Frequency offset estimation by differentially coherent frequency error characterization for OFDM wireless communications

A novel frequency offset estimation technique for OFDM wireless communications is proposed in this paper. By taking advantage of subcarrier-level differentially coherent detection, the proposed estimator based on frequency error characteristics can effectively overcome frequency-selective fading effects. Frequency error characterization is achieved by means of pseudo-noise (PN) matched filters (MF) on the subcarrier basis; thus, it inherently needs no assistance in the form of accurate timing information. In addition, the proposed technique can combat the rapid time-selectivity caused by a high Doppler spread because it requires channel stationarity within only short time duration due to the exploitation of a single training symbol. Furthermore, a linearized estimator is also proposed to reduce the computational complexity, resulting in some insignificant performance degradation. Extensive computer simulations have verified the superiority of the proposed technique.