Section 1 - Basic Characteristics

Question 1

What layers are common to both user and control plane transmissions

Answer 1

PHY, MAC, RLC and PDCP

Question 2

(T or F) SDAP is a layer used in control plane

Answer 2

False: User plane

Question 3

(T or F) RRC is a layer used in control plane

Answer 3

True

Question 4

What are the functions of the 5G MAC layer

Answer 4

Priority handling between logical channels in a UE and between UEs, padding, error correction, multiplexing/demux of MAC SDUs from different logical channels, beam management, RA procedures, mapping between logical and transport channels

Question 5

What are the functions of the RLC layer

Answer 5

Transfer upper layer PDUs, error correction, reordering 5G RLC data PDUs, duplicate detection, protocol error detection, segmentation, RLC re-establishment

Question 6

What are the functions of the PDCP layer

Answer 6

Transfer user data, in-sequence delivery of upper layer PDUs, duplicate detection, retransmission, ciphering, timer-based SDU discard

Question 7

What are the functions of the RRC layer

Answer 7

Broadcasting system information to NAS; establishment, maintenance and release of RRC; security; establishment, configuration, maintenance and release of point-point radio bearers; mobility functions; UE measurement reporting

Question 8

List the three main segments to which 5G NR targets

Answer 8

eMBB, Massive IoT, uRLLC

Question 9

Mention six key air enablers of NR

Answer 9

Scalable OFDM, flexible slot-based framework, mmWave, massive MIMO, beam sweeping, advance channel coding (LDPDC)

Question 10

Which numerologies can be used in the transmission of SSB

Answer 10

15, 30 and 120 kHz

Question 11

Which is the only numerology that supports extended cyclic prefix

Answer 11

60 kHz

Question 12

What is the maximum bandwidth supported in FR1

Answer 12

100 MHz

Question 13

What is the maximum amount of PRBs supported for any numerology

Answer 13

273, for 30kHz SCS

Question 14

What is the maximum bandwidth supported for 15kHz SCS

Answer 14

50 MHz

Question 15

How many symbols can form a mini-slot

Answer 15

2, 4 or 7

Question 16

What are the three types of symbols in the TDD configuration

Answer 16

DL, UL and flexible

Question 17

Explain the dynamic slot format configuration

Answer 17

RRC configures UEs with multiple slotFormatCombinations, each combination being a list of slot formats for a number of consecutive slots. The UE is configured with SFI-RNTI to monitor PDCCH for SFI (slot format indication). PDDCH dynamically indicates the SFIs for a number of upcoming slots.

Question 18

Can the dynamic slot format override DL and UL symbols configured by RRC

Answer 18

No

Question 19

What are self-contained slots

Answer 19

A single slot that contains DL control information, DL data and ACK, mainly used for LLC

Question 20

What are the main characteristics associated with a BWP

Answer 20

Numerology, bandwidth and frequency location

Question 21

Is BWP configuration the same for all UEs?

Answer 21

No, the BWP is UE-specific

Question 22

What’s the main difference between NSA and SA

Answer 22

In NSA, the control plane goes through E-UTRAN