CN-121619200-B - Sampling frequency offset tracking method, device, computer equipment and storage medium

CN121619200BCN 121619200 BCN121619200 BCN 121619200BCN-121619200-B

Abstract

The application relates to a sampling frequency offset tracking method, a device, computer equipment and a storage medium, which comprise the steps of carrying out signal synchronization processing according to a frame structure of a received signal to obtain a frame starting point, carrying out preliminary sampling frequency offset compensation and channel estimation according to a preamble symbol to obtain a preamble channel estimation result, carrying out decision feedback channel estimation according to a data symbol to obtain a decision feedback signal estimation result, carrying out correlation operation on a time domain channel response signal sampling point corresponding to an effective peak position to obtain a correlation value, calculating residual sampling frequency offset according to the correlation value, updating a sampling frequency offset estimation value by combining a filter coefficient, and carrying out iterative sampling frequency offset compensation according to the updated sampling frequency offset estimation value so as to track the sampling frequency offset in real time. The application realizes the symbol-by-symbol real-time tracking of the sampling frequency offset by respectively generating the channel estimation value based on the preamble symbol and the data symbol, and can realize the real-time tracking without pilot frequency.

Inventors

WANG YUQING
YE YUAN
YANG SHUN
LUO CHAOZHI
SHAO ZHIQIANG
YI HAO
HUANG HONGZHI
NIE SHA
WEN JUAN
SU JIAN
WANG JIAYI
JIANG RENYONG

Assignees

湖南先进技术研究院

Dates

Publication Date: 20260512
Application Date: 20260202

Claims (9)

1. The sampling frequency offset tracking method is characterized by comprising the following steps of: Performing signal synchronization processing according to a frame structure of a received signal to obtain a frame starting point, wherein the received signal comprises a short training sequence symbol, a preamble symbol and a data symbol; Performing preliminary sampling frequency offset compensation and channel estimation according to the preamble symbol to obtain a preamble channel estimation result; Performing decision feedback channel estimation according to the data symbols to obtain a decision feedback channel estimation result; Acquiring a first time domain channel response signal and a second time domain channel response signal according to the preamble channel estimation result and the decision feedback channel estimation result; Determining effective peak positions of the first time domain channel response signal and the second time domain channel response signal, and performing correlation operation based on time domain channel response signal sampling points corresponding to the effective peak positions to obtain correlation values, wherein the effective peak positions are the first peak positions and the second peak positions under the condition that position errors between the first peak positions and the second peak positions are within the range of a preset threshold value, the first peak positions are peak positions of the first time domain channel response signal, and the second peak positions are peak positions of the second time domain channel response signal, and the preset threshold value is +/-3 sampling points; Calculating residual sampling frequency offset according to the correlation value, updating a sampling frequency offset estimation value by combining a filter coefficient, and performing iterative sampling frequency offset compensation according to the updated sampling frequency offset estimation value so as to track the sampling frequency offset in real time; the step of obtaining a first time domain channel response signal and a second time domain channel response signal according to the preamble channel estimation result and the decision feedback channel estimation result comprises the following steps: Performing inverse fast fourier transform on the preamble channel estimation result to obtain the first time domain channel response signal; And performing inverse fast Fourier transform on the decision feedback channel estimation result to obtain the second time domain channel response signal.
2. The method of claim 1, wherein the performing signal synchronization processing according to the frame structure of the received signal to obtain a frame starting point comprises: Acquiring a received signal; And carrying out signal synchronization processing according to the short training sequence symbol and the preamble symbol of the received signal to obtain the frame starting point.
3. The method of claim 1, wherein the performing preliminary sampling frequency offset compensation and channel estimation according to the preamble symbol to obtain a preamble channel estimation result comprises: Performing time-frequency domain transformation processing on the preamble symbol to obtain frequency domain data of the preamble symbol; performing correlation operation according to the frequency domain data of the preamble symbol and the reference symbol to obtain a preamble channel estimation result; and generating a preliminary sampling frequency offset estimation value according to the preamble channel estimation result, and performing preliminary sampling frequency offset compensation according to the preliminary sampling frequency offset estimation value.
4. The method of claim 1, wherein the performing channel estimation based on the data symbols to obtain a decision feedback channel estimation result comprises: performing time-frequency domain transformation processing on the data symbols to obtain first frequency domain data of the synchronized data symbols; sequentially performing equalization processing, demapping processing and decoding processing on the first frequency domain data; if the decoding is correct, recoding and mapping the decoding result to obtain second frequency domain data of the mapped data symbol; And performing correlation operation according to the second frequency domain data and the first frequency domain data to obtain a decision feedback channel estimation result.
5. The method of claim 1, wherein the performing a correlation operation based on the time domain channel response signal sampling points corresponding to the effective peak positions to obtain a correlation value includes: Wherein, the As the value of the correlation(s), For the first time domain channel response signal at the effective peak position Is used for the sampling points of the (a), For the second time domain channel response signal at the effective peak position Is a conjugate of the sampling point of (a).
6. The method of claim 5, wherein calculating a residual sampling frequency offset from the correlation value, and updating the sampling frequency offset estimate in combination with the filter coefficients, comprises: Wherein, the For the residual sampling frequency offset, As the phase of the correlation value, For the sampling frequency of the signal, For the length of the preamble symbol, For the updated sampled frequency offset estimate, For the preliminary sampling frequency offset estimate, In order for the coefficients of the filter to be present, 。
7. A sampling frequency offset tracking device, comprising: The synchronous module is used for carrying out signal synchronous processing according to the frame structure of the received signal to obtain a frame starting point, wherein the received signal comprises a short training sequence symbol, a preamble symbol and a data symbol; the first channel estimation module is used for carrying out preliminary sampling frequency offset compensation and channel estimation according to the preamble symbol to obtain a preamble channel estimation result; The second channel estimation module is used for carrying out decision feedback channel estimation according to the data symbols to obtain a decision feedback channel estimation result; The time-frequency domain conversion module is used for acquiring a first time domain channel response signal and a second time domain channel response signal according to the preamble channel estimation result and the decision feedback channel estimation result; the peak processing module is used for determining effective peak positions of the first time domain channel response signal and the second time domain channel response signal, and carrying out correlation operation based on time domain channel response signal sampling points corresponding to the effective peak positions to obtain correlation values, wherein the effective peak positions are a first peak position and a second peak position under the condition that a position error between the first peak position and the second peak position is within a range of a preset threshold value, the first peak position is the peak position of the first time domain channel response signal, and the second peak position is the peak position of the second time domain channel response signal, and the preset threshold value is +/-3 sampling points; The sampling frequency offset tracking module is used for calculating residual sampling frequency offset according to the correlation value, updating a sampling frequency offset estimation value by combining a filter coefficient, and performing iterative sampling frequency offset compensation according to the updated sampling frequency offset estimation value so as to track the sampling frequency offset in real time; the time-frequency domain conversion module is further configured to perform inverse fast fourier transform on the preamble channel estimation result to obtain the first time domain channel response signal, and perform inverse fast fourier transform on the decision feedback channel estimation result to obtain the second time domain channel response signal.
8. A computer device comprising a memory and a processor, the memory storing a computer program, characterized in that the processor implements the steps of the sampling frequency offset tracking method of any one of claims 1 to 6 when the computer program is executed.
9. A computer readable storage medium having stored thereon a computer program, which when executed by a processor implements the steps of the sampling frequency offset tracking method of any of claims 1 to 6.

