A two-hop amplify-and-forward scheme for extended orthogonal space time coding in cooperative networks

We investigate and propose a new amplify-and-forward cooperative relay networks scheme in which a full-rate and full-diversity extended-orthogonal space-time block coding (EOSTBC) scheme is used. Utilizing a feedback channel, a simple phase rotation is applied at the relay nodes to extract full diversity and array gain. A feedback quantization approach which reduces the overhead in the feedback channel for practical systems is also proposed. The performance of the proposed scheme, with and without optimum power allocation strategy, is investigated. Average bit error rate simulations confirm the utility of the scheme. The results also confirm the improvement in bit error rate (BER) performance over quasi-orthogonal space time block codes (QOSTBC).