Exploiting I/Q Imbalance in Direct Conversion Transceivers for Improving the Performance of a V-BLAST OFDM System

A receiver for a MIMO OFDM communication system using direct conversion transceivers is proposed. The novel receiver takes advantage of the I/Q imbalance inherent to the direct conversion operation. It can be shown that the I/Q imbalance in multicarrier communication systems creates an additional frequency diversity. By adequately exploiting such diversity at the receiver, the overall performance can be considerably improved. Simulation results considering a MIMO OFDM system using V-BLAST show that, when exploiting the I/Q imbalance, gains of up to 5 dB at a BER of 10^-4 can be obtained with respect to the ideal system, without I/Q imbalance.