Generalized projection algorithm for blind interference suppressionin DS/CDMA communications

摘要

New blind adaptive interference suppression algorithms for DS/CDMAncommunication systems are presented. A generalized projection algorithmnis presented to update a multiple access interference (MAI) suppressionnfilter in a static communication environment. The algorithm adaptivelynadjusts the filter coefficients by iteratively projecting them ontonconstraint sets. The constraint sets consist of data sets and propertynsets, which are obtained from the received signal and prior knowledge ofnthe desired signal, respectively. A space alternating generalizednprojection algorithm with approximate EM mapping is also presented tonsuppress the MAI in a dynamic communication environment. This algorithmnjointly estimates the filter and desired signal amplitude using anstochastic approximation of the EM algorithm. The performancencharacteristics of the proposed algorithms are shown by outputnsignal-to-interference ratio and bit-error-rate simulation results. Thenresults show that the proposed algorithms significantly outperform thenexisting adaptive algorithms in steady state