A non-coherent GFSK demodulation method and apparatus based on the K-best algorithm

Abstract

This invention discloses a noncoherent GFSK demodulation method based on the K-best algorithm. It performs demodulation calculations on GFSK modulated signals using a multi-symbol maximum likelihood detection method. If the number of branches in the current demodulation calculation stage is greater than K, the demodulation value of stage k is calculated. Based on the demodulation values ​​of stages k-2, k-1, and k, and the received symbol value of stage k-1, a conjugate relation value is calculated. K is the preset number of branches to retain in each stage, k is the current demodulation calculation stage, and the conjugate relation value is the relationship between the received symbol value and the demodulation value of stage k-1. The similarity value between the received symbol value and the demodulation value of stage k-1 is calculated based on the conjugate relation value and the corresponding branch integrator value. The K branch demodulation values ​​with the highest similarity values ​​are retained. The demodulation values ​​of the next K branches are calculated based on the retained K branch demodulation values ​​until stage T demodulation calculations are completed. The maximum value among the K branch demodulation values ​​of stage T is selected as the final demodulation value, where T is the observation length of the multi-symbol maximum likelihood detection method.

Description

Technical Field

[0001] This invention relates to the field of communication technology, and specifically to an incoherent GFSK demodulation method and apparatus based on the K-best algorithm. Background Technology

[0002] GFSK (Gaussian Frequency Shift Keying) is a widely used modulation method. Its advantages include constant envelope transmission, which can effectively resist nonlinear distortion of RF power amplifiers. At the same time, the Gaussian filter brings high frequency bandwidth utilization. It is widely used in low data rate and low cost personal wireless audio / video transmission systems and modern communication devices (such as Bluetooth).

[0003] Traditional techniques for demodulating GFSK modulated signals include coherent and non-coherent demodulation, but these techniques all have some problems, such as...

[0004] Coherent demodulation can achieve the theoretical limit of demodulation performance, but it requires carrier recovery, which is more complex and may also require preamble overhead.

[0005] Noncoherent demodulation does not require carrier recovery and can achieve optimal performance. It is usually based on the maximum likelihood detection method with multiple symbols, but it has extremely high complexity, huge computational load, poor anti-interference ability, and does not provide LLR (log-likelihood ratio) for subsequent error correction decoders. Summary of the Invention

[0006] Based on the above situation, the main objective of this invention is to provide a noncoherent GFSK demodulation method based on the K-best algorithm, which reduces the complexity of the demodulation algorithm, significantly reduces computing resources, enhances the anti-interference capability of the demodulation algorithm, improves demodulation performance, and extends the wireless range while achieving optimal performance.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A noncoherent GFSK demodulation method based on the K-best algorithm, the method comprising the following steps:

[0009] S10: Demodulate the received GFSK modulated signal based on the multi-symbol maximum likelihood detection method;

[0010] S20: If the number of branches in the current demodulation calculation stage is greater than K, the demodulation value of stage k is calculated based on the multi-symbol maximum likelihood detection method. Based on the demodulation values ​​of each branch of stage k-2, stage k-1, and stage k, and the received symbol value of stage k-1, the conjugate relation value of each branch is calculated. K is the preset number of reserved branches in each stage, k is the current demodulation calculation stage, and the conjugate relation value is the conjugate relation value between the received symbol value of stage k-1 and the demodulation value of stage k-1.

[0011] S30: Calculate the similarity value between the (k-1)th level received symbol value and the (k-1)th level demodulated value based on the conjugate relation value and the integral plate value of the corresponding branch;

[0012] S40: Retain the demodulation values ​​of the K branches with the highest similarity values, and delete the demodulation values ​​of the remaining branches;

[0013] S50: Continue executing step S20 based on the demodulation values ​​of the K branches retained to calculate the demodulation values ​​of the next level K branches, until the T-level demodulation calculation is completed. Select the maximum value among the demodulation values ​​of the K branches at level T as the final demodulation value output, where T is the observation length of the multi-symbol maximum likelihood detection method.

