QO-STBC coded protocol for cooperative communications

In this paper, the quasi-orthogonal space-timeblock-code (QO-STBC) cooperative communications with relay selection and phase-rotation methods for four communication nodes are investigated. Specifically, both of relay selection and phase-rotation methods could achieve a diversity of four but they use a different number of relay nodes at a time. In addition, a code rate of the proposed scheme is twice the ordinary cooperative communications. Computer simulation results show a significant probability of error improvement of about 7 dB over the conventional decode-and-forward protocol.