School of Specs Ambient IoT — a tag with no batteryIn depth

176 checked sources · In depth · 95 minutes

Ambient IoT — a tag with no battery

Ambient IoT is 3GPP's name for a device that runs on harvested energy and has no battery worth the name. It began as one study in 2022 and has grown into an area of work that seventeen groups have touched, filling more than ten thousand documents and changing or creating fifty-three specifications. This course is not a guided read of one document, because there is no single document behind it. It is a map: what the work is for, which group did which part, what each affected specification is for and what this work put in it, how far along everything is, and where to go for the detail. Every statement points at an entry in a register built from 3GPP's own paperwork on this machine, and the course stops where that paperwork stops.

Start at chapter 1 Sit the final test

This course was built from a source register generated 2026-08-04.

Same subject, different depth: quick start · overview ·

The chapters

Part 1 What the work is for

  1. 1 A tag with no battery, and the gap it was meant to fill What 3GPP means by Ambient IoT, the gap the founding study named, and what the first real specification says it covers. 7 min
  2. 2 Study first, then build, then do it again How 3GPP turns an idea into binding text — study item, work item, phase two — with Ambient IoT as the worked example. 7 min
  3. 3 Seventeen groups, and where the weight sat Every group that appears in the Ambient IoT record, what each contributed, and what the document counts do and do not tell you. 7 min

Part 2 The radio groups

  1. 4 RAN1 and the radio problem Why a radio for a battery-less device is hard, which studies carried the question, and what RAN1 finally wrote down. 7 min
  2. 5 RAN2, RAN3, RAN4 and RAN5 — protocols, interfaces, performance, tests The four radio groups below the plenary that do not run the physical layer, and the eleven specifications between them. 6 min

Part 3 The system groups

  1. 6 SA1 and the requirements nobody designed against yet The group that started the whole area, what it asked for, the specification it left behind, and why it went quiet in 2025. 7 min
  2. 7 SA2 and the specification that did not exist How the architecture group turned a requirement into a new stage 2 specification, what TS 23.369 says it covers, and why more letters to other groups left SA2 than left any other group. 7 min
  3. 8 SA3, and why a device with no battery is a hard security problem What the security group set out to study, the specification it produced, and how far the record actually lets you go on this subject. 7 min

Part 4 Protocols, management and the layer above

  1. 9 CT1, CT3, CT4 and CT6 — one work item description, four groups How the protocol groups share a single work item, the specification that went from nothing to 144 change requests, and the number you must never add up. 7 min
  2. 10 SA5 and SA6 — running it, billing it, and building on top of it The two smallest system groups in the area, the eleven specifications they touch, and the work item whose description has no objective to quote. 6 min
  3. 11 The fifty-three specifications, and what this work put in each Every document the area touches, in three groups — the ones written for it, the reports, and the existing ones that had to be amended. 8 min

Part 5 Where it stands and where to read on

  1. 12 Where the work stands, and what a percentage is worth What is finished, what is running, and why a completion figure in the 3GPP work plan is not a statement about today. 7 min
  2. 13 How to follow this area yourself The short names to search for, the documents that decided things, the folders they live in, and the order to do it in. 8 min
  3. 14 What the record cannot tell you Eleven questions a reader will reasonably ask that this data cannot answer, each with what to do instead. 6 min

Testing yourself

Every question at once

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

Open all the questions

The final test

20 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
14
Words written for you
18,390
Checked sources
176
Sources this course cites
176

Every source