Joint carrier frequency offset and channel estimation for MIMO-OFDM systems using extended H _∞ filter

We address the problem of joint carrier frequency offset (CFO) and channel estimation for multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) systems over time-varying channels. The CFOs between different pairs of transmit and receive antennas are considered to be different. The method is derived based on the extended H _∞ filter (EHF). Compared to the conventional extended Kalman filter (EKF)-based method, the EHF-based method does not require any knowledge of the noise distributions, so it is more flexible and robust to the unknown disturbances. Simulation results are provided to illustrate the performance of this method.