The Impact of an Antenna Array in a Relay Network

Cooperative diversity is a form of distributed space- time macrodiversity capable of mitigating the detrimental effects of multipath fading in a wireless network. Prior work on cooperative diversity has focused on the case that all terminals have a single antenna. However, in many practical situations, it is feasible for one or more terminals to be equipped with an array of multiple antennas. This paper investigates the impact of the presence of a single antenna array in a three terminal orthogonal relaying network. The array may be at the source, relay, or destination. The information outage probability under diversity combining is derived, and closed form expressions given wherever possible. The numerical results suggest that it is best to place the array at the destination, and that it is better to place the array at the relay than at the source.