Nokia试题

Senserio： UL Interference Troubleshooting

In wireless network,sometimes we find some uplink interference coming from either interference from BTS or external from uncertain source.(上行干扰 BTS内部或者外面不确定源)

1. pleace calculate Normal Value of PrxNoise. Prxnoise is the noise level in the BTS ,digital

receiver when there is no load,(thermal noise+noise figure).Thermal noise can be calculated by following formula.

Formula: Thermal noise: 10*log10(1000*kTB) where(热噪声) K:1.38E-23

T:temperature in Kelvin B:3.84E6

Assume T=300

Thermal noise: 10*log10(1000*kTB)=10*log10(1000*1.38E-23*300*3.84E6) 2. How impact to the system if interference exists?

3. What info element in DT tool can check UL interferecon level? What KPI counter you need to

check first before on-site visit? 4. After collecting those KPI info,find there is one area having UL interference with 7-？ Cells

suffering UL Interference What is your criteria to choose sites with highly potential interference source finging?

5. Now you are ready to find the UL interference what kind of tool and info need to prepare

before going for troubleshooting

6. When on-site visit ,what BTS unit you need to measure?(answer unit) measurement at BTS

unit we will need confirm the the interference in not from BTS or

Due to budget limitation there is only 50 she can capansion What KPI or count you propose to evaluate whether this site transmission expanseion cadidate

After Iub expansion,customer want to improve user experience in HSDPA by purchasing 15 code ,code multiplexing and 16QAM feature ,what parameters setting you need to change according to these features?

Because of R99 and HSDPA in share carries ,what is possible negative impact you expact

After you propose to customer with Dual carriers solution to setors the negative impact,HSDPA user is pushing to 2nd carrier these are two options diretedRRC for HSDPA layer and IFHO to 2nd carrier Please explain the advantage of DiretedRRC for HSDPA layer compared to IFHO to 2nd carrier

In order to verify the 14.4M HSDPA Throughput performance you may need to send DT team to verify ,What info can prove this site is having 14.4Mbps per site with 15code inDT log?

If you find the DL application throughput is only 2Mbps what in good RF coverage and quality you may ask RAN engineer to use E2K, tool to help What is the purpose in the E2K

When DT pass by a building entrance during the Drive test ,the call is drop due to UE camp on Indoor cell in idle mode in front of building entrance and call drop in door cell due to RF signaling fading quickly

Note: This indoor site has 3 sectors ,1st Cell serving B3-B1,2nd Cell serving 1F-3F and 3rd cell serving 4F-6F. All three sectors have same setting :PtxPrimaryCPICH=33dbm,MaxBitRateDLPSNRT=384bps,MinAllowedBitRateDL=64bps,InitiaBitRateDL=128kbps

a. Please find a solution for above prolem

b. Unfortunately,customer complains that there is high drop call when UE close to window

on 3F,youfind there is other RF signaling from outdoor Please find a solution for this problem

c. The other issue is that user working in 4F-6F suffering low DL Throughput even no DL

throughput during the office hour,especially from 10:00AM-13:00P, Below chart show this cell is suffering High code blocking Please propose a short term plan to solve this issue(Parameter Tuning)?and long term plan to solve the capacity issue.

Show daily KPI of Code Block Hourly KPI of Code Block 两张图

After commercial launch for 2 years ,user traffic keep growing lead to congestion in Iub in order to avoid to this service impact and improve user experience Now operator decide to expansion itansmiision capacity in iub with Hbbrid Back Haul Solution The Hybrid use 1*E1 for R99 RT and NRT service and the others using XDSL with 10M/0Mfor HSDPA service We expact user can get theroatical 14.4Mbps in DL if per site.

Cluster Tuning

Now you are in charage of one cluster tuning Before go for analysis you need to send DT team for drive testing according to the route agreed by customer

1. Now you are helping to setup DT tool with 3UE’s Scanner and GPS Please explain

function or purpose of UE Scanner and GPS during the drive test

2. After setup tool you need to setup script for each call pattern you may need to

config AMR short call AMR long call Packet call FTP Download 128M and scanner a. what is the major testing purpose for AMR short call? What singaling message

indicate call setup successful?

b. What is the major testing purpose for AMR Long call ?what signaling message

indicate call successful complete?Please also indicate the dutaill “Cause” of this message

c. For Packet call what setting need to config for Qos Negobalion What NAS

message will send this setting to SGSN and request IP Address d. For Scanner setting ,list at least two setting need to be configured

3.After DT log collection, you have to process the statistic result ,list at least two tools for port processding.

