Channel Estimation in MIMO-OFDM Systems by Tracking the Delay-Subspace

A time domain channel estimation method in MIMO- OFDM systems by tracking the delay-subspace is proposed. The time impulse response is estimated by transmitting known pilot symbols, and the estimation performance is improved by the Givens rotation based delay-subspace tracking and amplitudes tracking based on the LMS filtering. The simulations prove that the time domain channel estimation by tracking the delay- subspace can track faster fading channels, and is more accurate with low complexity.