Quasi-orthogonal type space-time block codes for cooperative wireless networks

In this paper we consider quasi-orthogonal distributed space-time block codes (D-STBCs) for application in cooperative wireless network. One scheme is designed by using appropriate signal rotations and set partitioning of two quasi-orthogonal codebooks. The codebooks are formed from the union of two modified quasi-orthogonal codes, then the union is pruned down by one-half. In contrast, the closed-loop D-STBC scheme is based upon applying full rotation feedback on the third and fourth relay. In simulation studies the new modified code is shown to outperform previous open loop and closed loop schemes in terms of end-to-end codeword error rate, and thereby has potential application in wireless relays networks.