Research On Multi-Beam Management Technologies Of LEO Satellite Communication System

Related technologies in the field of Low Earth Orbit(LEO)satellite communications have become a research hotspot at home and abroad.Since the multibeam LEO satellite network with dynamic changes in the network topology,network traffic and uneven spatial and temporal distribution presence in some areas overlapping beams covering the phenomenon,etc.,it may lead to serious ping-pong switching effect and waste of beam resources.Therefore,beam management related technologies have become the key to solving these problems.This thesis focuses on the coverage optimization problem in beam management technology,and discusses the impact of beam shut-off strategies on the performance of low orbit satellite communication systems.The main research work is summarized as follows:First of all,this thesis developed a simulation platform for low orbit satellite communication systems,and designed a satellite constellation and multi-beam antennas.Furthermore,this thesis established a coverage model for low orbit satellite networks,and the frequency reuse strategies between satellites and beams are given.Meanwhile,this thesis simulated and analysed the satellite beam coverage optimisation problem.On this basis,a beam shut-off strategy based on user location is proposed.This strategy aims at saving satellite beam resources while ensuring network service quality and system reliability.The simulation results show that the beam shut-off strategy can effectively reduce the number of user handovers and reduce the ping-pong handover rate on the basis of saving a large amount of beam resources and ensuring system reliability.Secondly,this thesis proposed a beam closure strategy based on traffic prediction,with the objective of maximising the saving of satellite beam resources,while taking into account the uneven spatial and temporal distribution of traffic in the network,and incorporating the possible future traffic demand in different regions into the constraint on the solution of the set of closable beams.A Convolutional Long Short-Term Memory(Conv LSTM)model is used to predict the distribution of service requirements in the network by obtaining historical service information from the physical network,and the set of closable beams for the next time slot is solved based on the service requirements predicted by the Conv LSTM model.The beam shut-off algorithm based on the traffic prediction is further proposed.The simulation results show that the beam shut-off strategy based on traffic prediction can improve the ping-pong handover effect of the low orbit satellite communication system while saving beam resources,effectively reducing the probability of network congestion,and improving the quality of service and system reliability.