[0014] Preferably, step S20 includes the following steps:

[0015] S201: Convolve the demodulated signals of each branch of the (k-2), (k-1), and (k)th stages with the Gaussian filter;

[0016] S202: Select the intermediate value after convolution, accumulate it, and generate candidate values ​​for complex-form matched filtering;

[0017] S203: Multiply the candidate value of the complex form matched filter with the phase cumulative complex value of the previous branch, and then perform a conjugate multiplication with the received symbol value of the (k-1)th level to obtain the conjugate relation value.

[0018] Preferably, S30 specifically includes:

[0019] The conjugate relation value is summed with the integral plate value of the corresponding branch, and then the absolute value of the summed integral plate value is squared to obtain the similarity value.

[0020] Preferably, the method further includes step S60:

[0021] The demodulation bit probability information is calculated based on the similarity value of the T-level retained branch. This demodulation bit probability information is provided to the error correction decoder for decoding and error correction.

[0022] Preferably, the value of K is a positive integer greater than or equal to 2 and less than or equal to 16.

[0023] The present invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to implement the steps of the method according to any one of claims 1-5.

[0024] The present invention also provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the method according to any one of claims 1-5.

[0025] The present invention also provides a computer program product, including a computer program / instructions, which, when executed by a processor, implement the steps of the method according to any one of claims 1-5.

[0026] The present invention also provides an incoherent GFSK demodulation device based on the K-best algorithm, comprising a demodulation module, a conjugate relation calculation module, and a distance calculation module:

[0027] The demodulation module is used to perform demodulation calculations on the received GFSK modulated signal based on the multi-symbol maximum likelihood detection method;

[0028] The conjugate relation calculation module is used to calculate the demodulation value of level k based on the multi-symbol maximum likelihood detection method when the number of branches in the current demodulation calculation level is greater than K. It then calculates the conjugate relation value of each branch based on the demodulation values ​​of each branch in levels k-2, k-1, and k, as well as the received symbol value in level k-1. Here, K is the preset number of retained branches in each level, k is the current demodulation calculation level, and the conjugate relation value is the conjugate relation between the received symbol value and the demodulation value in level k-1.

[0029] The distance calculation module is used to calculate the similarity value between the (k-1)th level received symbol value and the (k-1)th level demodulated value based on the conjugate relation value and the integral plate value of the corresponding branch, and retain the demodulated values ​​of the K branches with the largest similarity values, and delete the demodulated values ​​of the remaining branches.

[0030] When the conjugate relation calculation module calculates to level T, the distance calculation module selects the maximum value among the demodulation values ​​of the K branches at level T as the final demodulation value output, where T is the observation length of the multi-symbol maximum likelihood detection method.

[0031] Preferably, the conjugate relation calculation module includes a convolution calculation unit, a candidate value calculation unit, and a conjugate relation value calculation unit:

[0032] The convolution calculation unit is used to perform convolution operations on the demodulated signals of each branch of the (k-2), (k-1) and (k)th levels with the Gaussian filter;

[0033] The candidate value calculation unit is used to select the intermediate value after convolution, accumulate it, and generate complex-form matched filter candidate values.

[0034] The conjugate relation value calculation unit is used to multiply the complex form matched filter candidate value with the phase cumulative complex value of the previous branch, and then perform a conjugate multiplication with the received symbol value of the (k-1)th level to obtain the conjugate relation value.

[0035] Preferably, the distance calculation module calculates the distance between the (k-1)th level received symbol value and the (k-1)th level demodulated value based on the conjugate relation value and the integral plate value of the corresponding branch, specifically as follows:

[0036] The conjugate relation value is summed with the integral plate value of the corresponding branch, and then the absolute value of the summed integral plate value is squared to obtain the similarity value.

[0037] Preferably, the device further includes an LLR calculation module:

[0038] The LLR calculation module is used to calculate demodulation bit probability information based on the similarity value of the T-level retained branch. The demodulation bit probability information is provided to the error correction decoder for decoding and error correction.

