Single Channel Blind Separation of Non-Orthogonal Cochannel Signals with Higher Order Modulation

This paper presents one efficient blind separation method for non-orthogonal cochannel communication signals received by a single channel receiver. Unlike most existing works dealing with lower order modulation such as binary phase shift keying and quadrature phase shift keying in the context of single channel blind source separation, this method focuses on higher order modulation. This method is a blind alternative channel and sequence estimation method. The key for this method is the conversion of the separation problem in a multiple input single output system to a joint sequence estimation problem in a virtual multiple input multiple output system and the efficient implementation of semidefinite relaxation technique in a decision feedback and feedforward mode that is able to solve the joint sequence estimation problem in polynomial time. Simulation studies are used to demonstrate the effectiveness of the proposed methods.