Method, device and program product for determining influence of residual frequency offset on packet error rate performance

Abstract

The invention relates to the technical field of satellite communication, and discloses a method, equipment and a program product for determining the influence of residual frequency offset on packet error rate performance, which are applied to an SC-FDMA communication system with channel coding, and the method comprises the following steps: under the condition of no frequency offset and different signal-to-noise ratio conditions, carrying out analogue simulation to obtain system packet error rates under different constellation mapping; under the condition of no frequency offset and the same signal-to-noise ratio, calculating a first symbol error rate of the system under different constellation mappings; under the condition of different residual frequency offsets, calculating a second symbol error rate of the system under different constellation mappings; according to a comparison result of the first symbol error rate and the second symbol error rate, calculating a noise variance required for reaching the system packet error rate when the residual frequency offset exists; and determining a prediction result of the residual frequency offset on system performance reduction according to the noise variance. Therefore, by combining theoretical calculation with simulation means, the influence of the residual frequency offset on the system performance can be accurately predicted, the system design is optimized, and the communication quality and reliability are improved.

Description

Technical Field

[0001] The present invention relates to the field of satellite communication technology, and in particular to a method, a device and a program product for determining the influence of residual frequency deviation on packet error rate performance. Background Art

[0002] Single-Carrier Frequency Division Multiple Access (SC-FDMA) performs well in spectrum efficiency and combating frequency selective fading, but is sensitive to frequency deviation. Frequency deviation can cause distortion of the received signal, affect signal synchronization and demodulation, and thus reduce the performance of the communication system. Therefore, in order to achieve highly reliable signal reception, the correction of frequency deviation in the SC-FDMA system is crucial. However, in the actual burst transmission process, residual frequency offsets may still occur due to various dynamically changing factors, such as terminal movement and satellite orbit changes. This requires the terminal to further estimate and compensate for these residual frequency offsets in real time during the transmission process.

[0003] In related technical solutions, most frequency offset estimation methods use mean square error (MSE) as a measure of estimation performance. However, MSE does not directly reflect the specific impact of the residual frequency offset after frequency offset compensation on the performance of the communication system, especially when considering different constellation mapping methods. Constellation mapping is the process of converting digital signals into specific symbols during modulation. Different modulation technologies have different constellation point distributions, and therefore have different sensitivities to residual frequency offset. Some high-order modulation technologies have a low tolerance for frequency offset due to their small constellation point spacing. Even a small amount of residual frequency offset may lead to a significant increase in the packet error rate. Summary of the invention

[0004] The purpose of the present invention is to provide a method, device and program product for determining the impact of residual frequency offset on packet error rate performance, which can accurately predict the impact of residual frequency offset on system performance, thereby optimizing system design and improving communication quality and reliability.

[0005] In order to solve the above technical problem, the present invention provides a method for determining the influence of residual frequency offset on packet error rate performance, and the method is applied to an SC-FDMA communication system, comprising:

[0006] Under the condition of no frequency deviation and different signal-to-noise ratio, the simulation obtains the system packet error rate after channel coding and modulation using different constellation mapping methods;

[0007] Under the condition of no frequency deviation and the same signal-to-noise ratio, calculate the first symbol error rate of the system after channel coding and modulation using different constellation mapping methods;

[0008] Under different residual frequency offset conditions, calculating the second symbol error rate of the system after channel coding and modulation using different constellation mapping methods;

[0009] Calculating, based on a comparison result of the first symbol error rate of the system and the second symbol error rate of the system, a noise variance required to achieve the system packet error rate when there is a residual frequency offset;

[0010] The prediction result of the residual frequency offset on the degradation of system performance is determined according to the calculated noise variance.

[0011] In the first aspect, in the method for determining the influence of the residual frequency offset on the packet error rate performance provided by the present invention, under the condition of no frequency offset and different signal-to-noise ratios, the system packet error rate after channel coding and modulation using different constellation mapping methods is simulated and obtained, including:

[0012] Generating a bit data stream following a uniform distribution, and performing channel coding on the bit data stream;

[0013] Different constellation mapping methods are used to convert the channel-coded data into constellation point symbol data;

[0014] According to the constellation point symbol data, under different signal-to-noise ratio conditions, the system packet error rate in the absence of frequency offset is obtained through simulation.

[0015] On the other hand, in the method for determining the influence of the residual frequency offset on the packet error rate performance provided by the present invention, calculating the first symbol error rate of the system includes:

[0016] In an additive white Gaussian noise channel, the signal at the receiving end is demodulated to obtain a demodulated first signal; the demodulated first signal is expressed as: ,in represents the user transmission symbol after constellation mapping, is a complex Gaussian noise term with zero mean, The variance of ;in, express The real part of express The imaginary part of express The standard deviation of the real part, express The standard deviation of the imaginary part, Indicates the value of the standard deviation of the noise when there is no frequency deviation;

[0017] The symbol values ​​in the first quadrant are analyzed according to the constellation-mapped user transmission symbols in the demodulated first signal to obtain a first symbol error rate of the system after modulation using different constellation mapping methods.

[0018] On the other hand, in the method for determining the influence of the residual frequency offset on the packet error rate performance provided by the present invention, calculating the second symbol error rate of the system includes:

[0019] In an additive white Gaussian noise channel, the signal at the receiving end is demodulated to obtain a demodulated second signal; the demodulated second signal is expressed as: ,in ,in Represents the system symbol index, represents the normalized residual frequency deviation, Indicates the actual frequency deviation, represents the subcarrier spacing, Indicates the number of sampling points that a system symbol lasts. Indicates the number of IFFT points used in system modulation, Indicates the number of sampling points of the cyclic prefix;

[0020] The symbol values ​​in the first quadrant are analyzed according to the constellation-mapped user transmission symbols in the demodulated second signal to obtain a second symbol error rate of the system after modulation using different constellation mapping methods.

