Sunday, 7 January 2018

Satellites & Non-terrestrial networks (NTN) in 5G


Satellites has been an area of interest of mine for a while as some of you know that I used to work as Satellite Applications & Services Programme manager at techUK. I have written about how I see satellites complementing the mobile networks here and here.

Its good to see that there is some activity in 3GPP going on about satellites & Non-terrestrial networks (NTN) in 5G. While there are some obvious roles that satellites can play (see pic above), the 5G work is looking to cover a lot more topics in details.

3GPP TR 38.913: Study on scenarios and requirements for next generation access technologies looks at 12 different scenarios, the ones relevant to this topic ate Air to ground, Light aircraft and Satellite to terrestrial.
3GPP TR 38.811: Study on New Radio (NR) to support non terrestrial networks (Release 15) covers this topic a bit more in detail. From looking at how satellites and other aerial networks work in general, it looks at the different NTN architecture options as can be seen above.
People looking to study this area in detail should probably start looking at this TR first.

3GPP also released a news item on this topic last week. It also refers to the above TR and a new one for Release 16. The following from 3GPP news:

The roles and benefits of satellites in 5G have been studied in 3GPP Release 14, leading to the specific requirement to support satellite access being captured in TS 22.261 - “Service requirements for next generation new services and markets; Stage 1”, recognizing the added value that satellite coverage brings, as part of the mix of access technologies for 5G, especially for mission critical and industrial applications where ubiquitous coverage is crucial.

Satellites refer to Spaceborne vehicles in Low Earth Orbits (LEO), Medium Earth Orbits (MEO), Geostationary Earth Orbit (GEO) or in Highly Elliptical Orbits (HEO).

Beyond satellites, Non-terrestrial networks (NTN) refer to networks, or segments of networks, using an airborne or spaceborne vehicle for transmission. Airborne vehicles refer to High Altitude Platforms (HAPs) encompassing Unmanned Aircraft Systems (UAS) - including tethered UAS, Lighter than Air UAS and Heavier than Air UAS - all operating at altitude; typically between 8 and 50 km, quasi-stationary.

These Non-terrestrial networks feature in TSG RAN’s TR 38.811 “Study on NR to support non-terrestrial networks”. They will:
  • Help foster the 5G service roll out in un-served or underserved areas to upgrade the performance of terrestrial networks
  • Reinforce service reliability by providing service continuity for user equipment or for moving platforms (e.g. passenger vehicles-aircraft, ships, high speed trains, buses)
  • Increase service availability everywhere; especially for critical communications, future railway/maritime/aeronautical communications
  • Enable 5G network scalability through the provision of efficient multicast/broadcast resources for data delivery towards the network edges or even directly to the user equipment


The objective of TR 38.811 is to study channel models, to define the deployment scenarios as well as the related system parameters and to identify and assess potential key impact areas on the NR. In a second phase, solutions for the identified key impacts on RAN protocols/architecture will be evaluated and defined.

A second study item, the “Study on using Satellite Access in 5G” is being addressed in Working Group SA1.  It shall lead to the delivery of the corresponding Technical Report TR 22.822 as part of Release 16.

This study will identify use cases for the provision of services when considering the integration of 5G satellite-based access components in the 5G system. When addressing the integration of (a) satellite component(s), use cases will identify new potential requirements for 5G systems addressing:
  • The associated identification of existing / planned services and the corresponding modified or new requirements
  • The associated identification of new services and the corresponding requirements
  • The requirements on set-up / configuration / maintenance of the features of UE’s when using satellite components related features as well for other components from the 5G system
  • Regulatory requirements when moving to (or from) satellite from (or to) terrestrial networks


You may also like my presentation / video on 'Connectivity on Planes'.

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