Matrix computations (3rd ed.)
Smart Antennas for Wireless Communications: IS-95 and Third Generation CDMA Applications
Smart Antennas for Wireless Communications: IS-95 and Third Generation CDMA Applications
OFDMA for Broadband Wireless Access (Artech House Mobile Communications)
OFDMA for Broadband Wireless Access (Artech House Mobile Communications)
Co-channel interference cancellation for space-time coded OFDM systems
IEEE Transactions on Wireless Communications
Clustered OFDM with adaptive antenna arrays for interference suppression
IEEE Transactions on Wireless Communications
A time and frequency synchronization scheme for multiuser OFDM
IEEE Journal on Selected Areas in Communications
IEEE Journal on Selected Areas in Communications
Channel-independent synchronization of orthogonal frequency division multiple access systems
IEEE Journal on Selected Areas in Communications
A physical scattering model for MIMO macrocellular broadband wireless channels
IEEE Journal on Selected Areas in Communications
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The frequency synchronization issue of multiuser in the uplink of an orthogonal frequency-division multiple-access (OFDMA) system is investigated in this letter. We develop a subspace based blind carrier frequency offsets (CFOs) estimation algorithm for the base station (BS) equipped with uniform linear array (ULA). Due to the adoption of ULA at the BS and the narrowband signal assumption, CFOs of different users can be separated by their spatial information. Thus, unlike existing blind alternatives, which are subject to some specific carrier assignment schemes (CAS) or rely on null subcarriers, our proposed method can support generalized carrier assignment scheme (GCAS) and fully loaded systems, i.e., all subcarriers are available to users. Consequently, the dynamic channel assignment is available and the bandwidth efficiency is higher. Moreover, 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.