A study on channel estimation for OFDM systems using em algorithm based on multi-path doppler channel model

Abstract

In OFDM mobile communication with high-speed vehicle, due to the effect of large multi-path Doppler shifts varying independently with respect to the paths, the time allowed to the conventional methods of estimation of the channel characteristics is severely limited without using separate estimates of the Doppler shifts. As a result, the quality of performance of the data demodulation remains low using the estimates insufficiently smoothed of the noise. This report proposes a novel method using Expectation-Maximization (EM) algorithm for simultaneously estimating the Doppler shifts and the complex amplitudes of the path-wise channel responses. The results of computer simulation show capability of proposed method much superior to the conventional one. © 2007 Springer.