Low-Complexity ICI Reduction Method for OFDM Systems With Large Subcarrier Numbers

The intercarrier interference (ICI) resulting from the loss of orthogonality caused by the time-varying property of the propagation channels degrades the data detection performance of orthogonal frequency-division multiplexing (OFDM)-based wireless communication systems. Further, the severity of the problem increases when the mobile speed is relatively higher than the number of subcarriers. In this paper, a time-varying filtering method is proposed that reduces ICI by obtaining an approximation of linear system solutions such as zero-forcing (ZF) and minimum mean square error (MMSE). The update rates of the time-varying filter coefficients, which are actually the minimum phase versions of the channel impulse responses, are also minimized to reduce the computational complexity. The simulation results show that the proposed method with lower complexity effectively reduces ICI such that practical application is deemed feasible for OFDM systems with a large number of subcarriers.