Joint Frequency Offset and Channel Estimation for UL-MIMO-OFDMA Systems using the Parallel Schmidt Kalman Filters

Joint estimation of the carrier frequency offset (CFO) and channel response of each active user in the uplink of an OFDMA system over time-varying channels is investigated in this work. To cope with the enormous computational complexity involved in tracking the time variations of CFOs and channels, we propose to use the parallel Schmidt Kaiman Filter (PSKF) to break down the complicated optimization problem into multiple parallel but smaller optimization problems. This results in an estimation scheme whose complexity only grows linearly with the number of users. Simulations indicate that the proposed scheme can achieve high estimation accuracy.