The word "topology" in the telecom industry refers to the arrangement of the elements in a network's architecture. It's how all the cables, switches and cell towers are organized around each other in order to make sure a sender's message is delivered to their intended recipient.

There are growing indications that satellites may soon be added to that list of potential elements.

Of course, satellites can already play a role in the operation of a wireless network, including a 5G network. Their role to date primarily involves backhauling traffic from a cell site that's too rural to use fiber or microwave backhaul. But that's a rare situation given the sluggish performance and eye-watering cost of most satellite Internet connections.

That situation is rapidly changing with the rise of low Earth orbit (LEO) satellite operators like SpaceX's Starlink, Telesat's Lightspeed or OneWeb. Such satellite constellations promise speedy, inexpensive connections that might better serve 5G operators' backhaul needs. However, it must be noted that analysts from the likes of Cowen, MoffettNathanson and Viasat continue to poke holes in the notion that LEO satellite constellations will be able to meet widespread demand.

But backhaul is just one topological element that satellite operators are hoping to offer in the 5G era.

For example, a growing number of startups and veteran satellite providers are looking beyond backhaul to provide Internet of Things (IoT) services in direct competition to 5G providers. For example, startup Swarm is building tiny, phone-sized satellites that can beam a proprietary version of the LoRa Internet of Things communication standard to receivers on Earth. And Swarm isn't alone. Startup Sateliot is also promising IoT services using the 5G protocol. And longtime satellite player Iridium too is offering IoT services; already a third of its service revenues come from IoT applications.

How such services might be integrated into a 5G network remains to be seen.

However, there's another group of satellite players looking to provide 5G services directly to smartphone users. These companies essentially want to act as a mobile roaming partner in space, offering connections to 5G users who stray outside the reach of their provider's terrestrial network.

The newest entrant in this sector is Omnispace, which appears to be working with the likes of Verizon, Dish Network and the US Space Force to test 5G transmissions across its S-band 2GHz spectrum licenses. Other startups like Lynk and AST SpaceMobile are hoping to operate similar satellite services, although they want to conduct their transmissions inside of 5G operators' existing spectrum holdings. AST SpaceMobile already has permission to do so from the likes of Vodafone and AT&T.

But the role of satellites in 5G topology doesn't end there. The 3GPP standards organization is currently looking at technology that would add non-terrestrial networks (NTN) directly into the 5G standard. NTN capability is scheduled to be part of the 3GPP's Release 17 package of specifications, to be released next year. Already network testing companies like Keysight Technologies are preparing for that opportunity.

Analyst Lluc Palerm with research and consulting firm NSR said companies like Iridium and Inmarsat are particularly interested in the prospect of NTN in Release 17 because they hold spectrum between 1.5GHz and 2.5GHz – in the so-called L-band and S-band – that could be added to existing 5G networks.

"Release 17 could allow satellite connectivity to future 5G phones, albeit not at speeds people associate with 5G," Inmarsat said in response to questions from Light Reading.

Continued the company: "With areas of the globe not covered by cellphone services and other areas not covered by adequate roaming arrangements, satellite does offer a strong option to close this gap, especially for IoT or emergency operations. In particular, for IoT, the need and urgency for a 3GPP-standard hybrid satellite-terrestrial IoT solution within Release 17 have been expressed by MNOs [mobile network operators], satellite operators and verticals alike, including Inmarsat. Our L-band satellites would offer the potential to do so and can already provide global coverage, so this is where we are focusing at present."

Indeed, Inmarsat already conducted a test of 5G IoT capabilities with smartphone chipset vendor MediaTek last year.

"3GPP Release 17 could also offer opportunities for MNOs and satellite operators to collaborate in future," Inmarsat concluded.

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— Mike Dano, Editorial Director, 5G & Mobile Strategies, Light Reading | @mikeddano