Virtual topology dynamics and handover mechanisms in Earth-fixed LEO satellite systems

Handling network mobility in a highly dynamic LEO satellite network is a critical issue to achieve seamless and efficient integration of satellite and terrestrial networks. In Earth-fixed satellite systems, this task could be simplified by representing the network with a more static virtual topology. Virtual node (VN) approach is widely explored in satellite networks research; however, it has some deficiencies due to necessity of one-to-one correspondence between virtual nodes and physical satellites. In this work, a generic virtual topology model, namely multi-state virtual network (MSVN) architecture that alleviates these deficiencies, is proposed. A new mathematical model for MSVN is introduced along with its potential contribution to the overall system availability. Furthermore, possible handover mechanisms in Earth-fixed satellite systems are investigated, and new efficient handover mechanisms for both VN-based systems and MSVN-based systems are proposed. Comparing the handover mechanisms, we conclude with the benefits of using an MSVN-based Earth-fixed satellite system.