Phase tracking method and apparatus, electronic device, storage medium, and computer product

Abstract

This application relates to the field of communication technology, and provides a phase tracking method, apparatus, electronic device, storage medium, and computer product. The method includes: extracting a received synchronization header symbol block, a coded modulation mode indicator (CMMI) symbol block, and a data symbol block from a frequency offset compensated received quadrature phase shift keying (QPSK) signal; determining a first phase offset estimate of the synchronization header based on the received synchronization header symbol block; performing maximum likelihood estimation based on the CMMI symbol block to obtain a second phase offset estimate of the indicator segment's midpoint; unwinding the second phase offset estimate to obtain a third phase offset estimate of the indicator segment; determining a residual frequency offset estimate based on the first and third phase offset estimates; and performing phase compensation on the data symbol block based on the second and residual phase offset estimates, combined with phase estimation based on hard decision feedback. This application can accurately estimate the phase trajectory of data symbols.

Description

Technical Field

[0001] This application relates to the field of communication technology, and in particular to a phase tracking method, apparatus, electronic device, storage medium, and computer product. Background Technology

[0002] Low-Earth orbit (LEO) satellite communication systems, due to their advantages of wide coverage, low latency, and large capacity, can be applied in fields such as satellite internet, global positioning, and remote sensing monitoring. Meanwhile, driven by the demand for ultra-high-definition video transmission, satellite-to-ground transmission links are developing towards higher frequency bands and larger bandwidths. With the increase in frequency band, signal transmission loss in satellite-to-ground links increases, and there is a significant frequency offset when receiving quadrature phase shift keying (QPSK) signals. QPSK is a quaternary phase modulation with good noise immunity and is widely used in satellite links and other communication services. After carrier synchronization processing, the frequency recovery module output signal of the received QPSK signal still has residual frequency offset and phase deviation, which need to be further corrected using phase tracking methods to ensure reliable demodulation and decoding of the system.

[0003] In related technologies, traditional satellite communication systems achieve phase recovery through pilot-assisted linear interpolation, which uses the estimated phase deviation of two consecutive pilot blocks to track and derive the phase trajectory of data symbols through linear interpolation.

[0004] However, when using a low signal-to-noise ratio transmission mode, the pilot-assisted phase estimation scheme has a large phase estimation error due to the small number of pilot symbols, which in turn leads to inaccurate estimation of the phase trajectory of the data symbols and fails to meet the requirements for reliable demodulation. Summary of the Invention

[0005] This application aims to address at least one of the technical problems existing in the related art. To this end, this application proposes a phase tracking method, apparatus, electronic device, storage medium, and computer product to solve the problem that traditional satellite communication systems achieve phase recovery through pilot-assisted linear interpolation, which has a large phase estimation error when using a low signal-to-noise ratio transmission mode, in order to accurately estimate the phase trajectory of data symbols and thus meet the requirements for reliable demodulation.

[0006] The phase tracking method according to the first aspect of this application includes: Extract the receive synchronization header symbol block, the coded modulation mode indicator symbol block, and the data symbol block from the received quadrature phase shift keying signal after frequency offset compensation; The first phase deviation estimate of the received synchronization header is determined based on the received synchronization header symbol block; Based on the maximum likelihood estimation of the symbol block of the coding and modulation mode indicator segment, the second phase deviation estimate of the midpoint of the coding and modulation mode indicator segment is obtained. The second phase deviation estimate is unwound to obtain the third phase deviation estimate of the coded modulation mode indication segment; Based on the first phase deviation estimate and the third phase deviation estimate, the residual frequency offset estimate is determined; Based on the second phase deviation estimate and the residual frequency offset estimate, combined with phase estimation based on hard decision feedback, phase compensation is performed on the data symbol block.

[0007] According to one embodiment of this application, the step of performing phase compensation on the data symbol block based on the second phase offset estimate and the residual frequency offset estimate, combined with phase estimation based on hard decision feedback, includes: For the first data symbol block in the data symbol block, based on the second phase deviation estimate and the residual frequency offset estimate, and combined with different preset values, the initial phase deviation estimate and the final phase deviation estimate of the first data symbol block are determined; based on the initial phase deviation estimate and the final phase deviation estimate of the first data symbol block, the first phase compensation value of the first data symbol block is determined; and phase compensation is performed on the first data symbol block based on the first phase compensation value. For each data symbol block other than the first data symbol block, the initial phase deviation estimate and the final phase deviation estimate of the current data symbol block are determined based on the phase deviation estimate of the midpoint of the previous data symbol block and the residual frequency offset estimate updated based on the compensated previous data symbol block, combined with different preset values. A second phase compensation value for the current data symbol block is then determined based on the initial and final phase deviation estimates. Phase compensation is performed on the current data symbol block based on the second phase compensation value. The residual frequency offset estimate updated based on the compensated previous data symbol block is updated after phase estimation based on hard decision feedback for the compensated previous data symbol block.

[0008] According to one embodiment of this application, after performing phase compensation on each data symbol block, the method further includes: Demodulation based on phase-compensated data symbol blocks using hard-decision method; Based on the demodulation results, determine the estimated phase deviation value of the corresponding data symbol block midpoint; The residual frequency offset estimate is updated based on the phase offset estimate of the corresponding data symbol block midpoint and the phase offset estimates of all previous symbol block midpoints; wherein, all previous symbol blocks include the receive synchronization header symbol block, the coding modulation mode indicator symbol block, and a corresponding number of data symbol blocks.

