An adaptive implementation of the "one-shot" decorrelating detector for CDMA communications

Abstract

Researchers have already shown, in principle, that an optimum detector for multiple users in a code-division multiple-access (CDMA) environment exists and that its performance is vastly superior to the single user detector in a multiuser environment. However, the complexity of this detector increases exponentially with the number of users. In this work, an adaptive algorithm and a possible implementation of the "one-shot" decorrelating detector is proposed. The algorithm generates a suboptimum "near-far" resistant despreading waveform for correlation with a known signal in a CDMA environment. In a K-user environment, only the waveforms and respective delays of all active users are required. The algorithm can be easily extended to as many users as desired using a simple recursive equation.