[0039] This scheme employs the K-best algorithm for branch pruning, retaining the K branches with the largest distance values, i.e., the most likely branches. Then, fission is performed on these K retained branches, followed by further branch pruning, retaining the K most likely branches, and so on, until the demodulation of the observation length T is calculated. Finally, the demodulated value with the largest distance value in the T-level demodulation is selected as the final demodulated value. This invention's non-coherent GFSK demodulation method based on the K-best algorithm achieves optimal performance while reducing the complexity of the demodulation algorithm, significantly reducing computational resources, enhancing the anti-interference capability of the demodulation algorithm, improving demodulation performance, and increasing the wireless range.

[0040] Other beneficial effects of the present invention will be explained in detail through the introduction of specific technical features and technical solutions in specific embodiments. Those skilled in the art should be able to understand the beneficial technical effects brought about by these technical features and technical solutions through the introduction of these technical features and technical solutions. Attached Figure Description

[0041] The preferred embodiments of the noncoherent GFSK demodulation method and apparatus based on the K-best algorithm of the present invention will be described below with reference to the accompanying drawings. In the figures:

[0042] Figure 1 A tree diagram showing the output signal of the GFSK demodulation method with multi-symbol differential detection in the prior art;

[0043] Figure 2 This is a flowchart of an incoherent GFSK demodulation method based on the K-best algorithm according to a preferred embodiment of the present invention;

[0044] Figure 3 This is a tree diagram illustrating the output signal of the GFSK demodulation method based on the present invention;

[0045] Figure 4 This is a flowchart illustrating the demodulation process according to a preferred embodiment of the present invention;

[0046] Figure 5 and Figure 6 A schematic diagram of the GFSK demodulation method of the present invention when K is 4;

[0047] Figure 7 A comparison chart of demodulation performance and limiting performance for different K values;

[0048] Figure 8 This is a block diagram of an incoherent GFSK demodulation device based on the K-best algorithm according to a preferred embodiment of the present invention. Detailed Implementation

[0049] The present invention is described below based on embodiments, but the present invention is not limited to these embodiments. In the following detailed description of the present invention, some specific details are described in detail, but well-known methods, processes, procedures, and elements are not described in detail in order to avoid obscuring the essence of the present invention.

[0050] Furthermore, those skilled in the art should understand that the accompanying drawings provided herein are for illustrative purposes only and are not necessarily drawn to scale.

[0051] Unless the context explicitly requires it, the words "comprising," "including," and similar terms throughout the specification and claims should be interpreted as encompassing rather than being exclusive or exhaustive; that is, meaning "including but not limited to."

[0052] In the description of this invention, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0053] This technical solution proposes a GFSK noncoherent demodulation method based on the K-best algorithm, which can achieve optimal performance (close to coherent demodulation performance) with extremely low complexity.

[0054] A simple GFSK modulator takes an input bitstream as (p1, p2, ...), with values ​​±1, and samples each bit M times. The sampled bitstream is then filtered by a Gaussian filter g. υ The instantaneous phase accumulation of the Gaussian filter output after convolution is expressed as:

[0055]

[0056] Where β is the modulation index and υ is the sampling point.

[0057] Finally, the baseband complex modulation signal is expressed as:

[0058]

[0059] Where j is expressed as n is a sequence of symbols.

[0060] Assuming the modulated signal is affected by additive noise, the baseband received signal can be expressed as:

[0061] r k =hs k +z k

[0062] Where h is the channel gain, z k It is additive white Gaussian noise, and k is the nth symbol.

[0063] Generally speaking, existing GFSK demodulators based on multi-symbol differential detection use a set of symbols for maximum likelihood detection, and the demodulator output is expressed as:

[0064]

[0065] in,

[0066] (1) T is the observation length, which is the number of symbols used;

[0067] (2) Θ is the set of all possible matched filters;

[0068] (3) For one possible matched filter signal, it is composed of ±1 of each branch in the figure. For example, the first branch s1, s2, and s3 in the figure are +1, +1, and +1 respectively; the second branch s1, s2, and s3 are +1, +1, and -1 respectively; ...; the eighth branch s1, s2, and s3 are -1, -1, and -1 respectively. These 8 modulation signals are multiplied by the conjugate of r1, r2, and r3 respectively to calculate the demodulation value of each branch according to the above formula.

