A Rotating Blind Separation Algorithm Suitable for MIMO-STBC Systems without Precoder

Blind separating the intercepted signals is a research topic of high importance for both military and civilian communication systems. A blind separation algorithm suitable for Multiple Input Multiple Output (MIMO) systems in association with Space-Time Block Code (STBC) has been reported in literature by utilizing Independent Component Analysis (ICA). This algorithm can not deal with complex phase-shift keying (PSK) modulated signals since the real and imaginary parts are not mutually independent. In this paper, an extending algorithm is proposed by applying a rotation transform to maximize the independence between the real and imaginary parts without using a precoder (rotation) at the transmitter side. Simulations show that the new algorithm can separate complex PSK-modulated signals blindly with high Symbol Error Rate (SER) performance when Channel State Information (CSI) and coding matrix are unavailable.