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CN117955601A - A symbol-level full-band mapping air-to-ground anti-interference method based on Turbo coding - Google Patents

A symbol-level full-band mapping air-to-ground anti-interference method based on Turbo coding Download PDF

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CN117955601A
CN117955601A CN202410122015.9A CN202410122015A CN117955601A CN 117955601 A CN117955601 A CN 117955601A CN 202410122015 A CN202410122015 A CN 202410122015A CN 117955601 A CN117955601 A CN 117955601A
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interference
symbol
coding
turbo
decoding
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张�浩
罗广文
张敬敏
潘高峰
张瑞
蒋强
张晨旭
杨浩敏
于秉天
成春彦
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Beijing Institute of Technology BIT
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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
    • H04L1/0064—Concatenated codes
    • H04L1/0066—Parallel concatenated codes
    • 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
    • H03M13/29—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 combining two or more codes or code structures, e.g. product codes, generalised product codes, concatenated codes, inner and outer codes
    • H03M13/2957—Turbo codes and decoding
    • 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
    • H04B1/713—Spread spectrum techniques using frequency hopping
    • H04B1/715—Interference-related aspects
    • 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
    • H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
    • H04L1/0002—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the transmission rate
    • H04L1/0003—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the transmission rate by switching between different modulation schemes
    • 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
    • H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
    • H04L1/0009—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the channel coding
    • 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
    • H04L1/0071—Use of interleaving
    • 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
    • H04B1/713—Spread spectrum techniques using frequency hopping
    • H04B1/715—Interference-related aspects
    • H04B2001/7152—Interference-related aspects with means for suppressing interference
    • 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
    • H04B1/713—Spread spectrum techniques using frequency hopping
    • H04B1/715—Interference-related aspects
    • H04B2001/7154—Interference-related aspects with means for preventing interference

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  • Engineering & Computer Science (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Signal Processing (AREA)
  • Quality & Reliability (AREA)
  • Physics & Mathematics (AREA)
  • Probability & Statistics with Applications (AREA)
  • Theoretical Computer Science (AREA)
  • Error Detection And Correction (AREA)

Abstract

本发明公开的一种基于Turbo编译码的符号级全频带映射空地抗干扰方法，属于抗干扰数字信号处理领域。本发明实现方法为：对长度为K的原始信息进行Turbo重复编码，采用高阶QAM调制将码字映射到QAM符号，通过符号级全频带映射将同源QAM符号均匀映射到各跳，将跳频信号发送至部分频带干扰信道或时域脉冲干扰信道。在接收端进行干扰检测，对受扰位进行置零处理，删除接收信号中的干扰。对置零后的信号进行解跳，经过解交织后合并各跳同源QAM符号，进行解映射和译码。接收端所接收样本中同一信息位产生的冗余必有未受干扰部分，在迭代译码过程中，利用编码码字之间的约束关系，未受扰位会辅助受扰位收敛至正确值，降低译码器输出译码结果误码率，提高抗干扰性能。

The invention discloses a method for anti-interference of space and ground based on symbol-level full-band mapping of Turbo coding, which belongs to the field of anti-interference digital signal processing. The implementation method of the invention is: Turbo repetition coding is performed on the original information with a length of K, high-order QAM modulation is used to map the codeword to the QAM symbol, the same source QAM symbol is evenly mapped to each hop through symbol-level full-band mapping, and the frequency hopping signal is sent to a partial band interference channel or a time domain pulse interference channel. Interference detection is performed at the receiving end, the disturbed bit is zeroed, and the interference in the received signal is deleted. The signal after zeroing is de-hopped, and the same source QAM symbols of each hop are merged after deinterleaving, and demapping and decoding are performed. The redundancy generated by the same information bit in the sample received by the receiving end must have an uninterrupted part. In the iterative decoding process, the constraint relationship between the coded codewords is used, and the uninterrupted bit will assist the disturbed bit to converge to the correct value, reduce the bit error rate of the decoding result output by the decoder, and improve the anti-interference performance.

Description

Symbol-level full-band mapping space-to-ground anti-interference method based on Turbo coding and decoding
Technical Field
The invention discloses a symbol-level full-band mapping space-to-ground anti-interference method based on Turbo coding, in particular relates to an anti-interference method through channel coding and symbol-level mapping, and belongs to the field of anti-interference digital signal processing.