[0021] On the other hand, in the method for determining the influence of the residual frequency offset on the packet error rate performance provided by the present invention, when the constellation mapping mode is QPSK, the symbol of QPSK modulation in the first quadrant is ;in, represents an imaginary number;

[0022] The first symbol error rate of the system is calculated using the following formula:

[0023] ;

[0024] The second symbol error rate of the system is calculated using the following formula:

[0025] ;

[0026] ;

[0027] in, represents the first symbol error rate of the system, represents the second symbol error rate of the system, express The real part of express The imaginary part of express The real part of express The imaginary part of express The real part of express The imaginary part of express The real part of express The imaginary part of represents probability calculation, represents the complementary cumulative distribution function of the standard normal distribution, Indicates the standard deviation of the noise when there is frequency offset.

[0028] On the other hand, in the method for determining the influence of the residual frequency offset on the packet error rate performance provided by the present invention, when the constellation mapping mode is 8PSK, the symbol value set of 8PSK modulation in the first quadrant is ;in, represents an imaginary number;

[0029] The first symbol error rate of the system is calculated using the following formula:

[0030] ;

[0031] The second symbol error rate of the system is calculated using the following formula:

[0032] ;

[0033] , ;

[0034] in, represents the first symbol error rate of the system, represents the second symbol error rate of the system, represents the complementary cumulative distribution function of the standard normal distribution, The constellation points are At that time, The constellation symbol rotated by the frequency offset at the SC-FDMA symbol, The constellation points are At that time, The constellation symbol rotated by the frequency offset at the SC-FDMA symbol, The constellation points are At that time, The constellation symbol affected by frequency offset and noise received at the SC-FDMA symbol, The constellation points are At that time, The constellation symbol affected by frequency offset and noise received at each SC-FDMA symbol; express The real part of express The imaginary part of express The imaginary part of express The imaginary part of .

[0035] On the other hand, in the method for determining the influence of the residual frequency offset on the packet error rate performance provided by the present invention, when the constellation mapping mode is M-QAM, the symbol value set of the M-QAM modulation in the first quadrant is:

[0036] ;

[0037] in, Indicates the symbol value of M-QAM in the first quadrant, express The real part of express The imaginary part of represents the modulation order of QAM, is the average power of the transmitted symbol;

[0038] The first symbol error rate of the system is calculated using the following formula:

[0039] ;

[0040] ;

[0041] ;

[0042] ;

[0043] in, represents the first symbol error rate of the system, Indicates the symbol of M-QAM in the first quadrant corresponding to the first symbol error rate of the system The probability of a correct decision, represents the complementary cumulative distribution function of the standard normal distribution;

[0044] The second symbol error rate of the system is calculated using the following formula:

[0045] ;

[0046] ;

[0047] ;

[0048] ;

[0049] in, represents the second symbol error rate of the system, Indicates the symbol of M-QAM in the first quadrant corresponding to the second symbol error rate of the system The probability of a correct decision, The constellation points are At that time, The constellation symbol rotated by the frequency offset at the SC-FDMA symbol, express The real part of express The imaginary part of .

[0050] On the other hand, the method for determining the influence of the residual frequency offset on the packet error rate performance provided by the present invention further includes:

[0051] According to the prediction result of system performance degradation, the required frequency offset estimation accuracy within a set performance degradation range is determined.

[0052] In order to solve the above technical problem, the present invention further provides an electronic device, comprising:

[0053] Memory for storing computer programs;

[0054] A processor is used to implement the steps of the above-mentioned method for determining the influence of residual frequency offset on packet error rate performance when executing the computer program.

[0055] In order to solve the above technical problem, the present invention also provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the steps of the method for determining the impact of residual frequency deviation on packet error rate performance are implemented.

[0056] In order to solve the above technical problem, the present invention also provides a computer program product, including a computer program / instruction, which, when executed by a processor, implements the steps of the above method for determining the impact of residual frequency deviation on packet error rate performance.

[0057] It can be seen from the above technical scheme that a method for determining the influence of residual frequency offset on packet error rate performance provided by the present invention is applied to an SC-FDMA communication system, comprising: under the condition of no frequency offset and different signal-to-noise ratios, simulating and obtaining the system packet error rate after channel coding and modulation using different constellation mapping methods; under the condition of no frequency offset and the same signal-to-noise ratio, calculating the first system symbol error rate after channel coding and modulation using different constellation mapping methods; under the condition of different residual frequency offsets, calculating the second system symbol error rate after channel coding and modulation using different constellation mapping methods; according to the comparison result of the first system symbol error rate and the second system symbol error rate, calculating the noise variance required to achieve the system packet error rate when there is a residual frequency offset; according to the calculated noise variance, determining the prediction result of the degradation of system performance due to the residual frequency offset.

[0058] The beneficial effect of the present invention is that the method for determining the influence of the residual frequency deviation on the packet error rate performance provided by the present invention first simulates the system packet error rate under various constellation mapping modes in the ideal frequency-free condition where channel coding exists through software simulation; then, under the condition of the same signal-to-noise ratio, the symbol error rate of different constellation mapping modes under these ideal conditions is calculated; and then the symbol error rate of each constellation mapping mode under different frequency deviation conditions is further calculated. Afterwards, by comparing the symbol error rates in the case of no frequency deviation and with frequency deviation, the noise variance required to achieve the same packet error rate as without frequency deviation when there is frequency deviation is derived. Finally, based on this calculation result, the predicted result of the degradation of system performance when there is residual frequency deviation in the system is analyzed. In this way, through theoretical calculation combined with simulation means, the influence of the residual frequency deviation on the system packet error rate performance in the SC-FDMA communication system is accurately evaluated, and the specific influence of the residual frequency deviation on the communication performance in the SC-FDMA communication system using channel coding can be accurately predicted, thereby optimizing the system design and improving the communication quality and reliability. The above method can be applied to the signal of a single SC-FDMA symbol, and can also predict the impact on the signal of multiple SC-FDMA symbols, thereby providing more comprehensive guidance for the design and optimization of the communication system.

