Q03. WHAT IS THE CONDITIONS OF RE-ESTABLISHMENT?
Q04. WHAT IS THE RRC RE-ESTABLISHMENT TIME?
Q05. IF YOU SEND A WRONG CONFIGURATION THAN HOW WILL YOU KNOW IT’S A NETWORK ISSUE OR SOMETHING?
Q06. HOW DO YOU FIND NETWORK ISSUE?
Q07. WHAT IS NETWORK FORWARDING?
Q08. DEFINE LAB SETUP?
Q09. HOW WOULD YOU REPORT BUG TO THE DEVELOPMENT TEAM?
Q10. DEFINE HANDOVER REDIRECTION?
Q11. WHY HANDOVER REQUIRED?
Q12. WHAT IS THE I-RAT EVENT?
Q13. DEFINE C.A?
Q14. WHAT IS THE RELEASE VERSION YOU CURRENTLY WORKED ON?
Q15. WHY YOU WANT TO JOIN?
Q16. WHAT IS LTE EVENTS?
Q17. WHICH SYSTEM SIMULATOR YOU ARE CURRENTLY WORKING?
Q18. WHAT YOU DO ON ANITE-9000?
Q19. WHAT IS YOUR ROLE IN YOUR COMPANY?
Q20. DO YOU HAVE ANY QUESTION FOR ME?
Q21. X2AP, S1AP HANDOVER?
Q22. HOW RESOURCE BLOCK ALLOCATE TO UE
Q02. In which conditions ue have 2 ip addresses is it possible a ue can have 2 different ip or 2 same ip?
Q03. Define lab setup?
Q04. AT command for PDCP configurations and power on UE?
Q05. Replace 2 no’s values with each without create a new variable in python?
Q06. Define Handovers in LTE?
Q07. What are Cell re-selection procedures?
Q08. Difference between SRVCC and CSFB?
Q09. What is SDP protocol?
Q10. What is a magic cookie in IMS via message?
Q11. What is Standalone and Non-Standalone network architecture in 5G?
Q12. What is DRX?
Q13. Define a bug you have found yesterday?
Q14. How to report bug and what kind of tool you are using for debugging?
Q15. UE connects 2 pdn how many it have default bearer and dedicated bearer?
Q16. How many coding schemes are present in lte and their name with functionalities?
Q17. What is orthogonal coding scheme?
Q18. If your browsing an internet then ue required a dedicated bearer or default is enough define with details it’s possible or not and why?
Q19. What are the conditions of re-establishment and re-configurations in lte?
Q20. How many cells you can configure in SS?
Q21. How you analysis the logs?
Q22. How you capture UE logs?
Q23. Define SMS call flow architecture?
Q24. What are Attach failure cause?
Q2. Initial attach architecture?
Q3. Where GUTI allocates?
Q4. How MME know to send initial attach request particular S-Gw (out of 5-6 S-Gw present)?
Q5. How enb know to send initial attach request to particular MME (out of 5-6 MME present)?
Q6. RRC connection sent which channel?
Q7. What's IE present in create session request?
Q8. Types of handover in LTE?
Q9. About PCRF and its interface?
Q10. SIB information SIB1 to SIB8?
Q11. When S5 and S8 interface use?
Q12. Soft Handover and Hard Handover?
Q13. If UE has 16 Bearer than how much E-RAB will be established for a UE?
Q14. How many Bearers would be establishing between Single UE to Single PDN?
Q15. Can we use 2 Application via using 1 dedicated bearer or we have to require 2 bearers separately?
Q02. What is Power on procedure?
Q03. What is Msg1 and Msg2?
Q04. Explain Attach procedure?
Q05. What are Authentication IE's?
Q06. What are Security message IE's?
Q07. SRVCC call flow?
Q08. What is the difference between 2G, 3G and 4G?
Q09. Difference between CSFB and SRVCC?
Q10. While you working on RRC which Bug you have find out?
Q11. RRC Request IE's?
Q12. Events?
Q13. What is Resource?
Q14. Factorial Program in python?
Q15. Handover Type?
Q16. If DRX is disable does ue receive paging message?
Q17. Cell selection criteria?
Q18. Daily activity?
Q19. What is Rach?
Q20. Rlc all modes?
Q21. CPT in rlc?
Q22. Calling mode?
Q23. HARQ?
Q24. RRC re-establishment IE's?
Q25. Difference between SRB and DRB?
