AbstractThis work investigates the optimisation of Quality of Service (QoS) levels through experimentation on streaming multimedia applications with WiMAX. This work initially tests two algorithms, the intelligent Adaptive Buffer Control (iABC) and the Bandwidth Fluctuation Location Based Dynamic Transmission Rate Control before bring these together in the Resource Harvest and Redistribution - Call Admission Control (RHR-CAC) algorithm.The iABC algorithm augments ATM QoS categories within the wireless domain. iABC utilizes an intelligent adaptive buffering system for the existing users to redistribute the resources to facilitate further connections. iABC results demonstrates that additional connections can be accommodated while maintaining the QoS needs for the existing connections, improving the efficient use of resources. Whereas, the bandwidth fluctuation location-based dynamic transmission rate-limit control framework predicts when a user enters a weaker signal area and dynamically limits the bandwidth of other users to facilitate the QoS needs when the signal strength is reduced. The framework made its predictions based on location and mobile network coverage map queries before initiating the resource rate-limiting algorithm. This significantly improved QoS in video streaming and smoothing of bandwidth fluctuation. These two algorithms have initiated success with bandwidth management of harvesting bandwidth for one user without affecting the QoS of the others.
It is important to determine when simulating any QoS protocol, whether the perceived improvement will actually function under the planned usage, consequently it is vital to replicate the reality of the users behaviour. It is not just the technological issues that affect connectivity but also physical mobility. Therefore the geographical perspective of the user’s physical location impacts on the relevance of experiments, to ensure they reflect reality as closely as possible. Therefore mobility were investigated to select the best fit for this work. The results illustrate that the random waypoint or random walk models both emulated the reality of a user in a mobile environment, for a simulation.
The work culminates, with the RHR – CAC algorithm which builds on the previous algorithms within the WiMAX domain. This encompasses all QoS, service flows by harvesting resources from those provisioned but not activated to provide the resources to accept additional connections. This improves the efficient redistribution of resources while improving the connectivity rate at the call admission control. The results evidenced that QoS has been maintained for all current connection while ensuring that all service flow are not starved of bandwidth.
|Date of Award||Nov 2014|
|Supervisor||Mo Adda (Supervisor) & Carl Adams (Supervisor)|