A Simple Layered Space-Time Block Nulling Technique for DSTTD Systems

A double space-time transmit diversity (DSTTD) system employs four transmit antennas to multiplex two Alamouti space-time block code (STBC) units. In this letter, a specially-designed canceling mechanism is presented, which can efficiently separate the two STBC units for such systems. We show that the orthogonal structure, and so the merit of Alamouti STBC, can be kept. Compared with some previous interference cancelation methods, the proposed one requires much fewer floating-point operations (flops) while achieving similar error-rate performance.