[0059] In addition, the present invention also provides corresponding electronic equipment and computer-readable storage media for the method of determining the impact of residual frequency deviation on packet error rate performance, which has the same or corresponding technical features as the above-mentioned method for determining the impact of residual frequency deviation on packet error rate performance, and the effect is the same as above. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] In order to more clearly illustrate the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0061] Figure 1 A flow chart of a method for determining the influence of residual frequency offset on packet error rate performance provided by an embodiment of the present invention;

[0062] Figure 2 A schematic diagram of an SC-FDMA uplink frame structure provided in an embodiment of the present invention;

[0063] Figure 3 A schematic diagram of the SC-FDMA modulation process provided by an embodiment of the present invention;

[0064] Figure 4 A comparison diagram of approximate results when there is residual frequency offset in the QPSK constellation symbol provided by an embodiment of the present invention;

[0065] Figure 5 A comparison diagram of approximate results when there is residual frequency offset in the 8PSK constellation symbol provided by an embodiment of the present invention;

[0066] Figure 6 A comparison diagram of approximate results when there is residual frequency offset in the 16QAM constellation symbol provided by an embodiment of the present invention;

[0067] Figure 7 A comparison diagram of approximate results when there is residual frequency offset in the 64QAM constellation symbol provided by an embodiment of the present invention;

[0068] Figure 8 A comparison chart of theoretical results and simulation results under QPSK constellation modulation and 2 / 3 code rate provided in an embodiment of the present invention;

[0069] Fig. 9 A comparison chart of theoretical results and simulation results under QPSK constellation modulation and 3 / 4 code rate provided in an embodiment of the present invention;

[0070] Fig.10 A comparison chart of theoretical results and simulation results for 8PSK constellation modulation and 2 / 3 code rate provided in an embodiment of the present invention;

[0071] Fig.11 A comparison chart of theoretical results and simulation results under 8PSK constellation modulation and 3 / 4 code rate provided in an embodiment of the present invention;

[0072] Fig.12 A comparison chart of theoretical results and simulation results under 16QAM constellation modulation and 3 / 4 code rate provided in an embodiment of the present invention;

[0073] Fig.13 A comparison chart of theoretical results and simulation results under 16QAM constellation modulation and 5 / 6 code rate provided in an embodiment of the present invention;

[0074] Fig.14A comparison chart of theoretical results and simulation results under 64QAM constellation modulation and 3 / 4 code rate provided in an embodiment of the present invention;

[0075] Fig.15 A comparison chart of theoretical results and simulation results under 64QAM constellation modulation and 5 / 6 code rate provided in an embodiment of the present invention;

[0076] Fig.16 A schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0077] As an extension standard of the first generation system, the second generation satellite digital television broadcasting return channel (Digital Video Broadcasting-Return Channel via Satellite, DVB-RCS2) aims to provide standardized broadband interactive connection. DVB-RCS2 significantly improves the performance at the lower layer by adopting a more efficient modulation and coding scheme and expanding the modulation method to 8PSK (Phase Shift Keying) and 16QAM (Quadrature Amplitude Modulation). In addition, the standard applies adaptive coding and modulation technologies in the return link for optimization, especially for frequency bands such as Ka. In the DVB-RCS2 standard, all return channel satellite terminals (Return Channel Satellite Terminal, RCST) use Multi-Frequency Time-Division Multiple Access (MF-TDMA) technology to share the satellite return channel, and the transmission mode of the transmitted signal is burst transmission. In addition, the standard also proposes the use of SC-FDMA technology to share the satellite return channel in future evolution to further improve system performance.

[0078] In Long Term Evolution (LTE) and the fifth generation of mobile communication technology (5G NR), the uplink also uses the SC-FDMA system. Compared with previous technologies, LTE and 5G NR have optimized and expanded the modulation scheme, abandoned the 8PSK modulation method, and introduced a higher-order QAM modulation method.

[0079] SC-FDMA technology has significant advantages over MF-TDMA, especially in terms of spectrum efficiency and resistance to frequency selective fading. Compared with MF-TDMA, SC-FDMA can more effectively utilize spectrum resources and improve transmission efficiency. However, it should be noted that SC-FDMA technology is based on the evolution of Orthogonal Frequency Division Multiple Access (OFDMA) technology. Compared with MF-TDMA, SC-FDMA is more sensitive to frequency offset. Frequency offset can cause distortion of the received signal, affect signal synchronization and demodulation, and thus reduce the performance of the communication system. Therefore, in order to achieve highly reliable signal reception, the correction of frequency offset in the SC-FDMA system is crucial. High-precision frequency offset correction technology can ensure accurate reception and demodulation of signals, thereby maintaining the performance and stability of the communication system.

[0080] Before burst transmission, the terminal device can estimate the Doppler frequency deviation by receiving the downlink signal and ephemeris information. This step is crucial for pre-compensation of the uplink signal. Through this pre-compensation, the frequency deviation caused by the Doppler effect during the transmission of the signal can be reduced, thereby improving the transmission quality and synchronization accuracy of the signal. In order to further improve the performance of pre-compensation, the terminal device can be equipped with a receiver of the global navigation satellite system to obtain its precise location information (including longitude, latitude and altitude) and speed information. These data can help the terminal estimate the Doppler frequency deviation more accurately, because the Doppler frequency deviation is closely related to the terminal's moving speed and the change in position relative to the satellite. Although the frequency deviation pre-compensation mechanism has been considered before transmission, in the actual transmission process, due to various dynamically changing factors, such as the movement of the terminal, the orbit change of the satellite, etc., residual frequency offset may still be generated. This requires the terminal to further estimate and compensate for these residual frequency offsets in real time during the transmission process.

