LTE Interview Questions

Hi All below are the question list for interview preparation

• What is the main function of the LTE physical layer?
• What modulation schemes are supported in LTE?
• How many subcarriers are in a physical resource block in LTE?
• Describe the purpose of a cyclic prefix in LTE.
• What is EARFCN in LTE, and what does it stand for?
• What is the difference between FDD and TDD in LTE?
• What role does the eNodeB play in the LTE network?
• Explain the difference between NSA and SA architecture in 5G.
• What is the function of the Serving Gateway in LTE?
• What is the primary responsibility of the MME in LTE?
• Define inter-symbol interference (ISI) and how LTE addresses it.
• What is adjacent carrier interference (ACI), and what causes it?
• Explain inter-carrier interference (ICI) in OFDM.
• What is the benefit of OFDM in LTE?
• What problem does SC-FDMA address in LTE?
• How many resource blocks are in a 20 MHz LTE channel?
• What is PAPR, and why is it significant in LTE uplink?
• What is the purpose of the Service Data Adaptation Protocol (SDAP)?
• Explain the role of the Radio Resource Control (RRC) protocol.
• List three functions of the Packet Data Convergence Protocol (PDCP).
• How does the Radio Link Control (RLC) layer support error correction?
• Describe the purpose of DCI in the LTE physical layer.
• What are the different formats of DCI in LTE?
• Define RNTI and its significance in LTE.
• What is the function of the Physical Broadcast Channel (PBCH) in LTE?
• What information is carried by the Physical Downlink Shared Channel (PDSCH)?
• Explain the purpose of the PUCCH in LTE uplink.
• What is the significance of the Physical Uplink Shared Channel (PUSCH)?
• Describe the purpose of demodulation reference signals in LTE.
• What is a guard period in the context of LTE?
• Describe the relationship between subcarrier spacing and symbol duration in LTE.
• How is OFDMA different from SC-FDMA?
• What is HARQ, and where is it used in LTE?
• Explain the use of modulation and coding schemes in DCI.
• What is the significance of Control Channel Elements (CCEs) in LTE?
• Define the purpose of the QoS Class Identifier (QCI) in LTE.
• Describe the purpose of the Paging Control Channel (PCCH).
• What role does the Broadcast Control Channel (BCCH) serve?
• What is the function of the Common Control Channel (CCCH)?
• Describe the role of the Dedicated Control Channel (DCCH).
• Explain the difference between logical and transport channels in LTE.
• What is a physical channel in LTE?
• Describe the purpose of the S1 interface in LTE architecture.
• What does the E-UTRAN in LTE refer to?
• Define the purpose of the PDN Gateway in LTE.
• Describe the purpose of the Public Warning Message (PWS) system.
• What is the purpose of the NAS protocol in LTE?
• What is the main purpose of the Packet Data Convergence Protocol (PDCP)?
• Explain the term “Cell-specific DL RS” in LTE.
• What is the function of the Sounding Reference Signal (SRS) in LTE?
• Define the term “X2 interface” in LTE architecture.
• What is the role of the MME in handling UE states?
• Describe the use of Transmission Control Protocol (TCP) in LTE.
• Explain the purpose of the Network Access Server (NAS).
• Describe the term “handover” in the LTE network.
• What is the role of the P-GW in an LTE network?
• Explain the concept of EPS bearer in LTE.
• Describe the purpose of the RLC Transparent Mode (TM).
• What is the purpose of PDCCH in LTE?
• Define the Physical Control Format Indicator Channel (PCFICH).
• Describe the Physical Hybrid ARQ Indicator Channel (PHICH).
• Explain the structure of an LTE frame in FDD mode.
• How many symbols are in a normal cyclic prefix slot in LTE?
• What is the function of the Physical Random-Access Channel (PRACH)?
• Define the LTE cell reselection procedure.
• Explain the importance of security in NAS signaling.
• What is the use of the Control Resource Set (CORESET) in 5G NR?
• Describe the significance of CQI in the LTE network.
• Define “resource mapping” in the context of LTE.
• Explain the function of GTP-U in LTE.
• Describe the Evolved Packet Core (EPC) architecture in LTE.
• Define what “resource block” means in LTE.
• Describe the purpose of the LTE uplink scheduling.
• Explain how the Doppler effect impacts LTE signals.
• What are the primary elements of LTE protocol stack?
• Explain the purpose of the UE measurement report in LTE.
• Define the significance of a bearer in LTE.
• What is the difference between MTCH and DTCH?
• Describe the purpose of the S-GW in 5G.
• Explain the term “load balancing” in LTE.
• What are the types of modulation schemes used in 5G NR?
