Blind separation of synchronous co-channel digital signals using an antenna array. I. Algorithms

TLDR

The spatial response of the antenna array is assumed to be known imprecisely or unknown. The authors propose a maximum‑likelihood approach for separating and detecting multiple synchronous digital signals at an antenna array, introducing a finite‑alphabet‑based detection technique distinct from standard linear combiners. The method exploits the finite‑alphabet property to jointly estimate the array response and symbol sequences, and presents computationally efficient block and recursive algorithms for this estimation. The approach guarantees unique estimates for BPSK signals, works with unknown array geometry and propagation environments, and simulation results show promising performance.

Abstract

We propose a maximum-likelihood (ML) approach for separating and estimating multiple synchronous digital signals arriving at an antenna array at a cell site. The spatial response of the array is assumed to be known imprecisely or unknown. We exploit the finite alphabet property of digital signals to simultaneously estimate the array response and the symbol sequence for each signal. Uniqueness of the estimates is established for BPSK signals. We introduce a signal detection technique based on the finite alphabet property that is different from a standard linear combiner. Computationally efficient algorithms for both block and recursive estimation of the signals are presented. This new approach is applicable to an unknown array geometry and propagation environment, which is particularly useful In wireless communication systems. Simulation results demonstrate its promising performance.