Em-Based Semi-Blind Mimo-Ofdm Channel Estimation

This paper deals with semi-blind (SB) channel estimation of Multiple-Input Multiple-Output Orthogonal Frequency-Division Multiplexing (MIMO-OFDM) wireless communications system in the uplink transmission. Herein, we propose a new channel estimation approach using the well known EM technique. More precisely, we derive first the SB EM algorithm in the MIMO case. Then, a parallelizable version of this algorithm is introduced relying on the decomposition of the MIMO system into several MISO systems. Finally, we propose a reduced cost EM version where only the lattice points in the neighboring of the pilot-based detected symbols are considered.