A Simple ICI Suppression Method Utilizing Cyclic Prefix for OFDM Systems in the Presence of Phase Noise

Abstract

An extremely low-complexity inter-carrier interference (ICI) suppression method for OFDM systems in the presence of phase noise is proposed in this paper. The core idea is to utilize the ISI-free part of cyclic prefix (CP), which is simply ignored in traditional methods. We linearly combine the ISI-free samples in CP with the corresponding samples in the OFDM symbol to suppress ICI, and this scheme is called 'CP combining' throughout this paper. In addition, the optimum combining coefficients, in the sense of ICI power minimization, are derived, and a set of near-optimum coefficients are proposed to reduce the complexity. Simulation results show that the proposed CP combining method improves the system performance by 0.5 - 1.5dB. Furthermore, the proposed method can be incorporated with other phase noise mitigation methods to further improve the system performance.