[0009] According to one embodiment of this application, the demodulation based on the phase-compensated data symbol block using a hard-decision method includes: Despreading is performed on the phase-compensated data symbol blocks; The despread data symbol blocks are demodulated using a hard decision method to obtain the transmitted information bits.

[0010] According to one embodiment of this application, determining the first phase compensation value of the first data symbol block based on the initial phase deviation estimate and the final phase deviation estimate of the first data symbol block includes: The difference between the estimated end phase deviation of the first data symbol block and the estimated start phase deviation is calculated to obtain the difference result. The result of the difference operation is multiplied by a numerical value determined based on the symbol block length to obtain the multiplication result; The multiplication result is added to the estimated initial phase deviation of the first data symbol block to obtain the first phase compensation value of the first data symbol block.

[0011] According to one embodiment of this application, determining the first phase deviation estimate of the received synchronization header based on the received synchronization header symbol block includes: The maximum likelihood estimation is performed on the received synchronization header symbol block to obtain the phase deviation estimate of the midpoint of the received synchronization header; The phase deviation estimate of the midpoint of the receiving synchronization header is unwound to obtain the first phase deviation estimate of the receiving synchronization header.

[0012] The phase tracking apparatus according to a second aspect embodiment of this application includes: The extraction module is used to extract the receive synchronization header symbol block, the coding modulation mode indicator symbol block, and the data symbol block from the received quadrature phase shift keying signal after frequency offset compensation. The first determining module is used to determine the first phase deviation estimate of the received synchronization header based on the received synchronization header symbol block; The estimation module is used to perform maximum likelihood estimation based on the symbol block of the coding modulation mode indicator segment to obtain the second phase deviation estimate of the midpoint of the coding modulation mode indicator segment; The unwinding module is used to unwind the second phase deviation estimate to obtain the third phase deviation estimate of the coded modulation mode indication segment; The second determining module is used to determine the residual frequency offset estimate based on the first phase offset estimate and the third phase offset estimate; The compensation module is used to perform phase compensation on the data symbol block based on the second phase deviation estimate and the residual frequency offset estimate, combined with phase estimation based on hard decision feedback.

[0013] An electronic device according to a third aspect of this application includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement any of the phase tracking methods described above.

[0014] According to a fourth aspect of this application, the storage medium is a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the phase tracking method as described above.

[0015] A computer program product according to a fifth aspect of this application includes a computer program that, when executed by a processor, implements the phase tracking method as described above.

[0016] The above-described one or more technical solutions in the embodiments of this application have at least the following technical effects: After extracting the receive synchronization header symbol block, the coded modulation mode indicator (CMMI) symbol block, and the data symbol block from the frequency offset compensated receive quadrature phase shift keying (QPSK) signal, a first phase offset estimate of the receive synchronization header is determined based on the receive synchronization header symbol block. Maximum likelihood estimation is performed based on the CMMI symbol block to obtain a second phase offset estimate of the CMMI midpoint. The second phase offset estimate is then unwrapped to obtain a third phase offset estimate of the CMMI. Based on the first and third phase offset estimates, a residual frequency offset estimate is determined. Furthermore, based on the second and residual phase offset estimates, combined with phase estimation based on hard decision feedback, phase compensation of the data symbol block can be accurately performed. Because a hard decision feedback method is used to estimate and compensate the phase of the data symbol blocks in the received quadrature phase shift keying signal, instead of just using the estimated phase deviation of two consecutive pilot blocks and tracking it through linear interpolation, accurate phase tracking can still be achieved under low signal-to-noise ratio conditions. This reduces pilot resource overhead and improves the demodulation bit error rate performance of the received quadrature phase shift keying signal. Therefore, the phase trajectory of the data symbols can be accurately estimated, thereby meeting the requirements for reliable demodulation.

[0017] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is one of the flowcharts of the phase tracking method provided in the embodiments of this application.

[0020] Figure 2 This is a schematic diagram of the physical layer data frame structure of a satellite communication system in the phase tracking method provided in this application embodiment.

[0021] Figure 3 This is the second schematic flowchart of the phase tracking method provided in the embodiments of this application.

[0022] Figure 4 This is one of the simulation results of the phase tracking method provided in the embodiments of this application.

[0023] Figure 5 This is the second schematic diagram of the simulation results of the phase tracking method provided in the embodiments of this application.

[0024] Figure 6 This is a schematic diagram of the structure of the electronic device provided in this application. Detailed Implementation

[0025] The embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but should not be used to limit the scope of this application.

[0026] This application discloses a phase tracking method, apparatus, electronic device, storage medium, and computer product.

[0027] Figure 1 This is one of the flowcharts illustrating the phase tracking method provided in the embodiments of this application, such as... Figure 1 As shown, the phase tracking method includes: Step 110: Extract the receive synchronization header symbol block, the coding modulation mode indicator symbol block, and the data symbol block from the received quadrature phase shift keying signal after frequency offset compensation.

[0028] Step 120: Determine the first phase deviation estimate of the received synchronization header based on the received synchronization header symbol block.

[0029] Step 130: Perform maximum likelihood estimation based on the symbol block of the coding modulation mode indicator segment to obtain the second phase deviation estimate of the midpoint of the coding modulation mode indicator segment.

