Distributed Transmit-Antenna Selection Scheme for Relaying Systems with Selection Combining

The use of multiple antennas at the node terminals of relay networks potentially improves cooperative diversity in terms of both reliability and spectral efficiency. A simple practical approach to exploit such potentials at the transmitter side is to appropriately select one out of the many transmit antennas available. In this work, we propose and analyze a dualhop fixed-gain amplify-and-forward relaying system based on a distributed transmit antenna selection scheme, along with a selection-combining treatment of the direct and relaying signals at the destination. We derive analytical lower and upper bounds for the outage probability of the proposed scheme in singlefold integral form. In addition, asymptotic expressions for these bounds at high signal-to-noise ratio are obtained in closed form. Our results reveal that the proposed scheme achieves full diversity order. More importantly, the underlying distributed strategy of transmit antenna selection is shown to perform closely to the costly optimal centralized solution.