Low-orbit Constellation Satellite Communication System Based On Opnet Simulation Modeling

With the highlight advantages of seamless global coverage, small transmission loss, short delay, strong anti-destruction and anti-interference, small portable terminals, Low Earth Orbit (LEO) constellation satellite communication system is subject to a wide range of concerns at home and abroad, becomes a hot point in the new generation of mobile communications research, and has been widely used in the field of military and civilian. Research on the simulation and modeling of LEO constellation satellite communication system could simulate the course of its work, provide a useful reference for system construction and layout, and provide a strong support for theoretical research.This paper researched on developing LEO constellation satellite communication system simulation platform based on OPNET. The architecture, network configuration, work pattern and work characteristics of LEO constellation satellite communication system was introduced, the basic theory on OPNET modeling and simulation was represented. On the basis of understanding the structure and function of LEO constellation satellite communication system and OPNET simulation mechanism in depth, satellite, gateway station, user terminal, network control center four node models and corresponding process models were set up, the necessary communication process between the nodes was implemented.In this paper, the geometry model of satellite multi-beam antenna was researched, satellite multi-beam antenna model based on OPNET was implemented, satellite link budget suitable for LEO constellation satellite communication system was analyzed. The SNR distributing characteristic of users in the covering region was simulated by setting network simulation scenario. Simulation results indicate that the OPNET satellite multi-beam antenna model is appropriate to simulate the radiation characteristic of satellite multi-beam antenna.A network simulation scenario of covering the latitude zone near the equator was set up using four node models, statistics such as call arrival rate, handoff arrival rate, call blocking rate, handoff failure rate and channel utilization rate were simulated and collected; channel reservation strategy were simulated and compared with no channel reservations strategy on call blocking rate, handoff failure rate, channel utilization rate and grade of service.LEO constellation satellite communication system simulation platform simulated satellite multibeam antenna realistically, OPNET packet-based communications mechanism was used between the nodes, pilot frequency mechanism was implemented. Simulation platform has preferable scalability, cound be used to simulate and analyze radio resource management algorithm effectively and reliably, also could be used in LEO constellation satellite communication system layout.