[0030] Step 140: Unwrap the second phase deviation estimate to obtain the third phase deviation estimate of the coded modulation mode indicator segment.

[0031] Step 150: Determine the residual frequency offset estimate based on the first phase offset estimate and the third phase offset estimate.

[0032] Step 160: Based on the second phase deviation estimate and the residual frequency deviation estimate, combined with the phase estimation based on hard decision feedback, phase compensation is performed on the data symbol block.

[0033] It should be noted that the execution subject of the phase tracking method provided in this application embodiment can be a computer device, such as a mobile phone, tablet computer, laptop computer, handheld computer, in-vehicle electronic device, wearable device, ultra-mobile personal computer (UMPC), netbook, or personal digital assistant (PDA), etc. All data used in this application has been legally obtained after authorization.

[0034] The computer device of this application may be equipped with or connected to a phase tracking device, thereby controlling the phase tracking device to execute the phase tracking method of this application.

[0035] It should be noted that a satellite communication system is a communication system that uses artificial satellites to transmit information to Earth. (Refer to...) Figure 2 , Figure 2 This is a schematic diagram of the physical layer data frame structure of a satellite communication system in the phase tracking method provided in this application embodiment. Typically, the physical layer data frame structure of a satellite communication system mainly consists of three parts: a synchronization header, a coding / modulation mode indicator (CMMA) segment, and a data symbol segment. That is, one frame contains one synchronization header symbol block, one CMMA symbol block, and k data symbol blocks. Each symbol block (including the synchronization header symbol block, CMMA symbol block, and data symbol block) has a length of L symbols, where the data symbol block contains... Data symbols and Pilot symbols. Typically, the synchronization header is used for signal acquisition and frequency offset estimation, while pilots are inserted into the data symbol block for phase tracking at high signal-to-noise ratios.

[0036] Specifically, this application can receive QPSK signals transmitted by satellites and is defined as receiving quadrature phase shift keying signals (hereinafter also referred to as receiving signals).

[0037] Furthermore, frequency offset compensation can be performed on the received quadrature phase shift keying signal. This application does not provide a detailed description of the frequency offset compensation process, which can be implemented in any manner.

[0038] Furthermore, the synchronization header symbol block (which may be referred to as the received synchronization header symbol block in this application), the coded modulation mode indicator symbol block, and the data symbol block can be extracted from the received quadrature phase shift keying signal.

[0039] After obtaining the receive synchronization header symbol block, this application can perform phase estimation on the receive synchronization header symbol block, thereby obtaining the final phase deviation estimate of the receive synchronization header, which can be defined as the first phase deviation estimate. .

[0040] Furthermore, phase estimation can be performed on the symbol block of the coding modulation mode indicator segment to obtain the final phase deviation estimate of the coding modulation mode indicator segment, which can be defined as the third phase deviation estimate. .

[0041] In the process of phase estimation of the coded modulation mode indicator (CMMI) symbol block, a correlation estimator can first be used to estimate the phase of the extracted CMMI symbol block. Encoding and modulation pattern recognition can be achieved in the following ways: ; in, express The complex conjugate symbol block; This represents the l-th transmit coded modulation mode indicator segment symbol block corresponding to the coded modulation number n, which can be directly obtained and is a known value; This indicates phase angle calculation.

[0042] Furthermore, Substitute to The transmit-coded modulation mode indicator segment symbol block can be obtained. .

[0043] Furthermore, in obtaining the transmit-coded modulation mode indicator segment symbol block Subsequently, this application can obtain the phase deviation estimate of the intermediate point of the coded modulation mode indicator segment using the following maximum likelihood estimation method. And defined as the second phase deviation estimate: ; in, express The complex conjugate symbol block.

[0044] Furthermore, the second phase deviation estimate can be unwrapped using the following formula to obtain the final phase deviation estimate of the coded modulation mode indicator segment. : ; in, It is a sawtooth-shaped nonlinear function, guaranteeing The value of is in between, It is a parameter between 0 and 1, and in this application it can specifically be set to... .

[0045] Furthermore, the estimated phase deviation at the midpoint of the coded modulation mode can be used as an indicator. Subtract the estimated phase deviation value at the midpoint of the synchronization header Further, the normalized residual frequency offset estimate is calculated based on the symbol block length. Specifically, this can be achieved using the following formula: ; Where L represents the length of the symbol block.

[0046] After obtaining the residual frequency offset estimate and the second phase deviation estimate of the midpoint of the coding and modulation mode indicator segment, phase compensation can be performed on the data symbol block based on the second phase deviation estimate and the residual frequency offset estimate, combined with phase estimation based on hard decision feedback.

[0047] Specifically, for the first data symbol block in the data symbol block, its initial phase deviation estimate and final phase deviation estimate can be determined based on the second phase deviation estimate and the residual frequency deviation estimate, respectively, combined with different preset values ​​(wherein, the different preset values ​​are formed by combining different values ​​according to the symbol block length); then, based on the initial phase deviation estimate and final phase deviation estimate of the data symbol block, its phase compensation value is determined and defined as the first phase compensation value; thus, phase compensation can be performed on the data symbol block based on the first phase compensation value.

[0048] For each data symbol block other than the first data symbol block, the initial phase deviation estimate and the final phase deviation estimate are determined based on the phase deviation estimate of the midpoint of the previous data symbol block and the residual frequency offset estimate updated based on the compensated previous data symbol block, combined with different preset values. Based on the initial phase deviation estimate and the final phase deviation estimate of the data symbol block, the phase compensation value is determined and defined as the second phase compensation value. Then, phase compensation is performed on the data symbol block based on the second phase compensation value.