Background
In an interference-free communication scenario, communication systems face a complex balance between interference-free capability and communication rate. Traditional frequency hopping spread spectrum (frequency hopping spread) and direct sequence spread spectrum (direct spread) technologies encounter a series of challenges in the air-ground cooperative combat scenario, especially under the requirement of realizing real-time intercommunication of the combat units. Frequency hopping spread spectrum communication systems combat interference and eavesdropping by frequently changing the carrier frequency or pattern during transmission, however, conventional frequency hopping systems exhibit relatively low information transmission rates due to limited frequency variation and limited length of the frequency hopping sequence.
Direct sequence spread spectrum spreads the spectrum by multiplying the signal with a high speed pseudo-random code, which results in a relatively large bandwidth per symbol, resulting in a reduction in the transmission rate. In an air-ground cooperative combat scene, the combat units need to communicate in real time and efficiently, so that the traditional anti-interference technology often has difficulty in meeting the high requirement on the communication rate.
In view of the foregoing, current anti-interference communication technologies face a challenge in that it is difficult to maintain a sufficient communication rate while pursuing anti-interference capability. Therefore, new communication technologies or improvements are urgently needed to realize efficient, high-speed, interference-free communication systems in air-ground cooperative combat scenarios.
Disclosure of Invention
In order to solve the problem of lower information transmission rate of a traditional frequency hopping anti-interference communication system under the space-to-ground cooperative scene, the invention aims to provide a symbol-level full-band mapping space-to-ground anti-interference method based on Turbo coding and decoding. Compared with the traditional frequency hopping spread spectrum system, the invention has the advantage of stronger anti-interference capability on the premise of equal information efficiency.
The aim of the invention is achieved by the following technical scheme.
The invention discloses a symbol-level full-band mapping space-earth anti-interference method based on Turbo coding, which is characterized in that original information with the length of K is subjected to Turbo repetition coding to obtain a low-code-rate coded Turbo codeword, the codeword is mapped to a QAM symbol by adopting high-order QAM modulation, the homologous QAM symbol is uniformly mapped to each hop by symbol-level full-band mapping, frequency hopping processing is carried out, a frequency hopping signal is obtained, and the frequency hopping signal is sent to a partial frequency band interference channel or a time domain pulse interference channel. And performing interference detection at a receiving end, performing zero-setting processing on a disturbed position, and reducing the influence of the interference on the subsequent demodulation and decoding performances of the receiver by deleting the interference in a received signal. And (3) carrying out de-hopping on the signal after zero setting, merging the homologous QAM symbols of each hop after de-interleaving, and carrying out de-mapping and decoding. The redundancy generated by the same information bit in the sample received by the receiving end is required to have an undisturbed part, so that in the iterative decoding process, the undisturbed bit can assist the disturbed bit to be converged to a correct value by utilizing the constraint relation between the encoded code words, the error rate of the decoding result output by the decoder is reduced, and the anti-interference performance of the communication system is improved.
The invention discloses a symbol-level full-band mapping space-to-ground anti-interference method based on Turbo coding, which comprises the following steps:
Step one: and determining the original information length K, the Turbo coding rate R c and the repetition coding frequency R of the anti-interference communication system, wherein the frequency hopping frequency number h and the repetition coding frequency R meet the requirement of h < R.
And step one, determining the original information length K and the Turbo coding code rate R c according to the channel state and the communication rate requirement of the anti-interference communication system. The repetition coding number r is flexibly set. The code rate of the channel code after repeated coding is as follows:
R＝Rc/r (1)
step two: and performing Turbo repetition coding on the original information with the length of K to obtain a low-code-rate coded Turbo codeword.
Step two the original information is expressed as u= [ u 1,u2,…,uK ]. And (3) performing Turbo repetition coding with the code rate of R c and the repetition number of R on the original information. Note that R c =1/l, the codeword after Turbo encoding is expressed as:
c＝[c1,c2,…,cK] (2)
wherein c j (j=1, 2, …, K) is a matrix of dimension r×l:
Step three: and performing high-order M-QAM mapping on the low-code rate Turbo code word repeatedly coded in the step to map the code word to a QAM symbol.
Performing high-order M-QAM mapping on the low-code rate Turbo codeword repeatedly encoded as in equation (2) (3), where m=log 2 M, and the mapped symbol is expressed as:
Wherein the method comprises the steps of As a matrix of dimensions r x 1:
all symbols in the same matrix s i are called as homologous QAM symbols, and are operated Representing an upward integer arithmetic operation on x.
