OFDM channel estimation in the presence of frequency offset and phase noise

In this paper, we consider OFDM channel estimation in the presence of frequency offset and phase noise. In the literatures, most channel estimation methods assume perfect frequency synchronization and the knowledge of channel statistics. Phase noise and residual frequency offset cause inter-carrier interference (ICI), which consequently impairs the accuracy of channel estimation. The lack of knowledge of channel statistics can make channel estimation much harder. To resolve these problems, we propose with the aid of cyclic prefix (CP) based frequency offset estimation statistics-independent channel estimation. We iteratively search for the most likely channel impulse response (CIR) length, and use it not only for the optimum compensation of frequency offset, but also for finding the optimum window to filter the least square (LS) channel estimate which further suppress the effects of ICI and noise. The proposed scheme is compared with conventional methods for both non-interpolation and interpolation cases. Numerical results are presented to illustrate the effectiveness of the proposed scheme.