ITR: Message Ferrying: Mobility-Assisted Data Delivery in Highly Partitioned Networks

Georgia Tech Research Corporation, Atlanta GA

Investigators

Abstract

Mobile ad hoc networks form a vital component in realizing the vision of rapidly deployed communications capability in environments with little or no pre installed infrastructure. Applications range from battlefield scenarios to responding to natural and human-made disasters. In these situations the ability to communicate, even at low rates, is extremely valuable for coordinating efforts and sharing vital information. Most ad hoc network routing and data forwarding algorithms are designed for networks that are always connected. While it is certainly desirable to maintain a connected network, various conditions may cause a mobile ad hoc network to become partitioned, meaning that there is no single-hop or multiple-hop route between some (or all) source/destination node pairs. Node mobility, limited radio range, physical obstacles, severe weather, wide deployment area or other physical factors, might preclude some nodes from communicating with others and result in a partitioned network. The existence of network partitioning requires a new approach other than the traditional "store-and-forward" routing paradigm used in most current ad hoc routing algorithms, in which messages are dropped if no route is found to reach a destination. Instead, a device should be able to buffer and carry the messages until it has a chance to forward them. This project focuses on the development of a novel "Message Ferrying" (MF) scheme, inspired by its real life analog, that implements this "store, carry and forward" routing paradigm. The main idea of the MF scheme is to introduce non-randomness in the movement of nodes and exploit such non-randomness to help deliver data. The MF scheme overcomes partitioning in a mobile ad-hoc network by using a set of mobile nodes, called message ferries. These nodes have the responsibility to carrying messages between disconnected nodes by moving around the deployed area according to known routes and communicating with other nodes they meet. By using ferries as relays, nodes can communicate asynchronously with other nodes that are disconnected. The proposed work will consist of three main components: -The development of fundamental architectures, algorithms and protocols leading to successful designs of message ferrying systems, -The construction of system prototypes to provide a realistic understanding of the challenges in building and deploying message ferrying systems, and -Interfacing with on-going investigations of two contexts in which message ferrying can play an important role, namely surface transportation systems and robotic teams This work is among the first to investigate in-depth the use of non-random node mobility to assist in providing data connectivity in a partitioned network. This will have the effect of enhancing the usability of mobile ad hoc networks in contexts where such disconnection is inevitable. It may also lead to the development of systems (e.g., on college campuses) where message ferrying is used as a low-cost, grass roots messaging solution. We are also committed to activities that will promote the broader impact of the proposed work including, the development of modules based on our research for graduate and undergraduate classes, continued emphasis on inclusion of under-represented groups within our research efforts and outreach activities to Atlanta-based historically black colleges and universities.