Energy-Aware Co-Operative (ECO) Relay-Based Packet Transmission in Wireless Networks

In infrastructure wireless networks, nodes at the edge of the coverage area need to spend more energy to transmit their packets than those close to the Access Point (AP). Less energy is required if intermediate nodes can be used to forward data. To enable this, intermediate nodes need an incentive and there must be a mechanism for selecting these nodes. In this paper we propose Energy-aware Co-Operative (ECO) relaying for selecting relays to forward packets. The technique is based on the idea of Relative Energy Usage (REU), which reflects the proportion of energy that a node saves by forwarding its packets through relays. A node which saves more energy by using relays is more likely to be chosen as a relay. Conversely, nodes are only permitted to use relays proportionate to the amount of energy they themselves have spent as relays. We compare our scheme with direct transmission, minimum energy path (MnEP), and maximum residual energy path (MxRE). We show that ECO can transmit 50% more data than direct transmission, while using less energy on average. Although MnEP and MxRE can also transmit more data than direct transmission, they do so at severe energy cost to a small number of nodes, doubling the average energy usage, making them ill-suited to commercial networks.