Improved Fairness in Energy-Constrained Cooperative Ad-Hoc Networks

In ad-hoc networks, cooperative diversity is especially useful where the use of multiple antennas may be impractical. There has been a lot of work on improving the peer-to-peer link quality by using advanced coding or power and rate allocation between a single source node and its relays. However, how to efficiently and fairly allocate resources among multiple users and their relays is still unknown. In L. Dai et al., (2006) a novel multiuser cooperation protocol was proposed, where a power reward is adopted by each node to evaluate the power contributed to and by others so as to guarantee fairness. It was shown that in energy-constrained cooperative ad-hoc networks, fairness can actually bring significant throughput gains. In order to further improve the fairness, in this paper, we propose a price-aware cooperation protocol, where the residual energy information of each node is exploited to shape the relay set. Simulation results show that by using this price lever, fairness can be significantly improved compared to the fair cooperation protocol. This benefit turns out to bring much higher throughput than the traditional direct transmission (without cooperation) and full cooperation schemes.