A decision feedback CDMA receiver with partially adaptive interference suppression

Abstract

A novel CDMA receiver with adaptive multiple access interference (MAI) and narrowband interference (NBI) suppression is proposed for reverse link signal reception over multipath channels. The design of the receiver involves the following procedure. First, adaptive correlators are constructed based on the generalized side-lobe canceller (GSC) scheme to collect the multipath signals and suppress strong MAI and time-varying NBI. In particular, partial adaptivity is incorporated into the GSC for reduced complexity processing. A simple combiner with channel estimation then gives the symbol decisions. In order to enhance the performance of the adaptive correlators, a decision aided scheme is introduced which subtracts the reconstructed signal from the input data of the GSC, leading to improved output SINK and convergence. The proposed CDMA receiver is evaluated through simulations, and the results show that it can outperform the conventional MMSE receiver designed for time-invariant interference.