Joint Blind and Semi-Blind MIMO Channel Tracking and Decoding Using CMA Algorithm

Communication systems utilizing multiple transmit and receive antennas have attracted much attention in the recent years, because of their significantly increased capacities. Estimation of the multiple-input multiple-output (MIMO) fading channel is a major challenge for multiple antenna systems because the detection of information symbols depends critically on the availability of full or partial channel state information. Recently, there has been increasing interest in iterative channel estimation and data decoding, where data decision obtained from either hard or soft decoding is used as additional information to refine the channel estimates. This work addresses joint channel estimation and data recovery for a general system with multiple transmitting and multiple receiving antennas, impaired by multipath fading. A constant modulus algorithm (CMA) is used to find estimates of the channel and the transmitted data. To the best of our knowledge, this is a novel scheme on joint channel estimation and data detection which profits from a low complexity structure. Computer simulations are presented to confirm the robustness of the analysis and illustrate the acceptable performance of this new approach by considering its bit error rate (BER) and tracking behavior.