Joint channel and frequency offset estimation in distributed MIMO flat-fading channels

In this paper, we consider the problem of joint channel and frequency offset estimation in a flat-fading multi- input multi-output (MIMO) system. We assume that each pair of transmit and receive antennas has a different frequency offset. We present two computationally efficient iterative algorithms based on expectation conditional maximization (ECM) and space-alternating generalized expectation-maximization (SAGE) algorithms. The mean-square-error (MSE) performance of the interested parameters for the proposed algorithms is compared with the Cramer-Rao Bound (CRB). Simulation results show that the proposed iterative algorithms achieve the CRB and overcome the drawbacks of existing algorithms.