Reliable and Efficient Group Communication in Mobile Ad-Hoc Networks

The highly dynamic and unpredictable character of mobile ad-hoc networks poses significant challenges for group management. Node mobility often changes the multicast tree, and therefore, frequent flooding of updates from group members are required to refresh the multicast tree at the source node. However, the communication overheads resulting from such membership updates are undesirable in ad-hoc networks due to bandwidth constraints. Flooding also contributes to congestion and collisions; thereby degrading the performance of group communication. Therefore, performing membership updates while minimizing flooding is critical in the bandwidth efficiency of group communication in mobile ad-hoc networks. Furthermore, the performance of data distribution can be enhanced by adapting the multicast tree construction scheme to the mobility patterns of the roaming group members. This work proposes a novel strategy to support group communication (multicast) in mobile ad-hoc networks, with a focus on low overheads and resource requirements. A framework, called Courier, is proposed thatincludes a number of algorithms and techniques to maintain multicast memberships and to disseminate packets to multiple receivers in networks where all nodes can be mobile.