Q26. A3 and A4 which condition it will perform handover?
Q27. Nas dedicated message?
Q28. SRV Mapping?
Q29. CSFB call flow MO and MT?
Q30. DCI?
Q31. X2AP Handover?
Q32. I-RAT Handover?
Q33. Carrier Aggregation?
Q34. Paging & DRX?
Q35. Uplink and Downlink Speed Calculation?
Q36. Radio Link Failure?
Q37. RRC re-configuration?
Q38. CQI?
Q39. SMS flow?
Q3. What is your idea on handover and tau?
Q4. Which is the fastest handover?
Q5. Is there any possibility to change the gateway in HO?
Q6. UE having 3 bearers so in that one bearer is failing in handover than in situation what you will calling that handover success or failure?
Q7. in which message ue receive ip address?
Q8. How many eps bearer ue can have Actually?
Q9. What is Data bearers?
Q10. What is the maximum limit of E-RAB bearer?
Q11. How the pdn is getting connected using what basis and which parameters?
Q12. So who will be starting the dedicated bearer?
Q13. What are the role of HSS in the network?
Q14. Did you mean dedicated bearer is also try to create?
Q15. How PDN is selected see in the network there can be 10 pdn so ue 1 can connect to pdn2, ue 2 connect to pdn5. That can be mix and match it can connect any pdn so by using what parameter pdn is selected?
Q16. Why we require 4G?
Q17. Difference between 3G and 4G with technical answer?
Q18. Describe the LTE Architecture in details?
Q19. See in network there can be many S-GW than which S-GW will be selected?
Q20. Using the DNS what is the possibility select S-GW, means what it will check from DNS?
Q21. Where is the role of DNS server, role in the select in the S-GW?
Q22. HSS and DNS are same one?
Q23. How the latency will reduced in 4g by using what?
Q24. 3G user can access 4g network?
Q25. 4G user can access 3g network?
Q26. How call facility supported in lte?
Q27. So initial ue message what are the nas message possible in initial ue message?
Q28. Piggybacked message in initial ue message what is that?
Q29. Similar to attach request is their any other message in initial ue (service req) (tau req)?
Q30. Attach req contents?
Q31. Attach type available?
Q32. Esm message container in attach request?
Q33. In initial request ue that is the first message than how guti allocation is possible?
Q34. Why guti is being used?
Q35. What is the possibility of guti and why its coming as a new identity in picture?
Q36. What is the main ie in initial ue message without it there is no used for this message?
Q37. How network will differentiate between home and roaming subscriber?
Q38. What is that plmn id?
Q39. After finding that this ue is a roaming subscriber than what network will do?
Q40. Do you have any TTCN3 experience also?
Q41. How you debug attach reject log so you have got a log and the log you can see fetch and the getting attach reject what are the scenario of attach reject?
Q42. Have you heard for T-3412? And why is this is?
Q43. Why ue has to send TAU with timer?
Q44. Is it happened in idle and connected both?
Q45. When paging will happened you are getting the DL data than what are the scenario of paging?
Q46. Whenever you received a call than paging will happen with respect to ue? Either ue in idle or connected?
Q47. Tell me something you known in TTCN3?
Q48. What are your experience in python and main use of python?
Q49. How you can say this is flexible?
Q50. Weather it is a low level or high and medium level language?
Q51. Can you tell something about memory in python?
Q52. Stack and heap memory difference?
Q53. So how it will used in programming memory?
Q54. Can you tell about data types in python?
Q55. Mutable or immutable?
Q56. Day to day scenario what we will use mutable or immutable?
Q57. In python can you assign any negative number?
Q58. What are the different phases of testing you are worked on?
Q59. Have you work on preparing a test case?
Q60. So can you tell me the life cycle of defect? What kind of activity you will do till close that bug?
Q61. Do you have any question for me?
Q2. Tell us about handover procedure of X2?
Q3. What happen when target enb get down and serving enb send an handover request toward target enb?
Q4. IE used at the time of rrc reconfiguration initiate mobility of handover?
Q5. Soft handover and Hard handover?
Q6. What happens when after receiving the measurement report from ue serving enb want to established the connection but target enb suddenly down?
Q7. After getting the reconfiguration message on phy on ue than it passing through the MAC RLC PDCP layer till RRC so what they do?
Q8. How ue knows that this is a rrc reconfiguration message (crnti) ?
Q9. RLC modes and there difference?
