WIFI signal sampling rate error correction device and method

Abstract

The invention provides a WIFI signal sampling rate error correction device and method. The device comprises a signal acquisition and synchronization unit, a frequency offset estimation and compensation unit, a signal demodulation unit, a pilot frequency sampling rate error calculation unit, a first sampling rate error compensation unit, a data sampling rate error calculation unit, a second sampling rate error compensation unit and an EVM calculation unit which are connected with one another. According to the technical scheme, the problem that a high-precision WIFI signal demodulation function cannot be provided for the WIFI test instrument in the prior art is solved.

Description

Technical Field

[0001] This invention relates to the field of WIFI signals, and more specifically to a WIFI signal sampling rate error correction device and method. Background Technology

[0002] With the rapid advancement of digitalization across various industries, WiFi 7 is maturing in terms of standards, equipment, and terminal products. WiFi 6's highest modulation scheme is 1024-QAM, where the modulation symbol carries 10 bits of information. To further improve speed, WiFi 7 will introduce 4096-QAM, allowing the modulation symbol to carry 12 bits of information. Therefore, under the same encoding, WiFi 7's 4096-QAM achieves a 20% speed improvement compared to WiFi 6's 1024-QAM. WiFi 7's introduction of the higher-order modulation scheme 4096QAM, with its larger bandwidth of 320MHz, places extremely high demands on the EVM (Electronic Virtual Machine). In WiFi module testing, clock inconsistencies can introduce sampling rate errors, leading to deterioration of product performance during RF testing. To ensure the quality of the product under test, the requirements for testing instruments are further increased.

[0003] Therefore, there is a need for a WIFI signal sampling rate error correction device and method that can provide high-precision WIFI signal demodulation function for WIFI testing instruments. Summary of the Invention

[0004] The main objective of this invention is to provide a WIFI signal sampling rate error correction device to solve the problem that existing technologies cannot provide high-precision WIFI signal demodulation functions for WIFI test instruments.

[0005] To achieve the above objectives, the present invention provides a WIFI signal sampling rate error correction device, comprising: a signal acquisition and synchronization unit, a frequency offset estimation and compensation unit, a signal demodulation unit, a pilot sampling rate error calculation unit, a first sampling rate error compensation unit, a data sampling rate error calculation unit, a second sampling rate error compensation unit, and an EVM calculation unit, all interconnected.

[0006] The present invention also provides a method for correcting WIFI signal sampling rate error, which specifically includes the following steps:

[0007] S1 collects valid WIFI signals and performs synchronous processing on the WIFI signals.

[0008] S2 performs frequency offset compensation on the WIFI signal, and then demodulates the WIFI signal to obtain the constellation point data of the pilot and WIFI signals.

[0009] S3: Obtain theoretical reference points based on constellation point data of pilot subcarriers, calculate sampling rate error, and perform the first sampling rate error compensation.

[0010] S4: Obtain theoretical reference points based on constellation point data of data subcarriers, calculate sampling rate error and perform second sampling rate error compensation.

[0011] S5 calculates the EVM index using the compensated new constellation point data.

[0012] Furthermore, step S2 specifically includes the following steps:

[0013] S2.1, frequency offset estimation is performed using the autocorrelation method, and frequency offset compensation is performed on the WIFI signal.

[0014] S2.2 Demodulates the WIFI signal parameters to obtain relevant signal parameter information, including: bandwidth, protocol type, number of symbols, pilot subcarrier position and number, and data subcarrier position and number, and obtains the constellation point data of the pilot and data.

[0015] Furthermore, step S3 specifically includes the following steps:

[0016] S3.1, Obtain the theoretical reference point based on the constellation point data of the pilot subcarrier, and calculate the first sampling rate error using the data sampling rate and FFT length:

[0017]

[0018] Where NFFT is the FFT length and Fs is the data sampling rate. Δfs1 represents the phase difference obtained from the pilot subcarrier, GILEN represents the guard interval of the WIFI signal, and Δfs1 represents the first sampling rate error.

