Time Domain Channel Estimation Based on Power Roll-Off Strategy and Kalman Algorithm for MIMO-OFDM in WLAN

In this paper, a time-domain (TD) channel estimation scheme, based on power roll-roff strategy and Kalman algorithm, is proposed for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) based wireless local area networks (WLANs). The estimator is then extended to perform decision-directed (DD) channel estimation during data transmission. A power roll-roff strategy exploiting the clustering feature of WLAN MIMO channel is used to get the number of significant taps, which largely improves the performance of common time TD Kalman algorithm. The channel is assumed to be constant during one OFDM symbol but evolves in time according to the first-order Markov process. The performance for adopted tap length is investigated. Simulation results show that the proposed estimation scheme has good performance measured in terms of the mean squares error (MSE) and the bit error rate (BER).