Q10. Type of DCI and there used?
Q11. SR and BSR difference and who initiate it?
Q12. Type of BSR?
Q13. Type of mac ul and dl control element?
Q14. Difference between harq and arq?
Q15. Different type of harq?
Q16. How ue or enb know that what is the harq process number?
Q17. What is meant by logical channel id and group?
Q18. What is cqi and there range and who sent it?
Q19. Is each cqi values is directly connect to mcs? Or what is the scenario, range of mcs?
Q20. What is ca? Do you experience about log related in ca?
Q21. What is PHR?
Q22. What is timing advance and why it is used in mac dl ce?
Q23. Different type of SRBs and DRBs and when which SRB is used?
Q24. What message are sending on SRB0,1,2?
Q25. Rrc establishment message sent by ue on which srb?
Q26. Rrc reconfig message sent by network on which srb?
Q27. Tell me rach procedure?
Q28. How the preamble info will selecting by ue like which preamble we should use?
Q29. What mobility control info and each config dedicated in rrc reconfiguration ie?
Q31. At the time of receiving rrc connection setup how ue knows that its his rrc connection setup?
Q32. Where the ul resource grant for sending rrc connection setup complete?
Q33. If we received sib and rrc setup at same time than how ue recognize which time it decode rrc message and sib?
Q34. Which channel used for sending sr and bsr?
Q35. How much process used in fdd?
Q36. What is the message send on srb2?
Q37. What is criteria used to follow for crate srb2?
Q38. What is meant by authentication req used in attach procedure?
Q39. Did security is enabled before sending authentication req?
Q40. What is the first message on srb2 between ue and enb that ue send?
Q41. What is the requirement of security enabled 2 times in attach procedure?
Q42. When mme send security mode command and what is the info present in it?
Q43. So in the security mode command there is direct transfer of key to ue mme or something different procedure?
Q44. Failure cases of rrc reconfiguration?
Q45. After receiving rrc connection setup than ue need to send rrc connection setup complete message so need ul resource where that resource comes from?
Q46. After receiving rrc reconfiguration message from PHY to MAC and MAC to RLC than what is the first work that done by RLC and using what mode of operation?
Q47. Security in attach procedure come to deal by which layer?
Q48. Can you tell me what is pics and pixit in TTCN3?
Q49. What is use and how to use TTCN3 as for scripting?
Q50. What is used of python scripting?
Q51. Difference between set, list and tuple in python?
Q52. How to write dictionary program?
Q53. How to check the message if rrc reconfiguration message is miss than how you know that what is bug because you can’t even show the rrc message than how you find it?
Q54. What you used in python scripting if rrc configuration message bug found?
Q1. What is MIMO and what are the functionalities of MIMO?
- (MIMO) stands for Multiple Input Multiple Output.
- The functionalities of MIMO it have multiple antenna at the transmitter side and multiple antenna also have at the receiver side.
Q2. What is diversity and why it use in MIMO?
- Diversity is using to improve the reliability of the system.
- In diversity sender sends the data at different propagation (different paths).
- In MIMO we need the reliability or high speed data transmission so that we use two technique here 1. Spatial Diversity 2. Spatial Multiplexing.
Q3. What is Spatial Diversity?
- Spatial diversity is one of the fundamental benefits of MIMO technology.
- In short, diversity aims to improve the reliability of the system by sending same data over different propagation, or spatial, paths.
Q4. What is Spatial Multiplexing in MIMO?
- Spatial Multiplexing (SM, SMX) also known as Space Division Multiplexing (SDM) used to transmit data into independent channels separated by space.
- It’s like a pipeline through which data is flowing between the base station and the phone on a mobile network.
- Imagine a situation with one antenna on the base station and one on the phone that allows so much data to flow.
- Now, by installing more antennas on base station side with proper spatial separation, multiple virtual pipelines can be created in the space between phone and the base station.
- This creates multiple paths for more data to travel between the base station and mobile.
Q5. What are the advantages of MIMO?
- In MIMO UE experiencing good coverage (with high signal to noise ratios) can take advantage of the spatial multiplexing gain and can receive multiple parallel streams of data.
- Transmit and receive antenna have maximum number of parallel streams For example, 2x2 MIMO, 4x2 MIMO and 2x4 MIMO arc all capable of transferring a maximum of 2 parallel streams of data.
