Complexity Reduction for Time Variant Channel Estimation in 3GPP LTE Downlink

The Basis Expansion Model (BEM) is often employed to track the time variant multipath channels. Using an accurate estimation of the Doppler spread for the BEM gives better channel tracking performance for very high speed vehicles [1].We propose a modification of the conventional BEM for 3GPP LTE systems which is independent from the Doppler spread for all realistic speeds. It shows no significant loss of estimation accuracy compared to conventional BEM, thus providing a robust channel tracking for mobile equipment under changing multipath environment with the additional advantage of very low computational complexity. Simulation results of Mean Squared Error (MSE) are provided to support our claim. Index Terms—Channel estimation, doubly selective channel, basis expansion model (BEM), orthogonal frequency division multiplexing (OFDM), long term evolution (LTE)