Increasing the Performance of MANETs: Throughput and QoS Performance Enhancing Mechanisms for Unicast and Group Communicationin Proactive Mobile Ad Hoc Networks

Abstract

Mobile Ad hoc NETworks (MANETs) have the potential for increasing the information flow in emergency and rescue operations. Rapid response in areas without existing infrastructure is currently limited to single hop technologies, primarily voice communication using "walkie-talkies".

While MANETs can offer multi-hop broadband communication for emergency and rescue operations, there are challenges that currently limit their usefulness. These challenges are linked to aspects such as capacity, density, collisions and mobility, all of which affect the Quality of Service (QoS) and Quality of Experience (QoE) offered by the MANET.

The work in this thesis investigates problems related both to unicast and group communication for MANETs. In unicast communication, it is shown that the delay between a link break and the rerouting is affected by the interface queue size and the traffic load. Several solutions to reduce the rerouting time are proposed, e.g., reducing the interface queue, or avoiding links that are likely to be broken. Along with the rerouting time, the throughput in and out of a MANET is also affected by the position of one or more gateways.

Further, it is shown that the QoS of group communication voice traffic can be maintained with other traffic in the network, using preemptive mechanisms. Finally, a typical group communication forwarding algorithm is improved by combining it with another algorithm. Also, a preemptive selection of algorithm for lower priority traffic when voice traffic is active in the network is shown to improve the overall QoS for both the voice and lower priority traffic.