LTE knowledge test

**auto_art** · 2017-03-28, 06:33 AM

2017 D&S Technical Contest （RF）

Part I. True or False (one point for each question and 20 points in total)

For VoLTE service , voice code rate is selected by eNodeB.----- ( )
In order to reduce the packet loss, use AM mode for QCI1 in RLC layer.-- ( )
If the ANR is OFF, and the PCI of neighbor cell A and B are the same. When UE handover out from source site to cell A, the handover will succeed.---- ( )
When eNodeB received E-RAB RELEASE COMMAND from MME, if the release cause is “UE Not Available for PS Service”, it will be considered as MME call drop. ----( )
To have successful CSFB, the inter-RAT neighbor cell relation (Ncell) must be configured ----- ( )
Random access can be divided into two types: contention-based random access and Contention-free random access.-------- ( )
T300 timer starts when UE radio sent out message of RRC Connect Req.-----( )
If change the UeInactiveTimer from 10000 to 5000, the call drop times will increase. -----( )
The counter L.E-RAB.AbnormRel is equal to the sum of L.E-RAB.Abnormal.Radio, L.E-RAB.Abnormal.HOFailure, L.E-RAB.Abnormal.TNL and L.E-RAB.Abnormal.Cong. -------- ( )
If UE re-established success to the source site, in the source site it will consider as handover-out success. ----- ( )
The eNodeB sets up an X2 interface in two modes: X2 over S1 and X2 over U2000, as specified by the GlobalProcSwitch.X2SonLinkSetupType parameter.. -----( )
The PCI conflict is classified into PCI collision and PCI confusion.-----( )
To enable the coverage triggered blind HO, it is not necessary to open the "BlindHoSwitch". ---- ( )
The UTRAN is layered into a Radio Network Layer and a Transport Network Layer. -----( )
In UMTS, channelization code is used to distinguish different UE in uplink and different cell in downlink. -----( )
Each NB-IOT frame consists of 10 subframes, and each super frame consists of 1024 frames.----( )
After RNC is upgraded to a new Rxx version, RNC's statistic period is 60 mins if measurement task file is not sent to RNC from U2000.---- ( )
In UMTS, UE can be paging accurately under one cell when it stays in idle mode. -----( )
For HSUPA, RNC will try to setup RL in target cell after receiving 1A event. If RL setup failure happened in target cell because of HSUPA number limitation, RNC will do E2D then try to setup RL again.. ---- ( )
For CS+PS combined service scene at UMTS, if PS service occur call drop, CS service may not occur call drop synchronously ----( )

Part II. Single choice questions (2 scores for each question and 30 scores in total)

At Lampsite, how many pRRUs can be connected with one RHUB.? ( )

8
16
24
32

Which one is not the enhance feature for volte? （）

TTIB
ROHC
SPS
smart pre-allocation

When will eNodeB ask for ECGI from UE?（）
1. eNodeB receives a measurement report that PCI is not configured in NRT.
2. eNodeB receives a measurement report that PCI is not configured both in NRT and NCL.
3. eNodeB receives a measurement report that PCI is configured NRT. T300
4. eNodeB receives a measurement report that PCI is configured both in NRT and NCL.
At LTE, the correct order of downlink packet transmitting is. ( )

MAC-PDCP-RLC
MAC-RLC-PDCP
PDCP-RLC-MAC
RLC-MAC-PDCP VRRP

What is the maximum preamble ID number in normal?（）
1. 28
2. 32
3. 56
4. 64
Which following events triggers for intra-frequency during coverage-based handover? ( )
A. A1
B. A2
C. A3
D. A4
The coverage information can be found in which event of eNodeB log. ( )

