2 What it was supposed to be for, and what survived

2.1 The study that opened the subject

Before 3GPP writes rules it does homework, and the homework is a study report — a TR. The report that opened this subject is TR 22.837, and it says what it was for in one sentence.

"Verticals" is 3GPP's word for the industries that use a network rather than run one. The list in that sentence is the answer to "who would ever pay for this", and it is deliberately wide: driving and vehicle-to-everything links, drones, building maps of a space in three dimensions, cities, homes, factories, healthcare and shipping.

That report has been argued over harder than anything else here. 518 meeting documents name it, and 46 of them are change requests — more change requests than any other document in this area, and a change request is the only way a published document is ever altered TR 22.837.

2.2 From homework to requirements

The study produced a specification: TS 22.137, "Integrated Sensing and Communication". A TR is homework; a TS is a rule other people have to follow.

TS 22.137 is modest about itself.

The work item that wrote it says what those requirements had to cover.

119 documents name TS 22.137, four of them change requests TS 22.137. That is a small number next to the study's 518, and it is what a finished requirements document normally looks like: the argument happened in the study.

The same work item made one small change elsewhere. TS 22.261 holds the overall service requirements for the 5G system, and it got a new section pointing at the new document — four change requests, no more TS 22.261.

2.3 What survived into the rule-writing

Now compare that list of nine industries with what is actually being specified.

The stage 2 specification — how the system is put together — covers aerial objects and nothing else ^[6].

The security study says the same thing about itself.

And so does the radio work item, which is where a reader can see the narrowing most sharply: it names gNB-based mono-static sensing for UAV sensing target use cases, building on the radio study report ^[7]. "Mono-static" means the transmitter and the receiver sit in the same place; "bistatic" is where they do not.

2.4 Where the wider list is still alive

The other industries have not vanished. They moved to the application layer, which is the part of 3GPP that builds services on top of the network rather than inside it.

SA6, the group that owns that layer, opened its study with an objective that names three existing specifications by number:

Those three are the drone systems specification, the vehicle services specification and the spatial maps specification. So driving and mapping did survive — as consumers of a sensing result, not as the thing the radio is being taught to detect.

The report that came out of that study describes itself the same way: it identifies potential enhancements to application enablement services by using sensing results, and proposes architecture requirements, key issues and solutions ^[8].

2.5 The one thread to 6G

There is exactly one place in this data where sensing touches 6G: TR 22.870, the 6G use-case study, carries three documents tagged with a Sensing work item TR 22.870.

Three documents is thin. It is enough to say the subject was raised, and not enough to say anything about what 6G will do with it. Nothing else in this record connects the two.

2.6 Where to read this yourself

Four documents carry the use cases: TR 22.837 for the original nine industries, TS 22.137 for the requirements they became, TS 23.137 for the one that made it into stage 2, and TR 23.700-15 for what the application layer wants to do with a sensing result.

This school does not carry the text of any of them. Open TR 22.837 first — it is the one written to be read by somebody who does not already know why this work exists.