[0019] S3.2, perform the first sampling rate error compensation based on the sampling rate error calculated from the pilot subcarrier, and obtain the new constellation point data y(n):

[0020]

[0021] Where x(k) is the original data, h(·) is the interpolation filter, k is the time index of the original discrete signal, and n is the time index of the new constellation point data.

[0022] Furthermore, step S4 specifically includes the following steps:

[0023] S4.1, Based on the constellation point data of the data subcarrier, obtain the theoretical reference point, and perform a second sampling rate error calculation using the data sampling rate and FFT length:

[0024]

[0025] in, Δfs2 is the phase difference obtained from the data subcarrier, GILEN is the guard interval of the WIFI signal, and Δfs2 is the second sampling rate error.

[0026] S4.2, perform a second sampling rate error compensation based on the sampling rate error calculated from the data subcarrier, and obtain new constellation point data:

[0027]

[0028] The present invention has the following beneficial effects:

[0029] This invention provides an apparatus and method for computer compensation of sampling rate error based on pilot and data subcarriers, which realizes the compensation of sampling rate error of WIFI module signal and provides more accurate testing for WIFI module testing. Attached Figure Description

[0030] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. In the drawings:

[0031] Figure 1 A diagram of a WIFI signal sampling rate error correction device according to the present invention is shown.

[0032] Figure 2 The diagram shows a Wi-Fi signal constellation with sampling rate errors.

[0033] Figure 3 It shows the Figure 2 A constellation diagram of WIFI signals after sampling rate error compensation using the method provided in this invention. Detailed Implementation

[0034] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] like Figure 1The WIFI signal sampling rate error correction device shown includes: a signal acquisition and synchronization unit, a frequency offset estimation and compensation unit, a signal demodulation unit, a pilot sampling rate error calculation unit, a first sampling rate error compensation unit, a data sampling rate error calculation unit, a second sampling rate error compensation unit, and an EVM calculation unit, all interconnected.

[0036] The present invention also provides a method for correcting WIFI signal sampling rate error, which specifically includes the following steps:

[0037] S1 collects valid WIFI signals and performs synchronous processing on the WIFI signals.

[0038] S2 performs frequency offset compensation on the WIFI signal, and then demodulates the WIFI signal to obtain the constellation point data of the pilot and WIFI signals.

[0039] S3: Obtain theoretical reference points based on constellation point data of pilot subcarriers, calculate sampling rate error, and perform the first sampling rate error compensation.

[0040] S4: Obtain theoretical reference points based on constellation point data of data subcarriers, calculate sampling rate error and perform second sampling rate error compensation.

[0041] S5 calculates the EVM index using the compensated new constellation point data.

[0042] Specifically, step S2 includes the following steps:

[0043] S2.1, frequency offset estimation is performed using the autocorrelation method, and frequency offset compensation is performed on the WIFI signal.

[0044] S2.2 Demodulates the WIFI signal parameters to obtain relevant signal parameter information, including: bandwidth, protocol type, number of symbols, pilot subcarrier position and number, and data subcarrier position and number, and obtains the constellation point data of the pilot and data.

[0045] Specifically, step S3 includes the following steps:

[0046] S3.1, Obtain the theoretical reference point based on the constellation point data of the pilot subcarrier, and calculate the first sampling rate error using the data sampling rate and FFT length:

[0047]

[0048] Where NFFT is the FFT length and Fs is the data sampling rate. Δfs1 represents the phase difference obtained from the pilot subcarrier, GILEN represents the guard interval of the WIFI signal, and Δfs1 represents the first sampling rate error.

[0049] S3.2, perform the first sampling rate error compensation based on the sampling rate error calculated from the pilot subcarrier, and obtain the new constellation point data y(n):

[0050]

[0051] Where x(k) is the original data, h(·) is the interpolation filter, k is the time index of the original discrete signal, and n is the time index of the new constellation point data.

