A Multibeam Packet Satellite Using Random Access Techniques

The performance of a multibeam packet satellite using ALOHA type random access techniques is studied. The satellite provides either no buffer or an infinite buffer for successful packets on the uplink channels. A TDMA frame is organized in accordance with the traffic demand from each area. System throughput and packet delay have been successfully obtained. Aiming at improving the performance of the system, three different protocols are introduced and studied in the zero buffer case. It is demonstrated, through examples, that satisfactory system performance can be obtained using an appropriate protocol. However, system performance can also be severely degraded if the transition time for the satellite transponder to switch from one zone to another is not negligible. In this case, the performance can be restored via the use of a buffer of sufficiently large size.