Pilot-Assisted Time-Varying OFDM Channel Estimation Based on Multiple OFDM Symbols

Abstract

In this paper, we deal with channel estimation for orthogonal frequency-division multiplexing (OFDM) systems. The channels are assumed to be time-varying (TV) and approximated by a basis expansion model (BEM). Due to the time-variation, the resulting channel matrix in the frequency domain is no longer diagonal, but can be approximated as banded. Based on this band approximation, we propose a channel estimator that can combat both the additive noise and the out-of-band interference. Compared to our previous work, the proposed channel estimator can span multiple OFDM symbol intervals such that more time-correlation information can be explored to improve the estimation accuracy