IQ Imbalance Compensation in OFDMA based WiMAX Digital Receivers

WiMAX is one of the most promising technologies for broadcast wireless communication and based on the IEEE 802.16 standards. The WiMAX networks support high speed transmission. But some hardware design, such as the IQ (inphase quadrature) imbalance due to direct conversion in RF front-end, limits their throughput. This problem is especially serious in high-order modulation. Most current papers of this field focus on OFDM based systems, such as wireless local area networks (WLAN). Little attention has been paid to OFDMA based WiMAX systems. So we propose some time-domain compensation strategies to work on this problem according to the preamble symbol. In order to test the performance of compensation, we carry out simulation experiments in AWGN and multi-path fading conditions respectively. Simulation results show that the proposed strategies offer good effect.