Data combining scheme for ICI conjugate cancellation scheme in OFDM systems

ICI conjugate cancellation scheme proposed by Yeh et al. is the simplest scheme to mitigate the effect of intercarrier interference (ICI), but its carrier to interference ratio (CIR) performance at high carrier frequency offset (CFO) is worse than conventional OFDM system. Its CIR performance at high CFO can be improved by using phase rotated conjugate cancellation (PRCC) scheme, but it requires CFO estimation. In this paper we have proposed an optimal data combining scheme for ICI conjugate cancellation scheme to improve its performance at high CFO. In order to eliminate the requirement of CFO estimation, we have proposed a suboptimal approach for data combining. The proposed scheme is based on CIR optimization using Golden selection search algorithm and a novel approach to find the suboptimal values of weighting coefficients used at the receiver for data combing. The proposed scheme provides better CIR and BER performances in comparison to conventional ICI conjugate cancellation scheme.