gsm case

GSM RNPampRNO Cases

GSM RNPampRNO Cases Table of Contents

Table of Contents

Chapter 1 Assignment Problem 1 11 Title Can not make a call even there is high Rx level on mobile phone 1

111 Phenomenon Description 1 112 Cause Analysis 1 113 Handling Process 1 114 Suggestions and Summary 1

Chapter 2 Call Drop Problem 2 21 Title Interference causes Call Drop 2

211 Phenomenon Description 2 212 Alarm Information 2 213 Cause Analysis 2 214 Handling Process 2 215 Suggestions and Summary 2

22 Title Call Drop Problem Due to A-interface Congestion 2 221 Phenomenon Description 2 222 Alarm Information 3 223 Cause Analysis 3 224 Handling Process 3 225 Suggestions and Summary 3

23 Title Incorrect frequency led to a cell with abnormal traffic statistics 4 231 Phenomenon Description 4 232 Alarm Information 4 233 Cause Analysis 4 234 Handling Process 4

24 Title External interference leads to drop call 4 241 Phenomenon Description 4 242 Alarm Information 4 243 Cause Analysis 4 244 Handling Process 5 245 Suggestions and Summary 5

Chapter 3 Congestion Problem 6 31 Title High TCH congestion rate caused by reverse connection between antenna and feeder cable 6

311 Phenomenon Description 6 312 Alarm Information 6 313 Cause Analysis 6 314 Handling Process 6

32 Title TCH seizure failure for the difference of BCC and TSC 7 321 Phenomenon Description 7 322 Alarm Information 7 323 Cause Analysis 7 324 Handling Process 7

33 TitleTarget Cell Blocking Cause Outgoing Handover Failure for a New Site On-air Commission Test 7


Chapter 4 Handover 9 41 Title Co-BCCH and Co-BSIC caused wrong attempted incoming inter cell handover 9

Confidential Information of Huawei No Spreading without Permission

i



42 Title A interface identifier deferent cause BSC handover successful ratio was low 10 421 Phenomenon Description 10 422 Alarm Information 10 423 Cause Analysis 10 424 Handling Process 10 425 Suggestions and Summary 10

43 Title Non-configuration of BA2 table causes no handover 10 431 Phenomenon Description 10 432 Alarm Information 11 433 Cause Analysis 11 434 Handling Process 11 435 Suggestions and Summary 11

Chapter 5 Data Configuration Problem 12 51 Title zero outgoing interBSC handover success rate 12


52 Title Wrong CGI causes low outgoing inter BSC successs rate 13 521 Phenomenon Description 13 522 Alarm Information 13 523 Cause Analysis 13 524 Handling Process 13 525 Suggestions and Summary 13

53 Title Wrong parameter settings of IDLE SD Thrash leads to fake congestion 13 531 Phenomenon Description 13 532 Alarm Information 14 533 Cause Analysis 14 534 Handling Process 14


ii

GSM RNPampRNO Cases Chapter 1 HAssignment ProblemH

Chapter 1 Assignment Problem

11 Title Can not make a call even there is high Rx level on mobile phone

111 Phenomenon Description

There is high Rx level on mobile phone (idle state) but can not make a call

112 Cause Analysis

During the investigation by using Sagem testing MS we found that there are several cells covering the problem spot Rx level ranges from -76dBm to -92dBm All cells covered the place are 900 cells (all cells CRO = 0)

We have found the cell with highest Rx level covering very far (TA is more than 63) even though other cells covering closer (due to higher propogation loss their signal is lower)

The Rx level of the second strength cell is about -80dBm and its TA is 16

Considered that Rx_access_min in the 900 netwok equals 5

for 1st cell C1 = 105-76 = 29 = C2

for 2nd cell C1 = 105-80 = 25 = C2

1st cell C2gt2nd cell C2

therefore the cell which TAlt63 couldnt be chosen even the Rx level is high (-80dBm) and call cannot be established from it

113 Handling Process

To solve the problem need adjust downtilt or output power of the far coverage cell or implement extended cell technology

114 Suggestions and Summary

If possible make software simulation before new BTS installation and estimate coverage of the BTS In those situations when coverage is very far (Rxgt-80 TAgt63) we need adjust antannas downtilt during installation


