Page 24 - EngineerIT December 2022

SPACE SCIENCES

The Internet from Space:

RFIC advances in high capacity,

low latency LEO satellite user

and ground terminals

By Donal McCarthy, director of marketing and business development,
Microwave Communications Group at Analog Devices

his article introduces key market trends driving low Earth orbit (LEO) satellite of orbit and need to be replaced. LEO
deployments. It will discuss the basic operation of a LEO satellite system and satellites must be cost-effective to launch
Tpresent some of the semiconductor RFIC advances, which are enabling the next and relaunch replacements.
generation of Ku and Ka band LEO user and ground terminals. All these trends are making
industry watchdogs take note as the
LEO connectivity – The path to success LEO broadband connectivity business

Satellite communications (satcom) is an established means to transfer voice, video case is starting to look strong. If we
and data, and is used in a large variety of use cases across the prevailing orbitals called remember back in the1990s, this
geo-stationary equatorial orbit (GEO), medium Earth orbit (MEO), and LEO. Satcom is internet venture was the goal of several
seen as an effective means to communicate GPS for navigation, weather information, companies, but it was unfortunately
TV broadcast, voice, data, and is also used for imaging and science-based applications. a failure due to the high cost of
However, a new wave of promised high speed internet connectivity is planned around deployment and limited demand. Fast
LEO satellite constellations. This will deliver low latency, high-capacity broadband forward to today and we see remarkable
connectivity for next-generation internet communications. advances in semi-conductor technology
LEO satellites will play an important role in the continuing rollout of 5G cellular delivering unprecedented performance
connectivity. Satellite networks are becoming more involved in the 3GPP standardisation and integration. Coupled with the
and their expected role in the networks of the future is well under development. In exponential demand for high speed, low
2017, activities kicked off within the 3GPP standards body to understand the feasibility of latency internet connectivity in more
satcom networks within 5G connectivity. Through releases 15, 16, 17, and 18 of the 3GPP rural or underserved settings, and the
standard, several activities were developed to support the integration of these networks. integration of satcom into 5G standards,
LEO satellites can provide wide area coverage to underserved areas, provide continuity the LEO constellations of the future are
of service for people on the move, connect to machine-to-machine (M2M)/Internet of on a much better platform for success.
Things (IoT) devices, and be a notable upgrade path for 5G in a cost-effective manner. At the time of writing, it is expected
The next generation of LEO systems will orbit between 500 km and 2000 km above that users could achieve maximum
the Earth’s surface and will deliver a technically superior solution to satellite networks of downlink data speeds of 100 Mbps and
the past. Such proximity to the Earth means they will deliver lower latency connections, this could extend to 150 Mbps in the
which is important for consumer or business use cases (for example, internet gaming or future, which is ideal for multi-user, full-
the control of industrial/medical equipment in real time). LEO satellites should deliver time video streaming.
approximately 50 ms of latency (and this will improve with next-generation technology to One challenge with LEO is the
<20 ms) versus, for example, GEO that is 700 ms. ever-moving nature of satellites – the
A key enabler of LEO satellites is that their exposure to radiation is much lower due constellation really needs to be fully
to the lower orbit. This is important as it means the expensive and sometimes prohibitive deployed to become a minimal viable
radiation hardened testing can be relaxed. This will generate economies of scale as service. This means that the initial outlay
the cost to build a LEO satellite is now drastically reduced. Less radiation means wider is high as the number of LEO satellites is
availability of semi-conductor processes and, therefore, components for use. greater given their lower orbit. But even
Given the lower orbit, the expectation is for a much larger number of satellites so, this does not seem to be a deterrent
deployed. The average life span for such satellites will be much shorter than previous to success now and the business case for
use cases; perhaps between five and eight years, after which these satellites will fall out ubiquitous coverage is strong for investors.

EngineerIT | December 2022 | 24