Step four: the symbol-level full-band mapping is used for uniformly mapping the homologous QAM symbols to h frequency hopping frequency points of a frequency hopping system, so that the interference is fully dispersed at a receiving end, and the phenomenon that the homologous QAM symbols are all overlapped and interfered is avoided, and further, the subsequent demodulation and decoding performance is reduced.
The symbol-level full-band mapping in the fourth step is realized by an interleaver pi designed according to parameters (K, l, r, m, h). The length of the interleaver pi is Kxl x r/m, and the method is used for uniformly mapping r homologous QAM symbols onto h frequency hopping frequency points:
s′＝s(π) (6)
Where s' is the frequency hopping module input signal.
Step five: and step four, performing frequency hopping processing on the s' signal and obtaining a frequency hopping signal, and transmitting the frequency hopping signal to a partial frequency band interference channel or a time domain pulse interference channel.
Step six: and step five, receiving the signal transmitted in the step five, performing interference detection, performing zero-setting processing on the interfered position, and reducing the influence of the interference on the subsequent demodulation and decoding performances of the receiver by deleting the interference in the received signal.
And step six, interference detection is carried out, and whether interference exists and the interference position are judged according to the characteristics of the interference signals. Analyzing the received signal from the time-frequency domain, wherein for partial frequency band interference, the frequency domain shows that the amplitude of the received signal in the partial frequency band exceeds a preset interference judgment threshold value; for time domain impulse interference, the time domain is represented as that the amplitude of the received signal exceeds a preset interference judgment threshold value in a part of time period. And judging the interference position according to the judgment criterion, and carrying out zero-setting processing on the interfered position.
Step seven: and (3) de-hopping the signal after zero setting, and merging the receiving end homologous QAM symbols after de-interleaving.
Step eight: and D, demodulating and decoding the combined signals in the step seven, and utilizing the constraint relation among the encoded code words through an iterative decoding process, wherein the undisturbed bits can assist the disturbed bits to converge to a correct value, so that the error rate of a decoder is reduced, and the anti-interference performance of a communication system is improved.
Step eight the demodulator is in a soft input soft output mode. According to the maximum likelihood log ratio LLR algorithm, the demodulator soft output is:
Where r is the combined signal in step seven, b q is the bits in the corresponding symbol, and LLR (b q) is the soft information of the bits output by the demodulator.
The decoder adopts iterative decoding, and the iterative decoding criterion is shown in formula (8):
where y refers to the decoder input, and defines the log-likelihood ratio based on the mapping of the transmitting end u=1-2 x:
the above decoding criteria is reduced to a symbol decision form as shown in equation (10):
In the decoding iteration process, the soft information of the log likelihood ratio is interacted in an iteration manner among the component decoders; after the decoding iteration is finished, outputting a judgment result And comparing the error rate with the original information u to obtain the error rate of the anti-interference system.
Step nine: uniformly mapping the homologous QAM symbols to each frequency point to avoid the influence of interference on the homologous symbols; step six, detecting and zeroing the interference, and deleting the interference as much as possible before processing the received signal; and step seven, merging signals, overlapping the disturbed bit and the undisturbed bit, facilitating demodulation and decoding in the step eight, reducing the deterioration influence of residual interference on demodulation and decoding performance, and utilizing the constraint relation between coding code words, wherein the undisturbed bit can assist the disturbed bit to converge to a correct value, thereby reducing the error rate of a decoder and improving the anti-interference performance of a communication system.
The beneficial effects are that:
1. The invention discloses a symbol-level full-band mapping space anti-interference method based on Turbo coding, which adopts a low-code-rate channel coding anti-interference system and a high-order modulation demodulation method to realize decoupling of a frequency hopping frequency conversion rate and an information rate, breaks through the hardware limitation that the existing frequency hopping system is difficult to support the high information rate, and reduces the realization complexity of a radio frequency front end and an analog-digital conversion circuit.
2. The existing low-code-rate channel coding method has the problems of high hardware resource consumption and difficult realization, and cannot be applied to an anti-interference communication system. The symbol-level full-band mapping space-earth anti-interference method based on Turbo coding adopts the repeatedly coded Turbo code word, finishes low-code-rate coding with negligible complexity, realizes time diversity effect, fully breaks up interference to improve the anti-interference performance of a communication system, and can be applied to an anti-interference communication system platform with limited hardware resources.