1

GSM RNPampRNO Cases Chapter 2 HCall Drop ProblemH

Chapter 2 Call Drop Problem

21 Title Interference causes Call Drop


call drop in highway always occurs in only one direction of the road

212 Alarm Information

No alarm information

213 Cause Analysis

After checking eliminating hardware congestion path balance and coverage as a source for the problem Thus it was obviouse that the problem was due to interference


We did a drive test in the area using tems software connected to two phones one in idle mode and the other in dedicated mode we tested the road in both way And the Drop occured as suspected After analysing the logfiles of the DT we found that we found there is unjustified handover due to quality to a cell not suppose to serve in that area and it cause the call drop After checking the logfile of the mobile in the idle mode there was cell overshooting to the area of call Drop and causing Co-channel thus causing the call drop This cell didnt apear in the dedicated mode phon logfile

After changing the frequency a second drive test confirms that the problem was solved


Performing Drive test for some problems is Mandatory And some problem can be better viewed in idle mode

22 Title Call Drop Problem Due to A-interface Congestion


Total 41 calls were attempted form the Ashulia bazaar Site 24 (58) calls were blocked


2


DT was performed in the coverage area of DCS Ashulia Bazar on 14th December 2006 (between 6PM amp 7PM) As uplink (from Terminal) and downlink (from DT) data was simultaneously examined it was clear that there was available free TCH when the calls were blocked [Excerpt from customer complaint sent on 14th December 2006]


E1 remote alarm Mains supply failure Second extended IO alarm Second extended IO alarm

223 Cause Analysis

Huawei Team made a series of Drive test and signal tracing in the problem zone after getting complaint from the customer The alarms means Low

voltage and Rectifier fault alarmThis alarm happened many timesAlso High temperature alarm Because of the faulty E1 there occured E1 remote

alarms But even after the alarms were recovered the call blocking problems were not solved

Though the good signal level and good call quality there is a notable amount of blocked call in the site During the DT there were following message

from the L3 information when we encountered such block calls No circuitChannel available


From the traffic statistics it seems there is a notable amount of CM SERVICE REJECTIONS DUE TO CONGESTION in the CM Service rejection causes

The Description of this statistic item is if NSS cannot normally respond to a CM SERVICE REQUEST message due to the congestion after receivingthis message from MS MM layer NSS will respond MS a CM SERVICE REJECT message in which the rejection cause is congestion Another important statistics item is the Percentage of A-interface circuit (Busy) reached more than 90 in the site which is resulting in the failure of a call The traffic volume (excluding very early assignment) is 9606Erl in the peak hour 8708ERL in FR and 898 ERL in HR In terms of statistics excluding synchronization channel and NO7 channel 100 channels are available So the traffic per A inferface channel is 096 (9606 divided by 100) This value is much bigger than the recommended 07Erlchannel This shows there is serious congestion on the A interface thereby making it difficult to make calls especially during busy hour


The most critical thing required is to expand the A interface Currently we have notable rejections during busy hour because of A interface congestion this number should be brought down to zero by adding more circuits


3


23 Title Incorrect frequency led to a cell with abnormal traffic statistics


The customer RNP engineers reported that one cell was abnormal from the traffic statistics adding that the call drop rate became high and handover rate became low


High call drop rate and low handover rate

233 Cause Analysis

The frequency of the cell with abnormal traffic statistics was incorrect which led to interference among the cells As a result there was need for changing the frequency for this cell in question


1 Checked and analyzed the traffic statistics of this site

2 Went to the site and carried out dial test with the result of high call drop rate and low handover rate

3 Made local loop of radio frequency of that cell with abnormal traffic statistics with the result of 55 error

4Checked all the frequency of the site and neighbour sites with the result of finding out that this frequency was incorrect

5 Changed the frequency of the TRX and the error was corrected and the traffic statistics became normal

24 Title External interference leads to drop call


During the driver test MS faces drop call when the receiving signal is below -75dBm At the same area MS cant make call any more


No any alarm on OMC

243 Cause Analysis

1 weak signal


4


2 interference in Um interface(uplink and downlink)

3 TRX or CDU faulty

4 unbalance between uplink and downlink

5 radio parameters are unsuitable

6 transmission problem


1 checked all the alarms of hardware on OMC and found no alarms on the hardware

2 checked the traffic statistics and found that the cause is balance between uplink and downlink

3 analyzed the drive test data and didnt find any downlink interference

4 checked the traffic statictics and found that the Average num of idle TCHs in Interf band 5 and Average num of idle TCHs in Interf band 4 have big numbers it means there exists uplink interference The conclusion is proved by MS measurement reports which have high bit error rate in Abis interface

