Digital predistortion method and system suitable for mimo transmitter full-loop distortion compensation

Abstract

The invention belongs to the technical field of wireless communication, and discloses a digital predistortion method and system suitable for full-loop distortion compensation of MIMO transmitters, including: connecting the short-circuit channel to make N power amplifiers invalid, according to the input baseband signal and the feedback signal , calculate the parameter value of the joint pre-canceller, compensate the quadrature modulator error, quadrature demodulator error and crosstalk effect; disconnect the short-circuit channel to make N power amplifiers work normally, and calculate the pre-distortion according to the input baseband signal and feedback signal Parameter value of the power amplifier for power amplifier distortion compensation. The present invention can jointly eliminate the quadrature modulator error, quadrature demodulator error and crosstalk effect in advance, and then perform independent power amplifier distortion compensation, greatly improve the modeling accuracy and compensation performance of the compensation model, and effectively suppress the in-band distortion and The out-of-band spectrum is extended to meet the performance requirements of the broadband MIMO wireless communication system.

Description

technical field [0001] The invention belongs to the technical field of wireless communication, and in particular relates to a digital predistortion method and system suitable for full-loop distortion compensation of MIMO transmitters. Background technique [0002] In practical application scenarios, various errors inevitably exist in the loop due to factors such as unsatisfactory devices in the multi-antenna MIMO transmitter system, which limits the improvement of system performance and efficiency. Among them, the full-loop distortion of MIMO transmitter includes quadrature modulator error, quadrature demodulator error, crosstalk effect among multiple branches and power amplifier distortion. Quadrature modulator errors and quadrature demodulator errors mainly include that the amplitudes of the I and Q channels are not strictly equal, the phases do not meet the strict quadrature relationship, and there are DC offset errors. The crosstalk effect between multi-branches mainly ...

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Problems solved by technology

[0006] (1) In the actual MIMO transmitter system, with the increase of the number of MIMO branches, power amplifier memory depth and nonlinear order, the number of parameters of the compensation model in the above MIMO predistortion method will increase exponentially, It is revealed that the above-mentioned MIMO pre-distortion method has defects such as many model parameters and high computational complexity, and it is difficult to apply it to the actual system

[0007] (2) As the error increases, the existing MIMO predistortion methods have poor performance in suppressing in-band distortion and out-of-band spectrum spreading, and cannot meet the performance requirements of existing standards

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