Power Saving for Multi-Radio Relay Nodes in IEEE 802.11 Infrastructure Networks

In this paper, we propose a novel power saving scheme for relay nodes, equipped with multiple wireless network interface cards (WNICs), in IEEE 802.11 infrastructure networks. While most of recent studies have focused on power saving of end stations, the power saving of relay nodes can become even more critical when the relay nodes operate on battery power. When a relay node is equipped with multiple WNICs, the overall link capacity of the node increases proportional to the number of WNICs, and hence the time spent to relay a given amount of traffic can be reduced. Accordingly, the relay can stay at inactive state for a longer time, thus resulting in less overall energy consumption thanks to the reduced energy consumption by the relay’s host machine, despite of the increased energy consumption due to multiple WNICs. We in this paper develop the protocols for the power-saving relay node with multiple WNICs, and demonstrate the superiority to single WNIC relay nodes based on both mathematical analysis and simulations.