Research On Beam Position Division And Resource Allocation Algorithm In LEO Satellite System Based On Beam Hopping

The advent of the 5G era has promoted the development of the industrial Internet,mobile Internet,and the Internet of Things,and the number of access users has continued to increase.Both the network communication capacity and the user communication rate have been significantly improved compared with the previous generation of communication systems.However,the ground communication system covers less than 10%of the earth’s surface.In areas where there is no terrestrial wireless communication system coverage,such as manned spaceflight,high-sea exploration,and remote areas on land,the satellite communication system plays a key role and can provide users in these areas with the ability to access anytime and provide on-demand services.In addition,the satellite network can achieve global three-dimensional coverage and can be used as a supplement to the terrestrial network to relieve traffic pressure.The current LEO satellite constellation system is developing rapidly in global.The small size and light weight of LEO satellites also lead to the limitation of on-board resources.The fast-moving speed of satellite constellations makes the satellite service range change rapidly and the channel environment is complex.In addition,the distribution of users in different regions is far from the business needs,which also brings challenges to LEO satellite services.Under the condition of limited spaceborne resources,the beam-hopping technology can effectively improve the resource waste caused by the traditional fixed multi-beam technology,and the users in hotspot areas cannot meet the service demand,to maximize the resource utilization.The main work of this paper is aimed at the system of beam-hopping LEO satellite system,and studies the problem of beam position division and resource allocation.The main work of the thesis is divided into:1.Construction of the beam-hopping LEO satellite simulation platform.Based on the OPNET network simulation software,a simulation platform that can simulate the high dynamics of the LEO satellite system and simulate the implementation of the beam-hopping scheme was built.Based on the platform,the beam-hopping beam access model and the satellite coverage cell model based on the dynamic combination of wide beam and spot beam are studied,and the main functional nodes and processes of the beam-hopping LEO satellite simulation system are designed and realized,and the main functions and performance was verified.2.Research on the traffic beam position division strategy of the LEO satellite system under beam hopping.Since the service area(service beam position)of the satellite service beam on the ground under the beamhopping scheme is more flexible than that of the ground fixed cell under the traditional multi-beam scheme,the division of the LEO satellite service beam position is summarized as a multi-objective site selection,that is the P-center problem.Based on the P-center problem,a traffic beam position division algorithm based on beam position radius determination and a traffic beam position division algorithm based on beam position radius dynamic change are proposed,and the solutions are solved by genetic algorithm.Experiments show that these two algorithms can effectively reduce the queuing delay of downlink data packets in LEO satellites on the premise of ensuring the satellite throughput,and improved user communication service experience.3.Research on the resource allocation scheme of the beam-hopping LEO satellite system.Under the beam-hopping working mode of the LEO satellite,a multi-objective time-slot resource allocation scheme is proposed for the time slot resources allocated to each traffic beam position in the beam-hopping period.A "pre-allocation+highest cluster first" algorithm is proposed for beam resources.Based on the characteristics of interrelated constraints among resources such as frequency,power and beam,a joint resource allocation plan is formulated.Compared with the traditional multi-beam polling allocation scheme,the beam-hopping scheme is better than the former in terms of throughput performance and delay performance in scenarios where satellite resources are limited,ground users are unevenly distributed,and service requests are greater than satellite load.The beam-hopping scheme is more suitable for actual LEO satellite scenarios.