Closed-Loop EO-STBC Based on Selection of Cyclic Rotation for Asynchronous Cooperative Relay Networks over Frequency Selective Wireless Fading Channels

This paper proposes one-bit feedback extended orthogonal space-time block coding (EO-STBC) based on selection of cyclic phase rotation for asynchronous cooperative relay networks over frequency selective channels. The two relay nodes are assumed to be equipped with two half duplex antennas. Orthogonal frequency division multiplexing (OFDM) is implemented at the source node. A cyclic prefix (CP) is added at the source and relay nodes to mitigate the intersymbol interference (ISI) induced by multipath fading and timing errors between the relay nodes, which operate in a simple distributed STBC amplify-and-forward (AF) transmission type. This approach attains unity rate over each hop in the network and cooperative spatial diversity order 2R over the frequency selective fading channels. End-to-end frame error rate (FER) simulation results confirm that the proposed scheme significantly improves the performance over previous feedback methods with feedback limited to only one-bit per subcarrier based upon channel state information (CSI) available at the destination node.