- UE in poor coverage (with a low signal to noise ratios) can take advantage of the diversity gain to help improve their signal to noise ratio.
- The magnitude of the diversity gain is dependent upon the number of receive antenna and the level of correlation between each of the propagation paths, i.e. the gain is maximised for a large number of receive antenna and uncorrelated propagation paths.
- This dependency upon channel conditions means that MIMO is used to transfer multiple parallel streams of data in good coverage conditions to maximise throughput, and is used to transfer a single stream of data in poor coverage conditions to maximise the diversity gain.
Q6. What are the disadvantages of MIMO?
- The drawbacks of MIMO are its increased implementation complexity and increased hardware requirement.
- MIMO requires additional processing at both the transmitter and receiver.
- It also requires additional signalling in terms of feedback from the receiver and resource allocation infonnation from the transmitter.
- MIMO requires additional power amplifiers at the transmitter side and additional receiving paths
- at the receiver side.
- lt also requires additional antenna elements at both the transmitter and receiver.
Q7. What is open loop? Why it use in MIMO?
- Open loop MIMO sender requires feedback from the receiver in terms of Rank Indication (RI) and Channel Quality Indicator (CQI).
- It’s called 'open loop' because of sender does not requiring feedback from transmitter in terms of a Precoding Matrix Indicator (PMI).
- Open loop MIMO can be beneficial for high mobility scenarios which would cause a reported PMI to become invalid after only a short period of time
Q8. What is Close Loop in MIMO?
- In Closed loop MIMO sender require feedback from the receiver in terms of RI, CQI and PMI.
- The receiver selects a PMI to help improve the properties of the composite channel coefficient matrix.
- Closed loop MIMO allows senders to transmits with increased informations.
- But it also increased the signalling overhead.
Q9. What is diversity gain in MIMO?
- Diversity gain reduces the impact of fading when the fades on each propagation path are uncorrelated, i.e. one path may experience a fade while another path may not experience a fade.
- The receiver takes advantage of the paths which are not experiencing fades.
Q10. what is array gain in MIMO?
- Array gain is achieved from the beamforming effect which is generated when transmitting from multiple antenna elements.
- Beamforming directs the transmitted signal towards the UE and improves the received signal to noise ratio.
Q11. What is spatial multiplexing gain MIMO?
- Spatial multiplexing gain increases throughput by transferring multiple streams of data in parallel using the same set of time and frequency domain resources.
- Uncorrelated transmission paths allow the receiver to differentiate between the data streams.
Q12. According to 3GPP release 15 is mimo support in uplink direction if yes the what’s are combination support of mimo have?
- The 3GPP release 15 version of the specifications for New Radio (NR) supports MIMO in both the uplink and downlink directions.
- The uplink supports 2x2 MIMO and 4x4 MIMO, whereas the downlink supports 2x2 MIMO. 4x4 MIMO and 8x8 MIMO.
- The release 15 version of the specifications also supports Multi-User MfMO in both the uplink and downlink directions.
Q13. What is Single-User MIMO?
- Single User MIMO allocates a different subset of PRB to each UE, i.e. the UE are separated in the frequency domain.
- The UE which are scheduled during a specific time slot do not need to be spatially separated and a relatively high MCS can be allocated, because the transmissions to each UE do not interfere with each other.
Q14. What is Multi-User MIMO?
- Multi-User MIMO takes advantage of beamforming to allocate the same set of time and frequency domain resources to multiple UE.
- These UE are separated in the spatial domain so they are able to re-use Physical Resource Blocks (PRB) without generating significant levels of interference towards each other.
Q15. What are the advantage of MU-MIMO?
- Increased Network Capacity – Network Capacity is defined as the total data volume that can be served to a user and the maximum number of users that can be served with certain level of expected service.
- Improved Coverage – With massive MIMO, users enjoy a more uniform experience across the network, even at the cell’s edge, so users can expect high data rate service almost everywhere.
- User experience – Ultimately, the above two benefits result in a better overall user experience users can transfer large data files or download movies, or use data-hungry apps on the go,
Q.1. What are the KPIs for testing the performance and quality of LTE networks?
Ans. Validating the performance and quality of an LTE network requires a high rate and varied mix of data traffic to judge the end-user experience. Traffic mix can be based on the type of subscribers, applications/services used, usage, etc. Some of the key KPIs which need to be validated are:- Latency and packet loss
- Jitter
- Throughput
- Perceptual video and voice quality
Q.2. What are the challenges in testing IPv6 in an LTE network?
