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UBC Theses and Dissertations

Enhancements of CFDAMA protocol for multi-service applications in a GEO broadband satellite network Ibikunle, Olumide B.


The bursty behavior and the diverse quality of service (QoS) requirements of the component traffic generated at the user terminals (UTs) in current broadband satellite networks (BSN's) have been shown in numerous research projects to necessitate the use of dynamic medium access control (MAC) protocols such as the combined free/demand assigned multiple access (CFDAMA) protocol for efficient statistical multiplexing of the traffic from the several UTs on the uplink channel. Several predictive algorithms have been proposed to enhance the CFDAMA protocol performance by estimating the dynamic trends in the bursty UT traffic and allocating the uplink capacity based on those trends. In this thesis, we provide enhancements to the predictive algorithms of the CFDAMA protocol using a two-frame traffic momentum estimation strategy in a time division multiple access (TDMA)/multi-frequency (MF)-TDMA uplink frame format. Moreover, the performances of the CFDAMA protocol variants were enhanced for an application environment consisting of a mixture of real-time (RT) and nonreal- time (NRT) applications. For RT applications we take advantage of packet-level application profile information obtainable from the real-time protocol (RTP) and real-time control protocol (RTCP). The resulting protocol relies on the cross-layer application-profile description provided to implement intelligent resource request signaling (RRS), dynamic capacity allocation (DCA), and a priority-based local capacity allocation scheme. Simulation results for the proposed enhancements, when compared with previous variants of CFDAMA, display significant performance improvements in terms of minimizing the delay and delay jitter or distributing these performance metrics between the application types in the UT to meet the different QoS requirements.

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