Wednesday, 31 May 2023

New 5G NTN Spectrum Bands in FR1 and FR2

Release-17 includes two new FR1 bands for NTN; n255 (a.k.a. NTN 1.6GHz) and n256 (a.k.a. NTN 2GHz). The picture is from a slide in Rohde & Schwarz presentation available here. Quoting from an article by Reiner Stuhlfauth, Technology Manager Wireless, Rohde & Schwarz:

Currently, several frequency ranges are being discussed within 3GPP for NTN. Some are in the FR1 legacy spectrum, and some beyond 10 GHz and FR2. The current FR1 bands discussed for NTN are:

  • The S-band frequencies from 1980 to 2010 MHz in uplink (UL) direction and from 2170 to 2200 MHz in downlink (DL) direction (Band n256).
  • The L-band frequencies from 1525 to 1559 MHz DL together with 1626.5 to 1660.5 MHz for the UL (Band n255).1

These frequency ranges have lower path attenuation, and they’re already used in legacy communications. Thus, components are available now, but the bands are very crowded, and the usable bandwidth is restricted. Current maximum bandwidth is 20 MHz with up to 40-MHz overall bandwidth envisaged in the future [TR 38.811].

As far as long-term NTN spectrum use is concerned, 3GPP is discussing NR-NTN above 10 GHz. The Ka-band is the highest-priority band with uplinks between 17.7 and 20.2 GHz and downlinks between 27.5 and 30 GHz, based on ITU information regarding satellite communications frequency use.2 Among current FR2 challenges, one is that some of the discussed bands fall into the spectrum gap between FR1 and FR2 and that NTN frequencies will use FDD duplex mode due to the long roundtrip time.

Worth highlighting again that the bands above, including n510, n511 and n512 are all FDD bands due to the long round trip times.

The latest issue of 3GPP highlight magazine has an article on NTN as well. Quoting from the article:

The NTN standard completed as part of 3GPP Release 17 defines key enhancements to support satellite networks for two types of radio protocols/interfaces:

  • 5G NR radio interface family also known as NR-NTN
  • 4G NB-IoT & eMTC radio interfaces family known as IoT-NTN

These critical enhancements including adaptation for satellite latency and doppler effects have been carefully defined to support a wide range of satellite network deployment scenarios and orbits (i.e., LEO, MEO and GEO), terminal types (handheld, IoT, vehicle mounted), frequency bands, beam types (Earth fixed/Earth moving) and sizes. The NTN standard also addresses mobility procedures across both terrestrial and non-terrestrial network components. Release 17 further includes Radio Frequency and Radio Resource Management specifications for terminals and satellite access nodes operating in two FR1 frequency ranges allocated to Mobile Satellite Services (i.e., n255 and n256).

You can read it here.

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Posted by Zahid Ghadialy at 07:35
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