Ans. Although IPv6 is mandated in LTE, as of now, most of the existing networks and their components use IPv4. As a result, we have nodes with support for both IPv4 and IPv6 stacks in the network. The integration testing of IPv4/IPv6 poses a big challenge because all network services will need to be tested for interoperability without any issues between IPv4 and IPv6. Added to this, some tunneling schemes from IPv6 to IPv4 are another area of focus.Q.3. What are the key attributes to focus on during testing, to minimize the issues with LTE EPC nodes after deployment?
Ans. Few of the key attributes to focus on for better solution reliability are:The LTE EPC node should be validated with an optimized set of invalid scenarios. Prior experience in interop and field testing is a definite help for identifying such scenarios.
While testing for the scalability and benchmarking, next to real-time scenarios should be simulated, such as a different mix of traffic, simultaneous calls, new calls per second, etc).
Inter-RAT handover or inter-working with non-3GPP must be tested based on the existing coverage in the deployment area Redundancy and resiliency should be given more focus during testing from a deployment perspective.
Q.4. There are diameter based interfaces in earlier technologies. How is testing for those different from LTE EPC testing?
Ans. There are around 12-14 diameter based interfaces in LTE. There are many new interfaces like SWx, STa, and SWa that have been introduced to support non-3GPP interworking. At the same time, there are certain interfaces like Gx, Rx, and Sh which also exist in IMS for interfacing with the PCRF. But in the LTE context, there is a multitude of additional AVPs that require the test tools to be upgraded and complicate testing. The test scenarios are quite different in terms of message flow, handling, and parameter validation.Q.5. Do you recommend that conformance testing as per the specs by GCF/MSF is enough for an LTE node?
Ans. No, it is not enough. Conforming as per these specifications is necessary but not sufficient. It is advisable to conform to these specs as they are standardized and different stakeholders expect nodes to comply with these. But at the same time, based on our experience, the node should also be tested against many field-like complex scenarios, optimized negative scenarios, and interop testing scenarios.Q.6. What are the challenges in identifying the right traffic mix for load testing?
Ans. The traffic mix for LTE testing needs to consider different signaling events as well as data formats.Q.7. Can you give some examples of applications that would use dedicated bearers? Do these applications typically use network-initiated dedicated bearers or user-initiated?
Ans. Some examples of using dedicated bearers can be found in voice and video traffic. Applications like IPTV and video on demand, which require guaranteed bandwidth, may also require dedicated bearers. The dedicated bearers can be user-initiated or network-initiated. Mostly for voice and video applications the network would initiate dedicated bearers based on the SDP exchanged for the media for IMS calls. For applications like IPTV and video on demand, it could be either UE or network-initiated.Q.8. Can you share some of the important metrics collected for a high available EPC solution in carrier-grade networks?
Ans. The important metrics for carrier-grade EPC solutions validate the level of reliability and switchover time. Switchover could happen for both the control and the data plane. These important metrics are:- Switchover time for control plane
- Switchover time for data plane
- Amount of memory for buffered packets during switchover
- Transmission time for buffered packets
- Level of reliability
- Check all levels of redundancy for all resources, interfaces, and software solutions
- Signaling and data throughput after switchover
Q.9. Is there a way to monitor the UE messages from a simulated eNodeB?
Ans. Yes. Although the UE messages are encrypted, with a simulated eNodeB it is possible to collect the UE keys from the eNodeB simulator and UE exchanges. Alternatively one can use pre-shared information. The eNodeB simulator can also decipher the NAS messages exchanged between the UE and the EPC.Q.10. How is the voice quality measured in EPC testing and what aspects are covered as part of voice testing through EPC?
Ans. Voice quality is measured using multiple voice test tools to test the following:- Jitter
- Latency
- Voice quality
- Echo cancellation
- Comfort noise generation
- Voice break at handovers
Q.11. What are the essential scenarios which must be tested for an MME?
Ans. Following are the necessary scenarios which need to be tested for an MME:- Default bearer creation/deletion/modification
- Dedicated bearer creation/deletion/modification
- Network initiated triggers (default/dedicated bearers)
- Handover (S1, X2)
- TA updates
- Release/Idle mode
- Paging
- ISR
Q.12. What is a major challenge in testing IoT for voice scenarios like CS fall back?
