Abstract
In this paper, we present a novel extended orthogonal space-time block code (EO-STBC) scheme for a cooperative relay system with four relay nodes and without perfect synchronization. Full-rate and full-diversity can be achieved through using feedback channels. The relay nodes forward information symbols in a simple amplify-and-forward (AF) manner. The information symbols can be extracted with simple symbol-wise maximum-likelihood decoding. © 2009 IEEE.