• Describe the main purpose of the NG interface in 5G.
• What is the function of the SRS signal in LTE?
• Define the role of the AMF in 5G architecture.
• What is a subframe, and how long does it last in LTE?
• Describe the role of HARQ in reducing packet loss.
• Explain the term “Control Plane” in LTE.
• Describe the UE measurement report’s role in handovers.
• What is the purpose of uplink power control in LTE?
• Define the purpose of MIMO in LTE.
• Describe the LTE scheduling algorithms.
• What is the purpose of the Physical Downlink Control Channel?
• Define the function of the RLC Acknowledged Mode.
• Explain what “bearer management” means in LTE.
• What is an S1 bearer in the context of LTE?
• Describe the purpose of Random-Access Procedures in LTE.
• Explain the difference between UL and DL in LTE.
• What is the main function of the Packet Core Gateway?
• Define the term “DCI” in LTE and its purpose.
• What is the purpose of the DCI Format 0?
• Describe the process of EPS Attach in LTE.
• What is the function of the EPS Bearer Context Activation?
• Explain the primary role of the eNodeB scheduler in LTE.
• Define “Direct Tunnel” in LTE architecture.
• What is the difference between GBR and non-GBR bearers?
• Explain the LTE Idle Mode UE’s operation in the DRX cycle.
• Define “Default Bearer” in LTE.
• Describe the purpose of the RRC CONNECTED state.
• Explain the difference between SISO and MIMO.
• What is the role of the PDSCH in downlink communication?
• How does the RLC layer support segmentation?
• Define the purpose of a Service Request in LTE.
• What does PDCP header compression do?
• Describe the importance of ciphering in LTE.
• Define the concept of “UE context” in LTE.
• Explain the LTE Detach procedure.
• What is the role of an NG interface in 5G?
• How does Beamforming enhance LTE/5G performance?
• Explain the concept of CQI feedback in LTE.
• What is the purpose of the DRX mechanism in LTE?
• Describe the concept of a mobility anchor in LTE.
• Explain the LTE TDD special subframes.
• Define the MME’s role in attach requests.
• How does the RRC handle UE measurement reports?
• Describe the role of Physical Random Access Channel (PRACH).
• Explain the difference between PUSCH and PUCCH.
• What is the significance of the Control Plane in LTE?
• Describe the function of the Paging Channel in LTE.
• What is NAS signaling in LTE?
• Explain the LTE system information blocks (SIBs).
• Define Physical Cell Identity (PCI) in LTE.
• Describe the LTE cell reselection criteria.
• Explain the role of the EPS bearer in QoS management.
• What is the purpose of the UL-SCH in LTE?
• Define the term “semi-persistent scheduling” in LTE.
• Describe the functionality of Modulation Coding Scheme (MCS).
• Explain how LTE supports multicast transmissions.
• What is the purpose of the TTI bundling in LTE?
• Describe the HARQ process and how it is managed.
• What is the significance of the Physical Layer in LTE?
• Define the term “Logical Channel” in LTE.
• Explain the concept of “dual connectivity” in 5G.
• Describe how LTE handles retransmissions.
• What is the purpose of Random Access Preambles?
• Define the Broadcast Control Channel (BCCH) in LTE.
• Describe the differences between DCI Format 1 and Format 1A.
• Explain what Paging Occasions are in LTE.
• What is meant by “Transmission Power Control” in LTE?
• Describe how OFDM achieves orthogonality.
• Explain the purpose of the Cyclic Redundancy Check (CRC) in LTE.
• What is the role of PDCP in ensuring data integrity?
• Describe the OFDMA concept in LTE.
• Explain what is meant by “in-band” and “out-of-band” signaling.
• Define the NAS EMM state machine.
• Describe the purpose of the RNTI in LTE.
• What is HARQ feedback, and how is it used?
• Define the term “PRACH” in the LTE uplink.
• What is the function of the PHICH?
• Describe the role of the RLC UM mode in LTE.
• Explain how LTE uses cell-specific reference signals.
• Define the term “UL Grant” in DCI.
• What is the purpose of the PDSCH in LTE?
• Describe the LTE “cell reselection” process.
• What is the difference between NAS and RRC signaling?
• Explain the difference between FDD and TDD resource grids.
• Define “S1-flex” in LTE architecture.
• What is the role of OFDMA in the LTE downlink?
• Describe the role of eNB in managing cell re-selection.
• What is meant by “split bearers” in 5G dual connectivity?
• Define the term “Contention-Based Random Access.”
• What is the purpose of the PUCCH in LTE?
• Describe how LTE handles paging messages.
• What is the difference between standalone and non-standalone 5G?
