A Two-Stage Frequency-Offset Estimation and Compensation Scheme for OFDMA System

This paper reports a study of the carrier frequency offset (CFO) estimation and compensation in the uplink of the orthogonal frequency division multiple access (OFDMA) system with interleaved subcarrier assignment. The presence of CFOs between the transmitters and the uplink receiver will destroy the orthogonality among the different subcarriers, resulting in inter-carrier interference and multiuser interference. This paper proposes a pseudo oinverse CFO compensation method based on the signal structure. The proposed method can compensate the CFOs of all users simultaneously and isolate the signals from all users at the same time. this method provides a considerable signal-to-noise ratio gain on the bit error rate performance and has a relatively low implementation complexity