[0069] (4) argmax represents a function whose output value is such that Maximum The value of is given by the expression above, and the output value of argmax is . It is a T×1 vector, representing the demodulated output of length T. For example, The demodulated values ​​may be the first branch s1, s2, and s3.

[0070] Theoretically, as T increases, the performance of a GFSK demodulator with multi-symbol differential detection should improve, but... Figure 1 The tree diagram shown also leads to a geometric increase in computing resources, which results in problems such as extremely high complexity, huge computational load, and poor anti-interference ability of existing non-coherent demodulation.

[0071] Figure 2 A preferred embodiment of the noncoherent GFSK demodulation method based on the K-best algorithm according to the present invention includes the following steps:

[0072] S10: Demodulation calculation of the received GFSK modulated signal based on the multi-symbol maximum likelihood detection method. This involves using the algorithm of the GFSK demodulator with multi-symbol differential detection described above to demodulate the received GFSK modulated signal.

[0073] S20: If the number of branches in the current demodulation calculation stage is greater than K, then the demodulation value of stage k is calculated based on the multi-symbol maximum likelihood detection method. Based on the demodulation values ​​of each branch in stages k-2, k-1, and k, and the received symbol value of stage k-1, the conjugate relation value of each branch is calculated. Here, K is the preset number of retained branches in each stage, k is the current demodulation calculation stage, and the conjugate relation value is the conjugate relation between the received symbol value of stage k-1 and the demodulation value of stage k-1. The received symbol value of stage k refers to the received baseband signal, i.e., r in the above formula. k .

[0074] S30: Calculate the similarity value between the received symbol value of the (k-1)th level and the demodulated value of the (k-1)th level based on the conjugate relation value and the integral plate value of the corresponding branch;

[0075] S40: Retain the demodulation values ​​of the K branches with the highest similarity values, and delete the demodulation values ​​of the remaining branches;

[0076] S50: Continue executing step S20 based on the demodulation values ​​of the K branches retained to calculate the demodulation values ​​of the next level K branches, until the T-level demodulation calculation is completed. Select the maximum value among the demodulation values ​​of the K branches at level T as the final demodulation value output, where T is the observation length of the multi-symbol maximum likelihood detection method.

[0077] The noncoherent GFSK demodulation method based on the K-best algorithm of this invention achieves optimal performance while reducing the complexity of the demodulation algorithm, significantly reducing computational resources, enhancing the anti-interference capability of the demodulation algorithm, improving demodulation performance, and extending the wireless range. Its principle is as follows: Figure 3 As shown, if K is 4 in the K-best algorithm, meaning 4 branches are retained at each level, then when the tree diagram reaches the third level (i.e., the third symbol), 8 branches have already been calculated. This scheme will then use the K-best algorithm to prune the branches, retaining the K branches with the highest similarity values, which are the most likely branches. Next, fission is performed on these K retained branches, and after fission, pruning continues, retaining the K most likely branches, and so on, until the demodulation of the observation length T is calculated. Finally, the demodulation value with the highest similarity value in the T-level demodulation is selected as the final demodulation value. For example, the final demodulation value might be the first branch s1, s2, s3…sK.

[0078] In a preferred embodiment, such as Figure 4 As shown, step S20 may include the following steps:

[0079] S201: Convolve the demodulated signals of each branch of the (k-2), (k-1), and (k)th stages with the Gaussian filter;

[0080] S202: Select the intermediate value after convolution, accumulate it, and generate candidate values ​​for complex-form matched filtering;

[0081] S203: Multiply the candidate value of the complex form matched filter with the phase cumulative complex value of the previous branch, and then perform a conjugate multiplication with the received symbol value of the (k-1)th level to obtain the conjugate relation value.

[0082] In a preferred embodiment, step S30 may specifically be: summing the conjugate relation value with the integral plate value of the corresponding branch, and then calculating the square of the absolute value of the summed integral plate value to obtain the similarity value.

[0083] Next, taking K=4 as an example, the technical solution of the present invention will be described by way of example.

