A geograprically-aware, reliable multicast protocol for tactical sensor networks

This paper investigates a geographic addressing and routing mechanism developed at the US Army's Communications - Electronics Research, Development and Engineering Center (CERDEC) in Fort Monmouth, NJ under an innovative research collaboration project with Trident Systems Inc., Fairfax, VA. Developed to support applications in military sensor networks, the geographic wireless reliable multicast (GeoWiReM) protocol uses an on-demand, mesh-based multicast routing protocol as the forwarding mechanism to deliver packets to ad hoc regions of interest delimited by geographic position. Key to this innovative technology is the ability to establish dynamic group memberships on demand; a capability which enables a user to identify message recipients without required pre-configuration. In an operational application, such dynamic groups can be defined by simply highlighting a desired area on the map instead of associating IP addresses or node IDs to a preconfigured multicast group. In order to support the reliability and efficiency requirements demanded of a tactical military application, GeoWiReM employs such mechanisms as passive and negative acknowledgments (NACK), selective retransmission for missing or corrupt data, implosion avoidance and local recovery. Though developed for use in sensor and munitions networks, the flexibility of the protocol design can be employed in a wide variety of potential applications. This paper will examine the salient features of the GeoWiReM protocol and assess its performance using modeling and simulation techniques