Quasi-orthogonal STBC with minimum decoding complexity: performance analysis, optimal signal transformations, and antenna selection diversity

This letter presents a new method to directly analyze and optimize symbol error rate (SER) performance of minimum decoding complexity (MDC) ABBA space-time block codes based on a tight union bound on SER. Additionally, a new signal transformation for rectangular quadrature amplitude modulation is proposed to provide better performance than the existing ones with lower encoding/decoding complexities. It is also shown that MDC-ABBA codes achieve full-diversity with antenna selection and limited feedback. Index Terms--Quasi-orthogonal space-time block codes, ABBA codes, performance analysis.