3. The invention discloses a symbol-level full-band mapping space-earth anti-interference method based on Turbo coding, which adopts a symbol-level full-band mapping frequency hopping method to realize symbol-by-symbol frequency and time dual diversity, wherein the frequency diversity covers the whole frequency hopping bandwidth range, and the time diversity can span hundreds or even tens of thousands of symbol periods, so that the capacity of resisting high-power partial frequency band interference and burst pulse strong interference is improved.
Drawings
In order to more clearly illustrate the technical solution according to the invention, the drawings that are used in the invention will be briefly described below. The drawings in the following description are illustrative of certain embodiments of the invention and other drawings may be made by those skilled in the art without undue burden.
Fig. 1 is a signal processing flow diagram of an anti-interference system.
Fig. 2 is a block diagram of signal processing at the transmitting end and the receiving end.
Fig. 3 shows graphs of original information length k=240, turbo coding rate R c =1/7, repetition coding frequency r=15, frequency hopping frequency h=5, and decoder iteration frequency 8 times, and error rate under AWGN channel and scrambling condition.
Detailed Description
Example 1:
as shown in fig. 1 and fig. 2, the symbol-level full-band mapping space-to-ground anti-interference method based on Turbo coding disclosed in this embodiment includes the following steps:
Step one: and determining the original information length K, the Turbo coding rate R c and the repetition coding frequency R of the anti-interference communication system, wherein the frequency hopping frequency number h and the repetition coding frequency R meet the requirement of h < R.
And step one, determining the original information length K and the Turbo coding code rate R c according to the channel state and the communication rate requirement of the anti-interference communication system. The repetition coding number r is flexibly set. The code rate of the channel code after repeated coding is as follows:
R＝Rc/r (11)
step two: and performing Turbo repetition coding on the original information with the length of K to obtain a low-code-rate coded Turbo codeword.
Step two the original information is expressed as u= [ u 1,u2,…,uK ]. And (3) performing Turbo repetition coding with the code rate of R c and the repetition number of R on the original information. Note that R c =1/l, the codeword after Turbo encoding is expressed as:
c＝[c1,c2,…,cK] (12)
wherein c j (j=1, 2, …, K) is a matrix of dimension r×l:
Step three: and performing high-order M-QAM mapping on the low-code rate Turbo code word repeatedly coded in the step to map the code word to a QAM symbol.
Performing high-order M-QAM mapping on the low-code rate Turbo codeword repeatedly encoded as in equations (12) (13), where m=log 2 M, and the mapped symbol is expressed as:
Wherein the method comprises the steps of As a matrix of dimensions r x 1:
all symbols in the same matrix s i are called as homologous QAM symbols, and are operated Representing an upward integer arithmetic operation on x.
Step four: the symbol-level full-band mapping is used for uniformly mapping the homologous QAM symbols to h frequency hopping frequency points of a frequency hopping system, so that the interference is fully dispersed at a receiving end, and the phenomenon that the homologous QAM symbols are all overlapped and interfered is avoided, and further, the subsequent demodulation and decoding performance is reduced.
The symbol-level full-band mapping in the fourth step is realized by an interleaver pi designed according to parameters (K, l, r, m, h). The length of the interleaver pi is Kxl x r/m, and the method is used for uniformly mapping r homologous QAM symbols onto h frequency hopping frequency points:
s′＝s(π) (16)
Where s' is the frequency hopping module input signal.
Step five: and step four, performing frequency hopping processing on the s' signal and obtaining a frequency hopping signal, and transmitting the frequency hopping signal to a partial frequency band interference channel or a time domain pulse interference channel.
Step six: and step five, receiving the signal transmitted in the step five, performing interference detection, performing zero-setting processing on the interfered position, and reducing the influence of the interference on the subsequent demodulation and decoding performances of the receiver by deleting the interference in the received signal.
And step six, interference detection is carried out, and whether interference exists and the interference position are judged according to the characteristics of the interference signals. Analyzing the received signal from the time-frequency domain, wherein for partial frequency band interference, the frequency domain shows that the amplitude of the received signal in the partial frequency band exceeds a preset interference judgment threshold value; for time domain impulse interference, the time domain is represented as that the amplitude of the received signal exceeds a preset interference judgment threshold value in a part of time period. And judging the interference position according to the judgment criterion, and carrying out zero-setting processing on the interfered position.