[0081] At present, most existing frequency offset estimation methods use MSE as a measure of estimation performance. MSE is a widely used evaluation parameter that can intuitively quantify the accuracy of frequency offset estimation and measure the size of the error by calculating the average of the square of the difference between the estimated value and the true value. However, although MSE provides an evaluation method in theory, it does not directly reflect the specific impact of the residual frequency offset after frequency offset compensation on the performance of the communication system, especially when considering different constellation mapping methods. Constellation mapping is the process of converting digital signals into specific symbols during modulation. Different modulation technologies such as QAM and PSK have different constellation point distributions, and therefore have different sensitivities to residual frequency offset. Some high-order modulation technologies have a low tolerance to frequency offset due to their small constellation point spacing. Even a small amount of residual frequency offset may lead to a significant increase in the packet error rate. Therefore, in order to more comprehensively evaluate the impact of frequency offset compensation on system performance, a theoretical method is needed to supplement the evaluation of MSE to reveal how the residual frequency offset after compensation affects the actual performance of the system under a specific constellation mapping.

[0082] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0083] In order to enable those skilled in the art to better understand the solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. Figure 1 A flow chart of a method for determining the influence of residual frequency offset on packet error rate performance provided by an embodiment of the present invention, such as Figure 1 As shown, the method is applied to the SC-FDMA communication system, comprising:

[0084] S101. Under the condition of no frequency deviation and different signal-to-noise ratios, the system packet error rate after channel coding and modulation using different constellation mapping methods is simulated and obtained.

[0085] It can be understood that the Packet Error Rate (PER) refers to the ratio of the number of erroneously received data packets to the total number of received packets during data transmission, which is an indicator to measure the accuracy of data packet transmission within a certain period of time.

[0086] When executing step S101, software is used to simulate the system packet error rate under various constellation mapping modes in the ideal case of no frequency offset in the presence of channel coding. Specifically, the system packet error rate under different signal-to-noise ratio conditions and no frequency offset can be obtained after 16-state Turbo coding, using QPSK, 8PSK, and M-QAM constellation modulation modes. This step establishes the performance baseline of the system under ideal conditions.

[0087] S102. Under the condition of no frequency offset and the same signal-to-noise ratio, calculate the first symbol error rate of the system after channel coding and modulation using different constellation mapping methods.

[0088] It can be understood that the symbol error rate (SER) is a measure of the ratio of the total number of symbols that have errors within a certain period of time to the total number of symbols sent. In other words, it measures the proportion of symbol errors during data transmission.

[0089] When executing step S102, under the condition of maintaining the same signal-to-noise ratio, the symbol error rates of different constellation mapping modes under these ideal conditions (i.e., without frequency offset influence) are calculated. Specifically, the symbol error rate of the SC-FDMA modulation system after Turbo coding and constellation mapping under ideal conditions can be calculated. This step is a further analysis of the accuracy of the symbol transmission process.

[0090] S103. Under different residual frequency offset conditions, calculate a second symbol error rate of the system after channel coding and modulation using different constellation mapping methods.

[0091] It should be noted that the residual frequency offset refers to the actual remaining frequency offset after pre-compensation of the Doppler frequency offset.

[0092] When executing step S103, different residual frequency offsets are taken into account and the symbol error rate of each constellation mapping method is calculated. Specifically, the symbol error rate of the SC-FDMA modulation system after Turbo coding and constellation mapping can be calculated under different residual frequency offsets. This step reveals the specific impact of frequency offset on system performance.

[0093] S104: Calculate, based on a comparison result of the first system symbol error rate and the second system symbol error rate, a noise variance required to achieve a system packet error rate when there is a residual frequency offset.

[0094] When executing step S104, by comparing the symbol error rates in the case of no frequency offset and the case of frequency offset, the noise variance required to achieve the same system packet error rate as that in the case of no frequency offset (i.e., the system packet error rate obtained by simulation in step S101) when the frequency offset exists is derived. Thus, the degradation of system performance when the residual frequency offset exists can be evaluated, and the required frequency offset estimation accuracy within the acceptable performance degradation range can be determined accordingly.

[0095] S105: Determine a prediction result of the residual frequency offset on system performance degradation according to the calculated noise variance.

[0096] When executing step S105, the specific degree of system performance degradation when residual frequency offset exists in the system can be analyzed according to the noise variance calculated in step S104. That is, the present invention can accurately predict the specific impact of residual frequency offset on communication performance in an SC-FDMA system using channel coding.

[0097] In the above method for determining the influence of residual frequency deviation on packet error rate performance provided by an embodiment of the present invention, firstly, the system packet error rate under various constellation mapping modes in the ideal frequency-free condition where channel coding exists is simulated by software simulation; then, under the condition of the same signal-to-noise ratio, the symbol error rate of different constellation mapping modes under these ideal conditions is calculated; and then the symbol error rate of each constellation mapping mode under different frequency deviation conditions is further calculated. Afterwards, by comparing the symbol error rates in the case of no frequency deviation and with frequency deviation, the noise variance required to achieve the same packet error rate as without frequency deviation when there is frequency deviation is derived. Finally, based on this calculation result, the predicted result of system performance degradation when there is residual frequency deviation in the system is analyzed. In this way, through theoretical calculation combined with simulation means, the influence of residual frequency deviation on system packet error rate performance in SC-FDMA communication system is accurately evaluated, and the specific influence of residual frequency deviation on communication performance in SC-FDMA system using channel coding can be accurately predicted, thereby optimizing system design and improving communication quality and reliability. The above method can be applied to the signal of a single SC-FDMA symbol, and can also predict the impact on the signal of multiple SC-FDMA symbols, thereby providing more comprehensive guidance for the design and optimization of the communication system.

[0098] Figure 2 Schematic diagram of the SC-FDMA uplink frame structure provided by an embodiment of the present invention. The communication structure of the SC-FDMA system can be expressed as Figure 2 In the form of.

