tailieunhanh - Resource Management in Satellite Networks part 24

Resource Management in Satellite Networks part 24. 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 | 214 Tommaso Pecorella Giada Mennuti Simulations have evaluated the bandwidth loss measured as the number of slots per frame allocated to an RCST but not used to transmit data and the QoS performance of two DBA techniques based on a Receding Horizon Controller and a Smith Predictor Controller RHC and SPC respectively versus three fixed Fix n in Figure where n is the number of slots frame assigned to a single RCST allocation schemes with different bit-rate values 13 . A self-similar traffic with Hurst parameter H has been used to feed each RCST. Figure reports the bandwidth loss distribution a and the delay for the Expedited Forwarding EF Assured Forwarding AF and Best Effort BE DiffServ 14 - 17 traffic classes b c and d respectively . It can be observed that the bandwidth loss is greatly reduced by using DBA techniques whereas the overall QoS of the traffic classes is acceptable in particular by using the RHC scheme. However despite the great advantages of DBA techniques both in terms of QoS satisfaction and efficient resource utilization some new problems arise when they are applied. In particular Greedy traffic flows can compromise the whole satellite system s QoS. Compatibility between different control techniques and bandwidth request methods should be validated. Security issues on the signaling channel should be analyzed in order to prevent denial of service attacks based on fake bandwidth reservations. Those issues should be investigated and carefully addressed before using DBA techniques in any actual system. Dynamic bandwidth de-allocation Several approaches for bandwidth and handover management have been studied in the recent literature in the case of mobile satellite systems. Publications in this area investigate only bandwidth allocation and the intrasatellite handover management. In reference 18 an advanced bandwidth management strategy is proposed and evaluated allowing for bandwidth allo-cation deallocation and a novel inter-satellite