Closed-Form Estimators for Blind Separation of Sources - Part II: Complex Mixtures

The problem of multiuser detection in wireless communications systems adopts, in flat-fading channels, a blind source separation (BSS) formulation of instantaneous linear mixtures. This contribution addresses the closed-form solutions to BSS in the complex-mixture scenario. The algebraic devices which span a unifying framework for the complex BSS closed-form estimators are developed. With the aid of these tools, results originally encountered in the real-mixture case are extended to the complex case, thus highlighting the remarkable parallelism existing between the real and complex problems in the context of their analytic solutions. Computer simulations illustrate the theoretical results and compare the proposed methods to other BSS procedures.