmit the new channel initial information to the LDPC code decoding unit.
A working method of a system based on low-code-rate LDPC code interference information filling comprises the following steps:
the method comprises the following steps: and a repetition diversity unit of the sending end repeatedly generates a plurality of copies according to the coding result of the LDPC code coding unit, the copies are sent to the modulation unit in a parallel-to-serial manner, and after each copy is subjected to direct sequence spread spectrum, frequency hopping spread spectrum and up-conversion operation in the modulation unit, the same signal is transmitted to a channel through a plurality of different frequency hopping points.
Step two: after receiving the signal from the channel, the receiving end carries out demodulation processing, determines the frequency point interfered by the narrow-band noise, and transmits all demodulated signals to the diversity receiving unit.
Step three: the diversity receiving unit carries out serial-parallel conversion on the demodulation signals from the demodulation unit, divides the demodulation signals into a plurality of independent parallel demodulation signals, and combines and processes the parallel demodulation signals to enable the energy of the obtained useful signals to be maximum. And the combined signal is used as initial information of decoding and is transmitted to the LDPC code decoding unit and the information replacing unit at the same time.
Step four: during first iteration, the merged signal received by the LDPC code decoding unit is input into a decoder as initial information of a channel, and decoding initialization is performed through a minimum sum decoding algorithm.
Step five: when the iteration is performed for the (l-1) th time, the decoding hard decision information of the iteration is sent to the information replacement unit for the (l-1) th time; replacing the interference information of the frequency point load influenced by the narrow-band noise determined in the step two to obtain
Figure BDA0002954367100000021
Will be provided with
Figure BDA0002954367100000022
As initial information, the initial information is input to the decoding unit to participate in the first iteration decoding.
According to the decoding method of the LDPC code, in BPSK modulation under AWGN channel, the ith signal y received in decoding i Is shown in formula (1)
Figure BDA0002954367100000031
Wherein the content of the first and second substances,
Figure BDA0002954367100000032
is the i-th signal y received i The initial information of (1); y is i For the received i-th signal P { x i ＝1|y i Is subjected to a signal y i In the case of (1), the probability that the transmitted signal is "1", P { x i ＝0|y i Is subjected to a signal y i The probability that the transmitted signal is "0"; sigma 2 Is the noise variance.
In the min-sum decoding algorithm, factor
Figure BDA0002954367100000033
If there is no effect on the iterative process, equation (1) is expressed as:
Figure BDA0002954367100000034
calculating the average value of the amplitude of the non-interference information in the initial information according to the combined signal input to the information replacement unit in the step three; the average value of the amplitude is multiplied by a correction factor to serve as the amplitude of the replacement information, and the amplitude calculation formula of the replacement information is shown as formula (3):
Figure BDA0002954367100000035
wherein the content of the first and second substances,
Figure BDA0002954367100000036
is the amplitude of the ith replacement information in the ith iteration, N is the number of initial information, M is the number of interference information,
Figure BDA0002954367100000037
is an initial set of information, L p_jam For the set of interference information, alpha is a correction factor,
Figure BDA0002954367100000038
is that
Figure BDA0002954367100000039
The amplitude of the kth element in (b).
The notation of the replacement information is as follows:
Figure BDA00029543671000000310
wherein the content of the first and second substances,
Figure BDA00029543671000000311
is the sign of the ith replacement information at the ith iteration,
Figure BDA00029543671000000312
is the symbol of the ith variable node hard decision information at the (l-1) th iteration.
Will be provided with
Figure BDA00029543671000000313
Inputting the initial information into a decoding unit to participate in the first iterative decoding until the maximum iterative decoding times or correct decoding is reached; and finishing decoding iteration and outputting hard decision information as a decoding result.
