A self-adaptive and energy-efficient wireless multi-hop network

In wireless multi-hop networks, mobiles devices communicate with the others without relying on any infrastructure networks or centralized control. When two end devices are communicating, they commonly require intermediate devices to cooperate for maintaining the network connectivity. Although the communication is for only two devices, the other devices have to consume their battery power on relaying messages. As a result, the network-wide energy consumption is much higher than the energy consumed by only two end devices. To reduce the network-wide energy consumption, one potential way is to tradeoff between throughput and energy consumption on the intermediate devices. For example, when the throughput is not too high, i.e., less than 1Mbps, the intermediate devices can turn off the high-speed wireless network interface and switch to a low energy consumption one, called an energy-efficient vertical handover. Since there is no centralized control or infrastructure networks, the devices must perform a vertical handover based only on its own recorded information, i.e., local measurements executed by itself. To this end, an extended SDN controller, which has been proposed in a previous work, is considered. In addition, a new energy efficient vertical handover algorithm has been proposed. By utilizing the extended SDN controllers to exchange information among devices, the intermediate devices can perform the vertical handover by themselves and save energy. The effectiveness of the proposal has been confirmed by directly measured results.