基于低轨星座的星地路由技术研究

Research on Routing Between Satellite and Gateway Station Based on Low-Orbit Constellations

针对低轨(LEO)卫星通信系统卫星与信关站之间的馈电链路频繁切换,且星载设备处理能力受限的特点,提出基于软件定义网络(SDN)的星地一体路由架构,星地路由计算是研究的重点;地面控制中心结合卫星运动的规律性,周期性地计算各颗卫星对信关站的覆盖时间;采用最大覆盖时间准则选取切换卫星,计算切换时间进行切换预测,并将计算结果注入星上,到达计算的切换时间激活注入的星地路由;仿真结果表明,与信关站发出切换请求后再实时进行星地路由计算的标准星地路由协议相比,基于切换预测的星地路由协议在丢包率上有明显的优势,减少切换过程对星地路由造成的影响。

There is frequent handover of links between Low Earth Orbit(LEO)satellite and gateway station.In addition,equipment on the satellite has limited processing capacity.In view of the question above,this paper raises a routing protocol between satellite and gateway station based on SDN (Software Defined Network).Routing calculation is the focus of this paper.Considering the law of satellite operation,control center on the earth calculate the coverage time of every satellite.The satellite which covers the gateway station for the longest time is arranged to establish connection with the gateway station instead of the original satellite.And then the time of handover can be predicted.Then the routing between satellite and gateway station is transmitted to the satellite. When it reaches the predicted handover time,the routing transmitted to the satellite is triggered.According to the simulation result, compared with the routing protocol that calculates the routing between satellite and gateway station after handover,the routing protocol raised in this paper can rebuild touting quickly.It has a distinct advantage in packet loss rate.It reduces the impact of handover on routingbetween LEO satellite and gateway station.