Further comprises the following steps: the system based on the low-code-rate LDPC code interference information filling is suitable for a communication system influenced by strong interference narrow-band noise, and the method based on the low-code-rate LDPC code interference information filling is used for realizing anti-interference covert communication under the influence of high-power strong interference noise through the steps from the first step to the fifth step, so that the reliability of the communication system is improved.
Has the beneficial effects that:
1. the invention discloses a system and a method for filling interference information based on a low-code-rate LDPC code, which can reduce the influence of high-power strong interference noise by means of iterative update among an LDPC code decoding unit, an information replacing unit and a diversity receiving unit and data diversity sending and receiving. In the iterative process, the information transmission method in the LDPC code decoding algorithm is fully utilized, the method of updating and replacing the interference information in the channel initial information is used for more accurate decoding, the LDPC code decoder is used for relatively more accurately and hard judging the information to replace the interference information under the influence of high-power strong interference noise, and finally accurate hidden transmission of the information under high interference is realized.
2. The invention discloses a system and a method for filling interference information based on low-code-rate LDPC codes, which are suitable for a communication system greatly influenced by strong interference narrowband noise.
Drawings
FIG. 1 is a block diagram of a low-code rate LDPC code anti-interference communication system.
Fig. 2 is a structural diagram of an anti-interference communication system filled with low-code-rate LDPC code auxiliary interference information.
Fig. 3 is a flow chart of filling code-assisted interference information of an anti-interference communication system filled with low-code-rate LDPC code-assisted interference information.
FIG. 4 is a graph of bit error rate curves of 1-way transmission, 10-way transmission and 10-way transmission of LDPC code with no interference and 30% symbol interference, and with code-aided interference information filling added.
Detailed Description
For a better understanding of the objects and advantages of the present invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings and examples.
Example 1:
as shown in fig. 2, the system for filling interference information based on a low-code-rate LDPC code disclosed in this embodiment includes an LDPC code encoding unit, a repetition diversity unit, a modulation unit, a demodulation unit, a diversity reception unit, an LDPC code decoding unit, and an information replacement unit.
The LDPC code coding unit is used for carrying out LDPC code coding on the information bits and transmitting the coded signals to the repeat diversity unit.
The repetition diversity unit is used for repeating a plurality of coded signal copies and transmitting the same signals to the modulation unit.
And the modulation unit is used for modulating the same signals to obtain modulated signals and sending the modulated signals to the receiving end through a channel.
The demodulation unit is used for sensing the signal frequency band interfered by the narrow-band noise on the frequency spectrum, demodulating the received signal to obtain a demodulated signal, and then transmitting the demodulated signal to the diversity receiving unit.
The diversity receiving unit is used for combining (including selecting and combining) the received multiple statistically independent demodulated fading signals, and then transmitting the combined signals as channel initial information to the LDPC code decoding unit and the information replacing unit.
The LDPC code decoding unit is used for finishing the LDPC decoding function of the receiving system and outputting a final decoding result. And meanwhile, the hard decision information of the variable node is transmitted to the information replacement unit during each decoding iteration.
And the information replacement unit is used for processing the hard decision information and the channel initial information of the variable node transmitted by the LDPC code decoding unit to replace and update the interference information after each decoding iteration is finished, so as to obtain new channel initial information and transmit the new channel initial information to the LDPC code decoding unit.
As shown in fig. 3, the working method of the system based on low-rate LDPC code interference information filling disclosed in this embodiment includes the following steps:
