What is the future role of NTNs in 6G?

Non-terrestrial networks, or NTNs, will be a native component in 6G networks, according to 6G-NTN project member Dorin Panaitopol

For those behind Europe’s 6G-NTN project, non-terrestrial networks, or NTNs, are the only way to achieve ubiquitous coverage, project member Dorin Panaitopol told 6G Forum attendees. As such, Panaitopol — who is also an advanced radio access principal engineer a Thales — said that NTNs should be a native component in 6G networks and that the successful convergence between NTNs and terrestrial networks is paramount.

“In 5G, NTN started with Release 17, not with the first Release of 5G, which was release 15,” said in Panaitopol. But in 6G, there is a call for “NTN-friendly radio interface from day one,” he added.

Panaitopol identified a few key verticals for future NTNs in the 6G era, including utilities, agriculture and government. He also noted that in the consumer market, 6G-NTN believes that 7.5% (5.2 billion) of total number of mobile subscribers will be NTN users and that 5% of new cars will be NTN capable. One of his presentation slides put it simply: “Several millions of users are expected to require satellite connectivity,” it stated.

To deliver on this perceived need, 6G-NTN is currently developing support for 5G/6G and NTN convergence. “We need to improve the coexistence between NTN and NT spectrum,” Panaitopol stated early in the presentation, adding later that it’s also necessary to introduce new frequency bands to increase non-terrestrial network capacity.

When it comes to the architecture and design principles of an NTN, he said that non-terrestrial network infrastructure should be multi-tenant, meaning it can be used by multiple operators. “This is quite essential because the operators can share the same network to access the satellite component,” he explained.

Additional topics proposed for Rel-20 — and, therefore, 6G — include: enhanced TNT capabilities, like GNSS-free operation and the use of AI/ML; NTN-TN unified radio interface; a focus on mass market use cases, such as enhanced direct connectivity to smartphones and wearables; enhanced broadband connectivity; and public safety/mission critical applications.

6G-NTN has further identified AI/ML mitigation techniques for spectrum sharing, ensuring system affordability, carbon footprint reduction, dynamic orchestration, support of accurate network-based positioning and cyber and physical layer security as key goals for future NTNs, according to Panaitopol.