Research of next generation LEO satellite networks which have high affinity with the Internet

近年来，许多研究人员研究了泛在网络，它允许所有用户随时随地访问任何类型的信息。在这些网络中，LEO(低地球轨道)卫星网络预计将发挥关键作用，主要是因为它们的传播延迟很低。本研究的目的是研究下一代低轨卫星网络中与互联网有很高亲和力的基础技术。我们按原计划研究了以下四项关键技术：1.低轨卫星与地面终端直接通信。由于低轨卫星移动速度快，切换频繁，移动性管理包频繁产生。结果，无线电资源被浪费了。因此，我们提出了一种基于地理信息和低轨卫星轨道的低成本移动性管理技术。如果将TCP/IP应用于LEO卫星网络，由于传播时延等现象，很难实现效率和公平性。为此，我们提出了一种高效、强调公平的协议。该协议能够通过卫星跳数计算合适的数据速率，并预测往返时间。为了在低轨卫星网络上提出一种安全技术，我们提出了一种降低路由攻击对自组网的影响的方案。我们需要在未来将该方案扩展到LEO卫星网络。我们提出了一种交通控制方案，使相邻的卫星能够显式地交换关于其拥塞状态的信息。在该方案中，业务负载被分配，而不是集中在任何一颗卫星上。上述方案为下一代LEO卫星网络系统奠定了基础，并将为实现无缝网络环境做出很大贡献。从而达到了本研究的目的。

In recent years, a lot of researchers have studied ubiquitous networks that allow all users to access information of any kind at any time, from anywhere. In those networks, LEO (Low Earth Orbit) satellite networks are expected to play a key role, mainly due to their low propagation delay. The purpose of this research is to study fundamental technologies in nest generation LEO satellite networks which have high affinity with the Internet. We researched the four following fundamental technologies as originally planned:1. LEO satellites communicate directly with ground terminals. Since LEO satellites move quickly, handover occurs frequently and mobility management packets are generated often. As a result, radio resources are wasted. So, we proposed a low-cost mobility management technology based on geographic information and LEO satellite orbit.2. If TCP/IP is applied to LEO satellite networks, efficiency and fairness are difficult to achieve due to propagation delay and other phenomenon. So we proposed a high efficiency and fairness emphasizing protocol. This protocol enables calculation of a suitable data rate with predicting round trip time by satellite hop counts.3. To propose a security technology on LEO satellite networks, we proposed a scheme that reduces the impact of routing attack on ad-hoc networks. We need to extend this scheme for LEO satellite networks in the future.4. We proposed a traffic control scheme that enables neighboring satellites to explicitly exchange information on their congestion status. In this scheme, traffic load is distributed so as not to concentrate it on any certain satellite.The above proposed schemes serve as a foundation for the next generation LEO satellite network system, and will contribute largely to the implementation of a seamless network environment. Therefore, the purpose of this research was accomplished.