• Define “QoS flow” in 5G.
• Explain the purpose of S-GW in handover scenarios.
• What is the role of HARQ in LTE error correction?
• Define “Scheduling Request” in LTE.
• What is a Control Channel Element (CCE) in LTE?
• Explain the function of Channel Quality Indicator (CQI).
• Describe the role of gNB in 5G.
• What is meant by “frequency reuse” in LTE?
• Describe how LTE supports VoIP services.
• What is the function of the SDAP layer in 5G?
• Define the term “Dynamic Scheduling” in LTE.
• Describe the term “in-order delivery” in PDCP.
• What is the purpose of NAS authentication?
• Explain what DRX is in the LTE network.
• Define the difference between GBR and non-GBR bearers.
• Explain how LTE manages carrier aggregation.
• What is the function of a Tracking Area Update (TAU)?
• Describe the purpose of the Radio Link Control (RLC) layer.
• Define “PDSCH scheduling.”
• Explain the LTE contention-free access.
• What is the purpose of cyclic prefix in OFDMA?
• Describe the LTE network’s approach to latency reduction.
• Define the concept of “time domain scheduling.”
• Explain the function of logical channel prioritization.
• Describe the role of “DCI Format 2.”
• What is the purpose of SI-RNTI?
• Explain the concept of soft handover in LTE.
• Define “uplink power control.”
• Describe the UE RRC connection release process.
• What is the purpose of Layer 3 mobility?
• Explain LTE “cell access barring.”
• Define the term “inactivity timer.”
• Describe the LTE-specific transmission modes.
• What is the function of a “Paging Occasion”?
• Explain what uplink power control in LTE is.
• Define “Carrier Aggregation.”
• Describe the function of GTP-U in LTE.
• Explain the LTE procedure for RRC connection setup.
• What is the purpose of the core network?
• Define an EPS bearer in LTE.
• Describe “Transmission Mode 4” in LTE.
• What is meant by “UE-specific beamforming”?
• Explain the difference between PDCCH and PDSCH.
• Define what the MAC layer does in LTE.
• Describe the UE context transfer in LTE handover.
• What is a “Downlink Assignment” in LTE?
• Define the term “Uplink Grant” in LTE.
• Explain the role of the Xn interface in 5G.
• Describe how DCI is mapped to RNTIs.
• What is a Tracking Area in LTE?
• Define the term “PCI collision.”
• Explain what a PDCCH candidate is.
• What is the role of QCI in QoS management?
• Describe “standby mode” in LTE.
• Define “adjacent channel interference.”
• Explain the concept of random access preambles.
• Describe the purpose of the NG-U interface in 5G.
• What is the role of the gNB in 5G NR?
• Define “Random Access Response.”
• What is the purpose of the Serving Gateway in LTE?
• Explain how PRACH resources are allocated.
• Define the concept of the NAS Idle state.
• Describe the 5G NR logical channel structure.
• Explain the function of GTP-C in LTE.
• Define “Power Control Headroom” in LTE.
• What is the purpose of PHICH in LTE?
• Explain the LTE handover procedure.
• Define the concept of bearer binding in LTE.
• What is the significance of “priority handling” in MAC?
• Describe the use of RLC AM in LTE.
• Define the term “uplink grant.”
• Explain the difference between DL-SCH and UL-SCH.
• What is the role of the User Plane in LTE?
• Describe the purpose of a paging message.
• What is the function of cell reselection?
• Explain the purpose of the P-GW in QoS.
• What is the purpose of the MIB in LTE?
• How often is the MIB transmitted by the eNodeB?
• What modulation is required for MIB transmission?
• What is the size of the MIB in LTE?
• What type of channel does the MIB use in LTE?
• How many bits are used for System Frame Number in MIB?
• What is the function of the PHICH in LTE?
• How is the CRC used in MIB transmission?
• What is the rate of the convolutional encoder for MIB?
• What is the role of rate matching in MIB encoding?
• How many QPSK symbols are generated after modulation of the MIB?
• What is the purpose of scrambling in the MIB process?
• How is paging used in LTE networks?
• Why is paging essential for battery life in LTE devices?
• What is the paging cycle in LTE?
• What is the paging frame in LTE?
• How does LTE use paging group IDs?
• Define eNodeB-initiated paging.
• What is the role of the MME in LTE paging?
• How does DRX extend battery life in LTE?
• What is the DRX inactivity timer?
• How is the DRX cycle configured in LTE?
• What does the DRX guard timer do?
• Describe the short DRX cycle.
• What is the purpose of the RACH in LTE?
• When does a UE initiate the RACH procedure?
• Explain the difference between contention-based and contention-free RACH.
