Improved Doubly-Selective Radio Channel Tracking for Modern Wireless Systems

We present improvement to track time-variations in the doubly-selective (DS) channel for orthogonal frequency-division multiplexing (OFDM) systems. The MCE-BEM, a variant of basis expansion model (BEM) based on complex exponentials (CEs), is used to model time variations in the DS channel. In the MCE-BEM, CEs are defined by the highest Doppler frequency in the DS channel. We propose a method, based on spectral concentration of the MCE-BEM, to find the optimum highest frequency for CEs to be employed in the MCE-BEM. Simulations for 3GPP LTE-downlink confirm that the proposed modification improves the tracking accuracy, measured in mean square error (MSE), by nearly one order of magnitude at 700 km/h, and overall comparable to the state-of-the-art.