Every question of this course

Q1.1 What is TSG RAN?

• The body that runs the mobile networks themselves
• A plenary and six working groups that specify the radio side of a mobile network
• A company that builds base stations

It is a technical specification group inside 3GPP. The plenary decides and also owns documents; the working groups draft them. RAN

Q1.2 How many active documents does RAN keep alive?

• 1059
• 198
• 3599

RAN holds 1059. The plenary's own share of those is 198, and 3599 is the total for all of 3GPP. 1059 active RAN specifications

Q1.3 What is the difference between a TS and a TR?

• There is none; the letters are interchangeable
• A TS is a rule others must follow; a TR is homework done before deciding
• A TS is older than a TR

Specification and study report. Almost everything RAN produces is one of the two, or a paper arguing about one of them. TR 38.913

Q1.4 What does TS 38.300 set out to do?

• Describe the 5G core network
• Define every bit sent over the air
• Give an overview and overall description of the NG-RAN, with the details left to companion documents

It says so in its first clause, and it names the 38 series as where the detail lives. §1

Q2.1 Which group worries about the signal itself — what is sent over the air, and when?

• RAN1
• RAN3
• RAN5

RAN1 is the layer 1 group and owns the four documents that describe the 5G air interface, starting with 38.211. RAN1

Q2.2 Which group writes the test cases a phone has to pass?

• RAN2
• RAN4
• RAN5

RAN5 is the conformance testing group. RAN4 sets the radio requirements it tests against. RAN5

Q2.3 Which group has the most active documents?

• RAN1, with 66
• RAN2, with 62
• RAN4, with 427

RAN4 holds 427, more than any other group in RAN. RAN3 is next with 168. 427 active RAN4 specifications

Q2.4 What happened to RAN6?

• It is closed; its last meeting was one day by telephone in 2020
• It is the newest of the six
• It merged into RAN4

RAN6 held the old GSM radio work. Its last recorded meeting is 2020-10-26, and the renumbered GSM documents now sit with the plenary. 3GPPRAN6#18-Decision Teleconference

Q3.1 What are the two kinds of node an NG-RAN is built from?

• A mast and a router
• A gNB and an ng-eNB
• A gNB and a UPF

A gNB gives a device the NR radio; an ng-eNB gives it the 4G radio while still hanging off a 5G core. Both are NG-RAN nodes. §4.1

Q3.2 Which interface joins two base stations to each other, and which joins one to the core?

• The same interface does both
• Xn between base stations, NG to the core
• NG between base stations, Xn to the core

NG splits again into a control half towards the AMF and a user half towards the UPF. §4.1

Q3.3 Which four sublayers make up layer 2 of NR?

• MAC, RRC, IP and TCP
• PHY, MAC, RRC and NAS
• MAC, RLC, PDCP and SDAP

RRC sits above them and the physical layer below. Each sublayer offers something to the one above it. §6.1

Q3.4 What is special about RRC_INACTIVE?

• It is another name for RRC_IDLE
• The device is switched off
• The last serving base station still holds the context and the connection to the core, so coming back is a resume

The device may also move inside its notification area without telling the network, which is what makes the state cheap. §9.2.2.1

Q4.1 Once a specification is published, how is it changed?

• By publishing a replacement document
• Only by change request
• By the group editing it whenever it likes

190421 change requests sit in the local database, and the plenary approves them in bundles rather than one at a time. 190421 RAN meeting documents of type 'CR'

Q4.2 What is the commonest kind of RAN meeting document?

• Discussion papers, at 257341
• Study item descriptions
• Change requests

257341 RAN meeting documents are marked simply "discussion", against 190421 marked "CR". A RAN meeting is mostly argument. 257341 RAN meeting documents of type 'discussion'

Q4.3 A document's status reads "not pursued". What may you say about why?

• Nothing — the data carries the status and never the reason
• That nobody supported it
• That it will come back next quarter

RP-261197 is recorded as not pursued, and that is the whole of what the record holds. RP-261197

Q4.4 How much of RAN's text can be read on this machine?

• 470 of the 1059 are parsed into readable text
• None of it
• All 1059 active documents

The register holds titles and addresses, not document text, and none of RAN6's documents are parsed here at all. 470 of the 1059 active RAN specifications are parsed into text on this machine