• What is a RACH preamble?
• How many preambles are available in LTE?
• Define uplink synchronization in the context of RACH.
• Explain the purpose of the scheduling request (RA_SR) in RACH.
• What are the steps in contention-based RACH?
• Describe the significance of the RAR in RACH.
• What is the purpose of contention resolution in RACH?
• How is the RACH preamble format determined?
• What triggers the RLF (Radio Link Failure) in LTE?
• How does LTE handle an RLF situation?
• What causes a T310 expiry?
• What happens after an RLF due to maximum UL RLC retransmissions?
• Define the role of the MIB in initial UE attachment.
• What is the purpose of PSS and SSS in cell synchronization?
• How is the RSSI measured in LTE?
• What is the role of the RSSI threshold in cell search?
• What does the UE do if it cannot find a cell during initial acquisition?
• Describe the function of the Paging Control Channel (PCH).
• What information is included in the MIB?
• How does the eNodeB determine the paging occasion?
• What is the paging DRX?
• How does the UE identify its paging subframe?
• What triggers the UE to wake up during DRX?
• Explain HARQ in LTE.
• How does Chase Combining work in HARQ?
• Describe incremental redundancy in HARQ.
• What is synchronous HARQ?
• How does asynchronous HARQ differ from synchronous HARQ?
• What is the significance of the modulation and coding scheme (MCS) in HARQ?
• What is Power Headroom Reporting (PHR)?
• How is the power headroom calculated in LTE?
• When does the UE send a PHR report?
• What is the purpose of the PHR prohibit timer?
• Describe the extended PHR MAC control element.
• What does the RLF indication message do?
• What are the main events that trigger handover in LTE?
• Define intra-frequency handover.
• What is the purpose of inter-frequency handover?
• Explain the concept of inter-RAT handover.
• What is Event A3 in LTE handovers?
• Describe Event A5 and its role in handovers.
• What happens during X2 handover?
• Describe the role of MME in S1 handover.
• What is the main goal of DRX in connected mode?
• Define the paging group ID.
• How does the UE respond to an eNodeB-initiated paging request?
• Explain the role of contention-free RACH during handover.
• How does LTE use access class barring?
• What is the difference between adaptive and non-adaptive HARQ?
• How does the UE process a handover failure?
• What is the impact of the DRX guard timer?
• How many HARQ processes are there in FDD?
• Describe the UE’s initial acquisition procedure.
• Explain the UE Power On procedure in LTE.
• What are the events that trigger a UE handover in LTE?
• What is the purpose of the LTE UE synchronization process?
• What does the SIB2 message include in LTE?
• How does LTE use System Frame Numbers (SFN)?
• Define the purpose of paging subframes in LTE.
• How does LTE handle RLF in idle mode?
• What is the power headroom reporting range?
• What is the function of the drx-RetransmissionTimer?
• How is the drx-InactivityTimer configured?
• What happens during DRX in idle mode?
• Explain the concept of physical cell ID (PCID).
• What is the MIB’s role in initial acquisition?
• How is the UE-specific DRX cycle set?
• How does LTE implement HARQ for downlink transmissions?
• What is the purpose of ACK and NACK in HARQ?
• Explain the concept of CQI in LTE.
• Describe the RACH preamble format for TDD mode.
• Define guard time in relation to cell radius.
• What is the purpose of rate matching in HARQ?
• Describe the purpose of RLF recovery.
• What is the significance of the Paging Frame?
• Explain eNodeB-initiated paging vs. UE-initiated paging.
• Describe the Paging DRX cycle in LTE.
• What is an incremental redundancy mechanism?
• Explain the role of the UE Context in X2 handover.
• Describe the short DRX cycle in LTE.
• What is a contention-based preamble?
• How does LTE handle handover measurement events?
• Define “contention-free preambles.”
• How is DRX configured for idle mode?
• What is PHR-PeriodicTimer used for?
• Describe the function of T310 in handling RLF.
• What happens during the initial RSSI measurement?
• Explain PSS synchronization in LTE.
• How is power control used in RACH?
• Describe the handover decision process.
• What is the role of eNodeB in paging?
• Explain the concept of cell reselection.
• How does LTE use the RA-RNTI?
• What is the purpose of the PHR-ProhibitTimer?
• What happens when the MME initiates paging?
• Describe the UE’s cell selection process.
• How is the PHICH Ng value determined?
• Explain how MIB is encoded.
• Describe the HARQ process in downlink.
• What is CQI reporting in LTE?
• How does LTE determine paging occasions?
• What triggers the UE to initiate the RACH?
• Explain the process of adaptive HARQ.