[0084] like Figure 5 and 6 As shown, where, Figure 5 In the process, demodulation values ​​at levels 2, 3, and 4 of the tree diagram are selected. Convolve with a Gaussian filter, then select the median value of the convolution. Accumulate and generate a complex-form matched filter candidate value Exp(j*), then multiply it by the complex value of the phase accumulation from the previous branch, and finally multiply it by the corresponding intermediate received symbol r. k-1 Perform conjugate multiplication, and finally accumulate with the branch scoreboard.

[0085] like Figure 6 As shown, the absolute value of the integral board value of each branch is squared to obtain the similarity value. Then, the K branches with the highest similarity value (distance value) are retained, and the rest are pruned. Since K=4, each node has two integral board values, so there are 8 integral boards.

[0086] In a preferred embodiment, the value of K can be a positive integer greater than or equal to 2 and less than or equal to 16. Figure 7 This chart compares demodulation performance with the ultimate performance for different K values. As the chart shows, as K increases, the performance approaches the performance limit. When K = 16, the false alarm rate is around 10%, and the solution is only 0.5 dB away from the ultimate performance, which is very close. In the chart, PER represents the false alarm rate, and SNR represents the signal-to-noise ratio.

[0087] In a preferred embodiment, the GFSK demodulation method of the present invention may further include step S60: calculating demodulation bit probability information based on the distance value of the T-th reserved branch, wherein the demodulation bit probability information is provided to the error correction decoder for decoding and error correction.

[0088] In a specific implementation, the LLR value can be calculated using the following algorithm:

[0089]

[0090] Among them, E T It is represented by the Tth column (last column) of matrix E, which is used to record the cumulative distance value in the tree diagram.

[0091] The present invention also discloses a computer device, including a memory, a processor, and a computer program stored in the memory, wherein the processor executes the computer program to perform the steps of the method described in the present invention.

[0092] The present invention also discloses a computer program product, including a computer program / instructions, which, when executed by a processor, implement the steps of the method described in the present invention.

[0093] In addition, the present invention also provides a computer-readable storage medium, such as a chip or optical disc, on which a computer program is stored, wherein the computer program, when executed by a processor, implements the steps of the method described in the present invention.

[0094] It should be noted that the computer-readable storage medium described in the embodiments of this disclosure is not limited to the embodiments given above. For example, it can also be an electrical, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any combination thereof. More specific examples of computer-readable storage media may include, but are not limited to: electrical connections having one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fiber, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination thereof. In the embodiments of this disclosure, the computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in conjunction with an instruction execution system, apparatus, or device.

[0095] This invention also discloses a non-coherent GFSK demodulation device based on the K-best algorithm, such as... Figure 8 As shown, it includes a demodulation module, a conjugate relation calculation module, and a distance calculation module.

[0096] The demodulation module is used to perform demodulation calculations on the received GFSK modulated signal based on the multi-symbol maximum likelihood detection method; the conjugate relation calculation module is used to calculate the demodulation value of level k based on the multi-symbol maximum likelihood detection method when the number of branches in the current demodulation calculation level is greater than K, and calculate the conjugate relation value of each branch based on the demodulation values ​​of each branch of level k-2, level k-1, and level k, and the received symbol value of level k-1, where K is the preset number of retained branches in each level, k is the current demodulation calculation level, and the conjugate relation value is the value of the level k-2. The conjugate relation value between the received symbol value at level k-1 and the demodulated value at level k-1; the distance calculation module is used to calculate the distance value between the received symbol value at level k-1 and the demodulated value at level k-1 based on the conjugate relation value and the integral plate value of the corresponding branch, and retain the demodulated values ​​of the K branches with the largest distance values, and delete the demodulated values ​​of the remaining branches; when the conjugate relation calculation module calculates to level T, the distance calculation module selects the maximum value among the demodulated values ​​of the K branches at level T as the final demodulated value output, where T is the observation length of the multi-symbol maximum likelihood detection method.

