LTTS-Batch 2_Week2 LTTS-Batch 2_Week2 The number of attempts remaining is 1 1 / 50 1. What NR feature allows a slot to contain both downlink and uplink transmission within the same slot? a. Mandatory guard-band insertion b. Self-contained slot structure c. Fixed subframe structure d. Static TDD-only operation 2 / 50 2. Which two security functions does PDCP apply to user and signaling data? a. Scheduling and HARQ b. Compression and multiplexing c. Ciphering and integrity protection d. Segmentation and reordering only 3 / 50 3. A UE is allocated 50 PRBs for one slot with normal CP. How many Resource Elements (REs) does this allocation contain, before removing any DMRS or control overhead? a. 8,400 b. 16,800 c. 600 d. 700 4 / 50 4. Which channel coding scheme does NR use for its data channels (PDSCH/PUSCH)? a. Turbo coding b. Convolutional coding only c. LDPC (Low-Density Parity-Check) coding d. Reed-Muller coding only 5 / 50 5. Between LTE and NR, which physical-layer coding change was made specifically for control channels? a. LDPC coding was replaced by Turbo coding b. No coding scheme changed between LTE and NR c. Turbo coding was replaced by Polar coding d. Polar coding was replaced by Reed-Solomon coding 6 / 50 6. What is a 'mini-slot' in NR primarily used for? a. Increasing the cyclic prefix length b. Carrying only broadcast system information c. Replacing the SSB entirely d. Enabling low-latency transmissions shorter than a full slot 7 / 50 7. What is the key difference between synchronous and asynchronous HARQ? a. There is no meaningful difference between the two b. In synchronous HARQ the retransmission timing is fixed/predictable, while asynchronous HARQ can retransmit at a scheduler-chosen time c. Synchronous HARQ never retransmits data d. Asynchronous HARQ is only used for control channels 8 / 50 8. Which channel coding scheme does LTE use for its data channels (PDSCH/PUSCH)? a. Turbo coding b. Polar coding c. LDPC coding d. Reed-Solomon coding 9 / 50 9. What is the useful OFDM symbol duration (excluding the cyclic prefix) for 30 kHz SCS? a. 66.67 µs b. 33.33 µs c. 16.67 µs d. 8.33 µs 10 / 50 10. What does RSRQ (Reference Signal Received Quality) add on top of what RSRP measures? a. It measures only the UE's battery consumption b. It replaces the need for RSRP entirely with no relationship between them c. It accounts for interference and overall received power, giving a quality figure rather than just raw reference-signal strength d. It measures uplink transmit power exclusively 11 / 50 11. What is the purpose of RRC measurement reporting? a. To synchronize the UE's internal clock b. To let the UE report on serving/neighbor cell signal quality so the network can make mobility (e.g. handover) decisions c. To report the UE's data usage for billing d. To request a new IP address 12 / 50 12. What is the relationship between a Scheduling Request and a Buffer Status Report? a. An SR replaces the need for any uplink grant permanently b. An SR typically requests the opportunity to send a BSR, which then tells the network how much data is actually waiting c. A BSR is sent only in the downlink d. They are the same message with two different names 13 / 50 13. Which RLC mode provides in-sequence delivery and segmentation but no retransmission? a. None of RLC's modes provide segmentation b. AM c. UM (Unacknowledged Mode) d. TM 14 / 50 14. LTE's basic time unit is Ts = 1 / (15,000 × 2048) s and NR's basic time unit is Tc = 1 / (480,000 × 4096) s. What is the ratio κ = Ts / Tc? a. 128 b. 64 c. 32 d. 16 15 / 50 15. Why might an operator choose to keep a bearer in UM rather than upgrading it to AM, even though AM is more reliable? a. AM is not supported by any modern network b. UM uses less spectrum than AM c. UM avoids the retransmission delay that could hurt a latency-sensitive service more than the occasional lost segment would d. There is no valid reason — AM should always be used 16 / 50 