• How does LTE prevent RLF during handover?
• What is the purpose of random access preambles?
• Describe the LTE UE ON procedure.
• Explain how LTE uses dedicated preambles.
• Define Event A1 and its use in LTE.
• What is the role of the S1 interface in handover?
• How does LTE use paging cycle in DRX?
• What is an inter-frequency measurement?
• Explain the use of periodic PHR reports.
• Describe the process of UE synchronization in LTE.
• What is meant by synchronous HARQ?
• Define cell-specific reference signals.
• Describe the types of DRX timers in LTE.
• What is uplink power control?
• How does the DRX cycle help reduce latency?
• Define HARQ transmission in LTE uplink.
• How does the eNodeB initiate paging?
• Describe the purpose of short DRX.
• What is meant by adaptive HARQ?
• What are inter-frequency measurements?
• Define “Scheduling Request” in LTE.
• Describe how HARQ improves reliability.
• Explain T310’s role in RLF detection.
• What is paging based on location info?
• How does LTE prevent excessive DRX usage?
• What is the UE power headroom range?
• Explain how DRX uses onDurationTimer.
• How does LTE use HARQ for downlink?
• Describe how paging reduces signaling.
• What triggers the UE’s RRC connection request?
• How is power headroom calculated in PHR?
• What are LTE measurement events?
• Explain the impact of DRX on latency.
• Describe a contention-based RACH process.
• What does the paging group ID do?
• Explain the short DRX mechanism.
• What are the two types of RACH preambles?
• How does the UE handle paging DRX?
• What is MME paging in LTE?
• How is paging triggered in LTE?
• Describe contention-based random access.
• What is LTE RLF detection criteria?
• How does LTE use the PDCCH for HARQ?
• Explain paging optimization in LTE.
• What happens during eNodeB-initiated paging?
• What is the role of RLC in RLF recovery?
• How does LTE use paging frame settings?
• Describe how the DRX retransmission timer works.
• What is a paging subframe?
• How does LTE implement TTI bundling?
• Explain how DRX cycle benefits UE battery.
• Describe the use of CQI in HARQ.
• How does PDCCH work in HARQ?
• What does the paging cycle control?
• Explain why LTE uses multiple RACH formats.
• Define Event B2 and its purpose.
• How does LTE handle failed handovers?
• Describe power headroom reporting rules.
• How does the RACH assist with initial access?
• What is the LTE UE cell search process?
• Explain how HARQ feedback works.
• What is adaptive modulation in HARQ?
• What is the purpose of the DRX on-duration?
• How does LTE handle idle mode DRX?
• What does LTE’s paging message include?
• Explain RA_SR in LTE uplink scheduling.
• How does the UE measure signal quality?
• What triggers LTE handover measurements?
• What does the RA-RNTI represent?
• Explain the concept of DRX guard time.
• What information is contained in the System Information Block (SIB) 1?
• How does the LTE UE perform cell reselection in idle mode?
• Explain the process of calculating Power Headroom in dB.
• Describe the UE’s behavior when T310 expires.
• What is the purpose of System Information Block Type 2 (SIB2)?
• How is the maximum transmission power configured for a UE?
• What is the function of the RA preamble index?
• How does the LTE network handle an overload of paging requests?
• What is the role of the PRACH Configuration Index in LTE?
• Explain the LTE RLF recovery process involving RRC re-establishment.
• How does LTE handle inter-frequency measurements?
• What is meant by a Tracking Area in LTE?
• Define a “timing advance” in LTE.
• Describe the role of paging DRX in reducing network congestion.
• How does LTE measure the downlink channel quality?
• Explain how contention-free RACH is configured for handovers.
• What does the LTE feature Access Class Barring (ACB) accomplish?
• How does the DRX inactivity timer affect data reception?
• What is a PRB (Physical Resource Block) in LTE?
• How does LTE utilize the Control Format Indicator (CFI)?
• What role does the eNodeB play in DRX configuration?
• What is the primary use of DRX short cycles?
• Explain the concept of semi-persistent scheduling in LTE.
• What is the purpose of Physical Uplink Shared Channel (PUSCH)?
• Describe LTE’s Physical Random Access Channel (PRACH) structure.
• What is the purpose of LTE’s Physical Broadcast Channel (PBCH)?
• How does LTE use HARQ processes in the uplink?
• Explain LTE resource mapping for control channels.
• How is the RA preamble format chosen for TDD in LTE?
• What does the LTE term “random access response window” mean?
• Describe the function of the Paging Indicator Channel (PICH).
• What is the significance of the UE-specific DRX cycle?
• How does LTE manage multiple DRX timers?
• What is a contention-free preamble used for?