[0097] In a preferred embodiment, the conjugate relation calculation module 20 includes a convolution calculation unit, a candidate value calculation unit, and a conjugate relation value calculation unit. The convolution calculation unit is used to perform convolution operations on the demodulated signals of each branch of the (k-2), (k-1), and (k)th stages with a Gaussian filter. The candidate value calculation unit is used to select the intermediate value after convolution, accumulate it, and generate a complex-form matched filter candidate value. The conjugate relation value calculation unit is used to multiply the complex-form matched filter candidate value with the phase accumulation complex value of the previous branch, and then perform a conjugate multiplication with the received symbol value of the (k-1)th stage to obtain the conjugate relation value.

[0098] In a preferred embodiment, the distance calculation module calculates the distance between the (k-1)th level received symbol value and the (k-1)th level demodulated value based on the conjugate relation value and the integral plate value of the corresponding branch. Specifically, the conjugate relation value and the integral plate value of the corresponding branch are summed, and then the absolute value of the summed integral plate value is squared to obtain the similarity value.

[0099] In a preferred embodiment, the apparatus further includes an LLR calculation module, which is used to calculate demodulation bit probability information based on the similarity value of the T-th retained branch. The demodulation bit probability information is provided to the error correction decoder for decoding and error correction.

[0100] It will be understood by those skilled in the art that the above-described preferred solutions can be freely combined and superimposed without conflict. The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this disclosure. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings; for example, two consecutively indicated blocks may actually be executed substantially in parallel, or sometimes in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions. The numbering of each step in this document is for ease of explanation and reference only and is not intended to limit the order of execution. The specific execution order is determined by the technology itself, and those skilled in the art can determine various permissible and reasonable orders based on the technology itself.

[0101] It should be noted that the use of step numbers (letters or numbers) to refer to certain specific method steps in this invention is merely for the purpose of convenience and brevity in description, and is by no means intended to restrict the order of these method steps. Those skilled in the art will understand that the order of the relevant method steps should be determined by the technology itself and should not be unduly restricted by the existence of step numbers. Those skilled in the art can determine various permissible and reasonable orderings of steps based on the technology itself.

[0102] Those skilled in the art will understand that, without conflict, the above-mentioned preferred solutions can be freely combined and superimposed.

[0103] It should be understood that the above embodiments are merely exemplary and not restrictive. Various obvious or equivalent modifications or substitutions that can be made by those skilled in the art regarding the above details without departing from the basic principles of the present invention will be included within the scope of the claims of the present invention.

Claims

1. A non-coherent GFSK demodulation method based on the K-best algorithm, characterized in that, The method includes the following steps: S10: Demodulate the received GFSK modulated signal based on the multi-symbol maximum likelihood detection method; S20: If the number of branches in the current demodulation calculation stage is greater than K, the demodulation value of stage k is calculated based on the multi-symbol maximum likelihood detection method. Based on the demodulation values ​​of each branch of stage k-2, stage k-1, and stage k, and the received symbol value of stage k-1, the conjugate relation value of each branch is calculated. K is the preset number of reserved branches in each stage, k is the current demodulation calculation stage, and the conjugate relation value is the conjugate relation value between the received symbol value of stage k-1 and the demodulation value of stage k-1. S30: Calculate the similarity value between the (k-1)th level received symbol value and the (k-1)th level demodulated value based on the conjugate relation value and the integral plate value of the corresponding branch; S40: Retain the demodulation values ​​of the K branches with the highest similarity values, and delete the demodulation values ​​of the remaining branches; S50: Continue executing step S20 based on the demodulation values ​​of the K branches retained to calculate the demodulation values ​​of the next level K branches, until the T-level demodulation calculation is completed. Select the maximum value among the demodulation values ​​of the K branches at level T as the final demodulation value output, where T is the observation length of the multi-symbol maximum likelihood detection method.

2. The incoherent GFSK demodulation method based on the K-best algorithm according to claim 1, characterized in that, S20 includes the following steps: S201: Convolve the demodulated signals of each branch of the (k-2), (k-1), and (k)th stages with the Gaussian filter; S202: Select the intermediate value after convolution, accumulate it, and generate candidate values ​​for complex-form matched filtering; S203: Multiply the candidate value of the complex form matched filter with the phase cumulative complex value of the previous branch, and then perform a conjugate multiplication with the received symbol value of the (k-1)th level to obtain the conjugate relation value.

