Compensation of IQ-Imbalance and Phase Noise in MIMO-OFDM Systems

摘要

The degrading effect of RF impairments on the performance of wirelesscommunication systems is more pronounced in MIMO-OFDM transmission. Two of themost common impairments that significantly limit the performance of MIMO-OFDMtransceivers are IQ-imbalance and phase noise. Low-complexity estimation andcompensation techniques that can jointly remove the effect of these impairmentsare highly desirable. In this paper, we propose a simple joint estimation andcompensation technique to estimate channel, phase noise and IQ-imbalanceparameters in MIMO-OFDM systems under multipath slow fading channels. Asubcarrier multiplexed preamble structure to estimate the channel andimpairment parameters with minimum overhead is introduced and used in theestimation of IQ-imbalance parameters as well as the initial estimation ofeffective channel matrix including common phase error (CPE). We then use anovel tracking method based on the second order statistics of the inter-carrierinterference (ICI) and noise to update the effective channel matrix throughoutan OFDM frame. Simulation results for a variety of scenarios show that theproposed low-complexity estimation and compensation technique can efficientlyimprove the performance of MIMO-OFDM systems in terms of bit-error-rate (BER).