Call setup performance improvements over mobile satellite systems using IP multimedia system

Todaypsilas mobile satellite systems are built to support a packet switched all IP communications infrastructure based on IP multimedia subsystem (IMS) leveraging the benefits of solutions already available in terrestrial networks. IMS technology provides a SIP based open platform that enables operators to introduce multimedia applications quickly and in a cost effective manner. Although IMS is very well suited for terrestrial IP networks, it is challenged by high propagation delay satellite environment with low data rates to provide equivalent levels of quality of experience enjoyed by subscribers of circuit switched systems. In this article, we first provide an overview of Circuit Switched and IMS Packet Switched based call flows for mobile satellite systems. We then concentrate specifically on voice call setup time and show how Circuit Switched architecture provides significantly better performance. Lastly, we propose several advancements on SIP call signaling to improve the IMS Packet Switched call setup times.