A low complexity carrier frequency synchronization for OFDMA uplink transmissions

In this paper, we study the estimation of multiple carrier frequency offsets (CFOs) in a uplink orthogonal frequency division multiple access (OFDMA) system using training sequences. The proposed method can estimate the CFO values of all users in one OFDM block without knowing the channel responses. Unlike most earlier results, the proposed method does not involve any nonlinear search and thus has a much lower complexity. Simulation results show that our proposed method provides a comparable performance with the maximum likelihood (ML) CFO estimator.