A time-varying MIMO fading channel tracking scheme in space-time code system

Channel utilization is a very important factor in the wireless communication system because radio frequency resource is expensive almost in every country of the world. We address a scheme of channel tracking for multi-input multi-output (MIMO) time-varying fading channels in a space-time code (STC) system. It is shown that the proposed scheme, using the space-time recoding at the receiver for channel tracking, can provide significant error performance gains in the same channel utilization or tremendously improves channel utilization without sacrificing error performance comparing with no tracking. Error performance is maintained as good as classical space-time code system with 80% channel utilization even channel utilization is 99% in the new scheme. The new space-time recoding scheme can be considered as a pseudo blind channel estimation method in the MIMO system because pilot is very negligible. The influence of pilot length is also researched in the paper. The new channel tracking scheme may be easily generalized to M receive antennas and N transmit antennas and any space-time code scenario.