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 prac- tical systems is also proposed. The performance of the proposed scheme, with and without opti- mum 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) perfor- mance over quasi-orthogonal space time block codes (QOSTBC).