Context-Aware Relay Selection in Buffer-Aided Wireless Relay Networks

In this letter, we study relay selection strategies for file transfer in a two-hop buffer-aided relay network when the source and relay nodes have limited energy. We consider the fact that the constrained energies of the relays limit their transmission capabilities. Using the concept of a token as an approximate sign of the possibility for packet reception and forwarding by a relay, we propose a context (specifically, channel, energy, and queue state)-aware relay selection strategy, which dynamically defines a scheduling rule at each time slot, based on the channel states, residual energies, and queue sizes. At each time slot, the scheduling rule specifies which of the source or relay nodes should use the channel for packet transmission. Numerical results confirm that the proposed strategy generally provides a higher number of packet transfers and a lower file transfer time compared with existing algorithms.