[0099] The SC-FDMA system related parameters can take the following values:

[0100] Table 1 System related parameters

[0101]

[0102] Further, in a specific implementation, in the above-mentioned method for determining the influence of residual frequency deviation on packet error rate performance provided in an embodiment of the present invention, step S101 simulates and obtains the system packet error rate after channel coding and modulation using different constellation mapping methods under the condition of no frequency deviation and different signal-to-noise ratios, which may specifically include: generating a bit data stream that follows a uniform distribution, and channel coding the bit data stream; converting the channel-coded data into constellation point symbol data using different constellation mapping methods; and according to the constellation point symbol data, under different signal-to-noise ratios, simulating and obtaining the system packet error rate under the condition of no frequency deviation.

[0103] In the implementation, software is used to generate a series of 0-1 bit data streams that follow a uniform distribution, and then the generated bit data streams are channel-encoded through a Turbo encoder to provide additional error detection and correction capabilities for the subsequent transmission process. The encoded data is further converted into constellation point symbol data through different constellation modulation methods such as QPSK and 8PSK. Under different signal-to-noise ratio conditions, the system packet error rate in the absence of frequency deviation is simulated, that is, the modulated signal is demodulated and decoded at the receiving end, and the difference between the original data and the recovered data is compared to obtain the performance indicator of the packet error rate.

[0104] It should be added that the data transmission process of the SC-FDMA communication system of the present invention may include the following steps:

[0105] Step 1: Generate a Protocol Data Unit (PDU), which contains the raw bit data to be transmitted.

[0106] Step 2: Perform a scrambling operation on the original bit data to disrupt the long string of "0" or "1" in the data to reduce its potential impact on system performance.

[0107] Step 3: Add a cyclic redundancy check (CRC) to the end of the data packet so that the receiving end can use the check code to determine whether an error occurs during the transmission of the data packet.

[0108] Step 4: Perform Turbo encoding on the scrambled data and CRC code, and further enhance the randomness of the data through interleaving to improve the anti-interference capability.

[0109] Step 5: Map the encoded and interleaved bit data to constellation points to form constellation symbols in preparation for SC-FDMA modulation.

[0110] Step 6: The constellation point symbols are converted into time domain signals through SC-FDMA modulation and are ready to be transmitted on the physical channel.

[0111] Step 7: At the receiving end, perform the SC-FDMA demodulation process to reconvert the time domain signal into constellation point symbols.

[0112] Step 8: Demap the received constellation point symbols back to bit data.

[0113] Step 9: Perform deinterleaving and Turbo decoding on the demapped bit data to restore the originally transmitted data.

[0114] Step 10: Perform CRC check to verify the integrity and correctness of the data. If the check passes, it is considered that the data packet is received successfully; if the check fails, it is considered that the data packet is received incorrectly.

[0115] Step 11: For the data packets that pass the CRC check, perform a descrambling operation to restore the original data of the sender.

[0116] Figure 3 Schematic diagram of SC-FDMA modulation process provided by an embodiment of the present invention. Figure 3 As shown, first, the constellation point data is serial-to-parallel converted according to a group of P points, that is, the continuous bit stream is grouped to prepare for the subsequent P-point FFT processing. Then, the P-point Fast Fourier Transform (FFT) is performed on the grouped data to convert the data from the time domain to the frequency domain to form multiple parallel frequency domain signals. There are two main data generation methods for SC-FDMA modulation: Localized Frequency Division Multiple Access (LFDMA) and Interleave Frequency Division Multiple Access (IFDMA). In this example, the LFDMA method is used to map the frequency domain data processed by FFT to P consecutive subcarriers in the resource grid. After that, the N-point IFFT is performed on the data on the resource grid, the frequency domain signal is converted back to the time domain, and then the parallel-to-serial conversion is performed to generate the time domain signal for transmission. In order to eliminate inter-symbol interference (ISI), a cyclic prefix (CP) can be added in front of each transmission block. This is a protection interval used to ensure that the receiving end correctly decodes the signal.

[0117] Through simulation experiments, for Turbo coding with different code rates and different constellation modulation technologies, in an AWGN channel environment with different signal-to-noise ratio conditions, the performance curve of the system packet error rate without frequency offset is obtained.

[0118] Further, in a specific implementation, in the method for determining the influence of the residual frequency offset on the packet error rate performance provided in the embodiment of the present invention, step S102 calculates the first symbol error rate of the system, which may specifically include: first, in an additive white Gaussian noise channel, demodulating the signal at the receiving end to obtain a demodulated first signal; the demodulated first signal is expressed as: ,in represents the user transmission symbol after constellation mapping, is a complex Gaussian noise term with zero mean, The variance of ;in, express The real part of express The imaginary part of express The standard deviation of the real part, express The standard deviation of the imaginary part, Represents the value of the standard deviation of the noise when there is no frequency offset; then, the symbol values ​​in the first quadrant are analyzed according to the user transmission symbols after constellation mapping in the demodulated first signal to obtain the first symbol error rate of the system after modulation using different constellation mapping methods.

[0119] In the implementation, when calculating the system symbol error rate for different constellation mapping methods, it is assumed that the frequency offset estimation in the system has reached an ideal state. In the AWGN channel environment, the system symbol error rate is mainly affected by the noise level, which is similar to the performance of a single carrier transmission system. Specifically, in the AWGN channel, the received signal after SC-FDMA demodulation can be expressed as: When calculating and analyzing the symbol error rate, the present invention only considers the symbols in the first quadrant, taking into account the symmetry of constellation modulation, and does not need to consider the symbols in other quadrants. In constellation mapping, the constellation point symbols are symmetrical about both the x-axis and the y-axis. This symmetry means that the symbols in other quadrants will have the same symbol error rate statistical characteristics. Therefore, by analyzing the symbols in the first quadrant, the SER performance of the entire constellation diagram can be derived.

[0120] It should be noted that when there is no noise, the demodulated signal is a signal composed of the constellation point symbols, and the demodulation here refers to the SC-FDMA demodulation process. When there is noise, the demodulated signal is a signal composed of the constellation point symbols plus the noise.

