Multi-user code division multiple access receiver

Abstract

A receiver and method for receiving a code-division multiple-access (CDMA) signal combining symbol values spread by a plurality of spreading codes, which method comprises the steps of: (a) converting the CDMA signal to a baseband signal; (b) recognizing symbol boundaries in every multipath for every user in the baseband signal to produce a delay estimate; (c) estimating an attenuation and phase rotation impressed on the signal by each multipath to produce channel estimates; (d) generating new symbol estimates for every user at a sampling rate that is greater than a symbol rate of the signal; (e) generating an estimate of the received signal using said symbol estimates and channel estimates; (f) comparing the received signal with its estimate and feeding estimation error back to a means for estimating the transmitted symbols; (g) sampling the symbol estimates at the estimated symbol boundaries of each user to obtain final symbol estimates; and (h) repeating steps (b) through (g) with every new sample.