Correction of Carrier Frequency Offsets in OFDM-Based Spatial Multiplexing MIMO With Distributed Transmit Antennas

This correspondence focuses on the correction of carrier frequency offsets (CFOs) in orthogonal frequency-division multiplexing (OFDM)-based spatial multiplexing multi-input-multi-output (MIMO) with distributed transmit antennas, where the CFOs between the receiver and each transmit antenna are possibly different. Considering macroscopic fading and multipath Rayleigh fading, the average power of the intercarrier interference (ICI) caused by the CFOs is derived, and the optimal CFO correction value is then obtained by maximizing the average signal-to-interference-and-noise ratio (SINR). In particular, when the difference between the minimum and maximum values of the CFOs is no more than half of the adjacent subcarrier spacing, an upper bound of the average ICI power can be obtained, and a closed-form solution of the optimal CFO correction value is derived.