LTE Physical layer Interview Questions and Answers

Q01. Define Frame Structure?
Q02. How many Sub-frame present in single Frame-Structure, and size of each Sub-Frame in Time-domain?
Q03. How many Time-Slot are present in Sub-Frame?
Q04. What is Cyclic Prefix (CP) in Frame-Structure?
Q05. What is Sampling rate in LTE? What is the Sampling rate of Normal CP and Extended CP?
Q06. How many OFDM symbols are available in 1 Time slot in Normal CP and Extended CP? In Frequency-domain or Time-domain? in Sub-Frame and Frame?
Q07. Difference between OFDMA and SC-FDMA? What is the reason that OFDMA using in down-link and SC-FDMA using in up-link direction?
Q08. Define Sub-Carrier? How many Sub-Carrier are present in Resource Block(RB)?
Q09. What is the Smallest unit of Sub-Carrier?
Q10. In extended CP. How many resource elements present in a Resource Block(RB)?
Q11. In Normal CP. How many resource elements(RE) present in a Resource Block(RB)?
Q12. Difference between RB and PRB? their length in Time-domain and Frequency-domain?
Q13. What is the reason that OFDMA are using in downlink and SC-FDMA in up-link?
Q14. Types of Physical Channel?
Q15. Describe Physical Control Channel and Shared Channel?
Q16. Describe Downlink Channel and Uplink Channel in Physical Control Channel?
Q17. Describe Downlink Channel and Uplink Channel in Physical Shared Channel?
Q18. Describe Primary Synchronization Signal(PSS) and Secondary Synchronization Signal(SSS)?
Q19. Define which Sequence eNB used to generate PSS and SSS?
Q20. What are the job of Reference Signal in LTE? How many ReferenceSignal are present in 1 Resource Block(RB)? How many types ofReference Signal are available in LTE and their Description?
Q21. Radio Channel Processing step?
Q22. Describe Master Information Block (MIB), System Frame Number (SFN) and PHICH?
Q23. Describe PBCH and it's position in Frame Structure and what Information Carried by PBCH?
Q24. Describe PCFICH, it's position in Frame Structure and Information Carried by PCFICH?
Q25. Describe PDCCH, it's position in Frame Structure and Information Carried by PDCCH?
Q26. Describe PDSCH, it's position in Frame Structure and Information Carried by PDSCH?
Q27. Define PUCCH, it's position in Frame Structure and Information Carried by PUCCH?
Q28. Define PUSCH, it's position in Frame Structure and Information Carried by PUSCH?
Q29. What Modulation Technique are using in all Physical-Channel?
Q30. What is REG?
Q31. What is CCE? How many CCE’s are required to carry PDCCH? Explain different configurations?
Q32. What is DCI? What is sent in DCI format 0?
Q33. In case of 4×4 MIMO, how many reference signals are there in an RB? How much %age they occupied by Ref signals in this case?
Q34. What is the valid Cyclic Redundancy Check(CRC) length in bits?
Q35. Describe briefly that where and how many padding “0” bits are inserted in code segmentation?
Q36. Which channel case Turbo coding is used? which channel case Bit Repetition Coding is used?
Q37. In case of Turbo Encoder, If block size is 80, what will be the number of output bits?
Q38. In case of Convolutional Encoder- If block size is 80, what will be the number of output bits?
Q39. Define Channel Quality Index(CQI)? Which is the Parameter value that belong to Excellent condition of UE's?
Q40. Define PMCH, it's position in Frame Structure and Information Carried by PMCH?
Q41. Define PRACH? What Information Carried by PRACH?
Q42. What is RNTI? What is the types of RNTI (with their default values, if any)?
Q43. What is C-RNTI? Difference between C-RNTI and T-C-RNTI?
Q44. How will you get the Physical Cell ID from eNB even without reading BCH?
Q45. Explain why mobile cannot be connected to LTE in more than 300 km/hour speed. What is the limit?
Q46. In the case of 4 antennas with 4x4 MIMO, how many maximum layers can be configured?
Q47. Define CFI, UCI, HI in LTE?
Q48. Describe in detail about Preamble in LTE and which Layer initiate Preamble and why?
Q49. How many different Preamble id, Preamble Format, Zero co-relation Zone, Root Sequence, Frequency Offset are present and how they all are play an important role to generate Preamble id?