A method of evm phase estimation and compensation

Abstract

The invention discloses an EVM (Error Vector Magnitude) phase estimating and compensating method which comprises the following steps: in a time domain, adopting an OFDM (Orthogonal Frequency Division Multiplexing) system for converting data from the time domain to a frequency domain through the removal of cyclic prefixes and FFT (Fast Fourier Transform), and estimating a phase in an OFDM symbol according to received pilot frequency bit data and the pilot frequency bit data for the known symbol in the frequency domain; compensating the data in the OFDM symbol according to the estimated phase, thereby acquiring compensated data; adopting a criterion of Euclidean distance quadratic sum being minimal for estimating the position of a star map corresponding to the compensated data, thereby acquiring an estimated data; finally estimating residual phase deviation according to the compensated data and the estimated data, and then compensating the data in the OFDM symbol. The EVM phase estimating and compensating method has the advantages that the operation is simple and the EVM precision can be effectively increased.

Description

Technical field [0001] The present invention relates to the field of wireless communication, in particular to an EVM phase estimation and compensation method. Background technique [0002] EVM represents the vector difference between the ideal error-free reference signal and the actual transmitted signal, which is used to comprehensively measure the modulation quality of the system. In communication systems such as TD and LTE, the frequency band transmission of digital signals is that the baseband signal of the physical layer of the transmitting end is first orthogonally modulated, and then transmitted to the receiving end through the wireless communication channel, and then the original is restored after corresponding demodulation at the receiving end. Baseband signal. In this process, the modulation error generated by the modulator, the quality of the radio frequency device and the phase-locked loop noise, thermal noise, and modulator design will cause errors in the modulation...

AI Technical Summary

Problems solved by technology

[0005] Existing technical solutions usually only use the corresponding received pilot sequence and known sequence to estimate the phase, and then perform phase compensation on other subcarrier data through various fitting methods, because in the process of EVM measurement , the phase deviation between the subcarriers is very random, so there is a large error in the phase compensation according to the above method, which affects the measurement accuracy of EVM

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