A. L2_CHR_USER_DRB_INFO
B. L2_CHR_USER_DEDI_PREAMBLE_INFO
C. L3ChrRecord
D. PublicInfo

The interference of intra-freq neighbor cell would affect which factor of DL throughput？( )
1. RB Number
2. DL MCS
3. RSRP
4. DL Grant
What's the eNodeB's next step when it receives HANDOVER PREPARATION FAILURE with cause Unknown MME Code from target eNodeB during X2 handover procedure? ( )
1. S1 handover will be triggered
2. eNodeB will choose another cell to handover
3. Handover will be punlished and eNodeB will not handover to the target cell
4. UE will be released in the source cell.
When eNodeB receive S1 Setup failure message from MME, how long will eNodeB wait until it sends the next S1 Setup Request message ( ) ?
1. When time to wait IE is not included in S1 SETUP FAILURE message, it's 20S
2. When time to wait IE is not included in S1 SETUP FAILURE message, it's a random value between the parameter S1ReestMinTimer and S1ReestMaxTimer
3. When time to wait IE is not included in S1 SETUP FAILURE message, it's 60S
4. When time to wait IE is not included in S1 SETUP FAILURE message, eNodeB will not resend S1 Setup request message.
What frequency can be the Third Order Intermodulation product of 1800MHz and 2600MHz. ( )
1. 800MHz
2. 1000MHz
3. 1400MHz
4. 2800MHz
About power control of HSUPA, the correct answer is ( )
1. Outer loop power control uses target number of retransmission to calculate SirTarget.
2. Outer loop power control uses Bler to calculate SirTarget.
3. SirTarget is calculated by NodeB, which can improve the QoS of traffic.
4. When there are two traffics (HSUPA + R99) for a UE, SirTarget will be calculated for HSUPA traffic and R99 traffic respectively for inner loop power control.
Which of the following cases is not caused directly by SCCP low successful rate of IUPS interface? ( )
1. RRC attempt number increase
2. The IUPS flow decrease
3. The number of PS user online decrease
4. The success rate of PS RAB establishment decrease
NB-IOT is a cellular technology , which of the following benefits of NB-IOT is not correct? ( )
1. Wider coverage due to 20dB coverage gain and high power spectral density.
2. Low power consumption results 10 years battery life of terminal
3. RF hardware reuse from GSM, UMTS or LTE.
4. Massive connections by supporting 10K connections per cell.
Regarding the WTTx uplink data compress feature, which of the following description is incorrect ( )
1. The payload at the second package is not compressed.
2. Uplink data compress feature is not applicable for QCI 1 bearers or bearers of extended QCIs for push to talk (PTT) services.
3. When channel quality of the air interface and the PRB usage remain unchanged, enabling this function can increase the uplink transmission rate at the application layer.
4. Enabling this function reduces the uplink cell congestion duration, the number of times congestion occurs, and the ping delay when no congestion occurs.

Part III. Multiple choice questions (3 scores for each question and 30 scores in total)

Which of the followings are downlink physical channels for NB-IoT?（）

NPBCH
NPDCCH
NPPICH
PHDSCH

Which external event will influence MOS of VoLTE？（）

Handover
RRC Re-establish
Attach
eRAB abnormal release

Which cause is "the cell power exceeds the RRU capability" when activating a cell, which of the followings are the possible reasons?（）
1. Cell power configuration error
2. Lock the RRU max power
3. Use the old cabinet
4. The RRU power supply is exhaust.
When UE test under LTE cell, the DL rate is very low, which factor should be considered（）
1. DL PRB
2. DL PDCCH Grant
3. DL MCS
4. RANK2 Ratio
Which event combinations are used to trigger the coverage-based L2U PS HO.（）

A2+B1
A2+B2
A1+B1
A1+B2

Which of the following actions can be used when code LDR happened? ( ）

Load-based Inter-Frequency Handover
BE Rate Reduction
U2L Handover in the CS Domain
U2L Handover in the PS Domain
Code Reshuffling

Which of the following statements are correct for VoLTE? ( ）
1. If a UE is in the TTI bundling state, the eNodeB instructs the UE to enter DRX mode only when the UE needs to perform ANR measurement.
2. It is recommended that VoLTE Coverage Enhancement Based on Extended Delay Budget be enabled with TTI Bundling
3. The uplink IBLER of voice users cannot converge on the target value when RLC segmentation enhancement takes effect.
4. The VoLTE User Prior Access feature requires the DRX feature.

Which kinds of types of PRB usage may trigger MLB? ( )
A. Uplink GBR PRB usage
B. Downlink GBR PRB usage
C. Uplink total PRB usage (uplink GBR + non-GBR)
D. Downlink total PRB usage (downlink GBR + non-GBR)
Which parameter will impact HO success rate？（）

A. CellIndividualOffset
B. IntraFreqHoA3TimeToTrig
C. CellSpecificOffset
D. CellRadius

Which of the followings are used for the VoLTE QOS evaluation? ( )
1. MOS
2. PESQ
3. VQM
4. EVQM

Part IV. Short Answer Questions.

When the user makes a VOLTE call, there will be 3 QCI setup, please describe the use of these 3 QCI. (3scores)

Please refer to the following signalling flow chart for termination call setup procedure. Fill in the blank with the names of signalling message accordingly. (7scores)

Please list 4 different causes of RRC setup failure due to No reply? (4 scores)

At heavy traffic scenario, if the RRC SR is very poor at one cluster which includes hundreds of LTE cells, please list at least 4 solutions (including causes analysis and suggestions) to improve the RRC SR.(6 scores)