Information Sending Method, Device and Medium for Implementing High-Order Probability Shaping Modulation

Abstract

The present invention provides an information transmission method, a receiving method, an apparatus, and a storage medium for implementing high-order probability shaped modulation. The information transmission method comprises: inputting a received source sequence into an encoder for encoding, and outputting an encoded codeword sequence; performing bit sorting on the codeword sequence output by the forward error correction code encoder using an external binary flag sequence through a bit classification distribution matching operation to obtain a modified codeword sequence; mapping the modified codeword sequence to corresponding constellation points, wherein each m consecutive bits are mapped to a constellation point to obtain a modulation sequence; and transmitting the modulation sequence through an additive white Gaussian noise channel. Utilizing the above technical solution, shaping gain is generated by changing the probability distribution of channel input symbols without changing the complexity of the coded modulation system, thereby implementing high-order probability shaped modulation, reducing the bit error rate, and improving system performance.

Description

Technical Field

[0001] The present invention relates to the field of communication technologies, and particularly to a method for information transmission, a method for information reception, a device, and a storage medium for implementing high-order probability shaping modulation. Background Art

[0002] Under the background of global informatization, in order to meet the transmission requirements of users for low latency and high reliability, it is essential to combine channel coding with high-order modulation in a communication system. For traditional coding modulation systems, most channels use uniformly distributed constellations to map input symbols. Although this can maximize the source entropy, in an actual communication system, constellations with an equiprobable distribution will cause loss of mutual information and reduce the system performance. Summary of the Invention

[0003] Embodiments of the present invention provide a method for information transmission, a method for information reception, a device, and a storage medium for implementing high-order probability shaping modulation, so as to generate shaping gain by changing the probability distribution of channel input symbols without changing the complexity of the coding modulation system, thereby reducing the bit error rate and improving the system performance.

[0004] To achieve the above object, on the one hand, a method for transmitting information on a communication channel is provided, which is characterized by including:

[0005] S1, inputting the received source sequence into a forward error correction code encoder for encoding, and outputting an encoded codeword sequence;

[0006] S2, through bit classification distribution matching operation, using an external binary flag sequence with a length of L to select bits from the codeword sequence output by the forward error correction code encoder, and obtaining a changed codeword sequence; where flag[i] represents the flag at the i-th position in the external binary flag sequence, where 0 ≤ i < L, for 2 m -PAM mapping, m is a positive integer greater than 4; where the changed codeword sequence obtained through the bit classification distribution matching operation includes:

[0007] S21, identifying the flag, and judging whether i < L holds; if so, obtaining m bits of b0 to b through bit selection m-1 ; otherwise, taking out m bits from the codeword sequence output by the forward error correction code encoder in sequence for combination;

[0008] Among them, when i < L, the step of obtaining m bits of b0 to b through bit selection includes: m-1 When flag[i] = 1, let b

[0009] When flag[i] = 1, let b m-3=flag[i]=1, the valid bits of the remaining m-1 signal points are sequentially taken from the codeword sequence output by the forward error correction code encoder;

[0010] When flag[i]=0, let b m-3 = 0 and b m-2 =1, the valid bits of the remaining m-2 signal points are sequentially taken from the codeword sequence output by the forward error correction code encoder;

[0011] When flag[i] is empty, m bits are taken sequentially from the codeword sequence output by the forward error correction code encoder;

[0012] S22, combining all the bits obtained in step S21 sequentially to obtain a changed codeword sequence;

[0013] S3, mapping the changed codeword sequence to the corresponding constellation point, wherein each consecutive m bits are mapped to one constellation point to obtain a modulation sequence;

[0014] S4, transmit the modulated sequence through the additive white Gaussian noise channel.

[0015] Preferably, in the method, the external binary flag bit sequence is a pseudo-random binary flag bit sequence generated by a pseudo-random number generator.

[0016] Preferably, in the method, the received source sequence is a binary random sequence of Bernoulli distribution.

[0017] Preferably, in the method, the forward error correction coding is Polar code coding, and the forward error correction code encoder is a non-systematic polar encoder.

[0018] Preferably, in the method described above, m=5, in step S3, a 32-PAM modulation method based on Gray mapping is used to map each of the five consecutive bits in the changed codeword sequence to corresponding 32 constellation points to achieve the desired distribution of channel input symbols.