the method comprises the following steps: and a repetition diversity unit of the sending end repeatedly generates a plurality of copies according to the coding result of the LDPC code coding unit, the copies are sent to the modulation unit in a parallel-to-serial manner, and after each copy is subjected to direct sequence spread spectrum, frequency hopping spread spectrum and up-conversion operation in the modulation unit, the same signal is transmitted to a channel through a plurality of different frequency hopping points.
Step two: after receiving the signals from the channel, the receiving end carries out demodulation processing, determines the frequency point interfered by the narrow-band noise through spectrum sensing, and transmits all demodulated signals to the diversity receiving unit.
Step three: the diversity receiving unit carries out serial-parallel conversion on the demodulation signals from the demodulation unit, divides the demodulation signals into a plurality of independent parallel demodulation signals, combines the parallel demodulation signals, wherein the Maximum Ratio Combining (MRC) is used in the receiving and combining technology, and combines the plurality of parallel demodulation signals by using the Maximum Ratio Combining (MRC) to enable the energy of the obtained useful signals to be maximum. The resulting useful signal energy is maximized. And the combined signal is used as initial information of decoding and is transmitted to the LDPC code decoding unit and the information replacing unit at the same time.
Step four: during first iteration, the merged signal received by the LDPC code decoding unit is input into a decoder as initial information of a channel, and decoding initialization is performed through a minimum sum decoding algorithm.
Step five: when the iteration is performed for the (l-1) th time, the decoding hard decision information of the (l-1) th iteration is sent to an information replacement unit; replacing the interference information of the frequency point load interfered by the narrow-band noise determined in the step two to obtain
Figure BDA0002954367100000051
Will be provided with
Figure BDA0002954367100000052
As initial information, the initial information is input to the decoding unit to participate in the first iteration decoding.
According to the decoding method of the LDPC code, in BPSK modulation under AWGN channel, the ith signal y received in decoding i Is shown in formula (1)
Figure BDA0002954367100000053
Wherein the content of the first and second substances,
Figure BDA0002954367100000054
is the i-th received signal y i The initial information of (1); y is i For the received i-th signal P { x i ＝1|y i Is subjected to a signal y i In the case of (2), the probability that the transmitted signal is "1", P { x } i ＝0|y i Is subjected to a signal y i The probability that the transmitted signal is "0"; sigma 2 Is the noise variance.
In the min-sum decoding algorithm, factor
Figure BDA0002954367100000061
If there is no influence on the iterative process, equation (1) is expressed as:
Figure BDA0002954367100000062
the information replacement unit needs to judge the position of the interference information through spectrum sensing, and replaces the interference information at the corresponding position with the hard decision information calculated according to the variable node in the subsequent decoding iteration process, so that the influence of the interference information in the channel initial information on the decoding correctness is reduced. The specific implementation method comprises the following steps:
calculating the average value of the amplitude of the non-interference information in the initial information according to the combined signal input to the information replacement unit in the step three; the average value of the amplitude is multiplied by a correction factor to serve as the amplitude of the replacement information, and the amplitude calculation formula of the replacement information is shown as formula (3):
Figure BDA0002954367100000063
wherein the content of the first and second substances,
Figure BDA0002954367100000064
is the amplitude of the ith replacement information in the ith iteration, N is the number of initial information, M is the number of interference information,
Figure BDA0002954367100000065
is an initial set of information, L p_jam For the set of interference information, alpha is a correction factor,
Figure BDA0002954367100000066
is that
Figure BDA0002954367100000067
The amplitude of the kth element in (b).
The notation of the replacement information is as follows:
Figure BDA0002954367100000068
wherein the content of the first and second substances,