Ans. For voice testing, all the different scenarios like CS fallback, IMS calls, SRVCC, etc. have to be tested. The different voice application nodes like the IMS network, CS network of 3G network, SRVCC handling IMS application server, and SCP nodes have to be simulated such that they can receive and initiate triggers.The nodes need to be tested for different user capacities and different kinds of voice applications, like emergency calls, voice and video calls, multiband audio; and require multimedia application support in the simulators. This poses a major challenge.
Q.13. How it is ensured that voice and data go on simultaneously; is it possible on CS fall back?
Ans. Voice and data can go on simultaneously in CS fallback, depending on the network and UE capability. If the PS session is going on in LTE and voice is transferred to 3G, then the UE needs to support two kinds of radio at the same time. This may or may not be possible depending on the UE’s capability. Even in the case where both PS and CS are handed over to 3G, depending on the UE’s and the network’s capability, either the PS session may be suspended when the CS session is ongoing or both PS and CS sessions may go on simultaneously.Q.14. What are the best commercially available test tools for EPC core interoperability, inter-RAT, or non-3GPP testing?
Ans. Normally for interop, customers prefer to test with a real node from another vendor, rather than using commercially available test tools.Altran has frameworks for different LTE EPC core elements (i.e. MME, SGW, PGW, HSS, and PCRF) and eNodeB. We have used these for interop for some of our customers.
Q.15. Are there any end-end network monitoring solutions you would recommend? Which vendors?
Ans. From the monitoring or protocol analyzer perspective many tools are there which focus mainly on the access network side. For example Anritsu, R&S, Tektronix, and Aeroflex.From an end-to-end perspective, the few vendors that can be considered for network monitoring solutions are JDSU and Tektronix. Often, Wireshark or other tools used for testing can fulfill these requirements.
Q26. What is AMF? What is the essential function of AMF in 5G NR?
Q27. What is R(AN)? What is the essential function of R(AN) in 5G NR?
Q28. What is SMF? What is the essential function of SMF in 5G NR?
Q29. What is UPF? What is the essential function of UPF in 5G NR?
Q30. What is PCF? What is the essential function of PCF in 5G NR?
Q31. What is AF? What is the essential function of AF in 5G NR?
Q32. What is UDM? What is the essential function of UDM in 5G NR?
Q33. What is AUSF? What is the essential function of AUSF in 5G NR?
Q34. What is NEF? What is the essential function of NEF in 5G NR?
Q35. What is NRF? What is the essential function of NRF in 5G NR?
Q36. What is Network Slicing? What is the essential function of NSSF in 5G NR?
Q37. What is uRLLC? Why it’s use in 5G NR?
Q38. What is mMTC? Why it’s use in 5G NR?
Q39. What is eMBB? Why it’s use in 5G NR?
Q40. Bandwidth range use in NR?
Q41. What is MCG? What kind of functionality it play in 5G NR?
Q42. What is SCG? And what kind of funtionality it play in 5G NR?
Q43. What is Split Bearer in 5G NR? How’s it works?
Q44. Explain the data call flow when UE use MCG, SCG and Split Bearer in 5G NR?
Q45. What is Mn and Sn in 5G NR?
Q01. What is 5G NR? Why it’s need if we have 4G?
Q02. What are the limitations in 4G?
Q03. Explain 5G NR High Level Architecture?
Q04. Explain 5G NR Low Level Architecture?
Q05. What is Dual Connectivity?
Q06. What is MRDC?
Q07. What is ENDC?
Q08. What is NRDC?
Q09. Explain the Interfaces uses in 5G NR Architecture?
Q10. What is gNB? And what’s the use of gNB in 5G NR?
Q11. What is en-gNB? And How’s it different from gNB?
Q12. What is ng-eNB? And How’s it different from en-gnb?
Q13. What is EPC and 5G NRC?
Q14. What is NSA and SA? Name of the Deployment options available in NSA or SA as per 3gpp defined?
Q15. Explain frequency range define in 5G NR?
Q16. What is mmWave? Why it doesn’t it travels far from origin?
Q17. What’s are the Deployment option’s of RAN’s implementation availble in 5G NR.
Q18. What is CU, DU use in 5G NR?
Q19. Name of Interface use between CU and DU?
Q20. What is CU-CP and CU-UP?
Q21. Name of Interface use in CU-CP and CU-UP?
Q22. What do you mean by Class 1 and Class 2 messages?