[0049] After phase compensation of all data symbol blocks is completed, the frame data can be demodulated and further processed to obtain the data contained in the received signal.

[0050] According to the phase tracking method of this application embodiment, after extracting the receive synchronization header symbol block, the coded modulation mode indicator (CMMI) symbol block, and the data symbol block from the received quadrature phase shift keying (QPSK) signal after frequency offset compensation, a first phase offset estimate of the receive synchronization header is determined based on the receive synchronization header symbol block; maximum likelihood estimation is performed based on the CMMI symbol block to obtain a second phase offset estimate of the CMMI midpoint; the second phase offset estimate is unwrapped to obtain a third phase offset estimate of the CMMI; a residual frequency offset estimate is determined based on the first and third phase offset estimates; and then, phase compensation of the data symbol block can be accurately performed based on the second and residual phase offset estimates, combined with phase estimation based on hard decision feedback. Because a hard decision feedback method is used to estimate and compensate the phase of the data symbol blocks in the received quadrature phase shift keying signal, instead of just using the estimated phase deviation of two consecutive pilot blocks and tracking it through linear interpolation, accurate phase tracking can still be achieved under low signal-to-noise ratio conditions. This reduces pilot resource overhead and improves the demodulation bit error rate performance of the received quadrature phase shift keying signal. Therefore, the phase trajectory of the data symbols can be accurately estimated, thereby meeting the requirements for reliable demodulation.

[0051] In one embodiment, determining a first phase offset estimate of the received synchronization header based on the received synchronization header symbol block includes: The maximum likelihood estimation of the received synchronization header symbol block is performed to obtain the phase deviation estimate of the midpoint of the received synchronization header. The phase deviation estimate of the receiving synchronization header is unwound to obtain the first phase deviation estimate of the receiving synchronization header.

[0052] Specifically, this application refers to the extracted receive synchronization header symbol block. The phase deviation estimate of the midpoint of the receiving synchronization header can be obtained using maximum likelihood estimation. : ; in, Represents the known first One transmit synchronization header symbol block express The complex conjugate symbol block, This indicates phase angle calculation.

[0053] Furthermore, the obtained phase deviation estimate can be unwrapped to obtain the final phase deviation estimate of the receiving synchronization header. : ; in, It is the initial phase deviation of the data frame. It is a sawtooth-shaped nonlinear function, guaranteeing The value of is in between, It is a parameter between 0 and 1, and in this embodiment, it is taken as... .

[0054] Therefore, this application utilizes the known signal structure through maximum likelihood estimation to provide high-precision initial phase deviation point estimation in noisy environments. At the same time, it solves the ambiguity problem caused by phase periodicity by unwinding, extending the estimated phase deviation to a large continuous range so that it can reflect the real phase accumulation over a large range. This helps to accurately estimate the phase trajectory of data symbols, thereby ensuring that the final data frame meets the requirements for reliable demodulation.

[0055] In one embodiment, phase compensation is performed on the data symbol block based on the second phase offset estimate and the residual frequency offset estimate, combined with phase estimation based on hard decision feedback, including: For the first data symbol block in the data symbol block, based on the second phase deviation estimate and the residual frequency deviation estimate, and combined with different preset values, the initial phase deviation estimate and the final phase deviation estimate of the first data symbol block are determined; based on the initial phase deviation estimate and the final phase deviation estimate of the first data symbol block, the first phase compensation value of the first data symbol block is determined; based on the first phase compensation value, phase compensation is performed on the first data symbol block. For each data symbol block except the first data symbol block, the initial phase deviation estimate and the final phase deviation estimate of the current data symbol block are determined based on the phase deviation estimate of the midpoint of the previous data symbol block and the residual frequency offset estimate updated based on the compensated previous data symbol block, combined with different preset values. The second phase compensation value of the current data symbol block is then determined based on the initial and final phase deviation estimates. Phase compensation is performed on the current data symbol block based on the second phase compensation value. The residual frequency offset estimate updated based on the compensated previous data symbol block is updated after phase estimation based on hard decision feedback for the compensated previous data symbol block.

[0056] Specifically, for the first data symbol block (i.e., k=1, still represented by k in subsequent formulas and symbols), the estimated starting point phase deviation is expressed as: The estimated value of the phase deviation at the end point is expressed as: Then, the phase offset value can be estimated based on the midpoint of the second symbol block (i.e., the coding modulation mode indicator symbol block). The residual frequency offset estimate obtained from the above process Combined with different preset values ​​(as shown in the formula below) and The estimated initial phase deviation of the third symbol block was calculated. and the estimated value of the end phase deviation : ; ; Furthermore, phase estimation and compensation for data symbol blocks can be performed: Specifically, after obtaining the estimated start and end phase deviation values ​​of the first data symbol block, the phase compensation value of the data symbol block can be calculated using linear interpolation. .

[0057] Furthermore, this phase compensation value can be used to adjust the data symbols of the first data symbol block. Phase compensation is represented as: ; in, The symbol represents the data after phase compensation, and j represents the complex unit.