Figure BDA0002954367100000069
is the sign of the ith replacement information at the ith iteration,
Figure BDA00029543671000000610
is the symbol of the ith variable node hard decision information at the (l-1) th iteration.
Will be provided with
Figure BDA00029543671000000611
Inputting the initial information into a decoding unit to participate in the first iterative decoding until the maximum iterative decoding times or correct decoding is reached; ending decoding iteration, and outputting hard decision information as a decoding result;
in this embodiment, firstly, 30% of symbol interference is added to a channel in a BPSK communication system as narrowband noise interference, and bit error rate simulation is performed, where a bit error rate graph is as shown in fig. 4 ((2048, 1024) type LDPC +1 channel transmission +30% symbol interference + combined reactance curve), a repetition diversity unit and a diversity receiving unit are added on the basis of the communication system with the 30% strong symbol interference channel, that is, the system structure 1 (as shown in fig. 1) provided in this embodiment is adopted to perform bit error rate simulation, and a bit error rate graph is as shown in fig. 4 ((2048, 1024) type LDPC +10 channel transmission +30% symbol interference + combined reactance curve), as can be seen from the figure, the bit error rate performance of the 10 channel transmission communication system is greatly improved, and the coding gain is about improvement of 1.2db = ber 1e-4. An information replacement unit is added on the basis of the system structure 1, namely, the system structure (as shown in fig. 2) provided in the embodiment is adopted to perform bit error rate simulation, the bit error rate simulation is performed through the steps, and a bit error rate curve graph is shown as (type (2048, 1024) LDPC +10 channel transmission +30% symbolic interference + combined reactive curve + code-assisted interference information filling) in fig. 4.
Then, bit error rate performance simulation is performed on the BPSK communication system under an AWGN channel, in the simulation, bit error rate simulation of the BPSK modulation system without an LDPC code encoding and decoding unit is performed first, and after a bit error rate curve diagram is shown in fig. 4 (an ideal unencoded BPSK curve), LDPC code error rate simulation of the BPSK communication system (2048, 1024) under the AWGN channel is performed. In this simulation, an input signal is encoded (2048, 1024) by an LDPC code encoding unit, then modulated by a modulation unit, passed through an AWGN channel, demodulated, and sent to an LDPC code decoding unit, and the error rate graph is as shown in fig. 4 (model (2048, 1024) LDPC + interference-free curve). Then, the method is compared with a graph of adding 30% symbol interference bit error rate in a channel, namely a graph of ((2048, 1024) type LDPC +1 path transmission +30% symbol interference + combined reactance curve) as shown in FIG. 4. It can be known from the three curves in the figure that after passing through a (2048, 1024) LDPC code encoding system, the error rate performance is obviously improved, and under the condition that 30% strong symbol interference is added to a channel, the error rate performance of a communication system is rapidly deteriorated.
It can be seen from this comparison that, after adding the repetition diversity unit, the diversity receiving unit and the interference information replacing unit in the traditional BPSK communication system, the decoding performance can be effectively improved by the interference information filling and the low-bit-rate LDPC code.
The main content of the anti-interference communication system based on the low-code-rate LDPC code auxiliary interference information filling described above can effectively reduce the influence caused by narrow-band strong interference through the system structure provided by the embodiment of the invention, so that the received signal is replaced and updated, and the purpose of correct decoding is finally achieved. In practical application, some or all of the modules may be selected as needed to achieve the purpose of the solution of the embodiment. Through the above description of the embodiments, those skilled in the art can clearly understand the structure of the LDPC code assisted interference information filling system
The above detailed description is intended to illustrate the objects, aspects and advantages of the present invention, and it should be understood that the above detailed description is only exemplary of the present invention and is not intended to limit the scope of the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims (2)

