Alt-forwarding in mobile frequency-hop wireless networks

The terminals in a mobile store-and-forward wireless network must be able to react quickly to changes in propagation conditions and interference levels on the links in a network. Routing updates are often very slow in responding to changes in link quality, especially for the links that are not utilized frequently. The adaptive-forwarding protocol can assist the routing protocol by forcing some transmissions on less frequently utilized links, thereby updating the information about the states of these links. We say that alt-forwarding occurs for a given packet if that packet was originally scheduled for transmission on one link but the adaptive-forwarding protocol elects to transmit the packet on a different link. By forcing a packet on an alternative link, we allow the adaptive-transmission protocol to update the transmission parameters for the link, and we cause the adaptive-routing protocol to deliver the packet along a secondary route. The feedback gathered by utilizing an alternative link helps the networking protocols respond to dynamic conditions and discover more energy-efficient routes. We show that by designing the criteria for selecting an alternative link to account for the status of the link and the likelihood that the link leads to an efficient route, there is a significant increase in the energy efficiency of the network.