OFDM channel shortening in the presence of IQ imbalance

Abstract

In orthogonal frequency division multiplexing systems, channel-shortening methods are effective for overcoming inter-block interference (IBI) caused by the delayed waves that exceed cyclic prefix length. In direct-conversion receivers, IQ imbalance in analog circuits causes serious performance degradation. In this paper, we discuss the impact of both frequency-independent and frequency-selective IQ imbalances on the interference suppression capability of a channel shortening method. Both theory and simulations show that the channel shortening method can suppress IBI regardless of the presence of IQ imbalances.