A Combined Residual Frequency and Sampling Clock Offset Estimation for OFDM Systems

This paper proposes an improved joint tracking algorithm based on the spread spectrum pilots of the orthogonal frequency division multiplexing (OFDM) symbols to estimate the effects caused by the residual carrier frequency offset and the sampling clock offset. The significant factor of this method is that the difference of the pilot phases belonging to two distant OFDM symbols exempts it from channel estimation, which contributes to the calculation accuracy. Meanwhile the estimation robust is strengthened by utilizing the mean of several dispersions between different pilots. Simulation results show that the deviations of the frequency offset and the sampling clock offset estimated by the improved method is 21.7% and 15.8% respectively of those estimated by the algorithms presented in D. K. Kim et al. (1998) and J. Heiskala and J. Terry (2002)