Date of Award

2006

Document Type

Doctoral Thesis

Degree Name

Doctor of Philosophy

Department

Electronic Engineering

First Advisor

Dr. Dirk Pesch

Abstract

A Mobile ad hoc network is a collection of wireless mobile nodes forming a dynamic autonomous network without the aid of a fixed infrastructure. Due to the unpredictable nature of node movement the network topology changes frequently. As a consequence of the limited transmission range of the wireless network interfaces, multiple hops may be necessary for data trafficking between nodes in the network, thus requiring nodes to act as both a router and a host. Ad hoc networks when compared with traditional wireless networks have advantages such as, independence of fixed infrastructure such as access points and base stations, ease of deployment and configuration speed. Such network environments are attractive as spontaneous autonomous network formation is presented, without the need for a centralised system administrator entity.

Exigent challenges exist for mobile ad hoc networks with the issue of efficient routing being a critical concern. A routing protocol must address path generation, path selection, data forwarding and route path maintenance. With the protocol objective being the maximisation of network performance from an application point of view while minimising the routing protocol overhead. Presently, there exist several classes of mobile ad hoc network routing protocols such as, unicast, multicast and hybrid routing. The main contribution of the work presented in this thesis is the development of an overlay architecture for dynamic route management that can be utilised to enhance routing protocol performance for mobile wireless ad hoc networks. The proposed system is designed using fuzzy logic to generate an optimal broadcast flood limiting algorithm that promotes the generation of stable routes and allows the assignment of path weightings with adaptive cache entry expiry times. A reactive distributed policy based congestion control scheme is implemented to alleviate localised network congestion and a cache provisioning scheme for merging network nodes. This is a software solution that promotes distributed decision making while enhancing network performance.

Access Level

info:eu-repo/semantics/openAccess

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