[0019] On the other hand, a method for receiving information is provided, for receiving, at a receiving end, information sent using any of the above-mentioned information sending methods for implementing high-order probability shaping modulation, comprising:

[0020] S5, demodulating the symbol LLR sequence received from the additive white Gaussian noise channel into a bit LLR sequence;

[0021] S6, using an external binary flag sequence to perform an inverse operation of the bit classification distribution matching operation on the demodulated bit LLR sequence, delete the redundant bits inserted in step S2, and generate a new bit LLR sequence;

[0022] S7: Input the new bit LLR sequence generated in step S6 into the SC decoder for decoding to obtain a source estimation sequence.

[0023] On the other hand, an information sending device is provided, including a memory and a processor, the memory storing at least one program, and the at least one program being executed by the processor to implement any of the methods for sending information on a communication channel as described above.

[0024] On the other hand, an information receiving device is provided, including a memory and a processor, the memory storing at least one program, and the at least one program being executed by the processor to implement any of the methods for receiving information on a communication channel as described above.

[0025] On the other hand, a communication system is provided, comprising: the information sending device as described above; and the information receiving device as described above.

[0026] On the other hand, a computer-readable storage medium is provided, wherein the storage medium stores at least one program, and the at least one program is executed by a processor to implement any of the methods described above.

[0027] The above technical solution has the following technical effects:

[0028] The technical solution of the embodiment of the present invention performs forward error correction coding modulation based on a determined bit classification distribution matching BCDM operation without changing the complexity of the coding modulation system, sets bit selection rules for the constellation symbols under Gray mapping, and uses an external flag sequence to perform bit selection and redundant bit insertion, so as to obtain a channel input symbol sequence with an ideal Gaussian distribution, obtain the shaping gain of the coding modulation system by changing the symbol probability, realize high-order probability shaping modulation, obtain a lower bit error rate, and improve the performance of the system; further, the technical solution of the embodiment of the present invention is applicable to probability shaping under any high-order modulation, has universality, and the amount of redundancy introduced by the BCDM operation does not increase with the increase of the order. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a block diagram of a polar coded modulation system model based on BCDM operation in one embodiment of the present invention;

[0030] Figure 2 32-PAM constellation mapping based on BCDM operation adopted in one embodiment of the present invention;

[0031] Figure 3a and Figure 3b is a probability distribution diagram of channel input symbols under different pseudo-random number sequence lengths in an embodiment of the present invention;

[0032] Figure 4 It is a comparison diagram of simulation results, which compares the simulation performance of the communication method of the embodiment of the present invention with the communication method of a symbol sequence with a traditional uniform distribution. Specific embodiments

[0033] To further illustrate each embodiment, the present invention provides accompanying drawings. These accompanying drawings are part of the disclosure of the present invention, which are mainly used to illustrate the embodiments and can be used to explain the operating principle of the embodiments in conjunction with the relevant descriptions in the specification. With reference to these contents, those of ordinary skill in the art should be able to understand other possible implementation manners and the advantages of the present invention. The components in the drawings are not drawn to scale, and similar component symbols are usually used to represent similar components.

[0034] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0035] Embodiment 1:

[0036] The information sending and receiving method according to an embodiment of the present invention changes the probability distribution of channel input symbols without changing the complexity of the coding and modulation system, and realizes high-order probability shaping modulation. Specifically, the method of this embodiment includes the following steps:

[0037] S1. Input the received source sequence into a forward error correction code encoder for encoding, and output an encoded codeword sequence;

[0038] S2. Through bit classification distribution matching (BCDM, Bit Classification Distribution Matching) operation, use an external binary flag sequence with a length of L to select bits from the codeword sequence output by the forward error correction code encoder to obtain a changed codeword sequence; where flag[i] represents the flag at the i-th position in the external binary flag sequence, where 0≤i<L, for 2 <000!007>-PAM mapping, m is a positive integer greater than 4; where obtaining the changed codeword sequence through bit classification distribution matching operation includes:

[0039] S21. Identify the flag and determine whether i<L holds; if so, obtain m bits of b0 to b through bit selection m-1 [[ID= ;30]]; otherwise, take out m bits of the codeword sequence output by the forward error correction code encoder in sequence for combination;

[0040] Among them, when i<L, the steps of obtaining m bits of b0 to b through bit selection include: m-1

[0041] When flag[i]=1, let bm-3 =flag[i]=1, the valid bits of the remaining m-1 signal points are sequentially taken from the codeword sequence output by the forward error correction code encoder;

[0042] When flag[i]=0, let b m-3 = 0 and b m-2 =1, the valid bits of the remaining m-2 signal points are sequentially taken from the codeword sequence output by the forward error correction code encoder;

