Efficient support of circuit-mode and packet-mode services in micro-VSAT networks

This paper studies the provision of low data rate services in micro-VSAT networks such as the bandlimited quasisynchronous CDMA VSAT system currently being developed by ESA. It presents the results of a simulation study intended to evaluate the performance impact of several system design choices. The simulated network (which is a generalization of the first-generation system planned by ESA) is required to support voice, fax, electronic mail, and other data services, both in circuit and packet mode, which have different requirements in terms of data rate, symmetric or asymmetric data flow, etc. These services have to be supported with a very limited number of communication channels, resulting in a potentially high call blocking probability. In this context, the paper evaluates the call blocking reduction that can be obtained, firstly by sending user packets and acknowledgements via signalling channels instead of via traffic channels, and secondly by dynamically sharing traffic channels among several networks coordinated by a central control station. The impact of these design choices on other performance indicators, for example the call setup delay and the signalling channel load, is also evaluated