The Research Of Relevant Theory And Technology For Satellite Mobile Communication Network

Satellite communication is getting more and more attentions during the development of communication technologies, because of the characteristics of wide coverage and being unlimited to geography condition. Satellite communication mode is changing from single satellite to satellite network with the emergent demands of broadband mobile multimedia communication services and the improvement of satellite equipment manufacture technology. Compared with GEO satellite, NGSO satellite has smaller propagation delay and lower EIRP request for personal terminals. So satellite mobile communication network architecture has the features of consisting of NGSO satellites, on-board processing and inter satellite links. In 21th century, the object of satellite communication is to provide broadband intergrated personal service with low cost IP-based technology. The new object brings great challenges.This dissertation mainly studied the architecture and routing technology of satellite mobile communication network. New concept was introduced during the course of architecture design from the view points of satisfying basic demand. At the same time a compound unicast routing algorithm and a compound multicast routing algorithm based on ant colony optimization algorithm were presented, considering the difference between satellite communication network and terrestrial communication network. The major contributions of the dissertation include:Network connectivity degree based on time delay is presented and applied to the design and evaluation of network architecture. Network connectivity degree based on time delay measures the available paths which are fit to constrained conditions, while the concept of connectivity degree in traditional topology theory describes whether network is connected if some nodes or links are deleted. The proposed concept distinguishes available network from reachable network.The centralized management model which physically separates management subnet from service subnet is presented based on the diversity of satellite orbit altitude. A satellite in high orbit covers several satellites in low orbit, which exhibits inherent centralized management archeticture. The separation of management subnet and service subnet not only reduces the processing loads of service subnet, but also improves network performance.A compound unicast routing algorithm is presented, making use of the characteristics of satellite mobile communication network topology. Routing choice need consider static parameters and dynamic parameters. The path which is determined by static parameters is named static path, while static path becomes final path after the revision due to dynamic parameters. In static routing phrase, the characteristics of satellite regular movement and regular array of inter satellite links are considered in order to reduce search space; while in dynamic routing phrase the information of network flow distribution is supervised in real time, and once the information varies enough acutely, routing choice is corrected based on the results in static phrase, which could produce the final path balancing network traffic.A compound multicast routing algorithm based on ant colony optimization algorithm is presented. Multicast routing problem is proved to be a NP-hard problem. Ant colony optimization algorithm shows excellent performance when solving NP-hard problems. A compound multicast routing algorithm based on ant colony optimization algorithm could accelerate constringency course by controlling the procedure of ant colony algorithm according to satellite network topology.