• Describe how the network configures uplink power control.
• What is the role of the PHR prohibit timer in LTE?
• Explain how LTE employs error detection in HARQ.
• What is the primary function of the eNodeB’s scheduler?
• Describe how LTE handles MIB transmission reliability.
• What is the purpose of the PRACH Frequency Offset?
• How does the LTE UE perform physical layer synchronization?
• Explain how LTE prevents inter-cell interference.
• Describe the LTE procedure for an RRC Connection Release.
• What is a Measurement Gap used for in LTE?
• Explain the purpose of the paging occasion in DRX.
• What is the significance of the Evolved Packet Core (EPC)?
• How does LTE use the Control Channel Element (CCE)?
• What is the UE behavior during a paging cycle?
• Explain how LTE manages uplink synchronization loss.
• Describe the physical layer procedure for PUCCH.
• What is the paging frame number in LTE?
• How does LTE handle power control in high-load scenarios?
• What is the purpose of the SIB scheduling in LTE?
• Define the term “discontinuous reception” in LTE.
• What are the different CQI reporting modes in LTE?
• How does LTE manage interference using the X2 interface?
• What is the significance of the DL-SCH in LTE?
• How is the HARQ buffer used in LTE?
• Describe the function of MCS adaptation in LTE HARQ.
• What is the role of the RLC layer in LTE data integrity?
• Explain how LTE uses subframe numbering.
• How does LTE implement adaptive scheduling?
• Describe how PRACH resources are allocated in LTE.
• What is the purpose of DRX on-duration in connected mode?
• Explain LTE’s Hybrid ARQ process.
• How does LTE use MIB to initialize synchronization?
• What is the importance of the Physical Control Format Indicator Channel?
• Define the LTE term “Paging Frame” in detail.
• Explain the purpose of LTE System Information Block 3 (SIB3).
• What is the purpose of the UE’s access barring check?
• Describe how the UE handles paging messages.
• How does LTE use the RRC connection re-establishment?
• Explain how uplink and downlink resources are mapped.
• What is meant by the term “cell-specific reference signals”?
• How is eNodeB transmission power controlled?
• Explain the primary function of the eNodeB scheduler.
• Describe how LTE manages paging for high-priority messages.
• How does the UE identify its paging group?
• What is the role of CQI in adaptive modulation?
• Explain LTE paging frame selection.
• Describe LTE’s physical layer frame structure.
• How does LTE prevent simultaneous RACH collisions?
• Define “subframe” in LTE’s frame structure.
• Explain LTE’s handling of QoS over the air interface.
• What role does RLC play in LTE retransmissions?
• What is the purpose of DL Power Control?
• Describe the process of paging re-transmission.
• Explain the function of the LTE MAC layer.
• How is LTE PHR calculated in real-time?
• Define LTE’s “RRC connection reconfiguration.”
• Describe the use of Extended Power Headroom Report.
• How does LTE use the DRX short cycle timer?
• Explain LTE’s UL Power Control mechanism.
• Describe how LTE uses error-correction coding in HARQ.
• What is the purpose of Layer 2 in LTE?
• How does LTE handle inter-cell interference coordination?
• Describe the UE’s initial power-up acquisition.
• Explain why LTE uses HARQ synchronous mode in uplink.
• What is LTE’s adaptive MCS, and how is it used?
• Describe how HARQ retransmissions are scheduled.
• What is a scheduling grant in LTE?
• How is PHR reported in LTE multi-carrier scenarios?
• Explain the purpose of Layer Mapping in LTE.
• What is the function of TTI bundling in LTE?
• Define “CQI reporting interval” in LTE.
• How is DRX on-duration controlled in LTE?
• Describe LTE’s approach to signal detection.
• What is the purpose of the PUCCH resource indicator?
• How does LTE calculate RSRP?
• Explain the LTE parameter “NPRACH”.
• Describe how the MCS is adjusted during HARQ.
• What is the LTE power control mechanism for PUSCH?
• How does LTE handle idle mode handovers?
• Explain DRX cycle offset in LTE.
• What role does LTE’s HARQ Type 1 play?
• Define LTE’s “Paging Time Window.”
• Explain the concept of LTE layer 2 aggregation.
• What is the UE’s behavior during paging DRX?
• Describe LTE’s approach to scheduling priority.
• How does LTE manage RACH preamble transmissions?
• Explain LTE’s measurement gap configuration.
• What is the function of RACH preamble format 4?
• Describe LTE’s transport block formation.
• Explain the purpose of resource allocation type 0.
• What is the role of PHICH in HARQ acknowledgments?
• Describe the concept of LTE carrier aggregation.
