Design, development and implementation of a high performance wireless mesh network for application in emergency and disaster recovery

This thesis describes research into communication protocols required by a wireless mesh network (WMN) that would be deployed to support emergency rescue teams in a disaster recovery scenario. WMN applications in emergency and disaster recovery require the network to facilitate multimedia group communications to enable rescue team members to share information with each other and provide access to broadband services via www and email. The work presented in the thesis proposes a scheme to improve the performance of WMN to satisfy such application requirements. Several protocols have been designed and implemented to support the exchange of information between these protocols in order to meet the QoS requirements of real-time multimedia traffic and to avoid congestion whilst routing Internet traffic in a multiple gateway environment. A novel implementation of the MAODV routing protocol is developed and modifications are proposed to enhance the protocol's performance and reliability to support the multimedia multicast operation ofWMNs. A novel Load-Balanced Gateway Discovery routing protocol called LBGD-AODV is designed and implemented which provides a multiple gateway environment and balanced Internet traffic loading to more effectively utilize the available gateway resources and minimise network congestion. The proposed QoS scheme enables both protocols to exchange information on network congestion in order to calculate the network bandwidth consumption using a novel scheme at the network layer. This information is used to provide rate-adaptive admission control for multimedia traffic at the application layer. Furthermore, the scheme also provides strategies to support efficient priorities for multimedia traffic to ensure that all the critical priority flows are facilitated even when the network is congested. LBGD-AODV uses the bandwidth information to avoid congested routes to gateway nodes for Internet traffic. A WMN testbed is designed and developed using cross-platform hardware to evaluate the performance of the proposed protocols. The test results show that the objectives set in this study have been successfully achieved by improving the WMN performance for both UDP real-time multimedia traffic and TCP internet traffic