[0058] For any data symbol block other than the first data symbol block, the initial phase deviation estimate and the final phase deviation estimate of the data symbol block are determined based on the phase deviation estimate of the midpoint of the previous data symbol block (for the k-th data symbol block, the previous data symbol block is the (k+2)-th or (k-1)-th data symbol block) and the residual frequency offset estimate updated based on the compensated previous data symbol block, combined with different preset values. A second phase compensation value is then determined based on these two values. Phase compensation is performed on the data symbol block based on the second phase compensation value. The residual frequency offset estimate updated based on the compensated previous data symbol block is updated after phase estimation based on hard decision feedback using the compensated previous data symbol block. The specific phase compensation process and formulas can be referenced from the compensation process for the first data symbol block described above, and will not be repeated here.

[0059] This application employs a hard decision feedback method to perform phase estimation and compensation for the data symbol blocks of QPSK signals. Compared with traditional techniques, it can achieve accurate phase tracking under low signal-to-noise ratio conditions, reduce pilot resource overhead, and improve the bit error rate performance of QPSK demodulation.

[0060] In one embodiment, determining a first phase compensation value for the first data symbol block based on the initial phase offset estimate and the final phase offset estimate of the first data symbol block includes: The difference between the estimated end phase deviation of the first data symbol block and the estimated start phase deviation is calculated to obtain the difference result. The result of the difference operation is multiplied by a numerical value determined based on the length of the symbol block to obtain the multiplication result; The result of the multiplication is added to the estimated initial phase deviation of the first data symbol block to obtain the first phase compensation value of the first data symbol block.

[0061] Specifically, after obtaining the estimated starting phase deviation and the estimated ending phase deviation of the first data symbol block, the estimated ending phase deviation of the first data symbol block can be compared with the estimated starting phase deviation to obtain the result of the difference operation.

[0062] Furthermore, the result of the difference operation is multiplied by a value determined based on the length of the symbol block to obtain the multiplication result.

[0063] Furthermore, the multiplication result is added to the estimated initial phase deviation value of the first data symbol block to obtain the first phase compensation value of the first data symbol block.

[0064] More specifically, it can be achieved using the following formula: ; in, This represents the first phase compensation value.

[0065] This application can accurately determine the first phase compensation value of the first data symbol block based on the estimated initial phase deviation and the estimated final phase deviation of the first data symbol block. This allows for accurate phase compensation of the first data symbol block and facilitates subsequent phase compensation of other data symbol blocks based on the more accurate phase-compensated data symbol blocks. This helps to accurately estimate the phase trajectory of the data symbols, thereby ensuring that the final data frame meets the requirements for reliable demodulation.

[0066] In one embodiment, after phase compensation for each data symbol block, the method further includes: Demodulation based on phase-compensated data symbol blocks using hard-decision method; Based on the demodulation results, determine the estimated phase deviation value of the corresponding data symbol block midpoint; The residual frequency offset estimate is updated based on the phase offset estimate of the corresponding data symbol block midpoint and the phase offset estimates of all previous symbol block midpoints; wherein, all previous symbol blocks include the receive synchronization header symbol block, the coding modulation mode indicator symbol block, and the corresponding number of data symbol blocks.

[0067] Specifically, after performing phase compensation on each data symbol block, this application can perform hard-decision demodulation based on the phase-compensated data symbol blocks to obtain the transmitted information bits.

[0068] Then, the transmitted information bits, which are the result of demodulation, are remapped to recover the transmitted data symbols. Then, further respreading is performed to obtain the corresponding transmitted data symbol block (e.g., obtaining the k-th transmitted data symbol block). Specifically, this can be achieved using the following formula: ; in, For reference pilot symbols.

[0069] Furthermore, the phase deviation estimate of the intermediate point of the corresponding data symbol block (e.g., the k-th data symbol block) can be estimated using the transmitted data symbol block obtained from hard decision feedback. : ; in, express Complex conjugate symbol block.

[0070] Furthermore, the phase deviation estimate at the intermediate point can be unwrapped to obtain the final phase deviation estimate for the data symbol block. : .

[0071] Furthermore, the obtained phase deviation estimate is added to the existing phase deviation estimate sample of intermediate points to obtain... The normalized residual frequency offset estimate is updated using linear regression. : ; Furthermore, after updating the normalized residual frequency offset estimate, it can be used for the start and end phase estimation of the next data symbol block.

[0072] This application employs a hard decision feedback method to estimate and compensate the phase of data symbol blocks in the received quadrature phase shift keying signal, instead of relying solely on the estimated phase deviation of two consecutive pilot blocks and tracking it through linear interpolation. This enables accurate phase tracking even under low signal-to-noise ratio conditions, reduces pilot resource overhead, and improves the demodulation bit error rate performance of the received quadrature phase shift keying signal. Therefore, it can accurately estimate the phase trajectory of data symbols, thereby meeting the requirements for reliable demodulation.

[0073] In one embodiment, hard-decision demodulation based on phase-compensated data symbol blocks includes: Despreading is performed on the phase-compensated data symbol blocks; The despread data symbol blocks are demodulated using a hard decision method to obtain the transmitted information bits.

[0074] Specifically, this application can adjust the data symbols in the compensated data symbol block. Despreading is performed, and the spreading factor is expressed as... The data symbols obtained after despreading are represented as follows: , Among them, the number of data symbols after despreading .

[0075] Furthermore, the data symbols in the despread data symbol block are demodulated using a hard decision method to obtain the transmitted information bits.