5 this situation just exist one area which covered by sector 3 of site A sector 1 and 2 are normal

6 changed and swapped the TRX and CDU the problem still exists

7 because sector 1 and 2 are normal so transmission of Abis interface is ok

8 swapped antenna between sector 1 and 3 and found the problem still exists in that area

9 the frequency resource came from airforce so this is considered as external interference and brought spectrum tool to test the external interference A jam was found in one rooftop and produced the interference in one direction switched off this equipment and the problem was solved


External interference is normal case in some country when we face problems we shall analyze the problem step by step


5

GSM RNPampRNO Cases Chapter 3 HCongestion ProblemH

Chapter 3 Congestion Problem

31 Title High TCH congestion rate caused by reverse connection between antenna and feeder cable


High TCH congestion rate with some BTSs after expansion


None

313 Cause Analysis

The network needs expansion due to the capacity requirement and two transmitting antennas must be employed along with BTSss configurations increasing It is found out from the analyzing of traffic statistics result after expansion that the receiving level of downlink signal is much low The problem should locate in the stand-alone transmitting channel because all the expanded TRX are connected with the antenna by a stand-alone transmitting feeder cable


Check the transmitting channel from TRX HPA to Combiner and no connection fault of hardware is found 2 Both TRX and HPA are replaced but no improvement 3 When call tests are done near the BTS but the obvious difference of receiving level after expansion is not found from that of before expansion 4 Tracing the Abis interface signaling there are many TCH occupied failures when TA=2 The transmitting channels are interchanged the TCH congestion occurs in the old TRXs So the problem must locate in the feeder cable connected the antenna and the expanded TRXs 5 Checking the jumpers on the tower the transmitting antennas are connected reversely with the jumpers The main reason is that the antenna labels below the tower are not installed so that feeder cables are not in order on the platform of antennas The jumper of Cell 1 is connected with the antenna of Cell 2 and the jumper of Cell 2 is connected with the antenna of Cell 1 Meanwhile the coverage directions of BCCH and TCH TRXs is different the TCH occupied failures are very often


6


32 Title TCH seizure failure for the difference of BCC and TSC


In one place RNP engineer find that one sites TCH seizure failure rate is high and the other KPI is ok


No

323 Cause Analysis

BCC and TSC should be same if it is not same TCH seizure failure rate must be high


1Check the statistics find that immediately assignment failure rate and handover assignment failure rate are high but other site is ok after network optimization 2Check the frequency planning no same frequency or adjacent frequency interference 3Test the signal in the site no abnormal interference so the reason is not for interference 4For traffic this site is not busy no congestion so the reason is not for configestion 5Check the tables which have been modified HSN frequency and so on no problem 6Finally check the TSC parameter find that the TSC is different from BCC change these two parameter to be same the problem is solved

33 TitleTarget Cell Blocking Cause Outgoing Handover Failure for a New Site On-air Commission Test


In dual-band network the 1800 system is Huawei equipment another vender is S company Cell-A visualize outgoing handover successful rate is very low when we do commission test after cutover When we do drive test find that even the serving cell Rx-lev is as poor as -100dBm the mobile still doesnt handover to the other better signal strength G900 adjacent cell-B we use the forcing handover function several times but only few times handover successful


None


7


333 Cause Analysis

1Because force handover can be successful so we can make sure that there is no trouble about data for handover

2Trace the signaling check the same connect serial number it visualize that huawei BSC send handover required to MSC but there is no signaling of handover command for this handover required from MSC

3 Check the statistics the target G900 cell-B block rate is very high


Change the penalty time for handover failure from 10s to 20s The mobile cant attempt to handover into cell-B again within short time after handover failure the mobile handover to another adjacent cell successful and the problem solved


8

GSM RNPampRNO Cases Chapter 4 Handover

Chapter 4 Handover

41 Title Co-BCCH and Co-BSIC caused wrong attempted incoming inter cell handover


One day we found one cell (cell A) which was not on air but still had attempted incoming inter cell handovers and TCH seizures but all of them were failed


No Alarm

413 Cause Analysis

We checked there were many attempted incoming inter cell handovers but no incoming inter cell handovers no successful incoming inter cell handovers and no attempted outgoing inter cell handovers All the incoming inter cell handovers were failed The number of incoming inter cell handovers was always same as TCH seizures so it showed that all the TCH seizures failure were caused by handover

