Design Of Constellation In Global Satellite Communication Systems Based On Genetic Algorithm

With a dramatic rise in the number of mobile users,the data volume of communication business in networks becomes an explosive increase,and the ground communication network has been unable to satisfy people’s growing demand for global network and information.Considering the good feature of high coverage,good radio performance,stable channel condition and flexible network configuration in satellite mobile communication,it can not only achieve transmission of a large data volume around the world,but also provide service for remote areas like mountains and oceans which ground networks are not able to reach.Thus,building a global satellite communication system as an implement of ground communication networks to achieve global connectivity and improve network throughput becomes more and more significant.Satellite constellation design is a basic but important link in the construction of the global satellite communication system.As the limitation of single satellite coverage,more satellites are needed for a satellite constellation to enlarge the coverage of the satellite system and complete global communications.However,satellite constellation design is not the simple combination of similar satellites,how to increase the coverage,the satellite access model and the delay and throughput of communication must be taken into consideration.On the other hand,the construction cost of satellite constellation also needs to be considered at the beginning of the design.In most cases,a trade-off in the multi objectives is needed for an optimization is hard to achieve between the performance and the cost,so the satellite constellation design is a typical multi-objective optimization problem.A method of constellation design in global satellite communication systems using the genetic algorithm is proposed in this paper.This method considers both the communication performance and the construction cost in the system and divides the multi objectives into performance objectives and cost objectives.The performance objectives consist of the coverage rate and the performance of the delay between satellites and the access between satellites and the ground,while cost objectives contain the fabricating cost and the launch cost.Then,according to the constellation design model,the suitable coding scheme,fitness function and genetic operation which contains the selection,crossover and mutation in the genetic algorithm are designed to try to increase the communication performance and decrease the construction cost.Finally,different design schemes are proposed based on different demands in this paper,and then optimal solutions of the satellite constellations designed in all schemes are gotten and compared with each other to demonstrate the correctness and effectiveness of the method.