[0076] This application enables hard-decision demodulation based on phase-compensated data symbol blocks. By employing a hard-decision feedback method to estimate and compensate the phase of the data symbol blocks in the received quadrature phase shift keying signal, rather than simply using the estimated phase deviation of two consecutive pilot blocks and tracking it through linear interpolation, accurate phase tracking can still be achieved even under low signal-to-noise ratio conditions. This reduces pilot resource overhead and improves the demodulation bit error rate performance of the received quadrature phase shift keying signal. Therefore, the phase trajectory of the data symbols can be accurately estimated, thereby meeting the requirements for reliable demodulation.

[0077] Figure 3 This is a second schematic flowchart of the phase tracking method provided in the embodiments of this application, as shown below. Figure 3 As shown, the phase tracking method includes: S1: Perform synchronization header phase estimation on the received signal after frequency offset compensation; S2: Phase estimation of the coding modulation mode indicator segment; S3: Initial estimate of normalized residual frequency offset; S4: Start and end phase estimation of data symbol blocks; S5: Data symbol phase estimation and compensation, to obtain phase-compensated data symbols; S6: Phase estimation based on hard decision feedback; S7: Update the normalized residual frequency offset estimate.

[0078] To verify the effectiveness of the phase tracking method in this application, relevant tests and simulations were conducted. The simulation parameters are as follows: 1. QPSK modulation, 4x or 8x spread spectrum; 2. Low-Density Parity-Check Code (LDPC) encoding, with a block length of 8064 and a code rate of 1 / 2; 3. Number of data symbol blocks Length of each symbol block Data symbol length Pilot symbol length ; 4. Normalized carrier frequency offset is 0.064.

[0079] Figure 4 This is one of the schematic diagrams illustrating the simulation results of the phase tracking method provided in the embodiments of this application. Figure 5 This is the second schematic diagram of the simulation results of the phase tracking method provided in the embodiments of this application, as shown below. Figure 4 and Figure 5 As shown, Figure 4The paper demonstrates the phase compensation effect on the QPSK constellation diagram before (a) and after (b) using the phase tracking method of this invention, where the spreading factor is set to 8 times and the signal-to-noise ratio is set to -3.1 dB. It can be seen that the phase tracking method designed in this application is suitable for QPSK signal phase deviation compensation under low signal-to-noise ratio conditions.

[0080] Figure 5 This paper presents a comparison of the bit error rate (BER) of the hard-decision feedback-based phase tracking method and the pilot-assisted phase tracking method used in this application, with the spreading factor set to 4. It can be seen that, under the condition of BER less than 10⁻⁷, the demodulation threshold of the hard-decision feedback-based phase tracking method is approximately -2.9 dB, while the demodulation threshold of the pilot-assisted phase tracking method is approximately -0.7 dB, resulting in a BER performance improvement of 2.2 dB.

[0081] The phase tracking device provided in this application is described below. The phase tracking device described below can be referred to in correspondence with the phase tracking method described above.

[0082] Furthermore, this application also provides a phase tracking device.

[0083] The phase tracking device includes: The extraction module is used to extract the receive synchronization header symbol block, the coding modulation mode indicator symbol block, and the data symbol block from the received quadrature phase shift keying signal after frequency offset compensation. The first determining module is used to determine the first phase deviation estimate of the received synchronization header based on the received synchronization header symbol block; The estimation module is used to perform maximum likelihood estimation based on the symbol block of the coding modulation mode indicator segment to obtain the second phase deviation estimate of the midpoint of the coding modulation mode indicator segment; The unwinding module is used to unwind the second phase deviation estimate to obtain the third phase deviation estimate of the coded modulation mode indication segment; The second determining module is used to determine the residual frequency offset estimate based on the first phase offset estimate and the third phase offset estimate; The compensation module is used to perform phase compensation on the data symbol block based on the second phase deviation estimate and the residual frequency offset estimate, combined with phase estimation based on hard decision feedback.

[0084] The phase tracking device of this application, after extracting the receive synchronization header symbol block, the coded modulation mode indicator (CMMI) symbol block, and the data symbol block from the received quadrature phase shift keying (QPSK) signal after frequency offset compensation, determines a first phase deviation estimate of the receive synchronization header based on the receive synchronization header symbol block; performs maximum likelihood estimation based on the CMMI symbol block to obtain a second phase deviation estimate of the CMMI midpoint; performs unwinding processing on the second phase deviation estimate to obtain a third phase deviation estimate of the CMMI; determines a residual frequency offset estimate based on the first and third phase deviation estimates; and then, based on the second phase deviation estimate and the residual frequency offset estimate, combined with phase estimation based on hard decision feedback, accurately performs phase compensation on the data symbol block. Because a hard decision feedback method is used to estimate and compensate the phase of the data symbol blocks in the received quadrature phase shift keying signal, instead of just using the estimated phase deviation of two consecutive pilot blocks and tracking it through linear interpolation, accurate phase tracking can still be achieved under low signal-to-noise ratio conditions. This reduces pilot resource overhead and improves the demodulation bit error rate performance of the received quadrature phase shift keying signal. Therefore, the phase trajectory of the data symbols can be accurately estimated, thereby meeting the requirements for reliable demodulation.

[0085] In one embodiment, the first determining module is specifically used for: The maximum likelihood estimation is performed on the received synchronization header symbol block to obtain the phase deviation estimate of the midpoint of the received synchronization header; The phase deviation estimate of the midpoint of the receiving synchronization header is unwound to obtain the first phase deviation estimate of the receiving synchronization header.

