Turbo coding and decoding method and system under interference channel
By using Turbo code to use Turbo code for interfering channels, including interleaving processing, component encoding and iterative decoding, the problem of poor transmission performance of Turbo code in the deleted channel is solved, and the transmission performance under the channel is significantly improved.
Patent Information
- Application Number
- CN202411534485.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-31
- Publication Date
- 2025-04-08
AI Technical Summary
In the deletion channel, interference of deletion and noise leads to a degradation of transmission performance of the Turbo code.
A Turbo encoding and decoding method under an interfering channel is adopted, including obtaining input information sequences and performing interleaving processing, generating encoding sequences through the first and second component encoders, performing BPSK modulation and inputting interference deletion channels, and decoding calculations using iterative decoding methods, and finally calculating the bit error rate and frame error rate.
Through improved encoding and decoding methods, the transmission performance of Turbo code under interference deletion channels is improved, and the bit error rate and frame error rate are reduced.
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Abstract
Description
Technical Field
[0001] The present application relates to the field of communication and information processing technology, and in particular to a Turbo coding method and system under interference channels. Background Art
[0002] Turbo codes are widely used in communication systems for their superior performance in low signal-to-noise ratio and high noise environments and their strong anti-fading and anti-interference capabilities. Turbo codes are a type of parallel cascade code that combines convolutional codes with pseudo-random interleavers. This combination not only achieves pseudo-random coding, but also has outstanding decoding performance. It uses a new decoding idea - iterative decoding. Computer simulation results show that on an additive white Gaussian noise memoryless channel (AWGN), under specific parameter conditions, the bit error rate of Turbo codes can reach a performance that is 0.7dB different from the Shannon theoretical limit. With the passage of time, Turbo's coding and decoding schemes have been greatly improved, enabling it to achieve excellent performance in different channel environments, which is why Turbo codes can be widely used in communication systems.
[0003] J.Hagenauer first studied and derived iterative decoding and obtained a soft-input and soft-output decoding algorithm. However, the existence of the internal interleaver makes its performance difficult to analyze. Therefore, in 1996, S.Benedetto and G.Montorsi et al. introduced the concept of uniform interleaving (UI), and used joint technology to give a BER joint performance upper bound for Turbo codes, and pointed out that a good interleaver exists. In 1998, through the study and comparison of various component codes, the RSC component code with excellent performance was discovered. LCPerez et al. also conducted further research and found that the free distance of the code can be increased by increasing the interleaving length and using primitive polynomials, thereby improving the performance of Turbo codes. These research results provide important references for the subsequent development of Turbo codes.
[0004] In their paper “Performance Analysis and Application of Turbo Codes in Slow Fading Channels” [J]. Space Electronics Technology, 2004(3):41-45, Sun Ningning et al. proposed a construction method for Turbo codes in fading channels based on the characteristics of slow fading channels. Experiments verified that Turbo codes can achieve near-limit performance in such channels and are suitable for application in slow fading channels. On this basis, Zhang Lei et al. compared the bit error rates of Turbo codes in Gaussian channels, Rayleigh fading channels, and Ricean channels in their paper “Bit Error Rate Performance Analysis of Turbo Codes in Several Different Channels” [J]. Journal of Tianjin Vocational and Technical Normal University, 2014, 24(02).
[0005] In the erasure channel, the interference of erasure and noise causes the Turbo code to have poor transmission performance. Summary of the invention
[0006] The embodiments of the present application provide a Turbo coding method and system in an interference channel, so as to solve the transmission performance problem of Turbo code caused by deletion and noise interference in the deletion channel.
[0007] The embodiment of the present application provides a Turbo coding method under an interference channel, including:
[0008] Acquire an input information sequence, and input the input information sequence into an interleaver;
[0009] Inputting the input information sequence and the output information sequence of the interleaver into a first component encoder and a second component encoder for encoding to generate a coded sequence;
[0010] Perform BPSK modulation on the generated code sequence;
[0011] inputting the modulated sequence into an interference cancellation channel;
[0012] Multiplexing the sequences output by the interference cancellation channel to generate two information sequences and two check sequences;
[0013] The two generated information sequences and two check sequences are input into a decoder, and an iterative decoding method is used to perform decoding calculations to output a decoding sequence;
[0014] Compare the decoded sequence with the information sequence and calculate the bit error rate BER and frame error rate FER.