[0121] Furthermore, in a specific implementation, when the constellation mapping mode is QPSK, the symbol of QPSK modulation in the first quadrant is ;in, represents an imaginary number;

[0122] The following formula is used to calculate the system's first symbol error rate:

[0123] ;

[0124] in, represents the system first symbol error rate, express The real part of express The imaginary part of express The real part of express The imaginary part of represents probability calculation, Represents the complementary cumulative distribution function of the standard normal distribution.

[0125] When the constellation mapping mode is 8PSK, the symbol value set of 8PSK modulation in the first quadrant is ;in, Represents an imaginary number. For 8PSK, the symbol decision area is usually defined as a sector area, which is determined by the symmetry and phase spacing characteristics of the 8PSK constellation diagram. In the traditional decision strategy, the phase of the received signal is the main basis for deciding the symbol category. In order to ensure the uniformity of the calculation and simplify the calculation process, an alternative method is adopted. This method does not make a decision directly based on the phase of the received signal, but uses the in-phase and orthogonal components of the received signal to make a decision.

[0126] At this time, the symbol error rate is:

[0127] ;

[0128] When there is no frequency deviation , so the first symbol error rate of 8PSK system is:

[0129] .

[0130] When performing the above calculations, the present invention adopts reasonable approximate results, which effectively reduces the complexity of the calculations while ensuring the accuracy of the results.

[0131] When the constellation mapping mode is M-QAM, the symbol value set of M-QAM modulation in the first quadrant is:

[0132] ;

[0133] in, Indicates the symbol value of M-QAM in the first quadrant, express The real part of express The imaginary part of represents the modulation order of QAM, is the average power of the transmitted symbol. For 16QAM, ; For 64QAM, .

[0134] Define the function:

[0135] ;

[0136] At this time, the symbol of M-QAM in the first quadrant The probability of a correct decision is :

[0137] ;

[0138] in,

[0139] ;

[0140] The following formula is used to calculate the first symbol error rate of the system:

[0141] .

[0142] Further, in a specific implementation, in the method for determining the influence of the residual frequency offset on the packet error rate performance provided in the embodiment of the present invention, step S103 calculates the second symbol error rate of the system, which may specifically include: first, in an additive white Gaussian noise channel, demodulating the signal at the receiving end to obtain a demodulated second signal; the demodulated second signal is expressed as: ,in ,in Represents the system symbol index, represents the normalized residual frequency deviation, Indicates the actual frequency deviation, represents the subcarrier spacing, Indicates the number of sampling points that a system symbol lasts. Indicates the number of IFFT points used in system modulation, Indicates the number of sampling points of the cyclic prefix; then, the symbol values ​​in the first quadrant are analyzed according to the user transmission symbols after constellation mapping in the demodulated second signal to obtain the second symbol error rate of the system after modulation using different constellation mapping methods.

[0143] It should be noted that the first demodulated signal is the constellation point symbol obtained by demodulation without considering the frequency offset effect and only considering the noise effect. The second demodulated signal is the constellation point symbol obtained by demodulation after considering both the frequency offset effect and the noise effect. These two are used to calculate the subsequent symbol error rate. They are independent and are compared based on the assumption that the symbol error rate and the packet error rate are the same during the final calculation.

[0144] In implementation, while considering the impact of residual frequency offset on system performance, the calculation of the system symbol error rate under different constellation mappings needs to comprehensively consider the noise and the phase rotation effect caused by the residual frequency offset. In this case, the symbol error rate of the system is not only affected by the noise, but also by the residual phase rotation of the signal after the frequency offset estimation and compensation. Since the frequency offset estimation and compensation have been performed, the impact of the inter-carrier interference (ICI) caused by the residual frequency offset is relatively small. In order to simplify the calculation and reduce the complexity, the present invention assumes that the residual frequency offset mainly causes a fixed phase rotation between adjacent SC-FDMA symbols, and will not cause complex ICI. From Figures 4 to 7 The rationality of this approximation can be seen in .

[0145] In the AWGN channel, considering the influence of residual frequency offset, the signal after SC-FDMA demodulation can be expressed as .

[0146] Furthermore, in a specific implementation, when the constellation mapping mode is QPSK, the symbol of QPSK modulation in the first quadrant is ;in, represents an imaginary number;

[0147] The received signal is ,

[0148] in ;

[0149] The second symbol error rate of the system is calculated using the following formula:

[0150] ;

[0151] in, represents the second symbol error rate of the system, express The real part of express The imaginary part of express The real part of express The imaginary part of represents the standard deviation of the noise when there is frequency offset, The symbol is used to distinguish the standard deviation of the noise when there is frequency offset and when there is no frequency offset.

[0152] When the constellation mapping mode is 8PSK, the symbol value set of 8PSK modulation in the first quadrant is ; At this time, the received signal is ,in:

[0153] ;

[0154] The second symbol error rate of the system is calculated using the following formula:

[0155] ;

[0156] , ;

[0157] in, The constellation point is At that time, The constellation symbol rotated by the frequency offset at the SC-FDMA symbol, The constellation points are At that time, The constellation symbol rotated by the frequency offset at the SC-FDMA symbol, The constellation points are At that time, The constellation symbol affected by frequency offset and noise received at the SC-FDMA symbol, The constellation points are At that time, The constellation symbol affected by frequency offset and noise received at each SC-FDMA symbol; express The real part of express The imaginary part of express The imaginary part of express The imaginary part of .

[0158] When the constellation mapping mode is M-QAM, the symbol value set of M-QAM modulation in the first quadrant is:

[0159] ;

[0160] in, represents the modulation order of QAM, is the average power of the transmitted symbol; the received signal is ,in:

[0161] ;

[0162] Define the function:

[0163] ;

[0164] At this time, the symbol of M-QAM in the first quadrant The probability of a correct decision is :

[0165] ;

[0166] in,

[0167] ;

[0168] The following formula is used to calculate the second symbol error rate of the system:

[0169] ;

[0170] in, The constellation points are At that time, The constellation symbol rotated by the frequency offset at the SC-FDMA symbol, express The real part of express The imaginary part of .