• How does LTE handle re-transmissions in RLC?
• What is meant by CQI feedback reporting?
• Explain the role of TDD subframes in LTE.
• What does the PUCCH format indicate?
• Define the role of HARQ in RRC reconfiguration.
• How does LTE handle non-GBR bearers?
• What is the purpose of LTE’s MIB error checking?
• Explain the importance of LTE’s TTI (Transmission Time Interval).
• How is LTE RSRQ calculated?
• Describe the PDSCH mapping process.
• Explain how LTE maintains continuity during handover.
• What is the primary function of the DRX inactivity timer?
• Define the LTE MAC’s role in data scheduling.
• Describe LTE’s “short DRX cycle” benefits.
• What is meant by LTE’s “frame structure type 2”?
• Explain LTE paging load balancing.
• How does LTE handle buffer status reporting?
• Describe LTE’s data aggregation in MAC.
• Explain the concept of HARQ Type 2.
• What does an RRC message contain?
• How does LTE determine RACH transmission priority?
• Define the significance of TTI bundling in voice.
• What is LTE’s approach to resource block allocation?
• How does LTE use CQI to optimize throughput?
• Explain DRX configuration for low-power UEs.
• How is data transmitted in the PUSCH channel?
• Describe the purpose of LTE cell barring.
• What is the role of RB (Resource Block) in scheduling?
• How does LTE implement paging groups?
• Describe the function of the Physical Uplink Control Channel.
• What is the impact of DRX on real-time services?
• Explain how LTE maintains QoS during handover.
• Describe LTE’s Broadcast Channel functionality.
• What is a PDSCH resource assignment?
• How is PHR reported in LTE CA scenarios?
• Explain how LTE adjusts power for control channels.
• What is the UE behavior when paging is unsuccessful?
• Define the function of LTE’s HARQ feedback timer.
• Explain how LTE uses subframes for control signaling.
• What is the purpose of LTE downlink carrier aggregation?
• Describe the LTE PRACH format 2.
• Explain how LTE ensures reliable HARQ feedback.
• How does LTE manage synchronous HARQ?
• Describe how LTE achieves UE positioning.
• What is the UE response when paging occurs?
• Define the concept of cyclic redundancy in HARQ.
• How does LTE support multiple UE DRX configurations?
• What is the function of LTE’s RRC reconfiguration?
• Describe the LTE measurement configuration for RSRQ.
• Explain LTE’s solution for idle mode interference.
• Define the purpose of LTE’s uplink grants.
• What is meant by the “resource block group” in LTE?
• How does LTE use broadcast information for cell search?
• Describe the role of the CFI in LTE.
• What is an Extended PHR MAC control element?
• Explain how LTE handles data transfer in PUSCH.
• What does “downlink assignment index” indicate?
• Define LTE’s function in control format detection.
• Describe LTE’s paging occasion offset.
• How does LTE handle collisions in PDCCH?
• Explain LTE’s MIMO function in downlink.
• Describe how LTE uses the random-access response.
• What is the importance of the subframe indicator?
• Explain LTE’s approach to QoS scheduling.
• How is LTE’s power headroom calculated?
• Describe how LTE uses cell broadcast information.
• What is a physical layer frame in LTE?
• Define the significance of carrier spacing.
• What is LTE’s approach to cell interference?
• How does LTE prioritize bearer types?
• Explain the UE measurement process for handover.
• Describe the function of the SIB1 message.
• What is the purpose of LTE’s CQI in adaptive scheduling?
• How is the LTE RSRP used in resource allocation?
• What does RACH stand for in LTE, and what is its purpose?
• When is RACH initiated by the UE?
• What are the main occasions for a UE to use RACH?
• Explain the difference between contention-based and contention-free RACH.
• How does RACH achieve uplink synchronization between UE and eNodeB?
• Describe the four main steps in the contention-based RACH procedure.
• What information does the UE obtain from SIB2 to perform RACH?
• Define “preamble” in the context of LTE RACH.
• How many preambles are available per cell, and how are they divided?
• Why are multiple preamble formats used in LTE?
• Describe the main purpose of a longer sequence (T_SEQ) in certain preamble formats.
• How does a longer cyclic prefix (T_CP) benefit RACH in fading environments?
• What is the purpose of the PRACH configuration index?
• How does the PRACH frequency offset impact RACH transmissions?
• Explain how the UE uses the PRACH configuration index to determine the subframe for RACH transmission.
• What determines the length of a PRACH preamble?
• How does the root sequence index help in generating PRACH preamble sequences?
• What is the role of the zero correlation zone configuration?
• Explain the use of the High-Speed flag in PRACH preamble generation.
