Research On Link Planning For Optical Satellite Networks

With the deepening of research on space information technology and the demand for mass transmission of space-based information services,satellite networks have gradually become the inevitable trend of communication network development.Large-scale low-earth orbit(LEO)optical satellite networks have the advantages of high link bandwidth,low transmission delay,and large space-time scale,which have become a new research idea in spatial information technology in countries all over the world.However,in the large-scale LEO optical satellite network,dynamic links mainly include satellite-ground links(GSLs)and inter-layer links(ILLs).Their inherent frequent construction and demolition phenomenon intensifies the dynamics of the network,and at the same time,the specific constraints of links make the network topology uncertain.Therefore,how to realize the stable and efficient operation of optical satellite networks through dynamic link planning is very important.This paper takes GSLs and ILLs of optical satellite networks as the main body of research,focuses on three core challenges of dynamic link planning,namely "high dynamic,strong constraint and a large order of magnitude",and carries out research from the perspective of "theoretical model design,GSLs planning and ILLs planning".The combined solution of "dynamic link planning+snapshot routing technology" is adopted to complete the relevant innovative work of "dynamic link planning strategy of optical satellite networks,GSLs planning scheme of single-layer LEO constellation and ILLs planning scheme of dual-layer LEO constellation".The main research and innovation points of this paper are as follows:(1)A dynamic link planning strategy for optical satellite networks is proposed.Based on the design of the constellation model,links model,and networks model,a method combining link planning strategy and snapshot routing technology is used to achieve the advantage of reducing network dynamics and oscillations while ensuring the minimum loss of network capacity.(2)A planning strategy(GTWP)based on GSLs time window is proposed,which planned GSLs from four aspects:constraint setting,equilibrium setting,chain break update,and GSLs selection.Through the snapshot routing simulation verification,the GTWP strategy has the results that the number of snapshots is reduced by 54.5%,the network oscillation rate is reduced by 19.8%,and the network capacity loss is less than 0.3%compared with the planning strategy based on real link switching.Compared with the fixed-interval planning strategy,the GTWP strategy has the advantages of reducing the number of snapshots by 4%,reducing the network oscillation rate by 42.6%,and increasing the network capacity by 0.8%.(3)A planning strategy(ILDP)based on ILLs location distribution is proposed to plan ILLs from four aspects:ILLs scene distribution,ILLs location selection,GSLs constraint setting,and snapshot update.Through the snapshot routing simulation verification,the ILDP strategy has the advantage of increasing the success rate of service transmission by about 50%and reducing the average service transmission delay by about 10%,compared with the dual-layer LEO optical satellite network without ILLs.