Channel estimation and interference rejection for multichannel systems

Recently a number of schemes for blind channel estimation have been proposed to mitigate the problem of intersymbol (ISI) and co-channel interference (CCI) in mobile communication environments. In many of the proposed schemes no attention is paid to the fact that in most existing and scheduled future systems, training sequences will be available within the transmission protocol of the desired users. In this paper a semi-blind approach utilizing the rich structure inherent in the base station antenna array output and the knowledge of the desired user's training sequence is proposed in order to improve the transmission link performance. In the described approach cancellation of unknown interfering sources is performed based on blind estimation of their corresponding channels allowing the channels of the desired users to be estimated using a conventional training sequence based channel estimation algorithm.