Multiuser Channel Estimation and Tracking for MC-CDMA Uplink Transmissions

Abstract

We discuss channel acquisition and tracking in the uplink of a multi-carrier code-division multiple-access (MC-CDMA) system. Channel acquisition is performed jointly with noise power estimation following two different approaches. The first assumes independently faded subcarriers while the second exploits the fading correlation across the signal bandwidth to improve the system performance. Both schemes are based on maximum likelihood (ML) reasoning and exploit some training blocks carrying known symbols. Channel tracking is pursued through least-mean square (LMS) techniques, using data decisions provided by a partial parallel interference cancellation (PPIC) receiver