Maximum-likelihood carrier-frequency synchronization and channel estimation for MIMO-OFDM systems

In this paper, we propose a new scheme for maximum-likelihood (ML) estimation of both carrier- frequency offset (CFO) and channel coefficients in multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems. To reduce the prohibitive complexity of ML estimate, the expectation-maximization (EM) algorithm is employed. From Simulations, it is shown that the accuracy of proposed scheme is close to the Cramer-Rao bound (CRB) for both CFO and channel estimations.