[0052] Specifically, step S4 includes the following steps:

[0053] S4.1, Based on the constellation point data of the data subcarrier, obtain the theoretical reference point, and perform a second sampling rate error calculation using the data sampling rate and FFT length:

[0054]

[0055] in, Δfs2 is the phase difference obtained from the data subcarrier, GILEN is the guard interval of the WIFI signal, and Δfs2 is the second sampling rate error.

[0056] S4.2, perform a second sampling rate error compensation based on the sampling rate error calculated from the data subcarrier, and obtain new constellation point data:

[0057]

[0058] like Figure 2 and Figure 3 As shown, after correcting the WIFI signal sampling rate error using the method provided by this invention, Figure 2 This is the constellation diagram demodulated without sampling rate error correction, with an EVM of -34.5dB. Figure 3 The constellation diagram obtained after correcting the sampling rate error using the method of this invention has an EVM of -42.5dB, and the demodulation performance is significantly improved, better reflecting the quality of the actual signal. The horizontal and vertical axes are the normalized relative values ​​of the constellation diagram and have no units.

[0059] Of course, the above description is not intended to limit the present invention, and the present invention is not limited to the examples given above. Any changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present invention should also fall within the protection scope of the present invention.

Claims

1. A WIFI signal sampling rate error correction device, characterized in that, include: The interconnected signal acquisition and synchronization unit, frequency offset estimation and compensation unit, signal demodulation unit, pilot sampling rate error calculation unit, first sampling rate error compensation unit, data sampling rate error calculation unit, second sampling rate error compensation unit, and EVM calculation unit.

2. A method for correcting WIFI signal sampling rate error, using the apparatus described in claim 1, characterized in that, Specifically, the steps include the following: S1 collects valid WIFI signals and performs synchronous processing on the WIFI signals; S2, perform frequency offset compensation on the WIFI signal, then demodulate the WIFI signal to obtain the constellation point data of the pilot and WIFI signals; S3, based on the constellation point data of pilot subcarriers, obtain the theoretical reference point, calculate the sampling rate error, and perform the first sampling rate error compensation; S4, based on the constellation point data of the data subcarrier, obtain the theoretical reference point, calculate the sampling rate error, and perform a second sampling rate error compensation; S5 calculates the EVM index using the compensated new constellation point data.

3. The WIFI signal sampling rate error correction method according to claim 2, characterized in that, Step S2 specifically includes the following steps: S2.1, Frequency offset estimation is performed using the autocorrelation method, and frequency offset compensation is performed on the WIFI signal; S2.2 Demodulates the WIFI signal parameters to obtain relevant signal parameter information, including: bandwidth, protocol type, number of symbols, pilot subcarrier position and number, and data subcarrier position and number, and obtains the constellation point data of the pilot and data.

4. The WIFI signal sampling rate error correction method according to claim 2, characterized in that, Step S3 specifically includes the following steps: S3.1, Obtain the theoretical reference point based on the constellation point data of the pilot subcarrier, and calculate the first sampling rate error using the data sampling rate and FFT length: Where NFFT is the FFT length and Fs is the data sampling rate. Δfs1 represents the phase difference obtained from the pilot subcarrier, GILEN represents the guard interval of the WIFI signal, and Δfs1 represents the first sampling rate error. S3.2, perform the first sampling rate error compensation based on the sampling rate error calculated from the pilot subcarrier, and obtain the new constellation point data y(n): Where x(k) is the original data, h(·) is the interpolation filter, k is the time index of the original discrete signal, and n is the time index of the new constellation point data.

5. The WIFI signal sampling rate error correction method according to claim 2, characterized in that, Step S4 specifically includes the following steps: S4.1, Based on the constellation point data of the data subcarrier, obtain the theoretical reference point, and perform a second sampling rate error calculation using the data sampling rate and FFT length: in, Δfs2 is the phase difference obtained from the data subcarrier, GILEN is the guard interval of the WIFI signal, and Δfs2 is the second sampling rate error. S4.2, perform a second sampling rate error compensation based on the sampling rate error calculated from the data subcarrier, and obtain new constellation point data:

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