1. A system based on low code rate LDPC code interference information filling is characterized in that: the method comprises the following steps: an LDPC code encoding unit, a repetition diversity unit, a modulation unit, a demodulation unit, a diversity receiving unit, an LDPC code decoding unit and an information replacing unit;
the LDPC code coding unit is used for carrying out LDPC code coding on the information bits and transmitting the coded signals to the repeat diversity unit;
the repetition diversity unit is used for repeating a plurality of coded signal copies and transmitting the same signals to the modulation unit;
the modulation unit is used for modulating a plurality of same signals to obtain modulated signals and sending the modulated signals to a receiving end through a channel;
the demodulation unit is used for sensing a signal frequency band interfered by narrow-band noise on a frequency spectrum, demodulating a received signal to obtain a demodulated signal, and then transmitting the demodulated signal to the diversity receiving unit;
the diversity receiving unit is used for combining a plurality of received demodulated fading signals which are independent in statistics, including selection and combination, and then transmitting the signals to the LDPC code decoding unit and the information replacing unit as channel initial information;
the LDPC decoding unit is used for completing the LDPC decoding function of the receiving system and outputting a final decoding result; meanwhile, hard decision information of the variable node is transmitted to the information replacement unit during each decoding iteration;
and the information replacement unit is used for processing the hard decision information and the channel initial information of the variable node transmitted by the LDPC code decoding unit to replace and update the interference information after each decoding iteration is finished, so as to obtain new channel initial information and transmit the new channel initial information to the LDPC code decoding unit.
2. A working method based on low code rate LDPC code interference information filling system is characterized in that: the method comprises the following steps:
the method comprises the following steps: a repetition diversity unit of a sending end repeatedly generates a plurality of copies of the coding result of the LDPC code coding unit, the copies are sent to a modulation unit in a parallel-to-serial mode, and after each copy is subjected to direct sequence spread spectrum, frequency hopping spread spectrum and up-conversion operation in the modulation unit, the same signal is transmitted to a channel through a plurality of different frequency hopping points;
step two: after receiving the signal from the channel, the receiving end carries out demodulation processing, determines the frequency point interfered by the narrow-band noise, and transmits all demodulated signals to the diversity receiving unit;
step three: the diversity receiving unit carries out serial-parallel conversion on the demodulation signals from the demodulation unit, divides the demodulation signals into a plurality of independent parallel demodulation signals, and combines and processes the parallel demodulation signals to enable the energy of the obtained useful signals to be maximum; the combined signal is used as initial information of decoding and is transmitted to an LDPC code decoding unit and an information replacing unit at the same time;
step four: during first iteration, the merged signal received by the LDPC code decoding unit is input into a decoder as initial information of a channel, and decoding initialization is carried out through a minimum sum decoding algorithm;
step five: when the iteration is performed for the (l-1) th time, the decoding hard decision information of the iteration is sent to the information replacement unit for the (l-1) th time; replacing the interference information of the frequency point load influenced by the narrow-band noise determined in the step two to obtain
Figure FDA0003863238700000011
Will be provided with
Figure FDA0003863238700000012
As initial information, inputting the initial information into a decoding unit to participate in the first iteration decoding;
according to the decoding method of the LDPC code, in BPSK modulation under AWGN channel, the ith signal y received in decoding i Initial information ofAs shown in formula (1)
Figure FDA0003863238700000021
Wherein the content of the first and second substances,
Figure FDA0003863238700000022
is the i-th received signal y i The initial information of (a); y is i For the received i-th signal P { x i ＝1|y i Is subjected to a signal y i In the case of (2), the probability that the transmitted signal is "1", P { x } i ＝0|y i Is subjected to a signal y i The probability that the transmitted signal is "0"; sigma 2 Is the variance of the noise;
in the min-sum decoding algorithm, factor
Figure FDA0003863238700000023
If there is no influence on the iterative process, equation (1) is expressed as:
Figure FDA0003863238700000024
calculating the average value of the amplitude of the non-interference information in the initial information according to the combined signal input to the information replacement unit in the third step; the average value of the amplitude is multiplied by a correction factor to serve as the amplitude of the replacement information, and the amplitude calculation formula of the replacement information is shown as formula (3):
Figure FDA0003863238700000025
wherein the content of the first and second substances,
Figure FDA0003863238700000026
is the amplitude of the ith replacement information in the ith iteration, N is the number of initial information, M is the number of interference information,
Figure FDA0003863238700000027
is an initial set of information, L p_jam For the set of interference information, alpha is a correction factor,
Figure FDA0003863238700000028
is that
Figure FDA0003863238700000029
The amplitude of the kth element in (1);
the notation of the replacement information is as follows:
Figure FDA00038632387000000210
wherein, the first and the second end of the pipe are connected with each other,
Figure FDA00038632387000000211
is the sign of the ith replacement information at the ith iteration,
Figure FDA00038632387000000212
is the symbol of the hard decision information of the ith variable node in the (l-1) th iteration;
will be provided with
Figure FDA00038632387000000213
Inputting the initial information into a decoding unit to participate in the first iterative decoding until the maximum iterative decoding times or correct decoding is reached; ending decoding iteration, and outputting hard decision information as a decoding result;
further comprises the following steps: the system based on the low-code-rate LDPC code interference information filling is suitable for a communication system influenced by strong interference narrowband noise, and through the method based on the low-code-rate LDPC code interference information filling in the steps from the first step to the fifth step, the anti-interference covert communication is realized under the influence of high-power strong interference noise, and the reliability of the communication system is improved.
CN202110223043.6A 2021-02-23 2021-02-26 System and method for filling interference information based on low-code-rate LDPC code Active CN113037298B (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN2021102127327 2021-02-23
CN202110212732 2021-02-23