[0086] In one embodiment, the compensation module is specifically used for: For the first data symbol block in the data symbol block, based on the second phase deviation estimate and the residual frequency offset estimate, and combined with different preset values, the initial phase deviation estimate and the final phase deviation estimate of the first data symbol block are determined; based on the initial phase deviation estimate and the final phase deviation estimate of the first data symbol block, the first phase compensation value of the first data symbol block is determined; and phase compensation is performed on the first data symbol block based on the first phase compensation value. For each data symbol block other than the first data symbol block, the initial phase deviation estimate and the final phase deviation estimate of the current data symbol block are determined based on the phase deviation estimate of the midpoint of the previous data symbol block and the residual frequency offset estimate updated based on the compensated previous data symbol block, combined with different preset values. A second phase compensation value for the current data symbol block is then determined based on the initial and final phase deviation estimates. Phase compensation is performed on the current data symbol block based on the second phase compensation value. The residual frequency offset estimate updated based on the compensated previous data symbol block is updated after phase estimation based on hard decision feedback for the compensated previous data symbol block.

[0087] In one embodiment, the compensation module is further configured to: Despreading is performed on the phase-compensated data symbol blocks; The despread data symbol blocks are demodulated using a hard decision method to obtain the transmitted information bits.

[0088] In one embodiment, the compensation module is further configured to: Demodulation based on phase-compensated data symbol blocks using hard-decision method; Based on the demodulation results, determine the estimated phase deviation value of the corresponding data symbol block midpoint; The residual frequency offset estimate is updated based on the phase offset estimate of the corresponding data symbol block midpoint and the phase offset estimates of all previous symbol block midpoints; wherein, all previous symbol blocks include the receive synchronization header symbol block, the coding modulation mode indicator symbol block, and a corresponding number of data symbol blocks.

[0089] In one embodiment, the compensation module is further configured to: The difference between the estimated end phase deviation of the first data symbol block and the estimated start phase deviation is calculated to obtain the difference result. The result of the difference operation is multiplied by a numerical value determined based on the symbol block length to obtain the multiplication result; The multiplication result is added to the estimated initial phase deviation of the first data symbol block to obtain the first phase compensation value of the first data symbol block.

[0090] Figure 6 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 6As shown, the electronic device may include a processor 610, a communications interface 620, a memory 630, and a communication bus 640, wherein the processor 610, the communications interface 620, and the memory 630 communicate with each other through the communication bus 640. The processor 610 can call logic instructions in the memory 630 to execute the following method: extracting the receive synchronization header symbol block, the coded modulation mode indicator symbol block, and the data symbol block from the frequency offset compensated received quadrature phase shift keying signal; The first phase deviation estimate of the received synchronization header is determined based on the received synchronization header symbol block; Based on the maximum likelihood estimation of the symbol block of the coding and modulation mode indicator segment, the second phase deviation estimate of the midpoint of the coding and modulation mode indicator segment is obtained. The second phase deviation estimate is unwound to obtain the third phase deviation estimate of the coded modulation mode indication segment; Based on the first phase deviation estimate and the third phase deviation estimate, the residual frequency offset estimate is determined; Based on the second phase deviation estimate and the residual frequency offset estimate, combined with phase estimation based on hard decision feedback, phase compensation is performed on the data symbol block.

[0091] Furthermore, the logical instructions in the aforementioned memory 630 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to related technologies, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0092] In another aspect, embodiments of this application also provide a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, is implemented to perform the methods provided in the above embodiments, including, for example, extracting a receive synchronization header symbol block, a coded modulation mode indicator symbol block, and a data symbol block from a frequency offset compensated received quadrature phase shift keying signal; The first phase deviation estimate of the received synchronization header is determined based on the received synchronization header symbol block; Based on the maximum likelihood estimation of the symbol block of the coding and modulation mode indicator segment, the second phase deviation estimate of the midpoint of the coding and modulation mode indicator segment is obtained. The second phase deviation estimate is unwound to obtain the third phase deviation estimate of the coded modulation mode indication segment; Based on the first phase deviation estimate and the third phase deviation estimate, the residual frequency offset estimate is determined; Based on the second phase deviation estimate and the residual frequency offset estimate, combined with phase estimation based on hard decision feedback, phase compensation is performed on the data symbol block.

[0093] In another aspect, embodiments of this application also provide a computer program product having a computer program stored thereon. When the computer program is executed by a processor, it is implemented to perform the methods provided in the above embodiments, such as: extracting a receive synchronization header symbol block, a coding modulation mode indicator symbol block, and a data symbol block from the received quadrature phase shift keying signal after frequency offset compensation. The first phase deviation estimate of the received synchronization header is determined based on the received synchronization header symbol block; Based on the maximum likelihood estimation of the symbol block of the coding and modulation mode indicator segment, the second phase deviation estimate of the midpoint of the coding and modulation mode indicator segment is obtained. The second phase deviation estimate is unwound to obtain the third phase deviation estimate of the coded modulation mode indication segment; Based on the first phase deviation estimate and the third phase deviation estimate, the residual frequency offset estimate is determined; Based on the second phase deviation estimate and the residual frequency offset estimate, combined with phase estimation based on hard decision feedback, phase compensation is performed on the data symbol block.

