Frequency synchronization for uplink massive MIMO with partly calibrated subarrays

In this paper, we design a frequency synchronization method for multiuser orthogonal frequency division multiplexing (OFDM) uplink with a large-scale partly calibrated uniform linear array (ULA) at base station (BS). A beamforming parameter is introduced for each user to mitigate the harmful effect of inter-subarray uncertainties. The proposed method performs carrier frequency offset (CFO) estimation and subsequent data detection individually for each user. The Cramer-Rao bound of CFO estimation is derived. We also provide numerical results to show the effectiveness of the proposed method.