The third generation of mobile communication systems introduceudinteractive Multicast and Unicast multimedia services at a fast data rate ofudup to 2 Mbps and is expected to complete the globalization of the mobileudtelecommunication systems. The implementation of these services onudsatellite systems, particularly for broadcast and multicast applications toudcomplement terrestrial services is ideal since satellite systems are capableudof providing global coverage in areas not served by terrestrialudtelecommunication services. However, the main bottleneck of suchudsystems is the scarcity of radio resources for supporting multimediaudapplications which has resulted in the rapid growth in research efforts forudderiving efficient radio resource management techniques. This issue isudaddressed in this thesis, where the main emphasis is to design a dynamicudscheduling framework and algorithm that can improve the overalludperformance of the radio resource management strategy of a UMTSudcompatible satellite network, taking into account the unique characteristicsudof wireless channel conditions.udThis thesis will initially be focused on the design of the network andudfunctional architecture of a UMTS -compatible satellite network. Based onudthis architecture, an effective scheduling framework is designed, whichudcan provide different types of resource assigning strategies. A functionaludmodel of scheduler is defined to describe the behaviours and interactionsudbetween different functional entities.udAn OPNET simulation model with a complete network protocol stack isuddeveloped to validate the performance of the scheduling algorithmsudimplemented in the satellite network. Different types of traffic areudconsidered for the OPNET simulation, such as the Poisson Process, ONOFFudSource and Self Similar Process, so that the performance ofudscheduling algorithm can be analyzed for different types of services.udA novel scheduling algorithm is proposed to optimise the channeludutilisation by considering the characteristics of the wireless channel, whichudare bursty and location dependent. In order to overcome the channeluderrors, different code rates are applied for the user under different channeludconditions. The proposed scheduling algorithm is designed to give higherudpriority to users with higher code rate, so that the throughput of network isudoptimized and at the same time, maintaining the end users¿ service leveludagreements. The fairness of the proposed scheduling algorithm isudvalidated using OPNET simulation. The simulation results show that theudalgorithm can fairly allocate resource to different connections not onlyudamong different service classes but also within the same service classuddepending on their QoS attributes.
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