16. What is the main purpose of a CRC (Cyclic Redundancy Check) attached to a transport block? a. To detect whether the received transport block contains errors b. To encrypt the transport block c. To assign a scheduling priority d. To compress the transport block 17 / 50 17. What do the K0/K1/K2 scheduling offsets in NR indicate? a. The UE's measured SINR value b. The physical cell identity c. The timing relationships between scheduling grant, data transmission, and HARQ feedback d. The number of antenna ports configured 18 / 50 18. What does a Scheduling Request (SR) allow a UE to do? a. Request uplink resources from the gNB when it has data to send but no existing grant b. Directly transmit data without any grant c. Request a handover to another cell d. Report its battery level 19 / 50 19. What is the purpose of the RRC Connection Establishment procedure? a. To bring a UE from RRC_IDLE (or RRC_INACTIVE) into RRC_CONNECTED so it can exchange data b. To update the UE's subscriber profile in the HSS/UDM c. To perform a handover between two cells d. To move a UE from RRC_CONNECTED to RRC_IDLE 20 / 50 20. A 100 MHz FR1 carrier at 30 kHz SCS is configured with its maximum of 273 PRBs. What is the actual occupied transmission bandwidth? a. 196.56 MHz b. 98.28 MHz c. 49.14 MHz d. 100 MHz 21 / 50 21. What is paging used for in RRC? a. To measure a UE's uplink transmit power b. To notify a UE in RRC_IDLE or RRC_INACTIVE of incoming data or a system information change c. To compress a UE's IP headers d. To permanently disconnect a UE 22 / 50 22. Which LTE uplink physical channel is used to carry the user's actual uplink data? a. PRACH b. PUSCH (Physical Uplink Shared Channel) c. PUCCH d. PHICH 23 / 50 23. What is the highest-order modulation scheme originally defined for LTE PDSCH? a. 64QAM b. 256QAM c. QPSK d. 16QAM 24 / 50 24. What does HARQ combine that plain ARQ retransmission does not? a. Nothing extra — HARQ and ARQ are identical b. HARQ discards failed attempts entirely before retrying c. HARQ only works in the uplink direction d. HARQ combines the soft information from failed attempts with the retransmission to improve decoding odds 25 / 50 25. Which layer is responsible for HARQ retransmissions, distinct from RLC's own ARQ retransmissions? a. RRC b. PDCP c. MAC d. SDAP 26 / 50 26. Which of the following is a genuinely new RRC state introduced by NR, not present in LTE? a. RRC_INACTIVE b. RRC_DISCONNECTED c. RRC_CONNECTED d. RRC_IDLE 27 / 50 27. What is the main purpose of PDCP's header compression (ROHC)? a. To encrypt the RRC signaling channel b. To compress the physical layer's reference signals c. To reduce the number of HARQ retransmissions d. To reduce the overhead of IP/transport headers relative to small payloads like VoIP packets 28 / 50 28. In 5G NR, the subcarrier spacing is given by SCS = 15 kHz × 2^μ. What is the SCS for numerology μ = 2? a. 60 kHz b. 240 kHz c. 120 kHz d. 30 kHz 29 / 50 29. A TDD cell at 30 kHz SCS uses the slot pattern DDDSU, repeating continuously. What is the pattern periodicity, and how many full downlink (D) slots are there in one 10 ms frame? a. 5 ms periodicity, 12 D slots b. 2.5 ms periodicity, 15 D slots c. 1.25 ms periodicity, 16 D slots d. 2.5 ms periodicity, 12 D slots 30 / 50 30. What is the general purpose of beam management procedures (such as P1/P2/P3) in NR? a. To schedule daily pulse quizzes b. To assign IP addresses to UEs c. To find and maintain the best transmit/receive beam pair between gNB and UE, especially at higher frequencies d. To manage core network routing 31 / 50 31. Which channel coding scheme does NR use for its control channel (PDCCH)? a. Hamming coding b. LDPC coding c. Polar coding d. Turbo coding 32 / 50 32. Which NR measurement family is based on the SSB, analogous to LTE's cell-search-based measurements? a. CSI-RSRP b. SRS-RSRP c. PRACH-RSRP d. SS-RSRP 33 / 50 33. In HARQ, what does the New Data Indicator (NDI) toggling