A Pilot-aided Frequency Offset Estimation Algorithm for OFDMA Uplink Systems

In this paper, we propose a pilot aided carrier frequency offset (CFO) estimation algorithm for orthogonal frequency division multiplexing access (OFDMA) uplink systems based on two consecutive received OFDMA symbols. Assuming that the channels and the CFOs are static over the two consecutive symbols, we express the second received OFDMA symbol in terms of the CFOs and the first OFDMA symbol. Based on this signal model, a new estimation algorithm which obtains the CFOs by minimizing the mean square distance between the received OFDMA symbol and its regenerated signal is provided. The simulation results show that the proposed algorithm approaches the average Cramer Rao bound for moderate and high signal to noise ratio regions. Moreover, the algorithm can be applied for any carrier assignment schemes.