Nomadic Routers for Rapidly Deployable Wireless Networks

Source-initiated Adaptive Routing Algorithm (SARA)

This DARPA sponsored Phase II SBIR effort successfully demonstrated full-scale prototypes of the nomadic router, a network function that can be implemented either in hardware or within the software of mobile wireless computers. The nomadic router allows a collection of such wireless computers to organize themselves into a multi-hop wireless network without the aid of any established infrastructure or centralized administration and without any user-initiated configuration actions. Such rapidly deployable networks are ideal for addressing the needs of a wide range of tactical applications envisioned by the military for the digital battlefield of tomorrow.

The nomadic router developed in Phase II takes the form of software referred to as the Source-initiated Adaptive Routing Algorithm, or SARA. SARA provides two modes of operation, one for symmetric environments where reflexivity between nodes is expected, and a second mode for asymmetric wireless networks where significant variations in individual nodes' transmitter power yield an environment where a node that receives a message cannot presume that single-hop transmission back to the original sender is possible.

The SARA routing algorithms have been implemented on a number of operating systems and on two different wireless technologies. Additionally, a gateway that provides integration with existing, wired infrastructure was developed, simulation models were implemented, and a robotic demonstration platform was created.