• Describe the PRACH preamble generation process using cyclic shifts.
• How is the PRACH frequency domain mapped to resource blocks?
• What are the four main messages involved in the LTE Random Access Procedure?
• How does the UE decide on the power level for the first RACH request transmission?
• Describe the role of the parameter “preambleInitialReceivedTargetPower.”
• What is the purpose of the “powerRampingStep” parameter?
• Define RA-RNTI and explain how it is calculated.
• What is the significance of RA-RNTI in the RACH process?
• How does RA-RNTI vary with subframe number and frequency index?
• What information does the eNodeB transmit in the Random Access Response (RAR)?
• Explain how the Timing Advance value is used in the RACH process.
• What is TC-RNTI, and when is it assigned to the UE?
• Describe the purpose of the uplink resource grant in the RACH procedure.
• What is the backoff indicator, and when is it used?
• What does the UE do if it receives multiple RARs with the same preamble?
• Explain the role of contention resolution in the RACH process.
• How does the UE know that it has successfully completed the RACH procedure?
• What is the significance of the contention resolution identity?
• Describe the sequence of steps in the LTE Attach process.
• How does the RRC Connection Request message relate to the RACH procedure?
• What identity does the UE use in the RRC Connection Request message?
• Explain how the UE starts the T300 timer.
• What message follows the RRC Connection Request, and what does it include?
• How does the eNodeB assign a permanent C-RNTI to the UE?
• What are the three main security mechanisms in LTE?
• Explain the importance of the Authentication process in LTE.
• How is Integrity protection achieved in LTE?
• What role does Encryption play in LTE communication?
• What is the K key, and how is it used in LTE security?
• Explain how the Cipher key (CK) and Integrity key (IK) are derived.
• Describe the function of KASME in LTE security.
• What is the purpose of KNASint in LTE?
• How is the key KRRCint used in RRC traffic protection?
• Explain the role of the NAS encryption algorithm in protecting NAS traffic.
• What key is used to protect User Plane traffic in LTE?
• Describe the derivation process for KeNB.
• What are the benefits of a longer T_SEQ in preamble formats?
• How does LTE handle RACH in cells with fast-moving UEs?
• Why are specific cyclic shifts reserved in high-speed scenarios?
• How does SIB2 broadcast configuration parameters for RACH?
• Explain the function of the parameter “zeroCorrelationZoneConfig.”
• What is the role of Zadoff-Chu sequences in generating PRACH preambles?
• What are common causes of RACH failures?
• How does the UE handle RACH failure due to insufficient power?
• What happens if the eNodeB does not respond to the initial RACH request?
• Describe the role of the T300 timer in connection establishment.
• What is the eNodeB’s response if contention resolution fails?
• How is the PRACH signal structured in the frequency domain?
• What is the subcarrier spacing for PRACH in LTE?
• Compare the subcarrier spacing for PRACH with UL subframes.
• How does the PRACH format differ between FDD and TDD?
• What is the significance of using 6 PRBs in PRACH?
• Explain how a UE performs random access when multiple subframes are available.
• What techniques are used to optimize RACH in high-load scenarios?
• How does the PRACH configuration index influence network performance?
• Why does LTE implement power ramping for RACH transmissions?
• Describe how the eNodeB configures the RACH backoff mechanism.
• How can the zero correlation zone be adjusted for better RACH performance?
• What is the purpose of restricting cyclic shifts in larger cells?
• Explain how the high-speed flag modifies PRACH configuration.
• When is contention-free RACH preferred over contention-based RACH?
• How is contention-free RACH used in LTE handovers?
• What information is carried in the PRACH preamble during handover?
• Describe how a UE obtains a dedicated preamble for contention-free access.
• How does the eNodeB differentiate between UEs in contention-free RACH?
• What are the advantages of using contention-free RACH in handover scenarios?
• What is the role of NAS messages in the LTE Attach procedure?
• Explain the difference between NAS integrity and encryption protection.
• How does the RRC protocol handle connection re-establishment?
• What is the purpose of the NAS security mode command?
• How does the RRC layer secure communication after attach completion?
• How does the UE handle simultaneous RACH requests with the same preamble?
• Describe the behavior of the UE when two UEs select the same preamble.
• What is the purpose of contention resolution in the case of identical preambles?
• How does the eNodeB resolve RACH collisions?
• Explain the impact of RACH configuration on the cell search process.
• Describe the purpose of the Authentication Request in NAS security.
• How does the eNodeB verify the UE’s identity during attach?
• What is the difference between authentication and encryption in LTE?
• How is the RRC security mode established?
• Explain how NAS security keys are derived and used during the attach process.