Adaptive blind joint source-phase separation in digital communications

The authors present a set of adaptive algorithms for the blind separation of independent sources (BSS). Source separation consists of recovering a set of independent signals from some linear instant mixtures of them, the coefficients of the mixing matrix being unknown. The relative (or natural) gradient has been widely used in these problems. We propose to replace it by the median gradient. We extend the concept to the complex case to cope with digitally modulated signals. It results in a new family of methods with better performance and phase recovering properties. Examples include separation of instant mixtures of different communication signals to illustrate the solutions proposed. As a new result we apply the proposed algorithms to asynchronous CDMA