MASTER THESIS EVALUATION OF GROUP COMMUNICATION APPROACHES FOR DISCONNECTED MOBILE AD HOC NETWORKS
Dawit Alemayohu Kahsay, Hans van den Berg · 2015
Ad-hoc networks in tactical or emergency response operations may get partitioned into different groups of mobile nodes that have different tasks and movement patterns. Hence a tactical network can be both ad hoc and disrupted at the same time in different parts of the network. It will be difficult to maintain optimal communication using only conventional mobile ad hoc network Mobile Ad hoc Network (MANET) routing schemes. It leads to high packet loss as there are often no end-to-end connections in the network between sources and destinations. Thus, an optimum routing algorithm is needed that integrates Disruption/Delay Tolerant Network (DTN) routing schemes with conventional MANET routing schemes for efficient data dissemination among disconnected mobile ad hoc networks. In this thesis we first provide an extensive overview of existing work on hybrid MANET-DTN routing and proposals for implementation of two group routing approaches. Next, we extended NS2 to support DTN functionality along side the existing MANET functionality and then we examine and compare two group routing approaches that can be used for disconnected mobile ad hoc networks using simulation. The first approach is, to store messages at the group leader only. The group leader coordinates and controls all inter-group communication with other disconnected groups of mobile nodes. The second approach is to store all messages contained by a group in all member nodes of the group. In this approach, member nodes communicate with nodes of adjacent groups independent of each other. We evaluate the performance of the two approaches for different scenarios using four performance metrics, namely delivery ratio, average delay, number of duplicate messages, and average buffer size.