LTTS-Batch 2_Week2 LTTS-Batch 2_Week2 The number of attempts remaining is 1 1 / 50 1. What is the main purpose of PDCP's header compression (ROHC)? a. To reduce the overhead of IP/transport headers relative to small payloads like VoIP packets b. To encrypt the RRC signaling channel c. To compress the physical layer's reference signals d. To reduce the number of HARQ retransmissions 2 / 50 2. Which RLC mode provides full ARQ-based retransmission for lost or corrupted segments? a. RLC does not support retransmission in any mode b. AM (Acknowledged Mode) c. UM d. TM 3 / 50 3. What PDCP mechanism enables near-lossless handovers? a. Disabling ciphering during handover b. Re-establishing a new IP address for every handover c. Discarding all in-flight data before handover d. Using PDCP sequence numbers to allow forwarding and reordering of in-flight data across the handover 4 / 50 4. With 120 kHz SCS and normal cyclic prefix, how many OFDM symbols are transmitted in one 1 ms subframe? a. 112 b. 56 c. 14 d. 224 5 / 50 5. 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. 49.14 MHz b. 196.56 MHz c. 98.28 MHz d. 100 MHz 6 / 50 6. 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. They are the same message with two different names c. A BSR is sent only in the downlink d. An SR typically requests the opportunity to send a BSR, which then tells the network how much data is actually waiting 7 / 50 7. Which channel coding scheme does NR use for its control channel (PDCCH)? a. LDPC coding b. Hamming coding c. Polar coding d. Turbo coding 8 / 50 8. 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 9 / 50 9. 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 10 / 50 10. What is the frequency-domain bandwidth of one Resource Block (RB) when the SCS is 30 kHz? a. 1440 kHz b. 180 kHz c. 720 kHz d. 360 kHz 11 / 50 11. What is the purpose of RRC measurement reporting? a. To let the UE report on serving/neighbor cell signal quality so the network can make mobility (e.g. handover) decisions b. To request a new IP address c. To synchronize the UE's internal clock d. To report the UE's data usage for billing 12 / 50 12. What is the key difference between synchronous and asynchronous HARQ? a. In synchronous HARQ the retransmission timing is fixed/predictable, while asynchronous HARQ can retransmit at a scheduler-chosen time b. There is no meaningful difference between the two c. Asynchronous HARQ is only used for control channels d. Synchronous HARQ never retransmits data 13 / 50 13. Which RRC state is unique to NR, sitting between IDLE and CONNECTED and allowing fast resume? a. RRC_INACTIVE b. RRC_IDLE c. RRC_CONNECTED d. RRC_SUSPENDED (a state that does not exist in NR) 14 / 50 14. Which LTE downlink physical channel carries the actual user data (the transport block)? a. PCFICH b. PDCCH c. PBCH d. PDSCH (Physical Downlink Shared Channel) 15 / 50 15. Which LTE downlink physical channel carries scheduling assignments (DCI)? a. PDCCH (Physical Downlink Control Channel) b. PRACH c. PUCCH d. PDSCH 16 / 50 16. What do the K0/K1/K2 scheduling offsets in NR indicate? a. The number of antenna ports configured b. The UE's measured SINR value c. The physical cell identity d. The timing relationships between scheduling grant, data transmission, and HARQ feedback 17 / 50 17. 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 5.87 Gbps b. About 734 Mbps c. About 2.94 Gbps d. About 1.47 Gbps 18 / 50 18. Why does the network request the UE's capability information during RRC procedures? a. To assign the UE's physical cell ID b. To determine the UE's billing plan c. To learn what features and bands the specific UE supports, so it can configure it appropriately d. To trigger a mandatory software update 19 / 50 19. Between LTE and NR, which physical-layer coding change was made specifically for control channels? a. Turbo coding was replaced by Polar coding b. Polar coding was replaced by Reed-Solomon coding c. LDPC coding was replaced by Turbo coding d. No coding scheme changed between LTE and NR 20 / 50 20. Reading the protocol stack from RRC down to PHY, which statement correctly orders the layers by responsibility? a. RRC configures the connection; PDCP compresses/secures; RLC/MAC prepare and schedule; PHY transmits over the air b. MAC compresses headers; PDCP handles HARQ c. PHY configures the connection; RRC transmits over the air d. RLC assigns the physical cell ID 21 / 50 21. What NR feature allows a slot to contain both downlink and uplink transmission within the same slot? a. Fixed subframe structure b. Static TDD-only operation c. Self-contained slot structure d. Mandatory guard-band insertion 22 / 50 22. Which NR measurement family is based on the SSB, analogous to LTE's cell-search-based measurements? a. SRS-RSRP b. PRACH-RSRP c. CSI-RSRP d. SS-RSRP 23 / 50 23. In 5G NR, the subcarrier spacing is given by SCS = 15 kHz × 2^μ. What is the SCS for numerology μ = 2? a. 30 kHz b. 120 kHz c. 240 kHz d. 60 kHz 24 / 50 24. Which RRC state is characterized by no active data connection and minimal network-side context maintained for the UE? a. RRC_ACTIVE b. RRC_INACTIVE c. RRC_IDLE d. RRC_CONNECTED 25 / 50 25. If a bearer needs low latency and can tolerate occasional loss (such as VoIP), which RLC mode is the best fit? a. AM b. UM c. None of these — VoIP cannot use any RLC mode d. TM 26 / 50 26. If a bearer needs guaranteed, in-order, reliable delivery (such as a