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

TL;DR

This paper introduces a low-complexity joint estimation and compensation method for IQ-imbalance and phase noise in MIMO-OFDM systems, significantly improving bit-error-rate performance under multipath fading.

Contribution

It proposes a novel joint estimation technique using a subcarrier multiplexed preamble and a tracking method based on second order statistics for MIMO-OFDM impairments.

Findings

Effective impairment compensation reduces BER in simulations

Low-overhead preamble structure enables efficient parameter estimation

Method outperforms existing techniques in various scenarios

Abstract

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).