indicate? a. A completely new transport block being sent, not a retransmission b. A change in modulation scheme only c. That the UE has lost synchronization d. A retransmission of the same transport block 34 / 50 34. What is a Buffer Status Report (BSR) used for? a. Reporting the UE's GPS location b. Requesting a new physical cell ID c. Informing the network how much data is waiting in the UE's uplink buffers, to help size the next uplink grant d. Reporting the UE's downlink channel quality 35 / 50 35. What does Semi-Persistent Scheduling (SPS) / Configured Grant allow? a. The network to permanently disable a UE's uplink b. A UE to transmit or receive on a recurring pattern without needing a fresh grant every single time c. A UE to bypass HARQ entirely d. A UE to skip RRC connection setup 36 / 50 36. Which LTE downlink physical channel carries scheduling assignments (DCI)? a. PUCCH b. PDCCH (Physical Downlink Control Channel) c. PRACH d. PDSCH 37 / 50 37. How many bits does one 16QAM symbol carry? a. 6 b. 2 c. 4 d. 8 38 / 50 38. What PDCP mechanism enables near-lossless handovers? a. Re-establishing a new IP address for every handover b. Discarding all in-flight data before handover c. Disabling ciphering during handover d. Using PDCP sequence numbers to allow forwarding and reordering of in-flight data across the handover 39 / 50 39. Which RLC mode would typically be used for RRC signaling, where reliability matters most? a. TM b. UM c. Any mode, since RRC signaling has no reliability requirement d. AM 40 / 50 40. Which RLC mode provides no segmentation, reordering, or retransmission at all? a. TM (Transparent Mode) b. SM (Segmented Mode) c. AM (Acknowledged Mode) d. UM (Unacknowledged Mode) 41 / 50 41. What is the highest-order modulation scheme NR adds beyond LTE's maximum? a. 256QAM b. 1024QAM c. 16QAM d. 64QAM 42 / 50 42. Why does the network request the UE's capability information during RRC procedures? a. To learn what features and bands the specific UE supports, so it can configure it appropriately b. To trigger a mandatory software update c. To determine the UE's billing plan d. To assign the UE's physical cell ID 43 / 50 43. Which RRC state is unique to NR, sitting between IDLE and CONNECTED and allowing fast resume? a. RRC_SUSPENDED (a state that does not exist in NR) b. RRC_INACTIVE c. RRC_IDLE d. RRC_CONNECTED 44 / 50 44. How many bits per resource element does 256QAM carry? a. 10 b. 8 c. 6 d. 4 45 / 50 45. With 120 kHz SCS and normal cyclic prefix, how many OFDM symbols are transmitted in one 1 ms subframe? a. 14 b. 224 c. 56 d. 112 46 / 50 46. Estimate the raw peak physical-layer bit rate for a 100 MHz NR carrier at 30 kHz SCS (273 PRBs), 256-QAM, 4 MIMO layers, 100% downlink, ignoring coding and all overheads. a. About 2.94 Gbps b. About 1.47 Gbps c. About 734 Mbps d. About 5.87 Gbps 47 / 50 47. Which single statement best captures why this week's material (PHY through RRC) matters for real troubleshooting? a. Only PHY-layer knowledge is ever useful for troubleshooting b. Protocol layers are interchangeable and any layer can cause any symptom equally c. Knowing each layer's distinct responsibility lets you narrow down which layer is likely responsible for a given symptom d. It doesn't — troubleshooting only requires core network knowledge 48 / 50 48. What is the purpose of RRC Reconfiguration? a. To assign the UE's permanent identity b. To modify the UE's existing radio configuration (such as adding a bearer or updating measurement config) while it remains connected c. To permanently release the UE's connection d. To perform initial cell search 49 / 50 49. Which RRC state is characterized by no active data connection and minimal network-side context maintained for the UE? a. RRC_CONNECTED b. RRC_IDLE c. RRC_INACTIVE d. RRC_ACTIVE 50 / 50 50. Which layer would you check first if you suspected a header-compression or ciphering issue? a. MAC b. PDCP c. PHY d. RLC Your score is
