tailieunhanh - Resource Management in Satellite Networks part 33

Resource Management in Satellite Networks part 33. This book provides significant knowledge on innovative radio resource management schemes for satellite communication systems that exploit lower layer adaptivity and the knowledge of layer 3 IP QoS support and transport layer behavior. The book integrates competencies considering all the parts of system design: propagation aspects, radio resource management, access protocols, network protocols, transport layer protocols, and more, to cover both broadband and mobile satellite systems | 308 Gorry Fairhurst Michele Luglio Cesare Roseti Adaptive resource management can both guarantee efficient network utilization and satisfy QoS requirements using satellite links that are affected by variable weather conditions and large propagation delays. An approach tuning the satellite link parameters at the physical or link layer and trading bottleneck bandwidth with segment error rate can permit to improve TCP performance. Moreover where it is possible to evaluate the channel conditions in real-time further sophisticated cross-layer interactions could be exploited for an adaptive selection of the physical layer parameters. DAMA schemes may be used to achieve an efficient resource allocation but they degrade the TCP performance by adding an access delay that increases the whole end-to-end delay. Then explicit cross-layer approaches can also mitigate the interactions between TCP and DAMA MAC layer . The rationale is to use TCP information to estimate in advance the amount of resources needed for a given TCP source. This should permit MAC layer to perform capacity requests based on both the volume of queued data and the predicted TCP traffic behavior. Simulations show that this TCP-driven RRM scheme represents a good trade-off solution with respect to both fixed access schemes optimizing TCP performance and classical dynamic access schemes optimizing network efficiency. Transport protocols not based on TCP can also benefit from cross-layer methods. Multimedia traffic flows using UDP and UDP-Lite are also expected to benefit from improved communication between protocol layers in fact application performance can be tuned to link and physical layer conditions in order to achieve a system optimization. References 1 H. Kruse Performance of Common Data Communications Protocols over Long Delay Links an Experimental Examination in Proc. of the 3rd International Conference on Telecommunication Systems Modeling and Design 1995. 2 C. Partridge T. J. Shepard TCP IP .