Blind Multiuser Detection Based on Affine Projection Algorithm for MC-CDMA Uplink

A proved affine projection algorithm (APA) is proposed for uplink asynchronous multicarrier code-division multiple-access (MC-CDMA) systems with multipath Rayleigh-fading channel. The proposed technique is totally blind, i.e., the channel estimation of desired user (the spreading code is known) is carried out by subspace separation, which doesn't need the rank estimation in the first step, then the result is put into the proved affine projection filter as a parameter. During the update of the weight vector, the APA filter extracts the parameters of blind channel estimation, suppresses multiple access interference (MAI) and recovers the information of desired user. The effectiveness of the proposed blind approach is demonstrated by computer simulation results, which show that it assures satisfactory performances in severe near-far scenarios, while its performances close to those of non-blind minimum-mean-square error (NB-MMSE) receiver.