Joint Estimation of CFO and CIR in MIMO-OFDM Systems

Recently the integration of the Multiple-Input Multiple-Output (MIMO) architectures and Orthogonal Frequency Division Multiplexing (OFDM) technique has been widely considered as a potential strategy to enhance data rate, capacity and quality of broadband wireless OFDM systems.However, the inherent drawback of OFDM-based systems is their susceptibility to synchronization errors such as the Carrier Frequency Offset (CFO) and the primary challenge in MIMO based systems is the increasing complexity in channel estimation as the number of antennas increases.Various joint CFO and channel estimation for OFDM as well as MIMO-OFDM systems have been proposed till date. In this report, we consider an iterative Expectation-Maximization (EM) algorithm for the joint estimation of CFO and Channel Impulse Response(CIR) for MIMO-OFDM system in frequency selective fading channel.Simulation results show that EM algorithm gives marginally better performance over pilot-assisted Maximum Likelihood (ML)- based algorithm,proposed recently,in terms of MSE of both channel and frequency offset estimators.