4.Now you have the result for scanner what potential problem from scanner result please list at least 4methodologies to improve this problem and prioritize these method from High to Low

Scanner Average RSCP of Best Server Average ECNO of Best Server ECNO above -10 sample percentile RSCP above -85 sample percentile Drive result -62.48 -13.5 75% 95% 5.After coverage analysis you may go futther call event analysis,you find there Is always a drop call near the corner when UE is moving from point 1 and make a right turn to point2 then straight forward point3(street corner) it was found the serving cell ECNO is drop sharply due to building shadowing before SHO attempt to next neighbor cell ,in order to prevent this call drop what could be possible solution to optimize parameter in neighbor level without impact other neighbor SHO behavior

Please choose the most suitable according above requirement

a. change addition window from 2.5db to 4db in cell 1wcel object b. change drop window from 3db to 5db in well 1 wcell object c. change adjaECNOffset from 0db to 2db in cell 1->cell2 adjs object

As we know no matter service call (AMR.NRT PS) or signaling message (Location update GPRS attach ) the first step is setup RRC connection between UE and RNC ,Below is the part of RRC connection setup message ,please help to complete it fill-out missing part1-4

Please list some example for DT KPI and network statistic KPI for acceptance before network claim cominercial insearth At least 3 for each and include res KPI target EXSHO successful rate>95%

1.WCDMA Chip rate is 3.84 Mcps, frequency band width is 5 MHz 2.Processing gain of PS384(DL) is 10log（3.84E6/384K） db(note:Gp(db)=W/R

3.Frame synchronization is achieved with the P-SCH channel,Slot synchronization is actue with the S-SCH channel

4.during random access ,the P-FACH channel is sent by the nodeB to tell the UE,that the NodeB is acquired the preamble transmission of the random access

5.regarding 16QAM modulation 4 data bits are modulation to one symbol 6 In E-DPCCH, 10 bit indicating whether the UE needs more resources or not

7.In WCDMA R99,the retransmission is Acknowledgment lodgment in layer is

terminated at RNC,In HSOPA, the retransmission is acknowledgment in layer is terminated at BTS,therefore it can save Iub bandwidth.

8.In HSDPA UE Category ,with 15 code and 16QAM modulation UE can get the theoretical 14.4,Mbps throughput

1.There are down link primary scrambling codes A 32 B64 C128 D512

2.Scrambling code is used to separate in uplink A.cells B.users C.channel D,service 3.CPICH is one kind of channel A.Physical B Logical C.Transport D.Synchronisa (同步) 4.With temperature rising,thermal noise desity

A.gets higher B.get lower C.keep constant D is selected to the type on NodeB 5.Which function following can not be used to improve the cell coverage A MHA B 6-sectors C Extended cell D.Add carrier 6.Which is UL channel among following transport channel? A.BCH B PCH C FACH D RACH

7.When UE send measurement report with event 4A to RNC,it means: A Report SHO measurement

B RLC buffer absolute payload exceeds define Threshold in UE（RLC缓存绝对值超出门限）

C Trigger one of five ISHO reason D Trigger one of five IFHO reason

8.The frequency of Power control command for WCDMA is A 1000HZ B 1500HZ C 500HZ D 2hz

9.Iur is the logical interface between

A BTS and RNC B MS and BTS C RNC and RNC D RNC and MSC 10.Following which channel is used for carrier user data in Ul for HSUPA A E-AGCH B E-DPCCH C E-DPDCH D E-HICH

11 In optimization,we use Mapinfo to display the RF coverage info in geographily What function in Mapinfo we can use to display the RSCP or ECNO with pre-define legend

A Thematic Map（专题地图） B Prism Map C Geocode

D Crystal Report

12 what parameter can increase the minimum power per RL Note: kind of try to reduce the PC operation window E CPICHtoRefRABoffset from 0 to -2db

The parameter defines the offset of the primary CPICH transmission power, and the maximum DL transmission power of the reference service channel in DL power allocation. The maximum

transmission power of the reference service is calculated (in dBm) by subtracting the value of the parameter from the transmission power of the primary CPICH.

