GMSK signal incoherent demodulation method and device

Abstract

The invention relates to a GMSK signal incoherent demodulation method and device. The method comprises the following steps: obtaining a state grid chart by utilizing multi-symbol detection; obtaining a matched filter according to the state grid chart; enabling the received baseband signal to pass through a matched filter to obtain a signal correlation value; obtaining a branch metric value of each state node in the baseband signal according to the signal correlation value; updating the path metric value of each state node according to the branch metric value; reserving a path corresponding to the maximum path metric value of each state node, and taking the path as a surviving path of each state node; and backtracking the survival path of each state node to obtain demodulation data of the baseband signal. According to the method provided by the invention, the state grid is obtained through multi-symbol detection, and multiple pieces of symbol information are combined, so that the problem of insufficient memory length in related technologies is solved, errors are prevented from spreading along the grid, and the error probability of symbol judgment during demodulation is reduced.

Description

Technical Field

[0001] The present disclosure relates to the field of communication technology, and in particular to a GMSK signal non-coherent demodulation method and device. Background Art

[0002] Gaussian Filtered Minimum Shift Keying (GMSK), a constant-envelope continuous phase modulation (CPM) technology, is widely used in GSM, Bluetooth, satellite communication, and other systems due to its high spectral efficiency and resistance to nonlinear distortion.

[0003] In related technologies, GMSK signal demodulation is divided into coherent and incoherent demodulation. Incoherent demodulation does not require carrier synchronization, resulting in a simpler receiver design and a wide range of applications. In related technologies, GMSK incoherent demodulation typically uses differential phase detection, but this suffers from a significant performance loss compared to coherent demodulation. While differential detection avoids carrier phase synchronization, it suffers from two drawbacks: first, the noise amplification effect: the differential operation converts additive noise into multiplicative noise, resulting in poor noise immunity and limited applicability. Second, insufficient memory length: the introduction of the GMSK Gaussian prefilter causes the energy of a single symbol to spread only to adjacent symbols, resulting in inherent inter-symbol interference (ISI). Since it only uses information from adjacent symbols, a single symbol error can lead to subsequent consecutive incorrect decisions. Differential demodulation only exploits correlation between adjacent symbols and cannot combat deep ISI. Furthermore, differential detection performance deteriorates as the length of the signal response increases. Summary of the Invention

[0004] In order to solve the above technical problems, the present disclosure provides a GMSK signal non-coherent demodulation method and device.

[0005] The present disclosure provides a GMSK signal non-coherent demodulation method, comprising: obtaining a state grid diagram using multi-symbol detection; obtaining a matched filter based on the state grid diagram; passing a received baseband signal through the matched filter to obtain a signal correlation value; obtaining a branch metric value of each state node in the baseband signal based on the signal correlation value; updating a path metric value of each state node based on the branch metric value; retaining a path corresponding to the maximum path metric value of each state node and using the path as a surviving path of each state node; and backtracing the surviving path of each state node to obtain demodulated data of the baseband signal.

[0006] Optionally, the state grid diagram obtained by using multi-symbol detection includes: setting the window length of the multi-symbol detection to N to obtain the state grid diagram, wherein, within the time interval (n-N+1)T≤t≤(n+1)T, the number of states of the state grid diagram is , the state of the above state grid diagram is , the input of the above state grid diagram is , the next moment state of the above state grid diagram is , L is the preset partial response length, n is a positive integer, is the symbol period.

[0007] Optionally, obtaining a matched filter according to the state grid diagram includes: obtaining a matched filter according to the state grid diagram and a phase response function of the GMSK signal Get the instantaneous phase ,in, ; According to the instantaneous phase Get the phase function in the time interval (n-N+1)T≤t≤(n+1)T ,in, , ; According to the above phase function Get the above matched filter ,in, , j is the imaginary unit.

[0008] Optionally, the above signal correlation value ,in, is the received baseband signal, and * indicates conjugation.

[0009] Optionally, the branch metric value is the complex envelope of the signal correlation value, and the branch metric value is .

[0010] Optionally, the branch metric value of each state node in the baseband signal obtained according to the signal correlation value includes: at each state node and Substitute into the branch metric values respectively In the above example, we get two branch metrics for each state node.

[0011] Optionally, after obtaining the survivor path of each state node, the method further includes: obtaining the survivor path value of each state node, and determining the minimum survivor path value among the survivor path values of each state node; and subtracting the above minimum survivor path value from the survivor path value of each state node.

[0012] Based on the same inventive concept, the present disclosure also provides a GMSK signal non-coherent demodulation device, including: a multi-symbol detection module, used to obtain a state grid diagram using multi-symbol detection; a first calculation module, used to obtain a matched filter based on the above-mentioned state grid diagram; a matched filtering module, used to pass the received baseband signal through the above-mentioned matched filter to obtain a signal correlation value; a second calculation module, used to obtain a branch metric value of each state node in the above-mentioned baseband signal based on the above-mentioned signal correlation value; a path update module, used to update the path metric value of each state node based on the above-mentioned branch metric value; a path selection module, used to retain the path corresponding to the maximum path metric value of each state node, and use the path as the surviving path of each state node; and a demodulation module, used to trace back the surviving path of each state node to obtain demodulated data of the above-mentioned baseband signal.

[0013] Based on the same inventive concept, the present disclosure also provides an electronic device, comprising: a processor; a memory for storing executable instructions; wherein the processor is used to read the executable instructions from the memory and execute the executable instructions to implement any one of the above methods.

[0014] Based on the same inventive concept, the present disclosure also provides a computer-readable storage medium on which a computer program is stored, characterized in that the above-mentioned storage medium stores a computer program, and when the above-mentioned computer program is executed by a processor, the processor implements any one of the above-mentioned methods.

[0015] The technical solution provided by the present disclosure has the following advantages over existing technologies: It provides a non-coherent demodulation method for GMSK signals that eliminates the need for carrier phase recovery and differential detection, improving noise immunity during signal demodulation. Furthermore, the method provided by the present disclosure utilizes multi-symbol detection to obtain a state grid, combining multiple symbol information, thereby resolving the problem of insufficient memory length in related technologies. Furthermore, errors in a single symbol can be compensated by other symbols within the multi-symbol detection window, preventing error propagation along the grid and reducing the probability of error in the decision regarding that symbol during demodulation. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present disclosure and, together with the description, serve to explain the principles of the present disclosure.

[0017] In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0018] Figure 1 A flowchart of a GMSK signal non-coherent demodulation method provided by an embodiment of the present disclosure; Figure 2 A flowchart of another GMSK signal non-coherent demodulation method provided by an embodiment of the present disclosure; Figure 3 A schematic diagram of simulation test results based on the method provided in an embodiment of the present disclosure; Figure 4 A schematic diagram of another simulation test result based on the method provided in an embodiment of the present disclosure; Figure 5 A schematic structural diagram of a GMSK signal non-coherent demodulation device provided in an embodiment of the present disclosure; Figure 6 A schematic diagram of the hardware structure of an electronic device provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0019] In order to more clearly understand the above-mentioned purposes, features and advantages of the embodiments of the present disclosure, the scheme of the embodiments of the present disclosure will be further described below. It should be noted that the embodiments of the present disclosure and the features therein can be combined with each other in the absence of conflict.

[0020] In the following description, many specific details are set forth to facilitate a full understanding of the embodiments of the present disclosure, but the embodiments of the present disclosure may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present disclosure, not all of the embodiments.

[0021] First, a brief introduction to GMSK signals is given. The following technical solutions related to the properties of GMSK signals in the embodiments of the present disclosure can be referenced here.

[0022] The general form of the baseband signal of the GMSK signal is as follows: 。

[0023] Where, It is a time-varying phase function, and the modulation information of the GMSK signal is carried on this function; is the symbol information vector to be sent, the elements in the vector The value is in {-1, +1}.

[0024] The expression is: .

[0025] in, is the modulation coefficient, is the symbol period, is the phase response function, hour, is the pulse shaping function The integral is: .

[0026] Where, is the partial response length of the signal, representing the pulse shaping function duration of the session.

[0027] For GMSK signals, is the response of the Gaussian filter to a rectangular pulse: .

[0028] in, is the 3dB bandwidth of the filter, BT is the normalized 3dB bandwidth of the Gaussian filter. Q(t) is the complementary cumulative distribution function, which is used to describe the shaping effect of the Gaussian filter on the rectangular pulse. The subtraction of the two terms Q(∙) in the expression is essentially to calculate the integral of the Gaussian distribution function in the time window [-T / 2, T / 2].

[0029] In time interval The phase function of the GMSK signal can be further expressed as: .

[0030] in, is the accumulated phase, indicating The constant part of the total additional phase in the interval, ; is the instantaneous phase, indicating The changing portion of the total additional phase within the interval.

[0031] The present disclosure provides a GMSK signal non-coherent demodulation method. Figure 1 As shown, including: S1. Use multi-symbol detection to obtain the state grid diagram.

[0032] S2. Obtain a matched filter according to the state grid diagram.

[0033] S3. Pass the received baseband signal through a matched filter to obtain a signal correlation value.

[0034] S4. Obtain a branch metric value of each state node in the baseband signal according to the signal correlation value.

[0035] S5. Update the path metric value of each state node according to the branch metric value.

[0036] S6. Keep the path corresponding to the maximum path metric value of each state node, and use the path as the surviving path of each state node.

[0037] S7. Trace back the surviving path of each state node to obtain the demodulated data of the baseband signal.

[0038] The disclosed embodiments provide a non-coherent demodulation method for GMSK signals that eliminates the need for carrier phase recovery and differential detection, thereby improving the noise immunity of signal demodulation. Furthermore, the disclosed embodiments utilize multi-symbol detection to obtain a state grid, combining multiple symbol information to address the issue of insufficient memory length in related technologies. Furthermore, errors in a single symbol can be compensated for by other symbols within the multi-symbol detection window, preventing the error from spreading along the grid and reducing the probability of error in the decision regarding that symbol during demodulation.

[0039] Specifically, the overall process of the method provided in the embodiment of the present disclosure is as follows: Figure 2 As shown, first, multi-symbol detection is used to obtain a state grid and a matched filter (S1 and S2 above), then the received signal is passed through the matched filter (S3 above), and then a non-coherent detection amount decision is performed (S4 above), and finally a Viterbi calculation method is performed (S5 to S7 above) to obtain demodulated data.

[0040] In some embodiments, the above S1 includes: The window length of multi-symbol detection is set to N to obtain a state grid diagram, where the number of states in the state grid diagram within the time interval (n-N+1)T≤t≤(n+1)T is , the current state of the state grid is , the input of the state grid diagram is , the next moment state of the state grid diagram is , the transmitted bit sequence associated with the instantaneous phase (i.e., used to obtain the instantaneous phase) is the sequence of the current state of the state grid diagram plus the input of the state grid diagram ,for , L is the preset partial response length, and n is a positive integer.

[0041] Specifically, multi-symbol detection can simultaneously detect multiple states in the state grid diagram through a window, such as the state sequence in the above embodiment, thereby solving the problem of insufficient memory length in related technologies. In addition, the error of a single symbol can be compensated by other symbols in the multi-symbol detection window, avoiding the error from spreading along the grid and reducing the probability of error in the judgment of the symbol during demodulation.

[0042] The partial response length L is the pulse shaping function The Gaussian pulse is theoretically infinite in length, but in practice it must be truncated to a finite length LT. That is, g(t) is a Gaussian pulse function within the time interval 0 ≤ t ≤ LT and takes the value 0 outside this interval. In practice, the partial response length L is a modulation parameter and requires a comprehensive evaluation of the BT value, performance, and complexity during modulation design. In a specific embodiment, under the GSM standard, L = 3 (BT = 0.3). The partial response length L is the same for both modulation and demodulation.

[0043] In some embodiments, the above S2 includes: S21, according to the state grid diagram and the phase response function of the GMSK signal Get the instantaneous phase ,in, .

[0044] S22, according to the instantaneous phase Get the phase function in the time interval (n-N+1)T≤t≤(n+1)T ,in, , .

[0045] S23, according to the phase function Get the matched filter ,in, , j is an imaginary unit. The function of the matched filter is The general form of the baseband signal The expression is similar because the matched filter needs to contain the waveforms of all possible baseband signals, so that the received baseband signal can pass through the matched filter. Specifically, the received signal and the matched filter Do multiply-accumulate.

[0046] Specifically, the phase function The calculation process refers to the following formula: .

[0047] In some embodiments, the signal correlation value ,in, is the received baseband signal, and * indicates conjugation.

[0048] In specific implementation, the above S3 includes: The received signal passes through a matched filter to obtain the correlation value between the received signal and all possible transmitted signal waveforms within the time interval (n-N+1)T≤t≤(n+1)T. The signal length used for correlation is the window length N, from which the above signal correlation value can be obtained.

[0049] In some embodiments, the branch metric value is the complex envelope of the signal correlation value, and the branch metric value is .

[0050] In some embodiments, the above S4 includes: At each state node, and Substitute into the branch metric values respectively In the above example, we get two branch metrics for each state node.

[0051] In specific implementation, at (n+1)T time, for each state node, there is an input and Two choices, whereby each state node can obtain incoherent branch metrics for the two branches entering the node.

[0052] In some embodiments, the above S5 includes: At time (n+1)T, the two branch metrics obtained for each state node are added to the surviving path value of each state node at time nT to obtain the two path metrics of each state node at time (n+1)T.

[0053] In some embodiments, the above S6 includes: Compare the two path metrics in each state node, retain the path corresponding to the maximum path metric, and discard the other paths. After each state node completes the above operations, there will be only one surviving path. Keep the surviving path and the corresponding path metric. The remembered path length is .

[0054] In some embodiments, after the above S6, the method provided by the embodiment of the present disclosure further includes: Obtain the survivor path value of each state node, determine the minimum survivor path value among the survivor path values of each state node, and subtract the minimum survivor path value from the survivor path value of each state node to avoid data overflow and achieve normalization.

[0055] In some embodiments, the above S7 includes: Repeat steps S4 to S6 for each symbol (each symbol includes a state node), After that, start outputting every time you pass a symbol The demodulated value before the symbol, then select the surviving path with the largest path metric, trace back the data saved by the path, and demodulate the The information at the moment returns to the beginning and continues the next cycle until all symbol sequences in the received signal complete the above steps and finally obtain the demodulated data.

[0056] The present disclosure also provides two simulation test results, such as Figure 3 and Figure 4 As shown, Figure 3 and Figure 4 The horizontal axis is Eb / N0, Eb represents the energy of each bit, N0 represents the noise power within the unit bandwidth, Eb / N0 represents the ratio of the energy of each bit to the noise power within the unit bandwidth, and the vertical axis is the bit error rate BER.

[0057] Figure 3 Simulated different observation windows The method provided by the embodiment of the present disclosure improves the non-coherent demodulation performance of the GMSK signal multi-symbol joint detection, wherein: , As can be seen from the figure, Performance ratio Better 1dB, and The performance of the demodulation is only 1 dB different from that of theoretical coherent demodulation. This is because the larger the window length, the more symbols and information can be used, the better the demodulation performance, and the better the noise suppression effect.

[0058] Figure 4 The anti-frequency deviation performance of the method provided by the embodiment of the present disclosure is simulated, wherein: , , As can be seen from the figure, less than The normalized frequency deviation has almost no effect on the demodulation performance of the method provided by the embodiment of the present disclosure.

[0059] It should be noted that the method of the embodiment of the present application can be performed by a single device, such as a computer or server. The method of this embodiment can also be applied in a distributed scenario, where multiple devices cooperate with each other to complete the method. In such a distributed scenario, one of the multiple devices may only perform one or more steps of the method of the embodiment of the present application, and the multiple devices will interact with each other to complete the above method.

[0060] It should be noted that the above description is limited to some embodiments of the present application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recited in the claims may be performed in an order different from that described in the above embodiments and still achieve the desired results. Furthermore, the processes depicted in the accompanying drawings do not necessarily require the specific order or sequential order shown to achieve the desired results. In certain embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0061] Based on the same inventive concept, corresponding to any of the above embodiments and methods, the present application also provides a GMSK signal non-coherent demodulation device, such as Figure 5 As shown, including: The multi-symbol detection module 10 is used to obtain a state grid diagram using multi-symbol detection.

[0062] The first calculation module 20 is configured to obtain a matched filter according to the state grid diagram.

[0063] The matched filtering module 30 is configured to pass the received baseband signal through a matched filter to obtain a signal correlation value.

[0064] The second calculation module 40 is configured to obtain a branch metric value of each state node in the baseband signal according to the signal correlation value.

[0065] The path updating module 50 is configured to update the path metric value of each state node according to the branch metric value.

[0066] The path selection module 60 is configured to retain the path corresponding to the maximum path metric value of each state node and use the path as the surviving path of each state node.

[0067] The demodulation module 70 is used to trace back the surviving path of each state node to obtain demodulated data of the baseband signal.

[0068] The disclosed embodiments provide a non-coherent demodulation device for GMSK signals that eliminates the need for carrier phase recovery and differential detection, thereby improving the noise immunity of signal demodulation. Furthermore, the disclosed embodiments utilize multi-symbol detection to obtain a state grid, combining multiple symbol information to address the issue of insufficient memory length in related technologies. Furthermore, errors in a single symbol can be compensated for by other symbols within the multi-symbol detection window, preventing the error from spreading along the grid and reducing the probability of error in the decision regarding that symbol during demodulation.

[0069] For the convenience of description, the above devices are described as being divided into various modules according to their functions. Of course, when implementing this application, the functions of each module can be implemented in the same or multiple software and / or hardware.

[0070] The apparatus of the above embodiment is used to implement the corresponding GMSK signal non-coherent demodulation method in any of the above embodiments, and has the beneficial effects of the corresponding method embodiment, which will not be described in detail here.

[0071] Figure 6 A schematic structural diagram of an electronic device provided by an embodiment of the present disclosure is shown.

[0072] like Figure 6As shown, the electronic device may include a processor 1101 and a memory 1102 storing computer program instructions.

[0073] Specifically, the processor 1101 may include a central processing unit (CPU), or an application specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits of the embodiments of the present application.

[0074] Memory 1102 may include a large-capacity memory for information or instructions. By way of example and not limitation, memory 1102 may include a hard disk drive (HDD), a floppy disk drive, flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a universal serial bus (USB) drive, or a combination of two or more of these. Where appropriate, memory 1102 may include removable or non-removable (or fixed) media. Where appropriate, memory 1102 may be internal or external to the integrated gateway device. In a specific embodiment, memory 1102 is a non-volatile solid-state memory. In a specific embodiment, memory 1102 includes a read-only memory (ROM). Where appropriate, the ROM may be a mask-programmed ROM, a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), an electrically alterable ROM (EAROM), or flash memory, or a combination of two or more of these.

[0075] The processor 1101 reads and executes the computer program instructions stored in the memory 1102 to perform the steps of the GMSK signal non-coherent demodulation method provided in the embodiment of the present disclosure.

[0076] In one example, the electronic device may further include a transceiver 1103 and a bus 1104. Figure 6 As shown, the processor 1101 , the memory 1102 and the transceiver 1103 are connected via a bus 1104 and communicate with each other.

[0077] The bus 1104 may include hardware, software, or both. By way of example, and not limitation, the bus may include an Accelerated Graphics Port (AGP) or other graphics bus, an Extended Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), a HyperTransport (HT) interconnect, an Industrial Standard Architecture (ISA) bus, an InfiniBand interconnect, a Low Pin Count (LPC) bus, a memory bus, a MicroChannel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a Video Electronics Standards Association Local Bus (VLB) bus, or other suitable buses, or a combination of two or more of these. Where appropriate, the bus 1104 may include one or more buses. Although embodiments herein describe and illustrate a particular bus, this application contemplates any suitable bus or interconnect.

[0078] The following is an embodiment of a computer-readable storage medium provided in an embodiment of the present disclosure. The computer-readable storage medium and the GMSK signal incoherent demodulation method of the above-mentioned embodiments belong to the same inventive concept. For details not fully described in the embodiment of the computer-readable storage medium, please refer to the embodiment of the above-mentioned GMSK signal incoherent demodulation method.

[0079] This embodiment provides a storage medium containing computer-executable instructions. When the computer-executable instructions are executed by a computer processor, they are used to perform a GMSK signal non-coherent demodulation method.

[0080] Of course, the computer executable instructions of the storage medium provided by the embodiment of the present disclosure are not limited to the above method operations, but can also execute related operations in the GMSK signal non-coherent demodulation method provided by any embodiment of the present disclosure.

[0081] Through the above description of the embodiments, those skilled in the art will clearly understand that the present disclosure can be implemented using software and necessary general-purpose hardware. Of course, it can also be implemented using hardware, but in many cases the former is a more preferred embodiment. Based on this understanding, the technical solution of the present disclosure, or the portion that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as a computer floppy disk, read-only memory (ROM), random access memory (RAM), flash memory (FLASH), hard disk, or optical disk, and includes a number of instructions for enabling a computer cloud platform (which can be a personal computer, server, or network cloud platform, etc.) to execute the GMSK signal incoherent demodulation method provided by various embodiments of the present disclosure.

[0082] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprises a..." do not exclude the presence of other identical elements in the process, method, article or device that includes the above elements.

[0083] The foregoing are merely specific embodiments of the present disclosure, intended to enable those skilled in the art to understand and implement the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is not limited to the foregoing embodiments, but is intended to be construed in the broadest manner consistent with the principles and novel features disclosed herein.

Claims

1. A GMSK signal non-coherent demodulation method, characterized in that: include: The state grid diagram is obtained using multi-symbol detection; Obtaining a matched filter according to the state grid diagram; Passing the received baseband signal through the matched filter to obtain a signal correlation value; Obtaining a branch metric value of each state node in the baseband signal according to the signal correlation value; Update the path metric value of each state node according to the branch metric value; Keep the path corresponding to the maximum path metric value of each state node and use this path as the surviving path of each state node; The surviving path of each state node is traced back to obtain the demodulated data of the baseband signal.

2. The method according to claim 1, characterized in that The method of obtaining a state grid diagram by using multi-symbol detection includes: The state grid diagram is obtained by setting the window length of multi-symbol detection to N, wherein, within the time interval (n-N+1)T≤t≤(n+1)T, the number of states of the state grid diagram is , the current state of the state grid is , the input of the state grid diagram is , the next moment state of the state grid diagram is , the transmitted bit sequence for obtaining the instantaneous phase is the current state of the state grid diagram plus the input of the state grid diagram, which is , L is the preset partial response length, n is a positive integer, is the symbol period.

3. The method according to claim 2, characterized in that The step of obtaining a matched filter according to the state grid diagram comprises: According to the state grid diagram and the phase response function of the GMSK signal Get the instantaneous phase ,in, ; According to the instantaneous phase Get the phase function in the time interval (n-N+1)T≤t≤(n+1)T ,in, , ; According to the phase function Get the matched filter ,in, , j is the imaginary unit.

4. The method according to claim 3, characterized in that The signal correlation value ,in, is the received baseband signal, and * indicates conjugation.

5. The method according to claim 4, characterized in that The branch metric value is the complex envelope of the signal correlation value, and the branch metric value is .

6. The method according to claim 5, characterized in that Obtaining a branch metric value of each state node in the baseband signal according to the signal correlation value includes: At each state node, and Substitute into the branch metric values respectively In the above example, we get two branch metrics for each state node.

7. The method according to claim 1, characterized in that After obtaining the surviving path of each state node, it also includes: Obtaining the survivor path value of each state node, and determining the minimum survivor path value among the survivor path values of each state node; The minimum survivor path value is subtracted from the survivor path value of each state node.

8. A GMSK signal non-coherent demodulation device, characterized in that: include: A multi-symbol detection module, used for obtaining a state grid map by using multi-symbol detection; A first calculation module, configured to obtain a matched filter according to the state grid diagram; a matched filtering module, configured to pass the received baseband signal through the matched filter to obtain a signal correlation value; A second calculation module, configured to obtain a branch metric value of each state node in the baseband signal according to the signal correlation value; A path updating module, configured to update the path metric value of each state node according to the branch metric value; A path selection module is used to retain the path corresponding to the maximum path metric value of each state node and use this path as the surviving path of each state node; The demodulation module is used to trace back the surviving path of each state node to obtain demodulated data of the baseband signal.

9. An electronic device, characterized in that: include: processor; A memory for storing executable instructions; wherein the processor is used to read the executable instructions from the memory and execute the executable instructions to implement the method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: The storage medium stores a computer program, and when the computer program is executed by a processor, the processor implements the method according to any one of claims 1 to 7.

Images