file download), which RLC mode is the best fit? a. UM b. TM c. AM d. RLC mode has no effect on reliability 27 / 50 27. In HARQ, what does the New Data Indicator (NDI) toggling indicate? a. That the UE has lost synchronization b. A completely new transport block being sent, not a retransmission c. A change in modulation scheme only d. A retransmission of the same transport block 28 / 50 28. What is paging used for in RRC? a. To permanently disconnect a UE b. To notify a UE in RRC_IDLE or RRC_INACTIVE of incoming data or a system information change c. To measure a UE's uplink transmit power d. To compress a UE's IP headers 29 / 50 29. What is the useful OFDM symbol duration (excluding the cyclic prefix) for 30 kHz SCS? a. 16.67 µs b. 66.67 µs c. 33.33 µs d. 8.33 µs 30 / 50 30. Which layer would you check first if you suspected a header-compression or ciphering issue? a. RLC b. PDCP c. MAC d. PHY 31 / 50 31. What is the general purpose of beam management procedures (such as P1/P2/P3) in NR? a. To assign IP addresses to UEs b. To schedule daily pulse quizzes c. To manage core network routing d. To find and maintain the best transmit/receive beam pair between gNB and UE, especially at higher frequencies 32 / 50 32. What is a 'mini-slot' in NR primarily used for? a. Enabling low-latency transmissions shorter than a full slot b. Carrying only broadcast system information c. Increasing the cyclic prefix length d. Replacing the SSB entirely 33 / 50 33. Which RLC mode provides no segmentation, reordering, or retransmission at all? a. SM (Segmented Mode) b. UM (Unacknowledged Mode) c. TM (Transparent Mode) d. AM (Acknowledged Mode) 34 / 50 34. What is the highest-order modulation scheme NR adds beyond LTE's maximum? a. 256QAM b. 16QAM c. 64QAM d. 1024QAM 35 / 50 35. What is the purpose of the RRC Connection Establishment procedure? a. To perform a handover between two cells b. To bring a UE from RRC_IDLE (or RRC_INACTIVE) into RRC_CONNECTED so it can exchange data c. To update the UE's subscriber profile in the HSS/UDM d. To move a UE from RRC_CONNECTED to RRC_IDLE 36 / 50 36. 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. 1.25 ms periodicity, 16 D slots c. 2.5 ms periodicity, 15 D slots d. 2.5 ms periodicity, 12 D slots 37 / 50 37. 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. 600 b. 16,800 c. 8,400 d. 700 38 / 50 38. What is a Buffer Status Report (BSR) used for? a. Reporting the UE's downlink channel quality b. Requesting a new physical cell ID c. Reporting the UE's GPS location d. Informing the network how much data is waiting in the UE's uplink buffers, to help size the next uplink grant 39 / 50 39. Which channel coding scheme does LTE use for its data channels (PDSCH/PUSCH)? a. LDPC coding b. Polar coding c. Reed-Solomon coding d. Turbo coding 40 / 50 40. What does a Scheduling Request (SR) allow a UE to do? a. Report its battery level b. Request a handover to another cell c. Request uplink resources from the gNB when it has data to send but no existing grant d. Directly transmit data without any grant 41 / 50 41. Which two security functions does PDCP apply to user and signaling data? a. Scheduling and HARQ b. Ciphering and integrity protection c. Segmentation and reordering only d. Compression and multiplexing 42 / 50 42. Which two LTE control channels were retired in NR, with their functions folded elsewhere? a. PBCH and PUCCH b. PDSCH and PUSCH c. PCFICH and PHICH d. PDCCH and PRACH 43 / 50 43. What does CQI (Channel Quality Indicator) reported by the UE help the network decide? a. The number of antennas on the UE b. Which modulation and coding scheme (MCS) can be reliably used for that UE's current channel conditions c. The UE's IMSI d. The UE's physical location 44 / 50 44. 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 avoids the retransmission delay that could hurt a latency-sensitive service more than the occasional lost segment would c. There is no valid reason — AM should always be used d. UM uses less spectrum than AM 45 / 50 45. A 5G NR carrier uses 30 kHz SCS (μ = 1). How many slots are there in one 10 ms radio frame? a. 80 slots b. 40 slots c. 20 slots d. 10 slots 46 / 50 46. What is the purpose of RRC Reconfiguration? a. To modify the UE's existing radio configuration (such as adding a bearer or updating measurement config) while it remains connected b. To permanently release the UE's connection c. To assign the UE's permanent identity d. To perform initial cell search 47 / 50 47. What does Semi-Persistent Scheduling (SPS) / Configured Grant allow? a. A UE to skip RRC connection setup b. A UE to bypass HARQ entirely c. The network to permanently disable a UE's uplink d. A UE to transmit or receive on a recurring pattern without needing a fresh grant every single time 48 / 50 48. Which layer is responsible for HARQ retransmissions, distinct from RLC's own ARQ retransmissions? a. RRC b. PDCP c. MAC d. SDAP 49 / 50 49. What is the main function of the MAC layer's logical-to-transport-channel mapping? a. Multiplexing different types of logical channel data onto the physical layer's transport channels b. Performing header compression c. Establishing the RRC connection d. Encrypting user-plane data 50 / 50 50. Which channel coding scheme does NR use for its data channels (PDSCH/PUSCH)? a. Turbo coding b. LDPC (Low-Density Parity-Check) coding c. Reed-Muller coding only d. Convolutional coding only Your score is
