SWIFT: Resilient Spectrum-Sharing among Non-Geosynchronous Satellites

正在部署多个非地球同步轨道(NGSO)卫星星座。已经宣布了更多的消息。这些星座旨在在世界各地提供低延迟宽带通信服务，包括目前宽带基础设施很少或根本没有宽带基础设施的地区。由于卫星通常远离地面天线的视角，而地面天线可以指向一颗卫星，而忽略其他卫星，因此让每个星座独占使用自己的无线电频谱频道将是非常低效的。监管机构要求这些星座在共享频谱中运行。因此，星座之间偶尔会产生有害干扰。该项目通过技术机制、卫星星座运营商之间的协调协议以及频谱管理机构采取的公共政策的某种组合，调查减轻偶尔干扰的影响的战略。这个项目的成果将促进NGSO系统的部署，从而帮助为未得到服务的人带来宝贵的宽带服务。结果将有助于使这些系统提供的服务更具弹性，并改善频谱共享的有效性，增加总可实现容量。除了为学生创造研究机会和开发课程内容外，该项目还将通过每年带一个群体参加美国顶级电信政策研究会议，鼓励来自代表性不足群体的本科生和硕士水平的学生攻读博士学位。NGSO卫星星座之间的有害干扰发生在串联事件期间，即两个或更多卫星及其地面站形成接近一条线的东西的事件。本项目研究现有的和新的方法来减轻这些破坏性串联事件的影响。研究的方法包括旁视，即地面用户被分配到次优卫星；分割频谱段，这可能是不对称的；以及简单地通过切换到较低的数据速率来接受干扰。该项目调查卫星运营商之间的谈判安排、监管机构强加的默认协调安排，以及运营商达成谈判安排的动机。该项目使用定制的全球规模模拟器，该模拟器计算每个星座在每个时间步长的地面每个小区的信干噪比(SINR)、频谱效率、带宽、吞吐量和吞吐量退化，考虑了卫星间干扰、变化的天气和传播影响、基于人口和需求变化的不同小区大小、小区到卫星的自适应分配、地面站的分布和其他影响。该模拟器用于评估许多不同类型星座的各种干扰缓解方法和安排的结果，这些星座在卫星数量、高度、轨道类型、带宽、波束控制能力、市场焦点和其他特征方面有所不同。分析结果将提供洞察力，有助于指导频谱政策以及卫星运营商之间的进一步协调。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Multiple constellations of non-geosynchronous-orbit (NGSO) satellites are being deployed. More have been announced. These constellations aim to provide low-latency broadband communications services throughout the world, including regions with little or no broadband infrastructure today. Since the satellites are normally far apart from the perspective of an antenna on the ground, which can point at one satellite and ignore the others, it would be highly inefficient to give each constellation exclusive use of its own radio-frequency spectrum channels. Regulators have required the constellations to operate in shared spectrum. As a result, constellations may occasionally cause harmful interference to each other. This project investigates strategies for mitigating the effects of the occasional interference, through some combination of technical mechanisms, coordination agreements among the operators of satellite constellations, and public policies adopted by spectrum management agencies. The results of this project will facilitate deployment of NGSO systems and thus help bring valuable broadband services to the unserved. The results will help make services offered by these systems more resilient and improve the effectiveness of spectrum sharing, increasing the total achievable capacity. In addition to creating research opportunities for students and developing curriculum content, the project will encourage undergraduate and masters-level students from underrepresented groups to pursue PhD studies by annually bringing a group to the top telecommunications policy research conference in the US. Harmful interference between NGSO satellite constellations occurs during in-line events, which are events where two or more satellites and their ground stations form something close to a line. This project investigates both established and novel methods of mitigating the effects of these disruptive in-line events. The methods investigated include look-aside, in which ground users are assigned to a suboptimal satellite; splitting the spectrum band, which may be asymmetric; and simply accepting the interference through switching to a lower data rate. The project investigates negotiated arrangements between satellite operators, default coordination arrangements imposed by regulators, and the incentives for operators to reach negotiated arrangements. The project uses a custom-built global-scale simulator that calculates the signal to interference plus noise ratio (SINR), spectral efficiency, bandwidth, throughput, and throughput degradation for every cell on the ground for each constellation at each time step, accounting for inter-satellite interference, varying weather and propagation effects, different cell sizes based on population and demand variation, adaptive assignment of cells to satellites, distribution of ground stations, and other effects. The simulator is used to assess outcomes of the various interference mitigation methods and arrangements for many different types of constellations, where constellations differ in the number of satellites, altitude, type of orbit, bandwidth, beam steering capabilities, market focus, and other characteristics. Analytical results will provide insight that could help guide spectrum policy as well as further coordination among satellite operators.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.