The need for access point power saving in solar powered WLAN mesh networks

Wireless LAN mesh networks are now being used to deploy Wi-Fi coverage in a wide variety of outdoor applications. In these types of networks, conventional WLAN mesh nodes must be operated using continuous electrical power connections. This requirement may often be very expensive, especially when the network includes expansive outdoor wireless coverage areas. An alternative is to operate some of the WLAN mesh nodes using an energy sustainable source such as solar or wind power. This eliminates the need for a fixed power connection, making the node truly tetherless and allowing more flexibility in node positioning. In this article we first review the background and recent activities in the area of energy sustainable WLAN mesh networks. These types of networks are provisioned geographically, in that the assigned resources are a function of the geographic region where the network is to be deployed. The theory behind this is briefly described using some sample North American locations. We then discuss the current shortcomings of IEEE 802.11 when used in these types of networks. IEEE 802.11 requires that the access point be continuously powered, and this requirement is a major barrier to deploying cost-effective sustainable energy networks in certain applications. Recent work is then reviewed that has begun to address the changes that would be required to the standard to better support these types of networks.