[0043] When flag[i] is empty, m bits are taken sequentially from the codeword sequence output by the forward error correction code encoder;

[0044] S22, combining all the bits obtained in step S21 sequentially to obtain a changed codeword sequence;

[0045] S3, mapping the changed codeword sequence to the corresponding constellation point, wherein every m consecutive bits are mapped to one constellation point to obtain a modulation sequence;

[0046] S4, transmits the modulated sequence through the additive white Gaussian noise channel AWGN;

[0047] S5, demodulating the symbol LLR sequence received from the additive white Gaussian noise channel into a bit LLR sequence;

[0048] S6, using the external binary flag sequence to perform the inverse operation of the bit classification distribution matching operation on the demodulated bit LLR sequence, deleting the redundant bits inserted in step S2, and generating a new bit LLR sequence;

[0049] S7: Input the new bit LLR sequence generated in step S6 into the SC decoder for decoding to obtain a source estimation sequence.

[0050] Preferably, the external binary flag sequence is a pseudo-random binary flag sequence generated by a pseudo-random number generator. Preferably, the forward error correction code is a Polar code, and the forward error correction code encoder is a non-systematic polarization encoder. Preferably, the received source sequence is a binary random sequence of Bernoulli distribution, such as a Bernoulli binary source sequence with a success probability of 0.5. This embodiment of the present invention provides a high modulation order 2 based on BCDM operation. m-PAM generalized bit selection rule, m is greater than 4. Since a two-dimensional QAM signal can be obtained in an AWGN channel by orthogonally using two one-dimensional PAM signals, that is, two independent 32-PAM (pulse amplitude modulation) signals can be orthogonally obtained to obtain a 1024-QAM signal, and two independent 64-PAM signals can be used to form a 4096-QAM signal, and so on, this embodiment of the present invention describes high-order modulation of a one-dimensional PAM signal.

[0051] From this embodiment, it can be seen that the amount of redundancy introduced by the BCDM operation under high-order modulation does not increase with the increase of m, and meets all 2 m -Bit selection rules under PAM mapping, where m>4. Since two-dimensional QAM can be obtained by orthogonalizing two one-dimensional PAMs, 2 m -PAM mapping selection rules can be extended to 2 2m -Selection rules under QAM.

[0052] Example 2:

[0053] Polar codes are the first error-correcting codes with theoretically provable capacity. They are applicable to any binary input discrete memoryless channel and have low encoding and decoding complexity. In 2016, they were selected by the International Organization for Mobile Communications Standardization as the coding scheme for control channels in 5G communications. In a preferred embodiment of the present invention, m = 5, i.e., modulation is performed using 32-PAM mapping. This embodiment uses Polar codes as forward error correction (FEC) and 32-PAM mapping as modulation, and provides a generalized bit selection rule for higher modulation orders based on BCDM operations.

[0054] Figure 1 FIG. 1 is a block diagram of a polar coding modulation system model based on BCDM operation according to an embodiment of the present invention. Figure 1 In this preferred embodiment, at the transmitting end, a uniformly distributed Bernoulli source sequence is used. k is the length of the source sequence. First, the source sequence is encoded with Polar code, and the output codeword sequence is N is the length of the codeword sequence, Input the shaping code encoder and use BCDM operation to process it. Use the binary flag sequence of length N' generated by the pseudo-random number generator to perform bit selection and redundant bit insertion on the codeword sequence to change the symbol probability to obtain shaping gain. The output sequence after bit selection and redundant bit insertion is After passing through the 32-PAM modulator, the five consecutive bits are mapped into a 32-PAM symbol. Finally, the modulated signal after mapping is transmitted through the AWGN channel. After the modulated signal passes through the AWGN channel, the signal y = x + n is obtained, where x is the channel input information and n represents the mean of 0 and the variance of σ.2 At the receiving end, the signal or information output by the channel is first demodulated into bit LLRs using the Log-Likelihood Ratio (LLR). Figure 1 in Then, the same binary flag sequence is used to perform the inverse BCDM operation IBCDM to remove N' redundant bits in the bit LLR sequence to obtain the information sequence Final message sequence After decoding by the Polar code decoder, the estimated source bit sequence is obtained The coding modulation system can provide good bit protection capability, achieve low bit error rate and improve system performance.