[0015] Optionally, the first component encoder and the second component encoder have the same structure, wherein the basic code rate of the recursive convolutional code accounts for a set proportion, and the generating polynomial satisfies:
[0016]
[0017] Inputting the input information sequence and the output information sequence of the interleaver into the first component encoder and the second component encoder for encoding to generate a coded sequence comprises:
[0018] Input the input information sequence x to the first component encoder to output check bits y0-y5, and add a return-to-zero bit to the end of x so that the first component encoder is in a zero state after completing the encoding;
[0019] The output information sequence x' of the interleaver is input to the second component encoder to output the check bits y6~y 11, and append a return-to-zero bit to the tail of x', so that the second component encoder is in a zero state after completing the encoding;
[0020] The information bits, check bits and tail bits are input into the multiplexing module for puncturing and multiplexing to generate a coding sequence.
[0021] Optionally, the first component encoder and the second component encoder both include a plurality of sub-encoders, and the first component encoder and the second component encoder calculate the return-to-zero bit in an ending manner:
[0022] After encoding all the information bits, the values of the shift registers of the corresponding sub-encoders are encoded in sequence in the sub-encoders according to the specified feedback polynomial of the sub-encoders to reset the states of the corresponding sub-encoders to zero.
[0023] Optionally, inputting the modulated sequence into an interference cancellation channel includes:
[0024] Randomly interleave the modulated sequence according to the set interleaving length;
[0025] Inputting the interleaved sequence into a Gaussian channel;
[0026] The sequence generated by the Gaussian channel is randomly deinterleaved after the channel is deleted.
[0027] Optionally, the interleaver used for random deinterleaving is the same as the interleaver used for random interleaving.
[0028] Optionally, inputting the generated two information sequences and two check sequences into a decoder, and performing decoding calculation using an iterative decoding method includes:
[0029] An iterative decoding method is adopted, and both component decoders use the Max-Log-MAP decoding algorithm for calculation.
[0030] The embodiment of the present application further provides a Turbo coding system under interference channel, including a processor and a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, the steps of the Turbo coding method under interference channel are implemented as described above.
[0031] In terms of the encoder, the embodiment of the present application adopts the encoder structure under the CDMA2000 standard and makes corresponding improvements to obtain a coding method that is more suitable for an interference deletion channel, which is used to solve the problem that in the deletion channel, deletion and noise interference cause poor Turbo code transmission performance.
[0032] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:
[0034] Figure 1 The basic process diagram of the Turbo coding method under the interference channel of the embodiment of the present application is shown;
[0035] Figure 2 The structure of the Turbo coding method under the interference channel of the embodiment of the present application is shown;
[0036] Figure 3-4 The simulation results of the bit error rate and bit error rate of code 1 of the application example of this application transmitted under the Gaussian channel and the interference cancellation channel respectively;
[0037] Figure 5-6 The simulation results of the bit error rate and bit error rate of code 2 of the application example of this application transmitted under the Gaussian channel and the interference cancellation channel respectively;
[0038] Figure 7-8 The simulation results of the bit error rate and bit error rate of code 3 of the application example of this application transmitted under the Gaussian channel and the interference cancellation channel respectively;
[0039] Figure 9-10 The simulation results of the bit error rate and bit error rate of code 3 used as an example in the present application when transmitted under a Gaussian channel and an interference cancellation channel respectively. DETAILED DESCRIPTION
[0040] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.
[0041] The present application embodiment provides a Turbo coding method under interference channel, such as Figure 1 As shown, the following steps are included:
[0042] In step S101, an input information sequence is obtained and input into an interleaver. For example, an externally input information sequence x is input into an interleaver, and the output information bits are recorded as x'.
[0043] In step S102, the input information sequence and the output information sequence of the interleaver are respectively input into a first component encoder and a second component encoder for encoding to generate a coded sequence.
[0044] In some embodiments, Figure 2 As shown, the first component encoder and the second component encoder have the same structure, wherein the basic code rate of the recursive convolutional code accounts for a set proportion, for example, in some application examples, the basic code rate of the recursive convolutional code is one seventh, and the generating polynomial satisfies:
[0045]
[0046] Wherein, D represents a delay unit.