Publications (2)

Publication Number Publication Date
CN113037298A CN113037298A (en) 2021-06-25
CN113037298B true CN113037298B (en) 2022-12-16

Family

ID=76464892

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202110223043.6A Active CN113037298B (en) 2021-02-23 2021-02-26 System and method for filling interference information based on low-code-rate LDPC code

Country Status (1)

Country Link
CN (1) CN113037298B (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115296777B (en) * 2022-08-04 2024-03-12 北京理工大学 Codeword feedback compensation anti-interference method based on LDPC channel coding
CN115426003B (en) * 2022-08-15 2023-09-26 北京理工大学 Code word diversity frequency hopping anti-interference method based on LDPC channel coding

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7421041B2 (en) * 2004-03-01 2008-09-02 Qualcomm, Incorporated Iterative channel and interference estimation and decoding
US8958490B2 (en) * 2009-12-31 2015-02-17 Allen LeRoy Limberg COFDM broadcasting with single-time retransmission of COFDM symbols
CN104301006B (en) * 2014-09-26 2016-05-04 西安空间无线电技术研究所 A kind of multichannel slow frequency hopping signal anti-interference process system
CN105429670A (en) * 2015-11-03 2016-03-23 大连理工大学 Digital communication method based on combination of DSSS dispreading operation and LDPC decoding
CN105763203B (en) * 2016-02-14 2020-04-24 广西大学 Multi-element LDPC code decoding method based on hard reliability information
CN105846827B (en) * 2016-03-17 2019-02-01 哈尔滨工程大学 Iterative joint message source and channel interpretation method based on arithmetic code and low density parity check code
CN108768409A (en) * 2018-06-06 2018-11-06 重庆邮电大学 A kind of LDPC interpretation methods based on normalization minimum value of optimization

Also Published As

Publication number Publication date
CN113037298A (en) 2021-06-25

Similar Documents

Publication Publication Date Title
CN101710850B (en) Convolution Turbo encoding method and device for realizing encoding method
CN101425871B (en) Multi-element error correcting code transmitting and receiving apparatus, data communication system and related method
CN113037298B (en) System and method for filling interference information based on low-code-rate LDPC code
KR20070079448A (en) Iterative detection and decoding receiver and method in multiple antenna system
CN1802796B (en) Communication method and apparatus for multi-user detection
CN103532663A (en) Frequency hopping fountain code system and transmission method thereof
CN107231158B (en) Polarization code iterative receiver, system and polarization code iterative decoding method
WO1997024850A1 (en) Method and apparatus for decoding an encoded signal
CN109981224B (en) Deep space communication channel coding and decoding system and method thereof
CN1306367A (en) Effective band width cascade connected lattice code modem and decording method
CN113315553B (en) Simple and convenient dirty paper coding method capable of approaching information theory limit
US6279132B1 (en) Concatenated error control method and system for a processing satellite uplink
CN101299746B (en) Method and device for mapping/de-mapping constellation as well as linear transformation constellation map
CN110061803B (en) Low-complexity polar code bit interleaving coding modulation method
CN113746597A (en) Bit-interleaved Turbo coding LoRa modulation method
Бойко et al. Transmission of control information in 5G broadband telecommunication systems
CN108880758A (en) The iterative receiver algorithm for design of difference chaotic bit weaving code modulation system
CN104135347B (en) Dirty paper coding and decoding method based on joint lattice forming technology in cognitive network
CN110601699B (en) Method for realizing code rate dynamic variable multi-element LDPC code
CN102882654B (en) Encoding constraint and probability calculation based encoding and decoding synchronization method
CN110336640B (en) Decoding method for LT code of short code length system
KR20060098030A (en) An apparatus and a method for transmission which encoding a message with spact-time turbo code using feedback bit in mobile communication system
CN114257342B (en) Coding and decoding method for dual-user multiple access system based on non-binary polarization code
JP4543479B2 (en) Communication system and method
CN113660064B (en) Multi-data packet-based joint two-dimensional interleaving coding method suitable for power line communication system

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant