Non-coherent demodulation method, device and equipment of SOQPSK-A signal and medium

Abstract

The application provides a non-coherent demodulation method, device and equipment of a SOQPSK-A signal and a medium, comprising: receiving a signal, and performing differential phase detection on the original signal after matched filtering through the relative phase difference between two adjacent modulation symbols; constructing an extended state transition grid in the differential phase space through a 3-bit differential Viterbi algorithm, calculating branch metrics according to the extended state transition grid, recursively updating path metric values according to the branch metrics of the current state and the path metrics of the previous state time to determine a surviving path, and obtaining an optimal path through Viterbi path search; and segmenting and backtracking demodulation is performed on the optimal path through an overlapping window backtracking mechanism to output a demodulation result. The application reduces the problem of inconsistent path directions caused by phase ambiguity of the window boundary in the backtracking process, and can realize real-time demodulation of a low-delay and high-performance SOQPSK-A signal.

Description

Technical Field

[0001] This application belongs to the field of wireless communication technology, and in particular relates to a noncoherent demodulation method, apparatus, device and medium for SOQPSK-A signals. Background Technology

[0002] SOQPSK-A is a type of continuous phase modulation (CPM) with constant envelope and high spectral efficiency. However, its demodulation faces the following challenges:

[0003] 1) Complex channels (such as multipath fading and Doppler frequency offset) make carrier synchronization difficult and severely degrade coherent demodulation performance;

[0004] 2) Traditional non-coherent detection methods, such as differential detection, have high bit error rates and poor performance, and multi-symbol joint detection is highly complex.

[0005] 3) The continuous phase characteristic of SOQPSK-A signals causes 0° / 180° ambiguity in their demodulation grid. If the Viterbi algorithm waits for the entire frame to end before backtracking, it introduces unacceptable delays in long frame transmissions, failing to meet the requirements of real-time systems. If backtracking is done in segments, adjacent segments may converge to different phase grids, leading to incorrect boundary symbol decisions. Differential coding can only solve global phase ambiguity and cannot handle random transitions between blocks. Summary of the Invention

[0006] In view of this, this application aims to provide a noncoherent demodulation method, apparatus, device and medium for SOQPSK-A signals to solve at least one of the above problems.

[0007] To achieve the above objectives, the technical solution of this application is implemented as follows:

[0008] In a first aspect, this application provides a noncoherent demodulation method for SOQPSK-A signals, including:

[0009] The signal is received, and differential phase detection is performed on the original signal after matched filtering by the relative phase difference between two adjacent modulation symbols.

[0010] An extended state transition grid is constructed in the differential phase space using a 3-bit differential Viterbi algorithm. The branch metric is calculated based on the extended state transition grid. The path metric is recursively updated based on the branch metric of the current state and the path metric of the previous state to determine the surviving path. The optimal path is obtained through Viterbi path search.

[0011] The optimal path is demodulated in segments using an overlapping window backtracking mechanism to output the demodulation result. The overlapping window backtracking mechanism forces adjacent windows to inherit the surviving state and metric at the starting point of the overlapping area, so that the entire demodulation process is locked on the same phase grid.

[0012] Secondly, based on the same inventive concept, this application also provides a noncoherent demodulation device for SOQPSK-A signals, comprising:

[0013] The phase detection module is configured to receive the signal and perform differential phase detection on the original signal after matched filtering by the relative phase difference between two adjacent modulation symbols.

[0014] The path search module is configured to construct an extended state transition grid in the differential phase space using a 3-bit differential Viterbi algorithm, calculate a branch metric based on the extended state transition grid, recursively update the path metric value based on the branch metric of the current state and the path metric of the previous state to determine the surviving path, and obtain the optimal path through Viterbi path search.

[0015] The backtracking demodulation module is configured to perform segmented backtracking demodulation on the optimal path through an overlapping window backtracking mechanism to output the demodulation result; wherein, the overlapping window backtracking mechanism is to force adjacent windows to inherit the surviving state and metric at the starting point of the overlapping area so that the entire demodulation process is locked on the same phase grid.

[0016] Thirdly, based on the same inventive concept, this application also provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the method described in the first aspect.

[0017] Fourthly, based on the same inventive concept, this application also provides a non-transitory computer-readable storage medium, wherein the non-transitory computer-readable storage medium stores computer instructions for causing the computer to perform the method as described in the first aspect.

[0018] Compared with the prior art, the noncoherent demodulation method, apparatus, device and medium for SOQPSK-A signals described in this application have the following advantages:

[0019] The method described in this application employs a noncoherent demodulation algorithm for SOQPSK-A signals that combines 3-bit phase difference Viterbi with overlapping window backtracking. It uses the phase difference between symbols as a reference, refines the phase state division, improves performance using a grid diagram, and reduces the problem of inconsistent path directions caused by phase ambiguity at the window boundary during backtracking by using overlapping window backtracking. This enables real-time demodulation of SOQPSK-A signals with low latency and high performance. Attached Figure Description

[0020] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0021] Figure 1 This is a flowchart of a noncoherent demodulation method for SOQPSK-A signals according to an embodiment of this application;

[0022] Figure 2 This is a demodulation performance curve of the phase differential Viterbi described in the embodiments of this application;

[0023] Figure 3 This is a frequency offset resistance curve of the noncoherent demodulation method for SOQPSK-A signals described in the embodiments of this application;

[0024] Figure 4 This is a schematic diagram of the noncoherent demodulation device for SOQPSK-A signals described in an embodiment of this application;

[0025] Figure 5 This is a schematic diagram of the hardware structure of the electronic device described in an embodiment of this application. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0027] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in the embodiments of this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0028] In this embodiment, the SOQPSK signal is a continuous phase modulation signal, belonging to the constrained ternary CPM system. The SOQPSK signal can generally be described using the definition of a continuous phase signal (CPM), and its mathematical expression is as follows:

[0029] ;

[0030] In the formula, Indicates time and transmission data sequence Changing complex baseband signal The imaginary unit (satisfying) ), Representing a symbol period Internal energy Represents the phase function:

[0031] ;

[0032] Among them, modulation index The first term in the above formula represents the relevant phase, and its value is determined by the current time. and the previous Data symbols The first term is jointly determined; the second term is the cumulative phase, the value of which depends on the current time. All remaining data symbols from before And the set of values ​​for the cumulative phase is . The phase pulse function is expressed as follows:

[0033] ;

[0034] In the formula, It is a frequency pulse function, which in It takes a non-zero value. This indicates the phase-correlation length, also known as the memory length; When the value is 1, it is called the full response signal. When the value is greater than 1, it is a partial response signal.

[0035] The phase pulse function is obtained by integrating the frequency pulse function. During the duration of the frequency pulse function, the integral of the SOQPSK signal waveform is 1 / 2, completing the process. Phase shift.

[0036] SOQPSK-A uses a raised cosine pulse shaping function, the expression of which is:

[0037] ;

[0038] In the formula, It is based on the roll-off factor of The time scale factor is The raised cosine function is constructed, where, For window functions. If there is no window function... The impulse function will have an infinite length in the time domain; therefore, using Limit the frequency pulse to a finite range; factor Used to normalize waveforms, ensuring that the phase shift caused by a single frequency pulse function is within the normal range. .

[0039] ;

[0040] In the formula, The normalized time width of the flat region of the window function. This represents the normalized time width of the cosine roll-off transition region.

[0041] The embodiments of this application are described in detail below with reference to the accompanying drawings.

[0042] Please see Figure 1 As shown, this embodiment provides a noncoherent demodulation method for SOQPSK-A signals, specifically including the following steps:

[0043] Step S101: Receive the signal and perform differential phase detection on the original signal after matched filtering by using the relative phase difference between two adjacent modulation symbols.

[0044] Specifically, in this embodiment, the original signal is received from the communication link. This original signal contains effects such as modulation, noise, and distortion. Matched filtering is performed based on the correlation between the received signal and the known symbol waveforms, which helps reduce the impact of noise and improve demodulation accuracy. This embodiment also analyzes the phase difference between adjacent symbols to recover the transmitted data, effectively reducing the impact of phase drift and enhancing noise immunity.

[0045] Step S102: Construct an extended state transition grid in the differential phase space using the 3-bit differential Viterbi algorithm, calculate the branch metric based on the extended state transition grid, recursively update the path metric value based on the branch metric of the current state and the path metric of the previous state to determine the surviving path, and obtain the optimal path through Viterbi path search.

[0046] Specifically, in this embodiment, Differential Phase Viterbi is a noncoherent detection technique for Continuous Phase Modulation (CPM). By combining differential phase with the Viterbi algorithm, it uses the relative phase difference between symbols rather than absolute phase information for signal detection. The path selection is optimized through the dynamic programming characteristics of the Viterbi algorithm, achieving efficient demodulation without the need for carrier synchronization.

[0047] Furthermore, this embodiment combines 3-bit phase difference with the Viterbi algorithm, which is achieved through extended state definition. That is, the state corresponding to the 3-bit phase difference is used as the extended state to construct an extended state transition grid, and then the Viterbi algorithm is applied to search for the optimal path in the extended state transition grid.

[0048] Given an input binary information bit sequence, for a 1-bit difference, the state expansion is as follows: The number of states becomes For 2-bit differential, the state expansion is as follows: The number of states becomes For 3-bit differential, the state expansion is as follows: The number of states becomes The 3-bit scheme increases the number of states, leading to increased computational complexity, but the expanded number of states remains within an acceptable range.

[0049] In the implementation of the Viterbi algorithm, a state space (i.e., a grid of states) needs to be constructed. Each state represents a possible symbol or path. These states are connected through transitions. The distance or error between each symbol state is calculated, and each branch is assigned a metric. The total metric of the path is updated by adding the metric of the current branch to the metric of each path (updating the path metric is to find the optimal path during the decoding process). At each time step, the path with the largest (or optimal) metric is selected based on the path metric and marked as the surviving path. The path with the largest metric continues to transmit the state information of that path until the entire symbol sequence is decoded.

[0050] Among them, the 3-bit differential phase Viterbi branch metric The calculation formula is:

[0051] ;

[0052] in, ,Right now For signal Rather than delay conjugate signal The product of these two phases eliminates the effect of absolute phase. Indicates time; Indicates the symbol period; This represents a possible transmission sequence, which is the actual transmission sequence. One of the candidates; Indicates an index; This indicates taking the real part of a complex number; The local waveform generated after expanding the mesh diagram can be represented as:

[0053] ;

[0054] in, Indicates the accumulated phase. For instantaneous phase, The imaginary unit (satisfying) ).

[0055] The 3-bit differential Viterbi algorithm in this embodiment constructs a grid state in the differential phase space and uses the Viterbi algorithm to achieve maximum likelihood sequence detection in a noisy background. By expanding the historical state memory, it improves noise resistance and suppresses error propagation. Figure 2 The demodulation performance curves for phase differential Viterbi are shown in the figure. As can be seen from the figure, under the same bit error rate (BER) target, the 3-bit phase differential has a gain of about 0.6~0.8dB compared to the 2-bit phase differential scheme. This means that to achieve the same BER, the 3-bit phase differential requires a lower signal-to-noise ratio.

[0056] Step S103: Perform segmented backtracking demodulation on the optimal path through the overlapping window backtracking mechanism to output the demodulation result; wherein, the overlapping window backtracking mechanism is to force adjacent windows to inherit the surviving state and metric at the starting point of the overlapping area so that the entire demodulation process is locked on the same phase grid.

[0057] Specifically, in this embodiment, during the demodulation process described above, if backtracking is delayed after all metrics have been calculated, the delay is too large. Furthermore, when using segmented backtracking, the phase ambiguity of the SOQPSK-A signal can cause segments to be either forward or reversed, leading to errors at segment boundaries. Therefore, this embodiment employs an overlapping window backtracking mechanism to address these issues, ensuring that the optimal path backtracked from adjacent data blocks (windows) remains continuous at the connection point, thus locking onto the same phase grid (whether forward or reversed) and avoiding phase jumps at boundaries. The specific operation is as follows:

[0058] Assuming the window length is The overlap length is ;

[0059] Process the first window (index 1 to When the window ends, the normal metric is calculated, and the time point from point 1 to point 2 within that window is backtracked. The path; process the next window (index) arrive When this happens, the key point is the initialization of the state: taking the state obtained at the end of the previous window backtracking... The survival state at any given moment and its cumulative metric, serving as the current window in The initial state and initial metric at time t; then from Initially, based on the received signal and the state / metric inherited from the previous window, continue calculating within the current window ( arrive The measure of ). When traversing back to the current window, the traversal range is usually from arrive That is, the latter half of the overlapping area and the first half of the new data in the current window.

[0060] Because the previous window is The surviving state at any given moment is deterministic (whether the phase is forward or backward). The current window inherits this state and metric. The metric calculation and backtracking of the current window are entirely based on this inherited state. The inherited metric implicitly contains the phase grid direction (0° or 180°), forcing subsequent windows to demodulate in the same direction and eliminating inter-block jumps. Even if the previous window was "backward," this inherited state is still a point on the "backward" state grid. The current window continues to run the Viterbi algorithm on this "backward" grid, and the locally optimal path found is naturally also "backward," and is consistent with the previous window's... The states at any given moment are perfectly synchronized. The entire demodulation process operates on the same phase grid (whether forward or backward), ensuring the continuity of the path.

[0061] It should be noted that in this embodiment, the terms "forward" and "reverse" refer to the situation where the demodulation result of the SOQPSK-A signal may be locked in two different phase grids due to carrier phase ambiguity. Specifically:

[0062] "Forward" means the demodulator locks onto a phase grid with a phase reference of 0° for path search and traversal. "Reverse" means the demodulator locks onto a phase grid with a phase reference offset by 180° for path search and traversal. This is a possible result of phase ambiguity, a common phenomenon in carrier synchronization.

[0063] The core function of the overlapping backtracking mechanism in this embodiment is that, regardless of whether the demodulation of the previous window is locked on the "forward" or "reverse" grid, the subsequent window can ensure that the entire demodulation process continues to run on the same phase grid (0° or 180°) by forcibly inheriting the determined state at the end time of the previous window (including its implicit phase information), thereby eliminating decoding errors caused by phase grid jumps (such as jumping from "forward" to "reverse") at the data block boundary.

[0064] Window length It must be long enough (window length must meet the requirements) ,in, For SOQPSK-A constraint length, longer Improve reliability (but increase computation and latency) to ensure that in the first When the window ends ( (for window index), overlap start time ( , where is the step size, representing the number of new symbols processed and output in each window. The surviving paths of all states (indexed by time or symbol) have been fully merged, meaning the optimal path for each state should precede its own. The convergence has occurred within the range of a symbol (i.e., within the overlapping region). Subsequent windows continue to perform the Add-Compare-Select (ACS) operation based on the inherited metric. In this way, the inherited state has high reliability and can represent the probability that the state is on (or close to) the globally optimal path.

[0065] In addition, overlap length This determines the amount of data processed each time and the amount of data output during backtracking. ), larger Reduce the relative overhead of state inheritance and initialization between windows (computation) A single-symbol ACS (initialization only once) may be more efficient on average, with larger backtracked output data blocks, but it increases processing latency and memory requirements (for storing surviving path information). Smaller ACSs, on the other hand... It has low processing latency and low memory requirements, but the relative overhead of state inheritance and initialization between windows increases (only calculation is performed after each initialization). (ACS with 1 symbol), efficiency may decrease, and the backtracked output data block is smaller. Therefore, Usually much larger (For example or ), so that the non-overlapping area It becomes the main output. For example... , , In this embodiment, backtracking occurs immediately after processing every W symbols, but only symbols in the non-overlapping region are output. The backtracking depth is set reasonably to ensure reliable output symbols.

[0066] As mentioned earlier, even if a phase grid (possibly inverse) is locked using overlapping windows and state inheritance, the final output symbol sequence may still have global phase ambiguity. Using differential coding at the transmitter and differential decoding of the symbol sequence output by the VA (Viterbi Algorithm) at the receiver can effectively mitigate this global phase shift (0° / 180°). Figure 3 The frequency offset resistance performance of the proposed algorithm was simulated. As can be seen from the figure, The normalized frequency offset has almost no impact on demodulation performance.

[0067] This embodiment ensures that the entire demodulation process runs continuously on the same phase grid (whether forward or backward) by forcing adjacent windows to share the same state context (inheriting surviving states and metrics) at the start of the overlap area. This eliminates the problem of inconsistent path directions caused by phase ambiguity at the window boundaries. Selecting a sufficiently long overlap length is the key to ensuring the reliability of inherited states. At the same time, by using differential coding / decoding to solve global phase ambiguity and carefully designing the window length, backtracking strategy and state storage mechanism, low-latency, high-performance real-time demodulation of SOQPSK-A signals can be achieved.

[0068] It should be noted that the above description describes some embodiments of this application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in a different order than that shown in the above embodiments and still achieve the desired result. Furthermore, the processes depicted in the drawings do not necessarily require a specific or sequential order to achieve the desired result. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0069] Based on the same inventive concept, and corresponding to the methods of any of the above embodiments, the embodiments of this application also provide a noncoherent demodulation device for SOQPSK-A signals.

[0070] like Figure 4 As shown, the noncoherent demodulation device for the SOQPSK-A signal includes:

[0071] Phase detection module 11 is configured to receive signals and perform differential phase detection on the original signal after matched filtering by the relative phase difference between two adjacent modulation symbols.

[0072] The path search module 12 is configured to construct an extended state transition grid in the differential phase space using a 3-bit differential Viterbi algorithm, calculate the branch metric based on the extended state transition grid, recursively update the path metric value based on the branch metric of the current state and the path metric of the previous state to determine the surviving path, and obtain the optimal path through Viterbi path search.

[0073] The backtracking demodulation module 13 is configured to perform segmented backtracking demodulation of the optimal path through an overlapping window backtracking mechanism to output the demodulation result. The overlapping window backtracking mechanism is to force adjacent windows to inherit the surviving state and metric at the starting point of the overlapping area so that the entire demodulation process is locked on the same phase grid.

[0074] For ease of description, the above apparatus is described in terms of its functions, divided into various modules. Of course, in implementing the embodiments of this application, the functions of each module can be implemented in one or more software and / or hardware.

[0075] The apparatus of the above embodiments is used to implement the corresponding method in any of the foregoing embodiments and has the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0076] Based on the same inventive concept, corresponding to the methods of any of the above embodiments, embodiments of this application also provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the methods described in any of the above embodiments.

[0077] Figure 5 This embodiment illustrates a more specific hardware structure of an electronic device, which may include a processor 1010, a memory 1020, an input / output interface 1030, a communication interface 1040, and a bus 1050. The processor 1010, memory 1020, input / output interface 1030, and communication interface 1040 are interconnected internally via the bus 1050.

[0078] The processor 1010 can be implemented using a general-purpose CPU (Central Processing Unit), microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this specification.

[0079] The memory 1020 can be implemented in the form of ROM (Read Only Memory), RAM (Random Access Memory), static storage device, dynamic storage device, etc. The memory 1020 can store the operating system and other applications. When the technical solutions provided in the embodiments of this specification are implemented by software or firmware, the relevant program code is stored in the memory 1020 and is called and executed by the processor 1010.

[0080] The input / output interface 1030 is used to connect input / output modules to realize information input and output. The input / output modules can be configured as components in the device (not shown in the figure) or externally connected to the device to provide corresponding functions. Input devices may include keyboards, mice, touch screens, microphones, various sensors, etc., and output devices may include displays, speakers, vibrators, indicator lights, etc.

[0081] The communication interface 1040 is used to connect a communication module (not shown in the figure) to enable communication between this device and other devices. The communication module can communicate via wired means (such as USB, Ethernet cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.).

[0082] Bus 1050 includes a pathway for transmitting information between various components of the device, such as processor 1010, memory 1020, input / output interface 1030, and communication interface 1040.

[0083] It should be noted that although the above-described device only shows the processor 1010, memory 1020, input / output interface 1030, communication interface 1040, and bus 1050, in specific implementations, the device may also include other components necessary for normal operation. Furthermore, those skilled in the art will understand that the above-described device may only include the components necessary for implementing the embodiments of this specification, and not necessarily all the components shown in the figures.

[0084] The electronic devices described above are used to implement the corresponding methods in any of the foregoing embodiments and have the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0085] Based on the same inventive concept, corresponding to the methods of any of the above embodiments, this application also provides a non-transitory computer-readable storage medium that stores computer instructions for causing the computer to perform the methods described in any of the above embodiments.

[0086] The computer-readable medium of this embodiment includes permanent and non-permanent, removable and non-removable media, and information storage can be implemented by any method or technology. Information can be computer-readable instructions, data structures, program modules, or other data. Examples of computer storage media include, but are not limited to, phase-change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transfer medium that can be used to store information accessible by a computing device.

[0087] The computer instructions stored in the storage medium of the above embodiments are used to cause the computer to perform the methods described in any of the above embodiments, and have the beneficial effects of the corresponding method embodiments, which will not be repeated here.

[0088] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application (including the claims) is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the embodiments of this application as described above, which are not provided in the details for the sake of brevity.

[0089] Although this application has been described in conjunction with specific embodiments thereof, many substitutions, modifications, and variations of these embodiments will be apparent to those skilled in the art from the foregoing description. For example, other memory architectures (e.g., dynamic RAM (DRAM)) may be used with the embodiments discussed.

[0090] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the embodiments of this application should be included within the protection scope of this application.

Claims

1. A noncoherent demodulation method for SOQPSK-A signals, characterized in that, include: The signal is received, and differential phase detection is performed on the original signal after matched filtering by the relative phase difference between two adjacent modulation symbols. An extended state transition grid is constructed in the differential phase space using a 3-bit differential Viterbi algorithm. The branch metric is calculated based on the extended state transition grid. The path metric is recursively updated based on the branch metric of the current state and the path metric of the previous state to determine the surviving path. The optimal path is obtained through Viterbi path search. The specific formula for the branch metric is as follows: ； in, ,Right now For signal Rather than delay conjugate signal The product; ; In the formula, Indicates time, Indicates the symbol period, Indicates the transmission sequence. Indicates the accumulated phase. Represents branch metric, To generate the local waveform after expanding the mesh diagram, Indicates an index. This indicates taking the real part of a complex number. For instantaneous phase, The imaginary unit; The optimal path is demodulated in segments using an overlapping window backtracking mechanism to output the demodulation result. This overlapping window backtracking mechanism forces adjacent windows to inherit the surviving state and metric at the start of the overlapping region, ensuring the entire demodulation process operates on the same phase grid. This includes: Define the overlapping window structure, including window length. and overlap length ; In response to processing the first window, a metric is calculated and backtracked to time point 1 within the window at the end of the window. The path; In response to processing the next window, retrieve the data obtained at the end of the previous window. The survival state at any given moment and its cumulative metric, serving as the current window in The initial survival state and initial metric at each moment; The process continues in a loop through each subsequent window until all symbols have been demodulated, at which point the demodulated result is finally output.

2. The method according to claim 1, characterized in that: The current window inherits the complete state metric from the previous window at the start of the overlap. Subsequent windows continue to perform the add-compare-select operation based on the inherited metric. The inherited metric implicitly includes the phase grid direction to force subsequent windows to demodulate in the same direction.

3. The method according to claim 1, characterized in that: In response to processing each symbol with a window length, a backtracking operation is performed immediately, and during the backtracking operation, only symbols in the non-overlapping region are output.

4. The method according to claim 1, characterized in that: The window length satisfies ,in, The constraint length for continuous phase modulation.

5. The method according to claim 1, characterized in that: The window's backtracking range is arrive .

6. A noncoherent demodulation device for SOQPSK-A signals, characterized in that, include: The phase detection module is configured to receive the signal and perform differential phase detection on the original signal after matched filtering by the relative phase difference between two adjacent modulation symbols. The path search module is configured to construct an extended state transition grid in the differential phase space using a 3-bit differential Viterbi algorithm, calculate a branch metric based on the extended state transition grid, recursively update the path metric value based on the branch metric of the current state and the path metric of the previous state to determine the surviving path, and obtain the optimal path through Viterbi path search. The specific formula for the branch metric is as follows: ； in, ,Right now For signal Rather than delay conjugate signal The product; ; In the formula, Indicates time, Indicates the symbol period, Indicates the transmission sequence. Indicates the accumulated phase. Represents branch metric, To generate the local waveform after expanding the mesh diagram, Indicates an index. This indicates taking the real part of a complex number. For instantaneous phase, The imaginary unit; The backtracking demodulation module is configured to perform segmented backtracking demodulation on the optimal path using an overlapping window backtracking mechanism to output the demodulation result. The overlapping window backtracking mechanism forces adjacent windows to inherit the surviving state and metric at the start of the overlapping region, ensuring the entire demodulation process operates on the same phase grid. This includes: Define the overlapping window structure, including window length. and overlap length ; In response to processing the first window, a metric is calculated and backtracked to time point 1 within the window at the end of the window. The path; In response to processing the next window, retrieve the data obtained at the end of the previous window. The survival state at any given moment and its cumulative metric, serving as the current window in The initial survival state and initial metric at each moment; The process continues in a loop through each subsequent window until all symbols have been demodulated, at which point the demodulated result is finally output.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the method as described in any one of claims 1-5.

8. A non-transitory computer-readable storage medium, characterized in that, in, The non-transitory computer-readable storage medium stores computer instructions for causing a computer to perform the method described in any one of claims 1-5.

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