[0171] Furthermore, in a specific implementation, in the above-mentioned method for determining the influence of residual frequency deviation on packet error rate performance provided by an embodiment of the present invention, when executing step S104 and step S105, a key assumption is based on that when the SC-FDMA system adopts channel coding, under the same symbol error rate condition, the packet error rate performance of the system will also remain consistent. Based on this, by making an equivalent comparison between the symbol error rate calculated under ideal conditions (i.e., without the influence of frequency deviation) and the symbol error rate under the condition of considering the influence of residual frequency deviation, the present invention can derive the noise variance required to achieve the same system packet error rate as the ideal condition when there is residual frequency deviation. Using the obtained noise variance, the degradation of system performance under the influence of residual frequency deviation is further analyzed.

[0172] Furthermore, in a specific implementation, the method for determining the impact of residual frequency offset on packet error rate performance provided in the embodiment of the present invention may also include: determining the frequency offset estimation accuracy required within a set performance degradation range based on the prediction result of system performance degradation.

[0173] In practice, the present invention can determine the required frequency offset estimation accuracy under the condition of ensuring that the system performance is within an acceptable degradation range based on the prediction results of system performance degradation. This is of great significance for guiding the design and optimization of frequency offset estimation algorithms in actual systems, and it can help engineers make more informed decisions when designing systems to balance performance and consumption of computing resources.

[0174] exist Figures 8 to 15 In the simulation results, the accuracy of the proposed theoretical analysis was successfully verified under different constellation point mapping methods and different bit rates. These images visually demonstrate the consistency between theoretical predictions and actual simulations, thus providing strong empirical support for the performance evaluation of the communication system under study.

[0175] In the above embodiment, the method for determining the influence of the residual frequency offset on the packet error rate performance is described in detail. The present invention also provides a corresponding embodiment of an electronic device from the perspective of hardware.

[0176] Fig.16 This is a schematic diagram of the structure of an electronic device provided by an embodiment of the present invention. This embodiment is based on the hardware perspective, such as Fig.16 As shown, the electronic equipment includes:

[0177] A memory 20, for storing computer programs;

[0178] The processor 21 is configured to implement the steps of the method for determining the influence of the residual frequency offset on the packet error rate performance as mentioned in the above embodiment when executing the computer program.

[0179] Among them, the processor 21 may include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor 21 can be implemented in at least one hardware form of a digital signal processor (DSP), a field-programmable gate array (FPGA), and a programmable logic array (PLA). The processor 21 may also include a main processor and a coprocessor. The main processor is a processor for processing data in the awake state, also known as a CPU; the coprocessor is a low-power processor for processing data in the standby state. In some embodiments, the processor 21 may be integrated with a graphics processing unit (GPU), which is responsible for rendering and drawing the content to be displayed on the display screen. In some embodiments, the processor 21 may also include an artificial intelligence (AI) processor, which is used to process computing operations related to machine learning.

[0180] The memory 20 may include one or more computer-readable storage media, which may be non-transitory. The memory 20 may also include a high-speed random access memory, and a non-volatile memory, such as one or more disk storage devices, flash memory storage devices. In this embodiment, the memory 20 is at least used to store the following computer program 201, wherein, after the computer program is loaded and executed by the processor 21, it can implement the relevant steps of the method for determining the impact of the residual frequency deviation on the packet error rate performance disclosed in any of the aforementioned embodiments. In addition, the resources stored in the memory 20 may also include an operating system 202 and data 203, etc., and the storage method may be temporary storage or permanent storage. Among them, the operating system 202 may include Windows, Unix, Linux, etc. The data 203 may include but is not limited to the data involved in the above-mentioned method for determining the impact of the residual frequency deviation on the packet error rate performance.

[0181] In some embodiments, the electronic device may further include a display screen 22, an input / output interface 23, a communication interface 24, a power supply 25, and a communication bus 26. Those skilled in the art will appreciate that Fig.16 The structure shown in the figure does not constitute a limitation on the electronic device, and may include more or fewer components than shown in the figure. The electronic device provided by the embodiment of the present invention includes a memory and a processor. When the processor executes the program stored in the memory, it can implement the method for determining the influence of the residual frequency deviation on the packet error rate performance as mentioned above, and the effect is the same as above.

[0182] Finally, the present invention also provides an embodiment corresponding to a computer-readable storage medium. The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps recorded in the above method embodiment are implemented.

[0183] It is understandable that if the method in the above embodiment is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium and executes all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk and other media that can store program code. The computer-readable storage medium provided by the present invention can implement the above-mentioned method for determining the influence of residual frequency deviation on packet error rate performance, and the effect is the same as above.

[0184] Finally, the present invention also provides an embodiment corresponding to a computer program product. The computer program product includes a computer program / instruction, and when the computer program / instruction is executed by a processor, the steps recorded in the above-mentioned method embodiment for determining the influence of residual frequency offset on packet error rate performance are implemented. The computer program product provided by the present invention can implement the above-mentioned method for determining the influence of residual frequency offset on packet error rate performance, and the effect is the same as above.

[0185] It should also be noted that, in this specification, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0186] The above is a detailed introduction to the method, device and program product for determining the impact of residual frequency deviation on packet error rate performance provided by the present invention. The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same and similar parts between the various embodiments can be referenced to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description. It should be pointed out that for ordinary technicians in this technical field, without departing from the principle of the present invention, several improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the scope of protection of the present invention.

Claims

1. A method for determining the effect of residual frequency offset on packet error rate performance, characterized in that: The method is applied to an SC-FDMA communication system, comprising: Under the condition of no frequency deviation and different signal-to-noise ratio, the simulation obtains the system packet error rate after channel coding and modulation using different constellation mapping methods; Under the condition of no frequency deviation and the same signal-to-noise ratio, calculate the first symbol error rate of the system after channel coding and modulation using different constellation mapping methods; Under different residual frequency offset conditions, calculating the second symbol error rate of the system after channel coding and modulation using different constellation mapping methods; Calculating, based on a comparison result of the first symbol error rate of the system and the second symbol error rate of the system, a noise variance required to achieve the system packet error rate when there is a residual frequency offset; The prediction result of the residual frequency offset on the degradation of system performance is determined according to the calculated noise variance.