F PCRangeDL form 20 to 15db

The parameter defines the downlink power control range in relation to the maximum allocated transmission power of the radio link. The minimum transmission power is achieved by

subtracting the value of the parameter from the maximum transmission power of the radio link. However, the minimum BTS output power of the code channel defines the absolute lower limit for the minimum transmission power.

G PRACHrequiredReceivedCI -25 to -15db

This UL required received C/I value is used by the UE to calculate the initial output power on PRACH according to the Open loop power control procedure. This parameter defines the value of the IE Constant value, which is part of System Information Block 5. The value of the parameter depends on the propagation channel. H PtxSCCPCH1 from 0 to 2db(功率控制参数)

13 when UE and measurement report with Event 4A to RNC it means

有关4a 4b事件PS 业务的时候,经常会在空口消息中发现Event 4a和4b事件发生。协议上这样说：Transpot Channel Traffic Volumn exceeds absolute threshold 引起的就是PS业务的流量高于/低于一定门限值啦。比如你开始设定的是下行128k，但你只是浏览网页，根本用不了那么多，所以就会出现4b。一般4b事件触发Physical Channel Reconfiguration后导致Cell Update，手机会下滑到FACH状态。3GPP也规定，如果你不用那么大容量的信道，就要下滑到FACH状态并重配信道。可以看看UE在连接模式下的4种状态之间的转移！！这也是打开了DCCC开关后发生的现象。这个是TVM算法中的4A,4B事件，RLC层通过检测的BUFFER内的数据，来判断4A,4B事件，当然也会有一定的迟滞。商用网中，当负荷不高的情况下，我们会快速启动4A（升速），慢速启动4B（降速），主要是考虑用户感受。

DCCC 算法和状态迁移算法涉及到业务量测量，需要处理 4A和 4B 的报告。

4A报告表示待处理的业务量达到了一定门限，并且持续了一段时间，需要考虑为该业务升速。

4B 报告表示待处理的业务量低于一定门限，并持续了一段时间，可以考虑为该业务降低速率，以节省无线资源。 为了避免两套算法同时生效，设计了两个开关，当 DCCC开关打开时，状态迁移就不生效。 (4A升/4B降)

A Report SHO measurement

B RLC buffer absolute payload exceeds define threshold in UE C Trigger one of five ISHO reason D Trigger one of five IFHO reason

14.Please choose right sequency for ISHO for AMR Call

A Initial Compressed Mode configuration B GSM BSIC identification C GSM RSSI measurement D ISHO triggering reason E RRC handover from UTRAN command DACBE 多选

1 .what is right description of multiple access technology is wideband CDMA(WCDMA) A All cells at same carrier frequency if single carrier deployment at initial phase（最初阶段） B Separates （隔离）physical channels of users and common channels defines physical channel bit rate

C channelization cod used to separates physical channels of users and common channels defines physical channel bit rate D each carrier is 200KHZ

2.what is correct description of “incremental redundancy” in HSDPA HARQ A Re-transmitted blocks are indentical to the original block

B an erroneous block is not discarded, but is combined with sunsequent re-transmisions C each retransmission contains different redundancy version form the first transmitted data

D more re-transmission amount due to less redundancy bit

3.please choose correct description about mechanical tilting

A The resulting gain reduction depends on acimuth direction

B the horizontal half-power bean width increases with greater downtilt angle

C the horizontal half-power beam width（水平半功率波瓣宽度） is independent of downtilt angle

D there is indentical gain reduction in all azimuth direction

4.when ue in idle mode system information 11 is used to broadcast neighbor list for ue doing cell reselection however there is the limitation of SIB11,which only can include 47 neighbors in one wcel ,now you have to review the neighbor list for ADJS ADJG ADJI is not implemented due to no 2nd carrier ,what is your recommend filted to prevent hit the 47 neighbors limitation and feaisble solution

A number of adjs >31 and number of adjg>31 B number of adjs >31 and number of adjg>20 C number of adjs >15 and number of adjg>44 D number of adjs >24 and number of adjg>20

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