Robust frequency offset estimation for OFDM systems in SFN channel

In this paper, we propose two robust frequency offset estimation methods for OFDM systems in single frequency network (SFN) with large delay spread. Conventional guard-interval-based (GIB) estimation method is very sensitive to intersymbol interference (ISI) caused by long and strong echoes of the SFN channel. In order to minimize ISI-dependent performance degradation, we first introduce a suboptimal minimum variance unbiased (MVU) estimation method based on best linear unbiased estimation (BLUE) principle, and then we modify it to reduce the computational complexity. Simulation results verify that the proposed methods improve the root mean square error (RMSE) performance without error floor due to ISI in contrast with the conventional method. Also, the reduced-complexity method can achieve suboptimal performance in typical multi-path channel as well as the SFN channel.