6 What is on the shelf, and why the bands weigh so much

6.1 Why the shelf is the honest measure

Everything 3GPP decides ends up as a document, or as a change to one. So the plain way to ask what this work has produced is to ask which documents exist because of it, and which ones it opened up and edited.

That question also explains the shape of the whole subject. The radio half wrote new documents; almost everything else changed old ones, and the counts below are what that looks like from the outside.

6.2 What counts as being on this shelf

102 specifications are in this subject's register ^[3]. The whole 3GPP catalogue holds 3599 rows marked active ^[4].

Those two numbers answer different questions and should not be read as a ratio. The 102 were picked by a rule — named by at least thirty documents of this subject, or its own title says satellite or NTN and something here points at it. The 3599 is simply every active row in the catalogue.

A further 149 specifications are named by fewer documents than the register keeps, and were left out on purpose: a handful of mentions is as likely a filing mistake as a real link ^[5].

6.3 The four documents written for the new radio

Four documents exist because 3GPP decided a base station could be in orbit. Two are for the thing in orbit, two for the phone underneath it.

Document	What it covers	Documents	Change requests
TS 38.108 TS 38.108	what a satellite access node must transmit and receive	465	387
TS 38.181 TS 38.181	how that node is tested against TS 38.108	374	220
TS 38.101-5 TS 38.101-5	the same for the phone using satellite access	838	771
TS 38.521-5 TS 38.521-5	how the phone is tested	371	265

A satellite access node is the base station of this world: it terminates the radio protocols towards the phone and reaches the core network, and it spans both the payload in orbit and the equipment on the ground ^[6].

Note that one document covers both radios at once — NR, the 5G radio, and NB-IoT, the narrowband one built for sensors. The conformance document beside it splits the node into three kinds and tests each ^[7].

The phone's side is shorter and blunter: the minimum radio and performance requirements for a device supporting satellite access ^[8], with a conformance document that specifies the measurement procedures for testing it ^[9].

6.4 The same four again, on the older radio

The internet-of-things line runs on the older LTE radio, and it needed the same four documents over again: TS 36.108 for the node TS 36.108, TS 36.181 for its tests TS 36.181, TS 36.102 for the device TS 36.102 and TS 36.521-4 for its tests TS 36.521-4.

Read their scopes beside the ones above and it is the same sentences with the radio's name changed: minimum radio characteristics and minimum performance requirements, for a node in one document and for a device in the other ^{[10] [11]}.

One report sits across the whole radio subject: TR 38.863, which says of itself that it covers the radio-frequency and coexistence aspects of the Release 17 work item, and which carries 238 documents TR 38.863 ^[12].

6.5 The document it changes hardest

The new documents are not where most of the paper went. That is TS 38.133, the radio resource management requirements for NR — how a device measures its neighbours, when it may report and how fast it must react.

It carries 1426 documents of this subject, 1306 of them change requests, which is more than any other specification in this register TS 38.133. Its LTE twin, TS 36.133, carries 377 TS 36.133.

The same thing happens all over the shelf, with smaller numbers, and the list is worth reading as a bill for admitting a base station in orbit.

Document	What it is for in general	Documents
TS 24.301 TS 24.301	what a device says to the older 4G core	705
TS 38.331 TS 38.331	the radio control protocol of the 5G radio	589
TS 23.401 TS 23.401	the older packet core	570
TS 24.501 TS 24.501	what a device says to the 5G core	560
TS 23.501 TS 23.501	the 5G system architecture itself	486
TS 38.300 TS 38.300	the overall description of the 5G radio network	471
TS 22.261 TS 22.261	the 5G service requirements	122

Not one of those was written for satellites. Every one of them had to be opened and edited so that the transmitter could be allowed to fly.

6.6 Why the bands weigh so much

This subject has 155 short names sitting on 183 work plan rows ^{[13] [14]}. A large share of those names are one radio band each.

Each band item names RAN WG4 as its leading group. Each is split into a core part and usually a performance part, with a conformance part in RAN5 where devices have to be tested for it. So one band can be three or four rows before anybody writes a word.

• NR_NTN_LSband, Release 18 — the satellite L and S bands for the 5G radio, producing TR 38.741 NR_NTN_LSband TR 38.741

• NR_NTN_Sband, Release 19 — another S band, at 2000 to 2020 MHz NR_NTN_Sband

• NR_NTN_Ku_bands, Release 19 — the Ku band, whose core part alone carries 411 documents NR_NTN_Ku_bands ^[15]

• NR_NTN_combinedLband, Release 19 — the extended L band and the combined L-band ranges NR_NTN_combinedLband

• NR_NTN_CBW_30MHz, Release 18 — not a band but a channel width, 30 MHz NR_NTN_CBW_30MHz

• IoT_NTN_extLband, IoT_NTN_FDD_LS_band and IoT_NTN_FDD_S_band — the same exercise for the internet-of-things radio IoT_NTN_extLband IoT_NTN_FDD_LS_band IoT_NTN_FDD_S_band

• LTE_band_5G_bcast_GSO and LTE_band_246_5G_bcast_GSO_BWs — a broadcast band over a geostationary satellite, and new channel widths for it LTE_band_5G_bcast_GSO LTE_band_246_5G_bcast_GSO_BWs

The Ku band item says why it exists in one sentence.

ITU regions 1, 2 and 3 are how the world is divided when radio spectrum is allocated internationally. The justification treats that allocation as the whole reason: the band is already for satellites, so 3GPP writes it down.

Here is the part that explains the weight. Every band item names the same handful of documents: the 5G ones list TS 38.101-5, TS 38.108, TS 38.133, TS 38.181 and TR 38.863, and the internet-of-things ones list TS 36.102, TS 36.108, TS 36.133, TS 36.181 and TR 36.764 TR 36.764.

RAN4 carries 7490 documents of this subject over 34 of its meetings, more than any other group here RAN4. The bands are why.

6.7 Where this meets the rest

The system half wrote almost nothing new and edited a great deal — that is The system half: 5GSAT, phase by phase, and the specifications it names are core network documents rather than radio ones.

None of the counts above says how far any of this work has got. That is a different field in a different file, and it is Where it stands, how to follow it, and what the record cannot say.