Distributed Relay Selection for QoS Provisioning in Regenerative Relay Networks

In relay communications, the relay is in cooperation without doubt at a price of coordination signaling such as synchronization and associated channel state information (CSI) acquisition. Distributed relay selection based on average channel gain information available at the relays is preferred from the perspective of the cost of coordination signaling only if the link reliability can be maintained. In this paper, we propose a simple distributed scheme for relay selection such that a set of relays that satisfies QoS constraints is only activated and one of them is selected randomly from an opportunistic set of QoS relays. The proposed scheme avoids unnecessary power consumption caused by non-beneficial relay cooperation and performs comparable to the centralized best relay selection while it minimizes signaling overheads.