Adaptive RLS channel estimation in MIMO-OFDM systems

Owing to channel estimation playing a key role in coherent detection, this paper addresses a kind of adaptive RLS channel estimation in MIMO-OFDM systems. Because there are three different forgetting factors including adaptive, two-step and conventional ones applied to RLS channel estimation, this paper describes the principle of RLS channel estimation and analyzes the impact of the different forgetting factors on the performances of RLS channel estimation. Simulation results prove that the adaptive RLS algorithm with adaptive forgetting factor outperforms that with two-step or conventional forgetting factor in both estimation accuracy and robustness over the frequency-selective fading channel. Therefore, we can employ the adaptive RLS channel estimation by means of adjusting forgetting factor adaptively to track and estimate channel state parameters successfully in MIMO-OFDM systems.