From above exact phenomenon the most probability was that some closed cells(for example cell B) had Co-BCCH and Co-BSIC with cell A when other cell(cell C) intended to hand over to cell B and it wrongly handed over to cell A Of course the handover would fail because cell A was not on air


According to above analysis we checked the problem as following steps

1)Checked the BCCH and BSIC and found there was a cell B (2 Km away) Co-BCCH and Co-BSIC with cell A A and B didnrsquot have neighbor relation A was defined neighbor relation with other closed cells Some other cells which had neighbor relation with A can receive Brsquos signal because B had overshooting problem So those cells would consider the signal was come from A So it would handover to A wrongly

2)Changed the BSIC of A and down tilt the antenna of B after finished this we checked the performance of A and there were no attempted incoming handovers and TCH seizures


9


42 Title A interface identifier deferent cause BSC handover successful ratio was low


In Iran ESFAHAN MTCE Customer have one MSC and two BSC One MSC and one BSC belong to HUAWEI we found that HUAWEI BSC handover successful ration was low But ERRICSON BSC handover successful ratio was normal


No Alarm

423 Cause Analysis

Because our INTRA-BSC handover was normal so I think our handover data is correct We can found ERRICSON sites can send require to HUAWEI sites so two side data was consistent We checked the traffic statistic we can found our aim cell CGI So MSC data also was normal At last we doubted that link have some problems


Checked traffic statistic and found HUAWEI sites handover successful ratio was low But ERRICSON sites handover successful was normal

Checked BSC handover parameters everything is ok

Traced A interface link checked that cause valueprotocol error between MSC-BSC ---1100000 so I checked BSC and MSC A interface identifier I found MSC identifier is GSM_phase_2+ and HUAWEI BSC identifier is GSM_phase_2ERRICSON BSC identifier is GSM_phase_2+

I changed HUAWEI BSC identifier to GSM_phase_2+ that problem solved


We need to attention some practical problems although in theory GSM_phase_2+ and GSM_phase_2 are compatible But in fact we couldnt do that

43 Title Non-configuration of BA2 table causes no handover


In a recent GSM Project which involves 1 (2-module) BSC + 4 BTS312 (S222222) + 5 BTS312 (S222444) + 3 BTS312 (S2222) during drive test in the area it was noticed that in dedicated mode there was cell reselection and no handover from one cellsite to another


10



No Alarm

433 Cause Analysis

From the Serving + Neighbor window the serving cell was displayed with no neighbors being displayed Non-configuration of BA2 table suspected


1Reported the problem to BSS Engineer at the BSC site who did the configuration to check the adjacent relationship if it is ok and it was observed that there was no problem with the adjacent relationship

2Also checked was the BA2 table if configured or not in BSC and it was observed that the BA2 was not configured

3The BA2 table was then configured dynamically in the BSC Auto Data Configuration system by the BSS Engineer

4Implemented DT to ascertain the anomaly has being corrected BA2 list is used to inform the MS in the active mode to search the BCCH frequencies of adjacent cells BA list is sent through system information 5 5bis and 5ter During network optimization all BCCH frequencies in the network can be put into the BA2 table so as to use the performance measuring function of the undefined adjacent cells in the traffic statistics console to find out the adjacent missing cells MS must keep on measuring the BCCH signal levels of the serving cell as well as the neighbor cells In order to know the cells adjacent to the current serving cell neighbor cell description information will be broadcast periodically in the system information of each cell This information lists the BCCHs of all the neighbor cells MS must extract this information from the system information and use it as the basis of neighbor cell signal measurement


This problem was as a result of an oversight from the BSS Engineer on site As result of this all site installationconfiguration must be carefully checked by BSS Engineers and ensure to be in order before any other optimization measure is taken to solve problems discovered on site


11

GSM RNPampRNO Cases Chapter 5 HData Configuration

ProblemH


Chapter 5 Data Configuration Problem

51 Title zero outgoing interBSC handover success rate


From the traffic statisticas we a found a cell with high attempted outgoing inter BSC handover but with zero success There was only on external BSC neighbor


No Alarm

513 Cause Analysis

The main reasons causing the failure of handover between cells follow

1) Unreasonable handover data configuration

2) Problem with equipment (individual TRX damaged)