[0094] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0095] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the parts that contribute to the related technology, can be embodied in the form of software products. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate this application and are not intended to limit this application. Although this application has been described in detail with reference to the embodiments, those skilled in the art should understand that various combinations, modifications, or equivalent substitutions of the technical solutions of this application do not depart from the spirit and scope of the technical solutions of this application.

Claims

1. A phase tracking method, characterized in that, include: Extract the receive synchronization header symbol block, the coded modulation mode indicator symbol block, and the data symbol block from the received quadrature phase shift keying signal after frequency offset compensation; The first phase deviation estimate of the received synchronization header is determined based on the received synchronization header symbol block; Based on the maximum likelihood estimation of the symbol block of the coding and modulation mode indicator segment, the second phase deviation estimate of the midpoint of the coding and modulation mode indicator segment is obtained. The second phase deviation estimate is unwound to obtain the third phase deviation estimate of the coded modulation mode indication segment; Based on the first phase deviation estimate and the third phase deviation estimate, the residual frequency offset estimate is determined; Based on the second phase deviation estimate and the residual frequency offset estimate, combined with phase estimation based on hard decision feedback, phase compensation is performed on the data symbol block.

2. The phase tracking method according to claim 1, characterized in that, The phase compensation of the data symbol block based on the second phase offset estimate and the residual frequency offset estimate, combined with phase estimation based on hard decision feedback, includes: For the first data symbol block in the data symbol block, based on the second phase deviation estimate and the residual frequency offset estimate, and combined with different preset values, the initial phase deviation estimate and the final phase deviation estimate of the first data symbol block are determined; based on the initial phase deviation estimate and the final phase deviation estimate of the first data symbol block, the first phase compensation value of the first data symbol block is determined; and phase compensation is performed on the first data symbol block based on the first phase compensation value. For each data symbol block other than the first data symbol block, the initial phase deviation estimate and the final phase deviation estimate of the current data symbol block are determined based on the phase deviation estimate of the midpoint of the previous data symbol block and the residual frequency offset estimate updated based on the compensated previous data symbol block, combined with different preset values. A second phase compensation value for the current data symbol block is then determined based on the initial and final phase deviation estimates. Phase compensation is performed on the current data symbol block based on the second phase compensation value. The residual frequency offset estimate updated based on the compensated previous data symbol block is updated after phase estimation based on hard decision feedback for the compensated previous data symbol block.

3. The phase tracking method according to claim 2, characterized in that, After phase compensation is performed on each data symbol block, the following is also included: Demodulation based on phase-compensated data symbol blocks using hard-decision method; Based on the demodulation results, determine the estimated phase deviation value of the corresponding data symbol block midpoint; The residual frequency offset estimate is updated based on the phase offset estimate of the corresponding data symbol block midpoint and the phase offset estimates of all previous symbol block midpoints; wherein, all previous symbol blocks include the receive synchronization header symbol block, the coding modulation mode indicator symbol block, and a corresponding number of data symbol blocks.

4. The phase tracking method according to claim 3, characterized in that, The hard-decision demodulation based on the phase-compensated data symbol block includes: Despreading is performed on the phase-compensated data symbol blocks; The despread data symbol blocks are demodulated using a hard decision method to obtain the transmitted information bits.

5. The phase tracking method according to claim 2, characterized in that, The step of determining the first phase compensation value of the first data symbol block based on the initial phase deviation estimate and the final phase deviation estimate of the first data symbol block includes: The difference between the estimated end phase deviation of the first data symbol block and the estimated start phase deviation is calculated to obtain the difference result. The result of the difference operation is multiplied by a numerical value determined based on the symbol block length to obtain the multiplication result; The multiplication result is added to the estimated initial phase deviation of the first data symbol block to obtain the first phase compensation value of the first data symbol block.

6. The phase tracking method according to claim 1, characterized in that, Determining the first phase deviation estimate of the received synchronization header based on the received synchronization header symbol block includes: The maximum likelihood estimation is performed on the received synchronization header symbol block to obtain the phase deviation estimate of the midpoint of the received synchronization header; The phase deviation estimate of the midpoint of the receiving synchronization header is unwound to obtain the first phase deviation estimate of the receiving synchronization header.

7. A phase tracking device, characterized in that, include: The extraction module is used to extract the receive synchronization header symbol block, the coding modulation mode indicator symbol block, and the data symbol block from the received quadrature phase shift keying signal after frequency offset compensation. The first determining module is used to determine the first phase deviation estimate of the received synchronization header based on the received synchronization header symbol block; The estimation module is used to perform maximum likelihood estimation based on the symbol block of the coding modulation mode indicator segment to obtain the second phase deviation estimate of the midpoint of the coding modulation mode indicator segment; The unwinding module is used to unwind the second phase deviation estimate to obtain the third phase deviation estimate of the coded modulation mode indication segment; The second determining module is used to determine the residual frequency offset estimate based on the first phase offset estimate and the third phase offset estimate; The compensation module is used to perform phase compensation on the data symbol block based on the second phase deviation estimate and the residual frequency offset estimate, combined with phase estimation based on hard decision feedback.

8. 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 computer program, it implements the phase tracking method as described in any one of claims 1 to 6.

9. A storage medium, said storage medium being a non-transitory computer-readable storage medium, wherein a computer program is stored thereon, characterized in that, When the computer program is executed by the processor, it implements the phase tracking method as described in any one of claims 1 to 6.

10. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the phase tracking method according to any one of claims 1 to 6.

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