Multiuser Carrier Frequency Offset Estimation for OFDMA Uplink with Generalized Carrier Assignment Scheme

In this paper, we develop a blind carrier frequency offsets (CFOs) estimation algorithm for multiusers in the uplink of an orthogonal frequency-division multiple-access (OFDMA) system, where the base station equipped with uniform linear array (ULA). Due to the ULA at base station, different users could be separated by their spatial information. So unlike existing blind alternatives, which are subject to some specific carrier assignment schemes or rely on null carriers, our proposed method can support generalized carrier assignment scheme (GCAS) and full loaded systems. Thus, our method is more flexible and bandwidth efficient. Besides, the closed-form directions of arrival (DOAs) of all active users are also obtained, which can be used in downlink beamforming in frequency division duplex (FDD) systems. Performance of the proposed scheme is evaluated by computer Monte Carlo simulations.