Description

Sampling frequency offset tracking method, device, computer equipment and storage medium Technical Field The present invention relates to the field of wireless communications technologies, and in particular, to a sampling frequency offset tracking method, a device, a computer device, and a storage medium. Background Orthogonal frequency division multiplexing (OrthogonalFrequencyDivisionMultiplexing, abbreviated as OFDM) technology has been widely applied to wireless communication systems such as star link broadband communication, 4G/5G communication, wiFi6, and the like. The core idea is to decompose the high-speed bit stream into a plurality of low-speed sub-bit streams, respectively modulate the sub-bit streams to mutually orthogonal sub-carriers for transmission, and can effectively resist inter-code crosstalk. However, the OFDM system is extremely sensitive to frequency offset, and the sampling frequency offset (Sampling Frequency Offset, SFO) is used as a main frequency offset type, and is caused by clock mismatch between the transmitter and the receiver, so that orthogonality of subcarriers is destroyed, and data errors accumulate along with the number of carriers, thereby seriously affecting communication performance. The existing Sampling Frequency Offset Estimation (SFOE) method mainly relies on a preamble and a pilot, wherein the preamble is used for initial rough estimation, and the pilot is distributed in a data payload and used for tracking residual frequency offset. However, the OFDM frame of part of communication systems (such as HomePlugAV2 standard) is not provided with pilot frequency, so that the real-time tracking of residual frequency offset can not be realized, and even if the pilot frequency is arranged, the influence of multipath effect and noise on estimation accuracy is difficult to be restrained. In addition, cyclic prefix-based SFO estimation methods are limited by prefix length and channel reflection, with limited performance improvement. Therefore, a technical scheme capable of effectively suppressing multipath and noise interference and tracking sampling frequency offset in real time without depending on pilot frequency is needed to solve the defects of the existing method. Disclosure of Invention In order to solve the technical problems, the embodiments of the present application provide a sampling frequency offset tracking method, apparatus, computer device and storage medium, which are suitable for synchronous optimization of an Orthogonal Frequency Division Multiplexing (OFDM) system, and can effectively suppress multipath and noise interference without relying on pilot frequency, and can track sampling frequency offset in real time, and the specific scheme is as follows: in a first aspect, an embodiment of the present application provides a sampling frequency offset tracking method, including: Performing signal synchronization processing according to a frame structure of a received signal to obtain a frame starting point, wherein the received signal comprises a short training sequence symbol, a preamble symbol and a data symbol; Performing preliminary sampling frequency offset compensation and channel estimation according to the preamble symbol to obtain a preamble channel estimation result; Performing decision feedback channel estimation according to the data symbols to obtain a decision feedback signal estimation result; acquiring a first time domain channel response signal and a second time domain channel response signal according to the preamble channel estimation result and the decision feedback signal estimation result; Determining effective peak positions of the first time domain channel response signal and the second time domain channel response signal, and performing correlation operation based on time domain channel response signal sampling points corresponding to the effective peak positions to obtain correlation values, wherein the effective peak positions are first peak positions and second peak positions under the condition that position errors between the first peak positions and the second peak positions are smaller than a preset threshold value, the first peak positions are peak positions of the first time domain channel response signal, and the second peak positions are peak positions of the second time domain channel response signal; And calculating residual sampling frequency offset according to the correlation value, updating a sampling frequency offset estimation value by combining a filter coefficient, and performing iterative sampling frequency offset compensation according to the updated sampling frequency offset estimation value so as to track the sampling frequency offset in real time. In one embodiment, the performing signal synchronization processing according to a frame structure of a received signal to obtain a frame starting point includes: Acquiring a received signal; And carrying out signal synchronization processing according to the shor