3. The incoherent GFSK demodulation method based on the K-best algorithm according to claim 1, characterized in that, Specifically, S30 is: The conjugate relation value is summed with the integral plate value of the corresponding branch, and then the absolute value of the summed integral plate value is squared to obtain the similarity value.

4. The incoherent GFSK demodulation method based on the K-best algorithm according to claim 1, characterized in that, It also includes step S60: The demodulation bit probability information is calculated based on the similarity value of the T-level retained branch. This demodulation bit probability information is provided to the error correction decoder for decoding and error correction.

5. The incoherent GFSK demodulation method based on the K-best algorithm according to claim 1, characterized in that, The value of K is a positive integer greater than or equal to 2 and less than or equal to 16.

6. A computer device, comprising a memory, a processor, and a computer program stored in the memory, characterized in that, The processor executes the computer program to implement the steps of the method according to any one of claims 1-5.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1-5.

8. A computer program product comprising a computer program / instructions, characterized in that, When the computer program / instructions are executed by the processor, they implement the steps of the method according to any one of claims 1-5.

9. A non-coherent GFSK demodulation device based on the K-best algorithm, characterized in that, It includes a demodulation module, a conjugate relation calculation module, and a distance calculation module: The demodulation module is used to perform demodulation calculations on the received GFSK modulated signal based on the multi-symbol maximum likelihood detection method; The conjugate relation calculation module is used to calculate the demodulation value of level k based on the multi-symbol maximum likelihood detection method when the number of branches in the current demodulation calculation level is greater than K. It then calculates the conjugate relation value of each branch based on the demodulation values ​​of each branch in levels k-2, k-1, and k, as well as the received symbol value in level k-1. Here, K is the preset number of retained branches in each level, k is the current demodulation calculation level, and the conjugate relation value is the conjugate relation between the received symbol value and the demodulation value in level k-1. The distance calculation module is used to calculate the similarity value between the (k-1)th level received symbol value and the (k-1)th level demodulated value based on the conjugate relation value and the integral plate value of the corresponding branch, and retain the demodulated values ​​of the K branches with the largest similarity values, and delete the demodulated values ​​of the remaining branches. When the conjugate relation calculation module calculates to level T, the distance calculation module selects the maximum value among the demodulation values ​​of the K branches at level T as the final demodulation value output, where T is the observation length of the multi-symbol maximum likelihood detection method.

10. The incoherent GFSK demodulation device based on the K-best algorithm according to claim 9, characterized in that, The conjugate relation calculation module includes a convolution calculation unit, a candidate value calculation unit, and a conjugate relation value calculation unit: The convolution calculation unit is used to perform convolution operations on the demodulated signals of each branch of the (k-2), (k-1) and (k)th levels with the Gaussian filter; The candidate value calculation unit is used to select the intermediate value after convolution, accumulate it, and generate complex-form matched filter candidate values. The conjugate relation value calculation unit is used to multiply the complex form matched filter candidate value with the phase cumulative complex value of the previous branch, and then perform a conjugate multiplication with the received symbol value of the (k-1)th level to obtain the conjugate relation value.

11. The incoherent GFSK demodulation device based on the K-best algorithm according to claim 9, characterized in that, The distance calculation module calculates the distance between the (k-1)th level received symbol value and the (k-1)th level demodulated value based on the conjugate relation value and the integral plate value of the corresponding branch. Specifically, the distance calculation module calculates the distance between the (k-1)th level received symbol value and the (k-1)th level demodulated value as follows: The conjugate relation value is summed with the integral plate value of the corresponding branch, and then the absolute value of the summed integral plate value is squared to obtain the similarity value.

12. The incoherent GFSK demodulation device based on the K-best algorithm according to claim 9, characterized in that, The device also includes an LLR calculation module: The LLR calculation module is used to calculate demodulation bit probability information based on the similarity value of the T-level retained branch. The demodulation bit probability information is provided to the error correction decoder for decoding and error correction.

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