DefinePK

Abstract

In this paper time varying channel estimation method is proposed for relay based network. Specifically, pilot symbol assisted channel estimation method is presented for Amplify-and-Forward (AF) relay network using Orthogonal Frequency Division Multiplexing (OFDM) system in high mobility environment. The channel links among mobile user, relay station and base station are assumed to be time and frequency selective. The time variation of the channel is approximated by Basis Expansion Model (BEM). After formulating an appropriate system model for OFDM based relay network, two types of pilot patterns, known as block pilot and mixed pilot, are introduced for channel estimation purpose. Least square and minimum mean square error estimators are used to estimate the BEM coefficients. Using simulation it has been shown that, the channel estimation using mixed pilot symbols suffers from the inter carrier interference while block pilot based estimation can be more effective in high Doppler spread scenario.