Joint estimation of transmitter and receiver I/Q imbalances, CFO, and channel response for OFDM systems

In this paper, we study the problem of channel estimation in the presence of the transmitter and receiver in-phase and quadrature-phase (I/Q) imbalances and carrier frequency offset (CFO) for orthogonality frequency division multiplexing (OFDM) systems. A recently proposed concept called channel residual energy (CRE) is applied to solve the joint estimation problem. By minimizing CRE, we propose a new method to jointly estimate I/Q parameters, CFO and channel response using training sequences. The proposed method needs only one arbitrary OFDM block for training and can achieve a very good performance. When two repeated blocks are available for training, we propose a low complexity method to solve the joint estimation problem. Simulation results show that both the proposed methods provide a good performance.