Research On Key Technologies Of Task Distribution And Communication Routing For Self-organized Satellite Networks

With the development of space technology and communication technology,satellite communication network plays an increasingly important role in aircraft navigation,ground detection,video relaying,earthquake relief,military and national defense,and has wide economic and social benefits.The research of satellite network includes task distribution,routing technology,orbit control technology and antenna design.Among them,task distribution and routing technology is the most relevant research in computer science,and has also been paid much attention by many researchers.Compared with the traditional satellite network,the self-organized satellite network is different in the role division of nodes.It no longer determines tasks of nodes by the orbit height of satellites,but divides nodes into working satellites,service satellites and communication satellites based on function division of data collection,data processing and data transmission.Therefore,a new problem model is proposed for task distribution,and the original task distribution strategy is no longer applicable.Furthermore,because of the change of network structure,link interruption is more frequent,and data transmission is more flexible.The original centralized routing calculation for satellite network is difficult to adapt to the new network structure.So it is required to put forward the routing technology with flexibility,survivability and reconstruction ability to realize more efficient data transmission.In view of the above challenges,based on the existing self-organized satellite network structure,the task distribution and communication routing technology in self-organized satellite network is studied with earth observation as the mission goal.The main works and innovations are as follows:First,According to the change of nodes division in the new satellite network,the alternating direction multiplier method is applied to the task distribution optimization problem of the satellite network for the first time,so as to achieve more efficient task distribution decision.To optimize the specific scene of satellite network,we construct mathematical model by using wireless data transmission formula and taking the minimization of the total energy consumption as the optimization target.And design optimization algorithm by alternating direction method of multipliers to solve the task distribution problem,so as to achieve moderate accuracy requirements in a relatively short period of time.Through the design of simulation experiments based on MATLAB and CVX,compared with the traditional linear programming,it is verified that the algorithm proposed in this paper can achieve convergence and moderate accuracy in dozens of iterations in large-scale scenarios.Second,in consideration of frequent link interruption in self-organized satellite networks,we build a new multi-layer satellite network structure,realize the routing idea of contact graph,and enable the network to perform more efficient data transmission.According to the scenario requirement,we increase the hop limitation and node validity judgment in the routing process,and design the corresponding exception handling mechanism to further improve the transmission ability of the network.The network simulation software OPNET is used to build a satellite network simulation platform to achieve a variety of routing algorithms.Experiments show that the algorithm proposed in this paper can achieve more effective data transmission,and has higher throughput and shorter transmission delay,is more capable of surviving and reconstructing.