Recursive blind source separation for BPSK signals

Abstract

This paper addresses the important problem of separating and estimating the contributions of multiple users (sources) signals impinging on an antenna array in a wireless communication system. The proposed approach has key advantages over existing ones, which are listed below: (i) the structure of estimation is recursive, therefore it estimates the incoming bits on the fly as they reach the receive array instead of estimating a separating matrix. (ii) it exploits the finite alphabet property (here, BPSK) of the communication signals in an explicit manner, through the use of a finite-state trellis. (iii) perfect decisions are obtained in the absence of noise upon certain mild conditions on the transmitted signals (excitation conditions). Therefore (local) convergence is not an issue here.