Simulation Research Of TDMA Protocol For Communication Network Of Satellite Mobile

The emerge of satellite-based information network, which is a bond connecting traditional ground combat system with the high-tech warfare, has redesigned the pattern of wars, it plays an important role in modern warfare. Satellite-based information network, making use of the spacecraft, obtains information before having them treatment, transmission and relay etc. It uses multi-band frequency, combined with ground wired network, can transmit information between satellite of different level and different kinds, or some of the ground tactical networks, forms a satellite-based tactical communications network with the characteristic:all-directional, all-weather, full-business type, three-dimensional and integrated with form and function.The satellite access protocol in MAC sublayer is the key technology researching widely by engineers in satellite-based tactical communications network, in satellite system, multiple access protocol plays a key role in improving the utilization of satellite channel as well as guarantee the service of all kinds of business. TDMA protocol, which has been widely used in satellite communications system, has the characteristics of enhance flexibility of network applications, wide range of business, simple process in satellite and strong anti-interference ability.It can make full use of power and band in satellite transponder. Therefore, the protocol based on TDMA has been widely used both in military and civilian.Firstly this paper separately introduces the satellite-based tactical communications network and TDMA protocol, then gives a particular description about the structure of combined satellite tactical communications network based on TDMA protocol.This thesis, combined with the characteristics of tactical communications network, proposed a priority TDMA protocol in which slots can be allocated dynamically. After researching many dynamic allocation methods in TDMA protocol, this protocol can nicely meets the need of sending urgent data in high-priority ground tactical sites. Finally the paper provided the simulation modeling for both fixed TDMA protocol and priority dynamic TDMA on OPNET Modeler platform. By comparing the important parameters of the simulation results in the two allocation methods, for instance, end-to-end delay and throughput.It has been well proven that priority dynamic TDMA protocol is more adoptable for satellite communication system than fixed TDMA protocol. Network simulation provides a objective, reliable and quantitative foundation based on which network systems can be planed and designed.