Step seven: and (3) de-hopping the signal after zero setting, and merging the receiving end homologous QAM symbols after de-interleaving.
Step eight: and D, demodulating and decoding the combined signals in the step seven, and utilizing the constraint relation among the encoded code words through an iterative decoding process, wherein the undisturbed bits can assist the disturbed bits to converge to a correct value, so that the error rate of a decoder is reduced, and the anti-interference performance of a communication system is improved.
Step eight the demodulator is in a soft input soft output mode. According to the maximum likelihood log ratio LLR algorithm, the demodulator soft output is:
Where r is the combined signal in step seven, b q is the bits in the corresponding symbol, and LLR (b q) is the soft information of the bits output by the demodulator.
The decoder adopts iterative decoding, and the iterative decoding criterion is shown in formula (18):
where y refers to the decoder input, and defines the log-likelihood ratio based on the mapping of the transmitting end u=1-2 x:
the above decoding criteria is reduced to a symbol decision form as shown in equation (20):
In the decoding iteration process, the soft information of the log likelihood ratio is interacted in an iteration manner among the component decoders; after the decoding iteration is finished, outputting a judgment result And comparing the error rate with the original information u to obtain the error rate of the anti-interference system.
Step nine: uniformly mapping the homologous QAM symbols to each frequency point to avoid the influence of interference on the homologous symbols; step six, detecting and zeroing the interference, and deleting the interference as much as possible before processing the received signal; and step seven, merging signals, overlapping the disturbed bit and the undisturbed bit, facilitating demodulation and decoding in the step eight, reducing the deterioration influence of residual interference on demodulation and decoding performance, and utilizing the constraint relation between coding code words, wherein the undisturbed bit can assist the disturbed bit to converge to a correct value, thereby reducing the error rate of a decoder and improving the anti-interference performance of a communication system.
In the simulation of fig. 2, the set parameters are: original information length k=240, turbo coding rate R c =1/7, repetition coding number r=15, frequency hopping number h=5, and decoder iteration number 8. As can be seen from the observation image, the invention has stronger strong interference capability.
In the simulation of partial band interference, the interference bandwidth is 40%, the anti-interference system still has stronger error correction capability, and compared with the non-interference condition, the performance is only backed off by 2.4dB (@BER=1E-5). In the simulation of the time domain pulse interference, the interference duty ratio is 0.01, and the system has almost no performance loss.
What has been described above is the main content of the symbol-level full-band mapping space-to-ground anti-interference method based on Turbo coding. Through the simulation experiment, the anti-interference performance of the symbol-level full-band mapping space-to-ground anti-interference method based on the Turbo coding can be evaluated and compared.

Claims (7)

1.一种基于Turbo编译码的符号级全频带映射空地抗干扰方法，其特征在于：包括如下步骤，1. A method for space-to-ground anti-interference based on Turbo coding and decoding with symbol-level full-band mapping, characterized in that it comprises the following steps: 步骤一：确定抗干扰通信系统的原始信息长度K，Turbo编码码率Rc和重复编码次数r，跳频频点数h，跳频频点数h与重复编码次数r满足式h＜r；Step 1: Determine the original information length K, Turbo coding rate R c and the number of repetition coding r, the number of frequency hopping points h of the anti-interference communication system, and the number of frequency hopping points h and the number of repetition coding r satisfy the formula h＜r; 步骤二：对长度为K的原始信息进行Turbo重复编码，得到低码率编码的Turbo码字；Step 