Design of new training sequence and estimation scheme for frequency dependent I/Q imbalance in MB-OFDM based UWB systems

This paper analyzes the I/Q imbalance effect of direct-conversion receiver in wide-band wireless communication system and sets up frequency-selective I/Q imbalance model for ultra-wide band system. We design a new training sequence based on extra phase rotation and propose an estimation algorithm using diversity message introduced by I/Q imbalance during the demodulation process. Theoretical analysis and simulation results based on typical MB-OFDM based UWB system confirm that the estimation scheme proposed in this paper can achieve 5 dB EbNo advantage at PER=8%.