Networking and Signalling Aspects of a Satellite Personal Communications Network

A possible network architecture for the European Space Agency’s MAGSS-14 (Medium Altitude Global Satellite System) constellation is proposed and described. Network connectivity statistics are examined and a physical implementation of the ground segment control network, using 11 globally positioned gateway stations, is described. This example helps clarify the complex nature of S-PCN system connectivity and control. Using this example as the baseline architecture, an examination is made of GSM LAPDm signalling procedures over satellite. A slightly modified version of this protocol is used for these satellite network simulations. Mobility management signalling is initially examined, with a trade-off being made between location update and paging signalling allowing an optimum user location uncertainty distance to be found. User originated and terminated call setup signalling is also simulated. The results provide some useful insights into the use of modified LAPDm over satellite.