Towards energy-efficiency in selfish, cooperative networks

Cooperative communication has been proven effective in enhancing the performance of wireless networks, anda variety of techniques have been investigated to exploit the spatial diversity gain to provide reliable physical layer communications with multiple quality-of-service (QoS) requirements. In this paper, we propose an adaptive multi-relay selection with power allocation mechanism to offer energy fairness at each node for a cooperative network. Unlike traditional approaches where all nodes are considered to transmit in a collaborative manner, weexplicitly consider the situation where nodes exhibit some degree of selfish behavior. Specifically, we introduce anovel concept of the selfishness index and incorporate it into a utility function which denotes the degree a node can benefit from cooperative transmission. Theoretical analysis and extensive simulation results are supplemented toshow advantages in maximizing the network lifetime and guaranteeing the QoS in realistic wireless environments. We also consider the practical situation when nodes consume energy in mode switching, and carefully study the behavior of inter-cluster relay switching and the trade-off among network lifetime, switching cost and switching frequency.