[0055] In this embodiment, the 32-PAM modulator uses a 32-PAM modulation method based on Gray mapping to map five consecutive bits (x1x2x3x4x5) in the codeword sequence to corresponding 32 constellation points {±1, ±3, ±5, ±7, ±9, ±11, ±13, ±15, ±17, ±19, ±21, ±23, ±25, ±27, ±29, ±31} to achieve the desired distribution of channel input symbols. Figure 2 Schematic diagram of 32-PAM constellation mapping used in this embodiment.

[0056] In this embodiment, for 32-PAM mapping modulation, every five bits in a new sequence generated after bit selection and redundant bit insertion using a BCDM operation correspond to a constellation point, and elements used for every five bits in the new sequence are represented by b0 to b4. The steps of obtaining a changed codeword sequence by using the BCDM operation for bit selection and redundant bit insertion include the following:

[0057] Identify the flag bit and determine whether i < L, where L is the length of the external pseudo-random binary flag bit sequence and i is the flag bit at the i-th position in the flag bit sequence; if so, obtain 5 bits b0 to b4 through bit selection; otherwise, sequentially extract 5 bits from the codeword sequence output by the forward error correction code encoder and combine them; wherein the bit selection includes the following steps:

[0058] When the binary flag bit sequence flag[i]=1, let b2=flag[i]=1, and the valid bits of the remaining four signal points are from the code word sequence Take out in order;

[0059] When the binary flag bit sequence flag[i]=0, set b2=0, b3=1, and the valid bits of the remaining three signal points are from the code word sequence Take out in order;

[0060] When flag[i] is empty, the codeword sequence Five bits are sequentially taken out from the , and used to map into a PAM symbol;

[0061] Through the above bit selection step, 5 consecutive bits corresponding to the constellation points can be obtained. All the obtained bits are sequentially combined to obtain a changed codeword sequence.

[0062] Figure 3a and Figure 3b This is a probability distribution diagram of channel input symbols under different pseudo-random number sequence lengths, i.e., the lengths of the external pseudo-random binary flag bit sequence, using the method of an embodiment of the present invention; wherein, Figure 3a The corresponding pseudo-random number sequence length is 256. Figure 3b The corresponding pseudo-random number sequence length is 341. Therefore, it can be seen that the method of the embodiment of the present invention can map and generate transmission symbols with an ideal probability distribution by using a reproducible pseudo-random binary sequence and a set special bit selection rule to select bits, thereby achieving probability shaping and optimizing system performance.

[0063] Figure 4 This figure compares simulation results, comparing the performance of the communication method according to an embodiment of the present invention with that of a traditional communication method using uniformly distributed symbol sequences. The simulations were performed using 32-PAM high-order modulation and Polar code modulation, and performance is measured using the bit error rate (BER). Figure 4 The figure shows the comparison of system performance when the Polar code length is 2048, the code rate is 0.75, and the flag bit length L is 256 and 341 respectively. Figure 4 It can be seen that when the method of the embodiment of the present invention is used for communication, the system performance under 32-PAM modulation is better than the system performance under other equal probability constellation mappings. The simulation results prove the effectiveness of the modulation method based on BCDM operation in various forward error correction coding systems such as Polar coded modulation systems, and prove that the method of the embodiment of the present invention is applicable to all communication systems using forward error correction coding modulation.

[0064] Example 3:

[0065] The present invention also provides an information sending device, which includes a processor and a memory, and a computer program stored in the memory and runnable on the processor. When the processor executes the computer program, the steps of the above-mentioned method for sending information in an embodiment of the present invention are implemented.

[0066] Example 4:

[0067] The present invention also provides an information receiving device, which includes a processor and a memory, and a computer program stored in the memory and runnable on the processor. When the processor executes the computer program, the steps of the above-mentioned method for receiving information in an embodiment of the present invention are implemented.

[0068] Embodiment 5:

[0069] The present invention also provides a communication system, comprising the information sending device and information receiving device described above.

[0070] Furthermore, as an executable solution, the sending device or the receiving device may be a communication terminal, such as an intelligent communication terminal, such as a mobile phone.

[0071] Furthermore, as an executable solution, the processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or any conventional processor, etc. The processor is the control center of the computer unit and connects various parts of the entire computer unit using various interfaces and lines.

[0072] The memory can be used to store the computer programs and / or modules, and the processor implements the various functions of the computer unit by running or executing the computer programs and / or modules stored in the memory, and calling the data stored in the memory. The memory can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system and at least one application required for a function; the data storage area can store data created based on the use of the mobile phone, etc. In addition, the memory can include a high-speed random access memory, and can also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage device.

