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Resource Management in Satellite Networks part 22

Resource Management in Satellite Networks part 22. 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 | Chapter 6 CALL ADMISSION CONTROL 193 handover service scheme which aims at increasing channel utilization and thus reducing CBP. Toward this end the channels in that scheme are reserved only for the time intervals they are expected to be in use hence the name Time-based channel reservation algorithm. Therefore channel utilization is improved and CBP is reduced. In 45 46 the queuing time interval is considered to be dependent on the value of a parameter that was called handover threshold. This parameter should be appropriately selected in order to attain a trade-off between dropping and blocking probabilities as well as to achieve high channel utilization. In brief a handover request is sent to the next cell at a specific time instant which is determined by the handover threshold parameter. When a new call arrives it is accepted provided that an available channel exists in the current cell. However if the time interval until the occurrence of the first handover is shorter than the one defined by the handover threshold parameter then an available channel should also exist in the succeeding cell in order for the call to be accepted. It was shown that this scheme can provide different QoS levels based on the value of the handover threshold parameter. In 47 48 CAC algorithms based on a bandwidth allocation strategy with priority queues are examined. The handover admission policy introduced distinguishes between real-time and non-real-time services. To each accepted real-time connection bandwidth is allocated in a look-ahead horizon of 2 cells along its trajectory while non-real-time connections reserve bandwidth only in the forthcoming cell. According to that scheme each cell maintains four different queues called R S1 S2 and Q. Queue R contains those real-time connections that have reserved at least the minimum required bandwidth in the next two cells. Therefore the handover to the next two cells is guaranteed to be successful. Queue S1 contains those real-time .