Quadrature amplitude modulation signal frequency offset compensation method and device

A technology of quadrature amplitude modulation and frequency offset compensation, applied in the modulation carrier system, digital transmission system, electrical components, etc., can solve the problems of inaccurate frequency offset calibration, multi-column DMRS frequency offset estimation, and demodulation performance degradation, etc. Achieve high compensation accuracy, improve demodulation performance, and reduce EVM

Pending Publication Date: 2022-04-19
CERTUS NETWORK TECHNANJING +2
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  • Claims
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AI Technical Summary

Problems solved by technology

[0005] When there are few DMRS reference signals and many DMRS reference signals, there is a problem of inaccurate frequency offset compensation on some edge symbols, which leads to the degradation of demodulation performance
Taking 5GNR single-column DMRS scheduling as an example, channel estimation cannot perform necessary frequency offset estimation through multi-column DMRS, so frequency offset compensation cannot be performed. Eventually, after signal equalization, there is a certain frequency offset on all time-domain symbols, and Multi-column DMRS may also have inaccurate frequency offset calibration at the edge symbol position, which will eventually affect the signal demodulation capability
[0006] Therefore, the problem existing in the prior art is that the frequency offset compensation accuracy of the quadrature amplitude modulation signal is not high enough, which affects the signal demodulation capability

Method used

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  • Quadrature amplitude modulation signal frequency offset compensation method and device
  • Quadrature amplitude modulation signal frequency offset compensation method and device
  • Quadrature amplitude modulation signal frequency offset compensation method and device

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Embodiment Construction

[0036] Such as figure 1 As shown, the quadrature amplitude modulation signal frequency offset compensation method of the present invention is used to perform frequency offset compensation on the equalized constellation diagram, including the following steps:

[0037] (10) Determination of the amplitude value threshold: according to the orders of different QAM modulation modes, determine the normalized amplitude value upper and lower threshold values;

[0038] According to the order n of different QAM modulation modes (such as QPSK, 16QAM, 64QAM, 256QAM, etc.), determine the upper threshold value thresholdMax and the lower threshold value thresholdMin of the normalized modulus value;

[0039] Taking the 256QAM mapping formula in the following 3GPP protocol as an example, the maximum modulus of the constellation diagram after normalization is 4, which are respectively at the four vertices of the square, and the corresponding moduli are

[0040] A=sqrt(2)*15 / sqrt(170)=1.6269784,...

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Abstract

The invention discloses a quadrature amplitude modulation signal frequency offset compensation method and a quadrature amplitude modulation signal frequency offset compensation device, which are high in compensation accuracy. The quadrature amplitude modulation signal frequency offset compensation method is used for performing frequency offset compensation on a balanced constellation diagram, and comprises the following steps: (10) amplitude threshold determination: determining upper and lower thresholds of a normalized amplitude value according to orders of different modulation modes of QAM (Quadrature Amplitude Modulation); (20) reference complex value screening: performing modulus threshold comparison and complex value quadrant transformation on all complex values on an OFDM symbol 1 to obtain a complex value set for calculating a phase compensation factor; (30) complex number judgment: when the number of complex numbers in the complex value set is less than 4, skipping to (50) a phase compensation ending step, otherwise, continuing; (40) phase compensation processing: obtaining a phase compensation factor through calculation, and compensating the phase by using the phase compensation factor; and (50) ending phase compensation: outputting a complex value after phase compensation.

Description

technical field [0001] The invention belongs to the technical field of wireless communication, in particular to a method and a device for compensating frequency offset of a quadrature amplitude modulation signal. Background technique [0002] Frequency offset refers to the frequency deviation between the transmitter clock and the receiver clock, which is mainly caused by oscillator mismatch and Doppler frequency shift between the transmitter and receiver. Frequency offset always exists in wireless communication systems. [0003] Quadrature Amplitude Modulation (QAM) is a kind of vector modulation. Generally, the signal bits are mapped according to the Gray code encoding method to form complex modulation symbols. Currently, there are QPSK, 16QAM, 64QAM, 256QAM and other methods. The higher the modulation order is, the higher the capacity is. At the same time, it also has higher requirements for signal orthogonality, signal-to-noise ratio, and EVM [0004] In the existing co...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/34
CPCH04L27/3405H04L27/3411
Inventor 曹辰煜逯利军钱培专许闱帏
Owner CERTUS NETWORK TECHNANJING
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