Adaptive mimo predistortion method for joint compensation of multi-branch crosstalk and iq imbalance

Abstract

The invention discloses a self-adaptive MIMO pre-distortion method for hybrid compensation of multi-branch crosstalk and IQ imbalance, and mainly solves the problems of linearization of a power amplifier and compensation of the crosstalk effect and the IQ imbalance effect. The method is performed in an MIMO system and the method comprises the realization steps that S1, a forward predistorter performs nonlinearity characteristic inverse processing on two paths of input baseband signals so that pre-distortion signals are obtained; S2, the pre-distortion signals are interfered by the crosstalk effect and then inputted to the power amplified to perform power amplification; S3, the power amplifier output signals are interfered by the IQ imbalance effect and then IQ interference signals are obtained; S4, the IQ interference signals are compensated; S5, a crosstalk coefficient and a predistorter coefficient are estimated; and S6, the coefficient of a backward predistorter is copied to the forward predistorter. Anti-interference capacity of the predistorters can be effectively enhanced, realization complexity can be reduced, and the method can be used for linearization of the power amplifier in a broadband MIMO wireless communication system.

Description

technical field [0001] The invention belongs to the technical field of wireless communication, and relates to an adaptive MIMO (Multiple Input Multiple Output) system predistortion method for joint compensation of multi-branch crosstalk and IQ imbalance (In-phase and Quadrature-phase Imbalance) effects, which can be used for wideband MIMO In a wireless communication system, while realizing the linearization of the transmitter power amplifier, the anti-interference ability of the predistorter is improved. Background technique [0002] At present, digital predistortion technology has become the most cost-effective and promising technology in the linearization of RF power amplifiers in wireless communication systems. In the MIMO system predistortion method that compensates for crosstalk effects, Bassam S A et al. gave a crossover digital predistorter for the compensation of crosstalk and nonlinearity in MIMO transmitters in "Crossover digital predistorter for the compensation o...

AI Technical Summary

Problems solved by technology

However, in the actual predistortion structure feedback link, the performance of the down-conversion quadrature demodulator is often unsatisfactory, resulting in the IQ imbalance effect of the signal, which will cause deviations in the extracted predistorter coefficients and affect the performance of the power amplifier. Linearization performance

However, none of the existing MIMO system predistortion methods for compensating for crosstalk effects compensates for the IQ imbalance effect, and their performance in suppressing out-of-band spectrum spread and anti-interference is poor. On the other hand, most of the existing methods use the LS algorithm to Extracting the coefficients of the predistorter still has defects such as high computational complexity and huge data storage in the calculation link, which is not conducive to practical application

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