Adaptive identification and tracking of doubly selective fading channels for wireless MIMO-OFDM systems

In wireless MIMO-OFDM systems, accurate channel state information at the receiver is a prerequisite for large diversity and multiplexing gains. Here, we propose a pilot symbol assisted, LMS based, adaptive channel identification/tracking scheme for time-varying, delay-spread MIMO channels. Our scheme features automatic tuning of the LMS adaptation constants and modest computational complexity. No prior knowledge of channel statistics is required. Simulation results demonstrate the good performance of our algorithm for a wide range of SNR, maximum delay, and maximum Doppler.