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CDMA truy cập và chuyển mạch P5

The Satellite Switched CDMA Throughput Overview As we have discussed in Chapters 3 and 4, the satellite switched CDMA system provides on-board switching which operates with demand assignment control. This approach resolves both the multiple access and switching problems while it allows efficient utilization of the system resources. This is achieved with Traffic channel assignment algorithms which can maximize throughput and integrate the traffic of circuit calls and data packets. | CDMA Access and Switching For Terrestrial and Satellite Networks Diakoumis Gerakoulis Evaggelos Geraniotis Copyright 2001 John Wiley Sons Ltd ISBNs 0-471-49184-5 Hardback 0-470-84169-9 Electronic 5 The Satellite Switched CDMA Throughput 5.1 Overview As we have discussed in Chapters 3 and 4 the satellite switched CDMA system provides on-board switching which pprrates wtth demand assigmnont. control. This approach resolves both the multiple access and switching obt lm s whUe it allows efficient utilization of the system resources. This is achieved with Traffic channel assignment algorithms which can maximize throughput and integrate the traffic of circuit calls and data packets. A large population of end users may then access the geostationary satellite network which routes the circuit calls and data packets directly between them. A related method based on Time Division Multiple Access TDMA called Satellite Switched TDMA SS TDMA has been proposed for packet switched data see reference 1 . In this chapter we provide channel assignment algorithms for optimum suboptimum and random switch operation. In each case the system throughput has been evaluated by simulation and the performance results are compared. Performance analysis has been carried out for the case of optimum switch scheduling. The analysis is based on a discrete time Markovian model and provides the call blockingprobabilities and data packet delays. In Section 5.2 we describe the demand assignment system and present the Traffic channel assignment control algorithms. In Section 5.3 we provide the throughput analysis and in Section 5.4 we present the performance results. This work originally appeared in reference 2 . 5.2 The Demand Assignment System The SS CDMA demand assignment network is illustrated in Figure 5.1. The satellite has an N x N Code Division Switch CDS and a Control Unit CU . The interface between the satellite and the SUs called the Common Air Interface CAI consists of control and traffic .