[0073] Example 6:

[0074] The present invention also provides a computer-readable storage medium, wherein the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above method in the embodiment of the present invention are implemented.

[0075] If the module / unit integrated in the computer unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the present invention implements all or part of the process in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium. When the computer program is executed by a processor, it can implement the steps of the above-mentioned various method embodiments. Among them, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, USB flash drive, mobile hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random access memory (RAM) and software distribution medium. It should be noted that the content contained in the computer-readable medium can be appropriately increased or decreased according to the requirements of legislation and patent practice in the jurisdiction.

[0076] Although the present invention has been particularly shown and described in conjunction with preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made to the present invention without departing from the spirit and scope of the invention as defined in the appended claims, and all such changes are within the scope of protection of the present invention.

Claims

1. A method for transmitting information to implement high-order probability shaping modulation, characterized in that: include: S1, input the received source sequence into the forward error correction code encoder for encoding, and output the encoded codeword sequence; S2. Through bit classification distribution matching operation, use an external binary flag bit sequence with length L to select bits from the codeword sequence output by the forward error correction code encoder to obtain a modified codeword sequence; where flag[i] represents the flag bit at the i-th position in the external binary flag bit sequence, where 0 ≤ i < L, for 2 m -PAM mapping, where m is a positive integer greater than 4; where obtaining the modified codeword sequence through the bit classification distribution matching operation includes: S21, an identification flag bit, determines whether i < L holds; if so, m bits of bits from b0 to b are obtained through bit selection; m-1 otherwise, m bits of bits are sequentially taken out from the codeword sequence output by the forward error correction code encoder for combination; Among them, when i < L, the steps of obtaining m bits of b0 to b m-1 include: When flag[i]=1, let b m-3 =flag[i]=1, and the valid bits of the remaining m-1 signal points are sequentially taken from the codeword sequence output by the forward error correction code encoder; When flag[i]=0, let b m-3 = 0 and b m-2 =1, the valid bits of the remaining m-2 signal points are sequentially taken from the codeword sequence output by the forward error correction code encoder; When flag[i] is empty, sequentially extract m bits from the codeword sequence output by the forward error correction code encoder; S22, combining all the bits obtained in step S21 sequentially to obtain a changed codeword sequence; S3, mapping the changed codeword sequence to corresponding constellation points, wherein each continuous m bits are mapped to one constellation point, to obtain a modulation sequence; S4, transmitting the modulation sequence through an additive white Gaussian noise channel.

2. The information sending method according to claim 1, wherein: The external binary flag bit sequence is a pseudo-random binary flag bit sequence generated by a pseudo-random number generator.

3. The information sending method according to claim 1, wherein: The received source sequence is a binary random sequence of Bernoulli distribution.

4. The information sending method according to claim 1, wherein: The forward error correction coding is Polar code coding, and the forward error correction code encoder is a non-systematic polar encoder.

5. The information sending method according to claim 1, wherein: m=5. In step S3, a 32-PAM modulation method based on Gray mapping is used to map each of the five consecutive bits in the changed codeword sequence to corresponding 32 constellation points to achieve the desired distribution of channel input symbols.

6. An information receiving method for receiving, at a receiving end, information sent using the information sending method for implementing high-order probability shaping modulation according to any one of claims 1 to 5, characterized in that: include: S5, demodulating the symbol LLR sequence received from the additive white Gaussian noise channel into a bit LLR sequence; S6, performing an inverse operation of the bit classification distribution matching operation on the demodulated bit LLR sequence using an external binary flag sequence, deleting the m bits obtained by bit selection in the changed codeword sequence obtained in step S2, and generating a new bit LLR sequence; S7: Input the new bit LLR sequence generated in step S6 into the SC decoder for decoding to obtain a source estimation sequence.

7. An information transmitting device for implementing high-order probability shaping modulation, characterized in that: The method comprises a memory and a processor, wherein the memory stores at least one program, and the at least one program is executed by the processor to implement the method according to any one of claims 1 to 5.

8. An information receiving device, characterized in that: The method comprises a memory and a processor, wherein the memory stores at least one program, and the at least one program is executed by the processor to implement the method according to claim 6.

9. A communication system, characterized in that: include: The information sending device according to claim 7; and, The information receiving device according to claim 8.

10. A computer-readable storage medium, characterized in that The storage medium stores at least one program, and the at least one program is executed by a processor to implement the method according to any one of claims 1 to 6.

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