A Geometric Method for Blind Separation of Digital Signals with Finite Alphabets

We consider the problem of blind separation of discrete sources with finite alphabets. More specifically, multiple-amplitude-shift-keying (M-ASK) alphabet and complex quadrature amplitude modulation (QAM) alphabet are studied. The proposed separation method exploits the geometry of the received data constellation. The method relies on a finite-step noniterative algorithm, and therefore it is free from any convergence problem. Numerical simulation results are included to illustrate the performance of the proposed algorithm.