A Connection Admission Control Framework for UMTS based Satellite Systems.An Adaptive Admission Control algorithm with pre-emption control mechanism for unicast and multicast communications in satellite UMTS.

摘要

In recent years, there has been an exponential growth in the use ofudmultimedia applications. A satellite system offers great potential forudmultimedia applications with its ability to broadcast and multicast a largeudamount of data over a very large area as compared to a terrestrial system.udHowever, the limited transmission capacity along with the dynamicallyudvarying channel conditions impedes the delivery of good quality multimediaudservice in a satellite system which has resulted in research efforts for derivingudefficient radio resource management techniques. This issue is addressed inudthis thesis, where the main emphasis is to design a CAC framework whichudmaximizes the utilization of the scarce radio resources available in theudsatellite and at the same time increases the performance of the system for audUMTS based satellite system supporting unicast and multicast traffic.udThe design of the system architecture for a UMTS based satellite system isudpresented. Based on this architecture, a CAC framework is designedudconsisting of three different functionalities: the admission control procedure,udthe retune procedure and the pre-emption procedure. The joint use of theseudfunctionalities is proposed to allow the performance of the system to beudmaintained under congestion. Different algorithms are proposed for differentudfunctionalities; an adaptive admission control algorithm, a greedy retuneudalgorithm and three pre-emption algorithms (Greedy, SubSetSum, andudFuzzy).udA MATLAB simulation model is developed to study the performance of theudproposed CAC framework. A GUI is created to provide the user with theudflexibility to configure the system settings before starting a simulation. Theudconfiguration settings allow the system to be analysed under differentudconditions.udThe performance of the system is measured under different simulationudsettings such as enabling and disabling of the two functionalities of the CACudframework; retune procedure and the pre-emption procedure. The simulationudresults indicate the CAC framework as a whole with all the functionalitiesudperforms better than the other simulation settings.