[0047] Inputting the input information sequence and the output information sequence of the interleaver into the first component encoder and the second component encoder for encoding to generate a coded sequence comprises:
[0048] The input information sequence x is input to the first component encoder to output check bits y0-y5, and a return-to-zero bit is added to the tail of x, so that the first component encoder is in a zero state after completing the encoding. In some embodiments, the first component encoder and the second component encoder each include a plurality of sub-encoders, and the first component encoder and the second component encoder use the end method to calculate the return-to-zero bit:
[0049] After encoding all information bits, the values of the shift registers of the corresponding sub-encoders are encoded in turn in the sub-encoders according to the specified feedback polynomial of the sub-encoders to reset the states of the corresponding sub-encoders to zero. Specifically, Figure 2 As shown, Figure 2 The values of the three shift registers of the above sub-encoder are represented by s0, s1 and s2 respectively, and the three bits used for the end are represented by t0, t1 and t2 respectively. According to the feedback polynomial of the sub-encoder, we can get t0 = s1 ⊕ s2, t1 = s1 ⊕ s2, t2 = s1 ⊕ s2. Sending t0, t1 and t2 to the above sub-encoder for encoding in sequence can return the state of the above sub-encoder to the zero state.
[0050] The output information sequence x' of the interleaver is input to the second component encoder to output the check bits y6~y 11 , and append a return-to-zero bit to the end of x', so that the second component encoder is in a zero state after completing the encoding. Based on the above example, Figure 2The values of the three shift registers of the sub-encoder below are represented by s0', s1' and s2' respectively, and the three bits used for the end are represented by t0', t1' and t2' respectively. According to the feedback polynomial of the sub-encoder, it can be obtained that t0'=s1'⊕s2', t1'=s1'⊕s2', t2'=s1'⊕s2'. t0', t1' and t2' are sent to the sub-encoder below for encoding in sequence, that is, the state of the sub-encoder below can be set to zero state.
[0051] The information bits, check bits and tail bits are input into the multiplexing module for puncturing and multiplexing to generate a coding sequence.
[0052] In step S103, the generated coding sequence is subjected to BPSK modulation.
[0053] In step S104, the modulated sequence is input into an interference cancellation channel. In some examples, inputting the modulated sequence into the interference cancellation channel includes:
[0054] Randomly interleave the modulated sequence according to a set interleaving length, for example, the interleaving length is the length of one frame;
[0055] Inputting the interleaved sequence into a Gaussian channel;
[0056] The sequence generated by the Gaussian channel is subjected to random deinterleaving after the channel is deleted. In a specific example, the interleaver used for random deinterleaving is the same as the interleaver used for random interleaving.
[0057] In step S105, the sequences output by the interference cancellation channel are multiplexed to generate two information sequences and two check sequences, for example, y1s, y2s, y1p and y2p respectively.
[0058] In step S106, the two generated information sequences and two check sequences are input into a decoder, and decoding calculations are performed using an iterative decoding method to output a decoded sequence.
[0059] In step S107, the decoded sequence is compared with the information sequence to calculate the bit error rate BER and the frame error rate FER.
[0060] In some embodiments, the two generated information sequences and two check sequences are input into a decoder, and the decoding calculation is performed using an iterative decoding method, including:
[0061] An iterative decoding method is adopted, and both component decoders use the Max-Log-MAP decoding algorithm for calculation.
[0062] The embodiment of the present application also provides a simulation example of a Turbo coding method under an interference channel.
[0063] The simulation experiment of the embodiment of the present application adopts the Turbo coding method for interference cancellation channel proposed in the present application, and simulates the bit error rate of Turbo code in interference channel environment for four different Turbo code types (as shown in Table 1). In the simulation experiment, the BPSK debugging mode is adopted, the multiplication factor is 0.75, the number of decoding iterations is 12 times, and the four Turbo codes are respectively transmitted through AWGN additive white Gaussian noise channel and interference cancellation channel.
[0064] Table 1
[0065]
[0066] Figure 3 and Figure 4 These are the simulation results of the bit error rate and bit error rate of code 1 transmitted in Gaussian channel and interference deletion channel respectively. Figure 3 and Figure 4 The horizontal axis represents the signal-to-noise ratio (dB). The vertical axis represents the frame error rate and the bit error rate. The curve marked with a star symbol represents the bit error rate BER, and the curve marked with a diamond symbol represents the frame error rate FER.