Q23. Please tell me the Class 1 and Class 2 messages that’s are use in F1AP protocol?
Q24. Explain the protocol structure of 5G NR?
Q25. Please tell me the name of protocol use between UE and R(AN) in 5G NR?
ANR (Automatic Neighbour Relation)
TAU(Tracking Area Update)
First the question is How UE get to know that TAC is changed? So our answer is this information is present in a SIB1.
Now second question is when TAU report has to send?
Actually we have something called TAI list which is already has provided by MME to UE at the time of registration. For more information Refer TAI.
Below
I have attached the flow of TAU
procedure:
Note 1: It is triggered in both in IDLE and Connected mode, but Suppose
UE in connected mode and try to to move to new location, In this UE known to
the network and easily handed over to new cell but if UE found that its TAC isn’t
part of TAI list now than it will triggered TAU procedure to the MME.
Note 2: It doesn’t means UE always be in Connected mode but it can be
come again in IDLE mode.Than Suppose if N/W want to send some information to
the UE than in this case MME need to know the exact location of UE because
might be UE was is moving state in IDLE and doing its cell selection and reselection
than here also only extreme procedure which we have is TAU procedure. But as in
the above flow diagram we have seen that TAU is piggybacked on rrcconnectionsetupcomplete msg so its a connected mode msg so how this stuff
work. So The perfect answer is UE can begin the TAU procedure in IDLE mode but UE
must be in RRC Connected mode to actually complete the procedure.
5G PUCCH and 5G PUSCH
Channel coding for uplink control information (UCI)
UCI size including
CRC, if present
|
Channel code
|
1
|
Repetition code
|
2
|
Simplex code
|
3-11
|
Reed Muller code
|
>11
|
Polar code
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- For HARQ-ACK feedback of PDSCH with corresponding DCI, PUCCH resource set(s) containing one or more PUCCH resources are configured.
- One PUCCH resource is determined based on the UCI payload size and the PUCCH resource indicator field in the DL assignment. For HARQ-ACK feedback of PDSCH without corresponding DCI, SR, and CSI report, a PUCCH resource is configured for each.
- When multiple PUCCHs are overlapped fully or partially in time, the UCIs are multiplexed in a PUCCH.
- When a PUCCH is overlapped with a PUSCH fully or partially in time, the UCI is multiplexed (i.e. piggybacked) on the PUSCH.
- Each PUCCH resource is configured with a PUCCH format. Various PUCCH formats are specified as in Figure.
- Each PUCCH format supports either durations of 1 to 2 symbols, or durations of 4 to 14 symbols.
- PUCCH formats 0/2 are called as short-PUCCH, which can deliver UCI by 1 or 2 symbols. PUCCH formats 0/2 are beneficial to reduce latency.
- PUCCH formats 1/3/4 are called as long-PUCCH, which can deliver UCI with any of 4 to 14 symbols. PUCCH formats 1/3/4 are adopted to improve coverage.
- The frequency/time-domain resources for PUCCH transmissions in NR are flexibly configurable.
- In PUCCH format 0/1/4, multiple PUCCH resources can be CDMed on the same time/frequency resource.
- A short-PUCCH can be TDMed with a long-PUCCH or a short PUCCH within a slot.
NR PUCCH formats
5G PDCCH and 5G PDSCH
NR DCI formats
DCI format
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RNTI
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Notes
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DCI format 0_0
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RA-RNTI, TC-RNTI, C-RNTI, CS-RNTI
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Monitored on CSS or USS
Scheduling PUSCH
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DCI format 0_1
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C-RNTI, CS-RNTI
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Monitored in USS
Scheduling PUSCH
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DCI format 1_0
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SI-RNTI, RA-RNTI,
P-RNTI, C-RNTI, CS-RNTI
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Monitored in CSS or USS
Scheduling PDSCH
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DCI format 1_1
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C-RNTI, CS-RNTI
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Monitored in USS
Scheduling PDSCH
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DCI format 2_0
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SFI-RNTI
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Monitored in CSS
Indicating slot format for slot(s)
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DCI format 2_1
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INT-RNTI
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Monitored in CSS
Indicating pre-emption of DL resource
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DCI format 2_2
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TPC-PUSCH-RNTI, TPC-PUCCH-RNTI
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Monitored in CSS
Group-TPC command for PUSCH/PUCCH
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DCI format 2_3
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TPC-SRS-RNTI
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Monitored in CSS
Group-command for SRS
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