2: Turbo repetition encoding is performed on the original information of length K to obtain a low-code-rate encoded Turbo codeword; 步骤三：对步骤二重复编码的低码率Turbo码字进行高阶M-QAM映射将码字映射到QAM符号；Step 3: Perform high-order M-QAM mapping on the low-code-rate Turbo codeword repeatedly encoded in step 2 to map the codeword to a QAM symbol; 步骤四：通过符号级全频带映射将同源QAM符号均匀映射到跳频系统的h个跳频频点上，在接收端干扰被充分打散，避免同源QAM符号都被叠加干扰进而降低后续解调译码性能；Step 4: Use symbol-level full-band mapping to evenly map the same-source QAM symbols to the h frequency hopping points of the frequency hopping system. The interference at the receiving end is fully dispersed to avoid superimposing interference on the same-source QAM symbols, thereby reducing the subsequent demodulation and decoding performance. 步骤五：对步骤四所述s′信号进行跳频处理并得到跳频信号，将跳频信号发送至部分频带干扰信道或时域脉冲干扰信道；Step 5: Perform frequency hopping processing on the s′ signal in step 4 to obtain a frequency hopping signal, and send the frequency hopping signal to a partial frequency band interference channel or a time domain pulse interference channel; 步骤六：接收步骤五中发送的信号并进行干扰检测，并对受扰位进行置零处理，通过删除接收信号中的干扰来减小干扰对接收机后续解调、译码性能的影响；Step 6: Receive the signal sent in step 5 and perform interference detection, and set the disturbed bits to zero, thereby reducing the impact of interference on subsequent demodulation and decoding performance of the receiver by removing the interference in the received signal; 步骤七：对置零后的信号进行解跳，经过解交织后合并接收端同源QAM符号；Step 7: Deinterleave the signal after zeroing, and combine the same source QAM symbols at the receiving end after deinterleaving; 步骤八：对步骤七中合并后的信号进行解调和译码，通过迭代译码过程，利用编码码字之间的约束关系，未受扰位会辅助受扰位收敛至正确值；Step 8: Demodulate and decode the combined signal in step 7. Through the iterative decoding process, using the constraint relationship between the coded codewords, the undisturbed bits will assist the disturbed bits to converge to the correct value; 步骤九：步骤四将同源QAM符号均匀映射至各频点，避免同源符号均受干扰影响；步骤六对干扰进行检测和置零处理，在对接收信号进行处理前尽可能删除干扰；步骤七对信号进行合并，将受扰位和未受扰位叠加，通过步骤八中的解调和译码，降低残余干扰对解调和译码性能的恶化影响，利用编码码字之间的约束关系，未受扰位会辅助受扰位收敛至正确值，进而降低译码器的误码率，提高通信系统的抗干扰性能。Step nine: In step four, the same source QAM symbols are evenly mapped to each frequency point to avoid the same source symbols being affected by interference; in step six, the interference is detected and zeroed, and the interference is removed as much as possible before the received signal is processed; in step seven, the signal is merged, the disturbed bits and the undisturbed bits are superimposed, and the deterioration effect of residual interference on the demodulation and decoding performance is reduced through the demodulation and decoding in step eight. By using the constraint relationship between the coding codewords, the undisturbed bits will assist the disturbed bits to converge to the correct value, thereby reducing the bit error rate of the decoder and improving the anti-interference performance of the communication system. 2.如权利要求1所述的一种基于Turbo编译码的符号级全频带映射空地抗干扰方法，其特征在于：步骤一所述原始信息长度K和Turbo编码码率Rc根据抗干扰通信系统所处的信道状态与通信速率需求确定；重复编码次数r灵活设定；经重复编码后信道编码的码率为：2. A method for space-to-ground anti-interference based on Turbo coding and symbol-level full-band mapping as claimed in claim 1, characterized in that: the original information length K and Turbo coding rate R c in step 1 are determined according to the channel state and communication rate requirements of the anti-interference communication system; the number of repeated coding times r is flexibly set; the code rate of the channel coding after repeated coding is: R＝Rc/r (1)。R = R c /r (1). 3.如权利要求2所述的一种基于Turbo编译码的符号级全频带映射空地抗干扰方法，其特征在于：步骤二所述原始信息表示为u＝[u1,u2,…,uK]；对原始信息进行码率为Rc重复次数为r的Turbo重复编码；记Rc＝1/l，则进行Turbo编码后码字表示为：3. A method for space-to-ground anti-interference based on Turbo coding and symbol-level full-band mapping as claimed in claim 2, characterized in that: in step 2, the original information is represented as u=[u 1 ,u 2 ,…,u K ]; the original information is Turbo repetition coded with a code rate of R c and a repetition number of r; R c =1/1, then the codeword after Turbo coding is represented as: c＝[c1,c2,…,cK] (2)c＝[c 1 ,c 2 ,…,c K ] (2) 其中cj(j＝1,2,…,K)为一r×l维的矩阵：Where c j (j = 1, 2, ..., K) is an r × l-dimensional matrix: 4.