Seamless connectivity across GSO and non-GSO satellite systems
By Zachary Rosenbaum, Spectrum Management & Development, SES
For over 50 years, geostationary (GSO) satellites have provided vital infrastructure to the global communications ecosystem. Hundreds of them are in orbit today, delivering services ranging from Internet connectivity to weather and mapping data and to distribution of digital video-on-demand, streaming and satellite TV channels globally. Because the antenna on the ground does not need to track the GSO satellite in the sky, its design can be quite simple; and by virtue of the GSO altitude, broadband service can be started with just a single satellite covering one third of the globe. Due to their high altitude and wide field of view, it only takes about three GSO satellites to provide coverage that spans the entire Earth, which is far fewer than the number of satellites needed at non-GSO orbits for global coverage.
Non-GSO satellites have been in operation for even longer than GSO satellites, and are in use today for a broad set of applications ranging from Earth observation to GPS and to voice and data services – just to name a few. At the beginning of the 21st century, a major effort based on ambitious plans for large non-GSO constellations to connect the world resulted in ITU frameworks for GSO and non-GSO shared use of the C-, Ku- and Ka-bands. A similar effort is underway in the lead up to WRC-19 to create a framework for GSO and non-GSO shared use of the Q- and V-band frequencies to meet the requirements of next-generation satellites.
Under this shared use framework, SES’s O3b non-GSO constellation has been providing since 2014 high-throughput, fibre-like connectivity to Internet service providers, government agencies and enterprises around the world using the Ka-band frequencies – ultimately connecting millions of end users. In 2021, SES will launch the next generation of O3b satellites, called O3b mPOWER, with terabit-scale capacity and even more flexibility than the current generation.
Several other non-GSO satellite constellations are also planned to be in service in the coming years. Their closer distance to Earth compared to GSO satellites will support lower latency applications, but the coverage area of each satellite will be smaller. This is why some non-GSO constellations plan to launch hundreds – or even thousands – of these satellites into orbit to achieve global, continuous coverage (as announced by SpaceX, OneWeb or Amazon).
All too often we hear the question of which technology will win over time. This presupposes that the two types of satellite infrastructure are mutually exclusive, which is not necessarily the case. First, different applications on the Internet have different requirements that can make GSO or non-GSO satellite solutions more appropriate. Non-GSO high-throughput, low latency satellites are well-suited to enable latency-sensitive applications. However, if the end user is operating an “always on” low-data rate network spanning large areas (e.g. an Internet-of-Things weather sensor network), a GSO or hybrid solution with high availability (e.g. using C-band frequencies) may be more appropriate. Indeed, C-band satellites – all in GSO – are still the most reliable and most available form of satellite connectivity in the world today.
As an operator of both GSO satellites and the O3b non-GSO constellation, SES is also developing integrated GSO and non-GSO networks that will combine the advantages of both. High-throughput GSO satellites can deliver more than 100 Gbps of total capacity throughout their visible footprint – a tremendous reach capability. For non-GSO satellites, targeted high-throughput and low latency capacity can be delivered as needed to areas where there is specific demand for such connectivity. An end user consuming data from the Internet needs only one piece of hardware to connect to a GSO or non-GSO satellite, as necessary, to meet connectivity requirements. With seamless network integration, GSO and non-GSO satellites can adaptively react to this end user’s real-time needs for connectivity through an efficient and optimized traffic management system. The metric of success here is whether the end user gets the promised data rate, and not the technology used to deliver it. A number of SES customers around the world – from governments to mobile operators to cruise lines – have already early-adopted combined GSO/non-GSO solutions from SES to meet their differentiated connectivity needs.
Gone are the days when satellites were simply a “last resort” for connecting remote areas. Like traditional, terrestrial connectivity services, satellite is fast becoming a standardized and mainstream option for delivering high-speed broadband services to people anywhere in the world, whether on land, at sea or in the air. And as this new satellite ecosystem takes shape, the potential applications won’t be constrained to one orbit. Constellations are already operating together across orbits today, and as we move forward, we’ll see even more value created by optimized routing of traffic over multi-orbit networks. For example, the O3b mPOWER constellation will use software-defined networking with the ability to automatically switch between GSO and non-GSO satellites, as appropriate. We are likely to see combinations of GSO, non-GSO, and terrestrial technologies deployed to support the diverse latency and throughput requirements of native 5G networks.
As demand for data increases, the developing multi-orbit satellite universe is set to play a crucial role in delivering broadband access to connect the world in the cloud-scale era. An ITU framework that fosters such developments will be key to its success.
This article was first published on the ITU News Magazine, Issue No 2, 2019