3) Congestion

4) Interference

5) Clock problem

6) Coverage

7) uplinkdownlink unbalance

There was no interference or congestion or hardawre problem We suspect there is a a data configuration problem We checked the neighbor and found one external neighborThis neigbor was not online as we discovered from the BTS maintenance After checking the sites around we found a cell with the same BCCH as the external neighbor in the same BSC of the cell having the problem and serving in the same area and it was not defined as a neighbor So the problem was due to CO BCCH between undefined neighbor and offline external neighbor


After adding the missing neighbor the cell having the problem at hand and changing the BCCH of the neibor added the inter BSC handover returned to normal


When you have a handover problem check the neigbor defintion and possible cells that can be defined as a neighbor

Check for CO-BCCH CO-BISC problem

12


ProblemH


52 Title Wrong CGI causes low outgoing inter BSC successs rate


we found a problem of low outgoing inter BSC successs rate


No Alarm

523 Cause Analysis

call drop maybe caused by

1 Unreasonable Parameter Settings

2 Coverage

3 Interference

4 Transmission Failure


6 Uplinkdownlink Unbalance Caused by Antenna amp Feeder System


No alarms are foundNo problem in interfernce was found after further analysing we found that specfic cell in the BSC cause this problem and the cell is on the bordaer of the BSC after invetigating the External neighbors of this cell we found there neighbors having wrong CGI


correct the CGI the neighboring cell in the external neighbors relation table of the BSC

53 Title Wrong parameter settings of IDLE SD Thrash leads to fake congestion


Recently in TMIB network of Bangladesh we found that after comissioning new BSC at CTG(CB37) Version (G3BSC32V300R002C12) TCH congestion is around 5 to 10 in all cell at evening time After checking the traffic statistics it is found that at the evening time TCH is congested where as from Erl B table it

13

GSM RNPampRNO Cases 0

should not be congested It should carry more traffic then congestion After checking the SDCCH congestion found that no SDCCH congestion seen


No Alarm

533 Cause Analysis

At first we check the data configuration specially cell data that is set by customer when comission those sites and found that in Channel Management

Console the parameter IDlE SD Thrashold is put 24 Then from BTS Maintanance console check the BT view channel state and found that at evening time more TCH is converted to SDCCH where as dedicated SDCCH in IDLEIDLE SD Thrash When the number of idle SDCCH channels is less than or equal to the Idle SD Thrsh the system will try to find available TCHs and convert them to SDCCH channelsAs this parameter set to 24 that meansall the time there would be idle SD channel less than 24 and System will convert more TCH to SDCCH Also Min Recovery time is long (600S) so TCH channel would become less and leads to overflowSo the reason may be wrong setting of IDLE SD thrash leads to more TCH is Convered to SDCCH and leads fake congestion The default value of this parameter is 2


Tue 4 Apr 2006 093500 UTC OVS Local SE 85725jonysaha So the reason may be wrong setting of IDLE SD thrash leads to more

TCH is Convered to SDCCH and leads fake congestion The default value of this parameter is 2As for trail we change one site this parameter and check the KPI next day and found that for that site all cells congestion vanishes Later change all site this parameter


14


Table of Contents

Chapter 1 Assignment Problem 1 11 Title Can not make a call even there is high Rx level on mobile phone 1

111 Phenomenon Description 1 112 Cause Analysis 1 113 Handling Process 1 114 Suggestions and Summary 1

Chapter 2 Call Drop Problem 2 21 Title Interference causes Call Drop 2


22 Title Call Drop Problem Due to A-interface Congestion 2 221 Phenomenon Description 2 222 Alarm Information 3 223 Cause Analysis 3 224 Handling Process 3 225 Suggestions and Summary 3

23 Title Incorrect frequency led to a cell with abnormal traffic statistics 4 231 Phenomenon Description 4 232 Alarm Information 4 233 Cause Analysis 4 234 Handling Process 4

24 Title External interference leads to drop call 4 241 Phenomenon Description 4 242 Alarm Information 4 243 Cause Analysis 4 244 Handling Process 5 245 Suggestions and Summary 5

Chapter 3 Congestion Problem 6 31 Title High TCH congestion rate caused by reverse connection between antenna and feeder cable 6


32 Title TCH seizure failure for the difference of BCC and TSC 7 321 Phenomenon Description 7 322 Alarm Information 7 323 Cause Analysis 7 324 Handling Process 7

