A fast blind sequence estimation in digital communications

Abstract

The problem of blindly estimating multiple digital co-channel communication signals using an antenna array is studied in the presence of multipath fading. We develop a fast sequential-estimation algorithm for separating multi-user signals based on the geometric observation made by Hansen and Xu (see Proc. ICASSP'96, p.1085-88, Atlanta, GA, 1996). When the signals are constrained to a finite alphabet, it is possible to visualize the geometric properties of the problem, which can be exploited to sequentially extract the digital co-channel communication signals. We present simulation results comparing the speed and BER performance with different methods.