A simple distributed relay-assignment algorithm for multi-antenna relay networks

In multi-antenna relay networks, how to assign source-relay pairs is still a challenge. In this paper, we propose a simple distributed relay-assignment algorithm for multi-antenna relay networks, which exploits the ability of AOA (angle of arrival) estimating in a multi-antenna terminal. The proposed algorithm based on an opportunistic relaying model uses RTS packet to estimate AOA of the source and CTS packet to estimate AOA of the destination in potential relays, and then calculates the interval angle of each node. The best relay is chosen to be with the maximum interval angle between source-relay link and relay-destination link. An outage analysis for the proposed algorithm is provided within a limited area where available relaying nodes are uniformly distributed. Finally, simulation results show that the proposed algorithm offers great improvement on the reliability of the relaying links and is more suitable for multi-antenna relay networks than existing relay-assignment algorithms. The outage analysis is also verified.