Research Of Switching Virtual Connection For Satellite ATM Switching System

Asynchronous transfer mode (ATM) is a fast packet switching technique meeting with various QoS requests. ATM satellite switching system is expected to support multi-beams switching, and to realize earth stations to communicate each other conveniently. The advantage of ATM satellite depends heavily on the ability to perform multiplexing of various services. Different service has its own traffic characteristics and differentiated Quality of Service (QoS) requirement. So it is necessary to provide a strategy enabling ATM network to meet various QoS requests defined by different services while achieving highly resource utilization. Signalling technique plays a very important role in such strategy.Firstly, the theory of the ATM signalling is introduced. Secondly, according to the problem of protocol stacks for ATM signalling, which defined by ITU-T lacks necessary call/control functions, a new universal satellite ATM signalling model is proposed. The software design shows the signalling model can remedy parts that lack in standard protocol. The Q.2931/Q.2971protocol, which is the standard protocol for ground ATM networks, is realized difficultly in satellite ATM switching system due to high bit error ratio and high-latency. The paper also proposes a simplified Q.2931_S/Q.2971_S protocol aiming at this problem. Meanwhile, the satellite QoS technique, which has affinity with CAC, is also researched in this paper.Lastly, the hardware validations are finished by building the semi-physical simulation test-bench of broadband satellite communication system, which include the proposed signalling model, the signalling protocol in satellite ATM switching system, the open-loop onboard congestion control algorithm and the CAC algorithm. The results show that the model and protocol in the paper are correctness and feasible.Through analysis of satellite signalling technique, the unicast/multicast signalling protocol for satellite is advanced, which provides important basis for engineering application in the future.