Pilot-Aided IQ Imbalance Compensation for OFDM Systems Operating Over Doubly Selective Channels
Lanlan He, Shaodan Ma, Yik‐Chung Wu, Yiqing Zhou, Tung-Sang Ng, H. Vincent Poor · IEEE Transactions on Signal Processing · 2011
In this paper, pilot-aided in-phase and quadrature-phase (IQ) imbalance compensation for orthogonal frequency division multiplexing (OFDM) systems operating over doubly selective channels is addressed. Based on a reformulated system model and the least squares (LS) criterion, a joint IQ imbalance and channel estimation method is developed, and the corresponding compensation scheme is also proposed. Moreover, to further enhance the compensation performance, an iterative compensation algorithm is derived via an expectation-maximization (EM) algorithm. Simulation results show that the iterative compensation algorithm initialized by the proposed LS compensation scheme converges in a few iterations and its performance after convergence is close to the ideal case with perfect IQ imbalance and channel state information.