Seminar: Networking in Space

Speaker: Prof Mark Handley, UCL
UCL Contact: Fleur Adolphe (Visitors from outside UCL please email in advance).
Date/Time: 24 Oct 18, 13:00 - 14:00
Venue: Elvin Hall, UCL Institute of Education
Further Information: Register online ...

Abstract

Several consortia are planning to build dense low Earth orbit (LEO) satellite constellations in the next few years. Of these, SpaceX is the most ambitious. Filings with the US Federal Communications Committee detail a constellation referred to as Starlink, consisting of 4,425 LEO communication satellites. It will use phased array antennas for up and downlinks and laser communication between satellites to provide low-latency high bandwidth coverage over most of the world. A subsequent phase may add another 7,518 satellites in very low earth orbit (VLEO), increasing capacity and further reducing latency.

LEO constellations such as Starlink have the potential to revolutionize wide-area Internet communications. To understand the latency properties of such a network, we built a simulator based on public details from the FCC filings. In this talk, I will discuss possible ways to use the laser links to provide a network, and look at the problem of routing on this network. I will present preliminary results on how well such a network can provide low-latency communications, and examine its multipath properties. Such networks are very different from the current Internet. To achieve low latency, the path used must constantly change. Not only do link latencies change as satellites move overhead of groundstations, but latencies between satellites in crossing orbits change too, and those links are usually of short duration.

I conclude that a network built in this manner can provide lower latency communications than any possible terrestrial optical fiber network for communications over distances greater than about 3000 km. However, to achieve these benefits in a practical network will involve re-thinking many of the systems we take for granted in the current Internet.