9 The specification families, and what a number tells you

9.1 The problem a numbering scheme has to solve

Somebody in a meeting says "that is in three-eight-three-three-one". Everybody in the room knows which document, roughly what is in it, who owns it and which meeting to raise a change at. None of that is written on the number, and all of it is real.

A 3GPP number is a filing address with a convention layered on top: the series says which technology, the block within the series says which layer, and the block therefore says which group. It works well enough to be used constantly and badly enough to catch you once a year.

9.2 The series: which technology

Three series carry most of what RAN maintains today.

38 is NR — the 5G radio. It holds 264 active documents ^[1] and is where nearly everything in What NR is — the shape of the 5G radio network lives.

36 is E-UTRA — the 4G radio. It is still active work: TS 36.331 is RAN2's, and it is still changed The documents that attract the most change, and what that says.

37 is the series for things that span both radios. TS 37.340, the multi-connectivity description, is there.

Behind those sit the older families. The plenary holds 179 active documents from the 25, 43, 44, 45, 48, 49, 50 and 52 series ^[2] — 3G and GSM — among them TS 44.018 and TS 45.005.

9.3 The blocks inside the 38 series

Within 38, the hundreds block maps almost perfectly onto the working groups.

Block	Subject	Group	Example
38.1xx	radio performance	RAN4	TS 38.101-1, TS 38.104, TS 38.133
38.2xx	physical layer	RAN1	TS 38.211, TS 38.212, TS 38.213, TS 38.214
38.3xx	layer 2 and 3	RAN2	TS 38.300, TS 38.321, TS 38.331
38.4xx	interfaces	RAN3	TS 38.401, TS 38.413, TS 38.423, TS 38.473
38.5xx	device conformance testing	RAN5	TS 38.508-1, TS 38.521-1, TS 38.523-1, TS 38.533

The per-group shares of the series behind that table:

Owner	38-series documents
RAN4	138 [3]
RAN3	35 [4]
RAN1	34 [5]
RAN5	23 [6]
RAN2	22 [7]
plenary	10 [8]
RAN6	0 [9]

Notice that RAN4's 138 is far more than the 38.1xx block could hold. The rest are study reports, which do not follow the block rule at all — they are numbered from the 700s, 800s and 900s, and every group has some there.

That is the honest version of the pattern: the block rule holds for specifications and does not hold for study reports.

9.4 One block, worked through

The four documents everybody knows in a block are never the whole block. RAN2's 38.3xx holds more than the connection protocol and the three layer-2 protocols.

Number	What it is
TS 38.300	the overall description this course teaches from
TS 38.304	what the device does in idle and inactive
TS 38.305	positioning, at the same level of detail as 38.300
TS 38.306	what a device may declare about its radio capabilities
TS 38.340	the adaptation protocol used by relay nodes

That is the practical value of knowing the blocks. When a change request names a number you have not met, the block tells you which room it will be argued in before you have opened anything.

The same exercise on 38.4xx gives RAN3's interface family beyond the four protocols — TS 38.410 and TS 38.420 hold the general principles behind TS 38.413 and TS 38.423, and TS 38.470 does the same for TS 38.473.

Notice the pattern in those pairs: a "general aspects and principles" document and an "application protocol" document for each interface. Once you have seen it on one interface you can predict the other two.

9.5 Where the pattern breaks

TS 38.307 sits squarely in RAN2's block and belongs to RAN4. It is a requirements document about devices supporting a release-independent frequency band, which is RAN4's subject whatever number it happens to carry.

One exception in a block of a dozen is enough to make the rule unusable for anything that matters. Use it to orient yourself in a conversation; never to decide where to send a change request.

9.6 Reading a part number

Many RAN documents are split into parts, and the part number is written with a hyphen. TS 38.101-1 and TS 38.101-2 are the phone's radio requirements for the two frequency ranges.

TS 38.141-1 is base station conformance testing conducted over a cable, and TS 38.141-2 is the same thing radiated through the air.

Two rules save trouble here.

A number is a string, never a number. 22.270 and 22.27 are different documents. Nothing may strip a trailing zero, add one, or reformat a version. The same holds for release names, meeting numbers and document numbers.

A part is a separate document with a separate change history. A change request against 38.101-1 says nothing about 38.101-2. Where a feature affects both, there are two change requests.

9.7 Specifications and study reports

Two kinds of document, and the difference decides what you can do with it.

A specification — TS — is a rule other people have to follow. Once published it changes only by change request, and how that works is How a radio feature travels from a question to a rule.

A study report — TR — is homework: what a group looked at before deciding something. It is published, numbered and kept, and it stays useful because it records why a number is the number it is.

The mix differs sharply by group. 352 of RAN4's 427 documents are study reports ^[10] and 51 of RAN1's 66 are ^[11], while 72 of RAN5's 84 are specifications ^[12].

The full table is What the numbers say about the size and shape of each group.

9.8 Turning a number into something you can read

Three addresses do everything, and all three are built from the number.

The information page — status, title, owning group, releases, versions — is www.3gpp.org/DynaReport/ plus the number with its dots removed, plus .htm ^[13]. So 38.331 becomes 38331.htm.

The file folder, which holds every published version, is www.3gpp.org/ftp/Specs/archive/ plus the series, plus the number ^[14].

The whole catalogue comes from one page, the status report ^[15]. That is the page every count in this course ultimately descends from, and it is where to go when you need a total that has to survive being checked.

9.9 What is readable here and what is not

Of the 1059 active RAN documents, 470 are parsed into readable text on this machine ^[16]. The rest are not, and none of RAN6's are.

So this course can quote clauses of TS 38.300 because it is one of the 470, and cannot quote a clause of any other RAN document at all. Where a chapter names another specification it names it as a document, never as a sentence.

9.10 Where this meets the rest of the course

Which of these documents actually attracts change, and what that says about where the work is, is The documents that attract the most change, and what that says. How a document comes to exist in the first place is How a radio feature travels from a question to a rule.

The groups behind each block are The six working groups, and where the line between them runs, and the sizes behind the counts are What the numbers say about the size and shape of each group.