2. The method for determining the impact of residual frequency offset on packet error rate performance according to claim 1, characterized in that: Under the condition of no frequency deviation and different signal-to-noise ratio, the simulation obtains the system packet error rate after channel coding and modulation using different constellation mapping methods, including: Generating a bit data stream following a uniform distribution, and performing channel coding on the bit data stream; Different constellation mapping methods are used to convert the channel-coded data into constellation point symbol data; According to the constellation point symbol data, under different signal-to-noise ratio conditions, the system packet error rate in the absence of frequency offset is obtained through simulation.

3. The method for determining the impact of residual frequency offset on packet error rate performance according to claim 1, characterized in that: Calculating a first symbol error rate of the system, comprising: In an additive white Gaussian noise channel, the signal at the receiving end is demodulated to obtain a demodulated first signal; the demodulated first signal is expressed as: ,in represents the user transmission symbol after constellation mapping, is a complex Gaussian noise term with zero mean, The variance of ;in, express The real part of express The imaginary part of express The standard deviation of the real part, express The standard deviation of the imaginary part, Indicates the value of the standard deviation of the noise when there is no frequency deviation; The symbol values ​​in the first quadrant are analyzed according to the constellation-mapped user transmission symbols in the demodulated first signal to obtain a first symbol error rate of the system after modulation using different constellation mapping methods.

4. The method for determining the impact of residual frequency offset on packet error rate performance according to claim 3, characterized in that: Calculating a second symbol error rate of the system, comprising: In an additive white Gaussian noise channel, the signal at the receiving end is demodulated to obtain a demodulated second signal; the demodulated second signal is expressed as: ,in ,in Represents the system symbol index, represents the normalized residual frequency deviation, Indicates the actual frequency deviation, represents the subcarrier spacing, Indicates the number of sampling points that a system symbol lasts. Indicates the number of IFFT points used in system modulation, Indicates the number of sampling points of the cyclic prefix; The symbol values ​​in the first quadrant are analyzed according to the constellation-mapped user transmission symbols in the demodulated second signal to obtain a second symbol error rate of the system after modulation using different constellation mapping methods.

5. The method for determining the impact of residual frequency offset on packet error rate performance according to claim 4, characterized in that: When the constellation mapping mode is QPSK, the symbol of QPSK modulation in the first quadrant is ;in, represents an imaginary number; The first symbol error rate of the system is calculated using the following formula: ； The second symbol error rate of the system is calculated using the following formula: ； ； in, represents the first symbol error rate of the system, represents the second symbol error rate of the system, express The real part of express The imaginary part of express The real part of express The imaginary part of express The real part of express The imaginary part of express The real part of express The imaginary part of represents probability calculation, represents the complementary cumulative distribution function of the standard normal distribution, Indicates the standard deviation of the noise when there is frequency offset.

6. The method for determining the effect of residual frequency offset on packet error rate performance according to claim 4, characterized in that: When the constellation mapping mode is 8PSK, the symbol value set of 8PSK modulation in the first quadrant is ;in, represents an imaginary number; The first symbol error rate of the system is calculated using the following formula: ； The second symbol error rate of the system is calculated using the following formula: ； ， ； in, represents the first symbol error rate of the system, represents the second symbol error rate of the system, represents the complementary cumulative distribution function of the standard normal distribution, The constellation point is At that time, The constellation symbol rotated by the frequency offset at the SC-FDMA symbol, The constellation point is At that time, The constellation symbol rotated by the frequency offset at the SC-FDMA symbol, The constellation points are At that time, The constellation symbol affected by frequency offset and noise received at the SC-FDMA symbol, The constellation point is At that time, The constellation symbol affected by frequency offset and noise received at each SC-FDMA symbol; express The real part of express The imaginary part of express The imaginary part of express The imaginary part of .

7. The method for determining the impact of residual frequency offset on packet error rate performance according to claim 4, characterized in that: When the constellation mapping mode is M-QAM, the symbol value set of M-QAM modulation in the first quadrant is: ； in, Indicates the symbol value of M-QAM in the first quadrant, express The real part of express The imaginary part of represents the modulation order of QAM, is the average power of the transmitted symbol; The first symbol error rate of the system is calculated using the following formula: ； ； ； ； in, represents the first symbol error rate of the system, Indicates the symbol of M-QAM in the first quadrant corresponding to the first symbol error rate of the system The probability of a correct decision, represents the complementary cumulative distribution function of the standard normal distribution; The second symbol error rate of the system is calculated using the following formula: ； ； ； ； in, represents the second symbol error rate of the system, Indicates the symbol of M-QAM in the first quadrant corresponding to the second symbol error rate of the system The probability of a correct decision, The constellation point is At that time, The constellation symbol rotated by the frequency offset at the SC-FDMA symbol, express The real part of express The imaginary part of .

8. The method for determining the impact of residual frequency offset on packet error rate performance according to claim 1, characterized in that: Also includes: According to the prediction result of system performance degradation, the required frequency offset estimation accuracy within a set performance degradation range is determined.

9. An electronic device, characterized in that: The device comprises: Memory for storing computer programs; A processor, configured to implement the steps of the method for determining the influence of residual frequency offset on packet error rate performance as described in any one of claims 1 to 8 when executing the computer program.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the method for determining the influence of residual frequency offset on packet error rate performance as described in any one of claims 1 to 8 are implemented.

11. A computer program product comprising a computer program / instructions, characterized in that When the computer program / instructions are executed by a processor, the steps of the method for determining the influence of residual frequency offset on packet error rate performance as claimed in any one of claims 1 to 8 are implemented.

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