School of Specs Satellites — a base station in orbitOverview

680 checked sources · Overview · 50 minutes

Satellites — a base station in orbit

A non-terrestrial network is 3GPP's name for a network whose transmitter flies: a satellite in low, medium or geostationary orbit, talking straight to a phone or to a sensor with no mast in between. The work comes in two halves that rarely meet — a radio half, which carries NTN in its short names and sits in the RAN groups, and a system half, spelled 5GSAT, which sits in SA and CT. Eighteen group codes carry documents of it, 183 work plan rows under 155 short names run from Release 8 to Release 20, 35306 meeting documents sit against them over 550 meetings, and 102 specifications were created or changed. This course is for somebody who has to follow a conversation about that work: what the words mean, why it was wanted, what each half did release by release, what is on the shelf now, and how far each piece has got. Every number and every quotation points at the file or the database row it was read from, and the last chapter is about what that record cannot tell you.

Start at chapter 1 The whole thing on one page Sit the final test

This course was built from a source register generated 2026-08-05.

Same subject, different depth: quick start · in depth

The chapters

Part 1 What it is and why it was wanted

  1. 1 What a non-terrestrial network is Every word in the satellite vocabulary, each taken from the document that defines it, plus the newer ones Release 20 had to invent. 6 min
  2. 2 Why anyone wanted it The stated reasons, taken only from the justification text of the work items large enough to be quoted, and a plain warning about the ones that carry no reason at all. 6 min

Part 2 The two halves, and who runs them

  1. 3 How the work is cut up, and who carries it How to read the paperwork — study first, rules after, one plenary document per row, and a radio feature split three ways — then the release spread and the eighteen group codes that carry it. 7 min
  2. 4 The radio half, release by release The NTN line in order — two studies, three phases of rules, and Release 20 breaking into narrow items — then the same idea again on the older radio for sensors and trackers. 7 min
  3. 5 The system half: 5GSAT, phase by phase What the core network, the protocols and the trades around them had to change so that a phone can be served from orbit — four phases of it, plus backhaul, which runs the other way round. 7 min

Part 3 What exists, and where it stands

  1. 6 What is on the shelf, and why the bands weigh so much The eight documents this work wrote from nothing, the one it changes hardest, and why a large share of the short names in this subject are one radio band each. 7 min
  2. 7 Where it stands, how to follow it, and what the record cannot say How far each piece has got, read the only way the work plan allows — a number between 0 and 1 and a planned day — then the reading list, and a straight account of the questions this record cannot answer. 7 min

Testing yourself

Every question at once

35 questions, chapter by chapter, on one page — for revision after you have read the course.

Open all the questions

The final test

12 questions drawn across the whole course, marked at the end. 70 per cent to pass, and every miss says which chapter to go back to.

Sit the final test

What this course is built on

Chapters
7
Words written for you
9,110
Checked sources
680
Sources this course cites
226

Every source