Performance of Pilot Symbol Assisted Channel Estimation Techniques for Uplink MC-CDMA Systems using MMSE Receiver

In order to attain near-single user performance in uplink multicarrier code division multiple access (MC-CDMA) systems, multiuser detection (MUD) methods may be employed. However, most of MUD methods rely on simultaneous estimation of the channel frequency response of multiple users. In this paper, performance of a MC-CDMA system employing minimum mean-square error (MMSE) MUD at receiver is evaluated using three different pilot symbol assisted (PSA) channel estimation techniques. The MMSE estimation is superior in performance but it requires prior information about the channel. Other two methods: the maximum likelihood estimation (MLE) and the inverse discrete Fourier transform (IDFT) based channel estimation are simple to implement as they do not depend upon the knowledge of the channel statistics.