Quadrature amplitude modulation signal frequency offset compensation method and device

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...

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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

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