33 TitleTarget Cell Blocking Cause Outgoing Handover Failure for a New Site On-air Commission Test 7


Chapter 4 Handover 9 41 Title Co-BCCH and Co-BSIC caused wrong attempted incoming inter cell handover 9


i










ii






112 Cause Analysis





for 1st cell C1 = 105-76 = 29 = C2

for 2nd cell C1 = 105-80 = 25 = C2








1








213 Cause Analysis











2





223 Cause Analysis












3







233 Cause Analysis












No any alarm on OMC

243 Cause Analysis

1 weak signal


4



3 TRX or CDU faulty

















5







None

313 Cause Analysis





6






No

323 Cause Analysis








None


7


333 Cause Analysis







8


Chapter 4 Handover





No Alarm

413 Cause Analysis








9






No Alarm

423 Cause Analysis













10



No Alarm

433 Cause Analysis










11


ProblemH







No Alarm

513 Cause Analysis




3) Congestion

4) Interference

5) Clock problem

6) Coverage








12


ProblemH






No Alarm

523 Cause Analysis



2 Coverage

3 Interference











13




No Alarm

533 Cause Analysis







14










ii






112 Cause Analysis





for 1st cell C1 = 105-76 = 29 = C2

for 2nd cell C1 = 105-80 = 25 = C2








1








213 Cause Analysis











2





223 Cause Analysis












3







233 Cause Analysis












No any alarm on OMC

243 Cause Analysis

1 weak signal


4



3 TRX or CDU faulty

















5







None

313 Cause Analysis





6






No

323 Cause Analysis








None


7


333 Cause Analysis







8


Chapter 4 Handover





No Alarm

413 Cause Analysis








9






No Alarm

423 Cause Analysis













10



No Alarm

433 Cause Analysis










11


ProblemH







No Alarm

513 Cause Analysis




3) Congestion

4) Interference

5) Clock problem

6) Coverage








12


ProblemH






No Alarm

523 Cause Analysis



2 Coverage

3 Interference











13




No Alarm

533 Cause Analysis







14






112 Cause Analysis





for 1st cell C1 = 105-76 = 29 = C2

for 2nd cell C1 = 105-80 = 25 = C2








1








213 Cause Analysis











2





223 Cause Analysis












3







233 Cause Analysis












No any alarm on OMC

243 Cause Analysis

1 weak signal


4



3 TRX or CDU faulty

















5







None

313 Cause Analysis





6






No

323 Cause Analysis








None


7


333 Cause Analysis







8


Chapter 4 Handover





No Alarm

413 Cause Analysis








9






No Alarm

423 Cause Analysis













10



No Alarm

433 Cause Analysis










11


ProblemH







No Alarm

513 Cause Analysis




3) Congestion

4) Interference

5) Clock problem

6) Coverage








12


ProblemH






No Alarm

523 Cause Analysis



2 Coverage

3 Interference











13




No Alarm

533 Cause Analysis







14








213 Cause Analysis











2





223 Cause Analysis












3







233 Cause Analysis












No any alarm on OMC

243 Cause Analysis

1 weak signal


4



3 TRX or CDU faulty

















5







None

313 Cause Analysis





6






No

323 Cause Analysis








None


7


333 Cause Analysis







8


Chapter 4 Handover





No Alarm

413 Cause Analysis








9






No Alarm

423 Cause Analysis













10



No Alarm

433 Cause Analysis










11


ProblemH







No Alarm

513 Cause Analysis




3) Congestion

4) Interference

5) Clock problem

6) Coverage








12


ProblemH






No Alarm

523 Cause Analysis



2 Coverage

3 Interference











13




No Alarm

533 Cause Analysis







14





223 Cause Analysis












3







233 Cause Analysis












No any alarm on OMC

243 Cause Analysis

1 weak signal


4



3 TRX or CDU faulty

















5







None

313 Cause Analysis





6






No

323 Cause Analysis








None


7


333 Cause Analysis







8


Chapter 4 Handover





No Alarm

413 Cause Analysis








9






No Alarm

423 Cause Analysis













10



No Alarm

433 Cause Analysis










11


ProblemH







No Alarm

513 Cause Analysis




3) Congestion

4) Interference

5) Clock problem

6) Coverage








12


ProblemH






No Alarm

523 Cause Analysis



2 Coverage

3 Interference











13




No Alarm

533 Cause Analysis







14







