Channel estimation based on block-type pilot in OFDM systems over doubly-selective channels

In this paper, a novel rapid varying doubly-selective channel estimator for OFDM systems has been proposed, in which channel is modeled by basis expansion model (BEM). Unlike traditional BEM channel estimation algorithms, in which the comb-pilot is used and the large path delay is not considered, the proposed algorithm uses firstly block-type pilot to estimate the BEM coefficients of fast-varying doubly-selective channel at the pilot OFDM symbols, and then the BEM coefficients at the pilot OFDM symbols can be applied to interpolate for obtaining the BEM coefficients at data OFDM symbols using different interpolation algorithms. With Jake´s channel model, the simulation results show that the proposed algorithm is very effective.