Semi-Blind Channel Estimation Based on Superimposed Pilots for Single-Carrier MIMO Systems

The authors propose a semi-blind channel estimator based on superimposed pilots for the case of single-carrier single-user MIMO systems. The proposed estimator is based on the Expectation Maximization (EM) algorithm. Numerical results show that even with this semi-blind estimator, the classical approach of time-multiplexed pilots still outperforms the superimposed approach, except for a large number of receive antennas and not too short frames. Superimposed or overlaid pilots are of special interest as they cause no loss in the data transmission rate. However, only under particular conditions the Superimposed Pilots (SP) technique could be preferred to the classical time-multiplexed pilots technique.