233 Cause Analysis












No any alarm on OMC

243 Cause Analysis

1 weak signal


4



3 TRX or CDU faulty

















5







None

313 Cause Analysis





6






No

323 Cause Analysis








None


7


333 Cause Analysis







8


Chapter 4 Handover





No Alarm

413 Cause Analysis








9






No Alarm

423 Cause Analysis













10



No Alarm

433 Cause Analysis










11


ProblemH







No Alarm

513 Cause Analysis




3) Congestion

4) Interference

5) Clock problem

6) Coverage








12


ProblemH






No Alarm

523 Cause Analysis



2 Coverage

3 Interference











13




No Alarm

533 Cause Analysis







14



3 TRX or CDU faulty

















5







None

313 Cause Analysis





6






No

323 Cause Analysis








None


7


333 Cause Analysis







8


Chapter 4 Handover





No Alarm

413 Cause Analysis








9






No Alarm

423 Cause Analysis













10



No Alarm

433 Cause Analysis










11


ProblemH







No Alarm

513 Cause Analysis




3) Congestion

4) Interference

5) Clock problem

6) Coverage








12


ProblemH






No Alarm

523 Cause Analysis



2 Coverage

3 Interference











13




No Alarm

533 Cause Analysis







14







None

313 Cause Analysis





6






No

323 Cause Analysis








None


7


333 Cause Analysis







8


Chapter 4 Handover





No Alarm

413 Cause Analysis








9






No Alarm

423 Cause Analysis













10



No Alarm

433 Cause Analysis










11


ProblemH







No Alarm

513 Cause Analysis




3) Congestion

4) Interference

5) Clock problem

6) Coverage








12


ProblemH






No Alarm

523 Cause Analysis



2 Coverage

3 Interference











13




No Alarm

533 Cause Analysis







14






No

323 Cause Analysis








None


7


333 Cause Analysis







8


Chapter 4 Handover





No Alarm

413 Cause Analysis








9






No Alarm

423 Cause Analysis













10



No Alarm

433 Cause Analysis










11


ProblemH







No Alarm

513 Cause Analysis




3) Congestion

4) Interference

5) Clock problem

6) Coverage








12


ProblemH






No Alarm

523 Cause Analysis



2 Coverage

3 Interference











13




No Alarm

533 Cause Analysis







14


333 Cause Analysis







8


Chapter 4 Handover





No Alarm

413 Cause Analysis








9






No Alarm

423 Cause Analysis













10



No Alarm

433 Cause Analysis










11


ProblemH







No Alarm

513 Cause Analysis




3) Congestion

4) Interference

5) Clock problem

6) Coverage








12


ProblemH






No Alarm

523 Cause Analysis



2 Coverage

3 Interference











13




No Alarm

533 Cause Analysis







14


Chapter 4 Handover





No Alarm

413 Cause Analysis








9






No Alarm

423 Cause Analysis













10



No Alarm

433 Cause Analysis










11


ProblemH







No Alarm

513 Cause Analysis




3) Congestion

4) Interference

5) Clock problem

6) Coverage








12


ProblemH






No Alarm

523 Cause Analysis



2 Coverage

3 Interference











13




No Alarm

533 Cause Analysis







14






No Alarm

423 Cause Analysis













10



No Alarm

433 Cause Analysis










11


ProblemH







No Alarm

513 Cause Analysis




3) Congestion

4) Interference

5) Clock problem

6) Coverage








12


ProblemH






No Alarm

523 Cause Analysis



2 Coverage

3 Interference











13




No Alarm

533 Cause Analysis







14



No Alarm

433 Cause Analysis










11


ProblemH







No Alarm

513 Cause Analysis




3) Congestion

4) Interference

5) Clock problem

6) Coverage








12


ProblemH






No Alarm

523 Cause Analysis



2 Coverage

3 Interference











13




No Alarm

533 Cause Analysis







14


ProblemH







No Alarm

513 Cause Analysis




3) Congestion

4) Interference

5) Clock problem

6) Coverage








12


ProblemH






No Alarm

523 Cause Analysis



2 Coverage

3 Interference











13




No Alarm

533 Cause Analysis







14


ProblemH






No Alarm

523 Cause Analysis



2 Coverage

3 Interference











13




No Alarm

533 Cause Analysis







14




No Alarm

533 Cause Analysis







14

gsm case

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