  The degrading effect of RF impairments on the performance of wireless
communication systems is more pronounced in MIMO-OFDM transmission. Two of the
most common impairments that significantly limit the performance of MIMO-OFDM
transceivers are IQ-imbalance and phase noise. Low-complexity estimation and
compensation techniques that can jointly remove the effect of these impairments
are highly desirable. In this paper, we propose a simple joint estimation and
compensation technique to estimate channel, phase noise and IQ-imbalance
parameters in MIMO-OFDM systems under multipath slow fading channels. A
subcarrier multiplexed preamble structure to estimate the channel and
impairment parameters with minimum overhead is introduced and used in the
estimation of IQ-imbalance parameters as well as the initial estimation of
effective channel matrix including common phase error (CPE). We then use a
novel tracking method based on the second order statistics of the inter-carrier
interference (ICI) and noise to update the effective channel matrix throughout
an OFDM frame. Simulation results for a variety of scenarios show that the
proposed low-complexity estimation and compensation technique can efficiently
improve the performance of MIMO-OFDM systems in terms of bit-error-rate (BER).
