Message Ferrying for Sparse and Disconnected Mobile Networks

Project Overview

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. Such environments arise in critical situations ranging from battlefield scenarios to natural and human-made disaster events. 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. For example, in a disaster relief effort, robots equipped with short range radios may move out of range of one another while performing their tasks. In a battlefield, equipment intended to provide connectivity may be compromised so that it becomes inoperable. 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. Our work is concerned with the development of a novel ``Message Ferrying'' (MF) scheme, inspired by its real life analog, that implements this store, carry and forward routing paradigm. In the MF scheme, a set of mobile nodes called message ferries take responsibility for carrying messages between disconnected nodes. Message ferries move around the deployed area according to known routes and communicate with other nodes they meet. By using ferries as relays, nodes can communicate asynchronously with other nodes that are disconnected. 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 store, carry and forward message delivery is an important delivery paradigm that can be used to overcome partitioning in a mobile ad-hoc network. Our work is distinguished by its investigation of explicit support for such delivery through non-random node mobility. Our 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.
Interfacing with on-going investigations of two contexts in which message ferrying can play an important role: surface transportation systems and robotic teams.

The Message Ferrying project is supported by an ITR grant from the National Science Foundation and by an AFOSR MURI Grant.

People

Faculty and Staff:

Students:

Wenrui Zhao
Hyewon Jun
Shashi Merugu

Publications

Hyewon Jun, Mostafa Ammar, Ellen Zegura, "Power Management in Delay Tolerant Networks: A Framework and Knowledge-Based Mechanisms," Proceedings of the 2nd IEEE COnference on Sensor and Ad Hoc Communication and Networks, September 2005.

Wenrui Zhao, Mostafa Ammar, Ellen Zegura, "Multicast Routing in Delay Tolerant Networks: Semantic Models and Routing Algorithms," Proceedings of the SIGCOMM DTN Workshop, August 2005 (to appear).

Hyewon Jun, Wenrui Zhao, Mostafa Ammar, Ellen Zegura, Chungki Lee, "Trading Latency for Energy in Wireless Ad Hoc Networks using Message Ferrying," IEEE PerCom International Workshop on Pervasice Wireless Networking, March 2005

Meng Guo, Mostafa Ammar, Ellen Zegura, "V3: A Vehicle-to-Vehicle Live Video Streaming Architecture," IEEE International Conference on Pervasive Computing and Communications (PerCom), March 2005. .

Jeonghwa Yang, Yang Chen, Mostafa Ammar, Chung-Ki Lee, "Ferry Replacement Protocols in Sparse MANET Message Ferrying Systems," IEEE Wireless Communications and Networking (WCNC), 2005 (to appear).

Wenrui Zhao, Mostafa Ammar, Ellen Zegura, "Controlling the Mobility of Multiple Data Transport Ferries in a Delay-Tolerant Network," IEEE INFOCOM 2005, Miami Florida.

Wenrui Zhao, Mostafa Ammar, Ellen Zegura, "A Message Ferrying Approach for Data Delivery in Sparse Mobile Ad Hoc Networks," Proceedings of ACM Mobihoc 2004, Tokyo Japan, May 2004.

Wenrui Zhao, Mostafa Ammar, "Message Ferrying: Proactive Routing in Highly-Partitioned Wireless Ad Hoc Networks," Proceedings of the IEEE Workshop on Futrure Trends in Distributed Computing Systems, Puerto Rico, May 2003.

Wenrui Zhao, Mostafa Ammar, Ellen Zegura, "The Energy-Limited Capacity of Wireless Networks," The First IEEE International Conference on Sensor and Ad hoc Communications and Networks, Sanar Clara, CA, October 2004.

Shashi Merugu, Mostafa Ammar, Ellen Zegura, "Space-Time Routing in Wireless Networks with Preictable Mobility," College of Computing, Georgia Institute of Technology, Technical Report GIT-CC-04-07, March 2004.

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