Robust estimation of carrier-frequency offset and timing offset for OFDMA uplink systems over multi-path fading channels

Multi-path fading and multiple access interference largely degrade the performance of carrier-frequency offset and timing offset estimations in OFDMA uplink systems. This paper proposes a robust algorithm with low complexity for joint estimation of carrier-frequency offset and timing offset. The phase differences in the received sub-carrier signals between two consecutive training symbols are employed and a robust sequential least squares algorithm is used to improve the performance of the estimation. Simulation results show that the proposed low complexity algorithm outperforms the linear least squares (LLS) estimator and approaches the performance of the iteratively reweighted least squares (IRLS) estimator