SAGE based joint timing-frequency offsets and channel estimation in distributed MIMO systems

This paper proposes a timing-frequency offset estimation algorithm joint with channel estimation in distributed multi-input multi-output (MIMO) systems, in which different timing and frequency offsets are considered for each pair of transmit and receive antennas. Different from most of the existing methods which estimate the timing or frequency offsets separately, the proposed scheme makes a joint estimation with a maximum-likelihood (ML) estimation model. Furthermore, an iterative space-alternating generalized expectation-maximization (SAGE) estimator is proposed to provide a solution to the multi-dimensional extreme-value problem. And the Cramér-Rao bound (CRB) for multiple parameter estimation is also derived. Simulations show that the estimation performance of the proposed scheme can reach the CRB effectively.