[0067] Figure 5 and Figure 6 It is the simulation result diagram of the bit error rate and bit error rate of code 2 transmitted in Gaussian channel and interference elimination channel respectively. Figure 7 and Figure 8 It is the simulation result diagram of the bit error rate and bit error rate of code 3 transmitted in Gaussian channel and interference elimination channel respectively. Fig. 9 and Fig.10 These are the simulation results of the bit error rate and bit error rate of code 4 transmitted in Gaussian channel and interference elimination channel respectively.
[0068] According to the simulation examples, the method of the present application targets the characteristics of the interference cancellation channel and the basic principles of Turbo code encoding and decoding. In terms of encoding, the encoder structure under the CDMA2000 standard is adopted, and corresponding improvements are made to make the basic code rate after component encoder encoding lower; in terms of decoding, an iterative decoding method is adopted, and the decoding algorithm of the two component decoders adopts the Max-Log-MAP algorithm, which relatively reduces the decoding complexity; compared with other methods, the Turbo code encoding and decoding method is more suitable for interference cancellation channels and has obvious improvements in performance.
[0069] The embodiment of the present application further provides a Turbo coding system under interference channel, including a processor and a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, the steps of the Turbo coding method under interference channel are implemented as described above.
[0070] It should be noted that in the various embodiments of the present application, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.
[0071] The serial numbers of the above-mentioned embodiments of the present application are for description only and do not represent the advantages or disadvantages of the embodiments.
[0072] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to execute the methods described in each embodiment of the present application.
[0073] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.
Claims
1. A Turbo coding method under an interference channel, characterized in that: include: Acquire an input information sequence, and input the input information sequence into an interleaver; Inputting the input information sequence and the output information sequence of the interleaver into a first component encoder and a second component encoder respectively for encoding to generate a coded sequence; Perform BPSK modulation on the generated code sequence; inputting the modulated sequence into an interference cancellation channel; Multiplexing the sequences output by the interference cancellation channel to generate two information sequences and two check sequences; The two generated information sequences and two check sequences are input into a decoder, and an iterative decoding method is used to perform decoding calculations to output a decoding sequence; Compare the decoded sequence with the information sequence and calculate the bit error rate BER and frame error rate FER.
2. The Turbo coding method under interference channel according to claim 1, characterized in that: The first component encoder and the second component encoder have the same structure, wherein the basic code rate of the recursive convolutional code accounts for a set proportion, and the generating polynomial satisfies: Inputting the input information sequence and the output information sequence of the interleaver into the first component encoder and the second component encoder for encoding to generate a coded sequence comprises: Input the input information sequence x to the first component encoder to output check bits y0-y5, and add a return-to-zero bit to the end of x so that the first component encoder is in a zero state after completing the encoding; The output information sequence x' of the interleaver is input to the second component encoder to output the check bits y6~y 11 , and append a return-to-zero bit to the tail of x', so that the second component encoder is in a zero state after completing the encoding; The information bits, check bits and tail bits are input into the multiplexing module for puncturing and multiplexing to generate a coding sequence.
3. The Turbo coding method under interference channel according to claim 2, characterized in that: The first component encoder and the second component encoder both include a plurality of sub-encoders. The first component encoder and the second component encoder use the ending method to calculate the return-to-zero bit: After encoding all the information bits, the values of the shift registers of the corresponding sub-encoders are encoded in sequence in the sub-encoders according to the specified feedback polynomial of the sub-encoders to reset the states of the corresponding sub-encoders to zero.
4. The Turbo coding method under interference channel according to claim 3, characterized in that: Inputting the modulated sequence into the interference cancellation channel includes: Randomly interleave the modulated sequence according to the set interleaving length; Inputting the interleaved sequence into a Gaussian channel; The sequence generated by the Gaussian channel is randomly deinterleaved after the channel is deleted.
5. The Turbo coding method under interference channel according to claim 4, characterized in that: The interleaver used for random deinterleaving is the same as the interleaver used for random interleaving.
6. The Turbo coding method under interference channel according to claim 3, characterized in that: The two generated information sequences and two check sequences are input into the decoder, and the decoding calculation using the iterative decoding method includes: An iterative decoding method is adopted, and both component decoders use the Max-Log-MAP decoding algorithm for calculation.
7. A Turbo coding system under interference channel, characterized in that: The method comprises a processor and a memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the steps of the Turbo coding method under an interference channel according to any one of claims 1 to 6 are implemented.