ICI cancellation for relay communication systems with multiple frequency offsets

In this paper, an interchannel interference (ICI) cancellation method is proposed for multiple frequency offsets in orthogonal frequency division multiplexing (OFDM) systems. When signals are received from different transmitters simultaneously like in a relay communication, multiple frequency offsets may appear at the receiver. This causes interchannel interference (ICI) and severe performance degradation because OFDM systems are very sensitive to the frequency offsets. In this paper, we propose a method to eliminate the effect of the multiple frequency offsets for OFDM systems. The method is accomplished in two steps: compensation of the frequency offset in time domain and subsequent cancellation of the ICI in frequency domain. Through computer simulations, we verify the effectiveness of the proposed ICI cancellation method.