如权利要求3所述的一种基于Turbo编译码的符号级全频带映射空地抗干扰方法，其特征在于：步骤三中，4. A method for space-to-ground anti-interference based on Turbo coding and decoding symbol-level full-band mapping as claimed in claim 3, characterized in that: in step 3, 对如式(2)(3)重复编码的低码率Turbo码字进行高阶M-QAM映射，记m＝log2M，则映射后符号表示为：The low-rate Turbo codewords repeatedly encoded as shown in equations (2) and (3) are mapped to high-order M-QAM, where m = log 2 M. The symbol representation after mapping is: 其中为r×1维的矩阵：in It is an r×1 dimensional matrix: 称同一矩阵si中的所有符号为同源QAM符号，运算表示对x进行向上取整数运算。All symbols in the same matrix si are called homologous QAM symbols. Indicates that x is rounded up to an integer. 5.如权利要求4所述的一种基于Turbo编译码的符号级全频带映射空地抗干扰方法，其特征在于：步骤四所述符号级全频带映射通过根据参数(K,l,r,m,h)设计的交织器π实现；交织器π的长度为K×l×r/m，且满足将r个同源QAM符号均匀映射到h个跳频频点上：5. A method for space-to-ground anti-interference based on Turbo coding and symbol-level full-band mapping as claimed in claim 4, characterized in that: the symbol-level full-band mapping in step 4 is realized by an interleaver π designed according to parameters (K, l, r, m, h); the length of the interleaver π is K×l×r/m, and satisfies the uniform mapping of r homologous QAM symbols to h frequency hopping frequencies: s′＝s(π) (6)s′＝s(π) (6) 其中s′为跳频模块输入信号。Where s′ is the input signal of the frequency hopping module. 6.如权利要求5所述的一种基于Turbo编译码的符号级全频带映射空地抗干扰方法，其特征在于：步骤六所述干扰检测，根据干扰信号特征判定有无干扰以及干扰位置；从时频域分析接收信号，对于部分频带干扰，在频域上表现为部分频段上接收信号幅值超过预设干扰判定门限值；对于时域脉冲干扰，在时域上表现为部分时间段上接收信号幅值超过预设干扰判定门限值；根据上述判决准则判定干扰位置，并对受扰位进行置零处理。6. A symbol-level full-band mapping space-to-ground anti-interference method based on Turbo coding as described in claim 5 is characterized in that: the interference detection described in step six determines the presence or absence of interference and the interference position based on the characteristics of the interference signal; the received signal is analyzed from the time-frequency domain, and for partial frequency band interference, it is manifested in the frequency domain as the amplitude of the received signal in part of the frequency band exceeding the preset interference judgment threshold value; for time domain pulse interference, it is manifested in the time domain as the amplitude of the received signal in part of the time period exceeding the preset interference judgment threshold value; the interference position is determined according to the above-mentioned decision criteria, and the disturbed bit is set to zero. 7.如权利要求6所述的一种基于Turbo编译码的符号级全频带映射空地抗干扰方法，其特征在于：步骤八所述解调器为软输入软输出模式；根据最大似然对数比LLR算法，解调器软输出为：7. A method for space-to-ground anti-interference based on Turbo coding and symbol-level full-band mapping as claimed in claim 6, characterized in that: the demodulator in step 8 is in soft-input and soft-output mode; according to the maximum likelihood logarithm ratio (LLR) algorithm, the demodulator soft output is: 其中，r为步骤七中合并后的信号，bq为相应符号中的比特，LLR(bq)为解调器输出的该比特的软信息；Where r is the combined signal in step 7, bq is the bit in the corresponding symbol, and LLR( bq ) is the soft information of the bit output by the demodulator; 步骤八所述译码器采用迭代译码，迭代译码准则如公式(8)所示：The decoder in step 8 adopts iterative decoding, and the iterative decoding criterion is shown in formula (8): 其中，y指译码器输入，基于发送端u＝1-2x的映射，定义对数似然比：Where y refers to the decoder input, based on the mapping of u = 1-2x at the sender, the log-likelihood ratio is defined as: 上述译码准则被简化为如式(10)所示的符号判决形式：The above decoding criteria are simplified to the symbol decision form as shown in equation (10): 译码迭代过程中，对数似然比软信息在各分量译码器之间迭代交互；译码迭代结束后，输出判决结果并与原始信息u比较，得到抗干扰系统误码率。During the decoding iteration, the log-likelihood ratio soft information is iteratively interacted between the component decoders; after the decoding iteration is completed, the decision result is output And compare it with the original information u to get the bit error rate of the anti-interference system.
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