Iterative Receiver for MIMO-OFDM Systems with Joint ICI Cancellation and Channel Estimation

Abstract

In MIMO-OFDM systems, the time-varying fading of channel can destroy the orthogonality of subcarriers. This causes serious intercarrier interference (ICI), thus leading to significant system performance degradation, which becomes more severe as the normalized Doppler frequency increases. In this paper, we propose a low-complexity iterative receiver with joint frequency-domain ICI cancellation and pilot-assisted channel estimation to minimize the effect of time-varying channel. At the first stage of receiver, the interference between adjacent sub-carriers is subtracted from received OFDM symbols. The parallel interference cancellation (PIC) detection with decision statistics combining (DSC) is then performed to suppress the interference from different antennas. By restricting the interference to the limited number of neighboring subcarriers, the computational complexity of our proposed receiver can be significantly reduced. Furthermore, channel parameters estimated with pilot symbols placed in equispaced groups on FFT grid are used to improve the system performance during iteration. Simulation results show that the proposed MIMO-OFDM iterative receiver can effectively mitigate the effect of ICI and approach the ICI-free performance over time-varying frequency-selective fading channels.