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Nokia Siemens Networks Managed Services RTWP Optimisation Processes – VHA RAN

Filename: Day to Performance Management & Optimisation Date modified: 15-May-12

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Day to Day Performance Management & Optimisation – VHA RAN

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This publication is confidential and has been prepared and written by Vodafone Pacific Limited or one of its related bodies corporate ("Vodafone Hutchison Australia"). It is subject to copyright. No part of this document may be disclosed, copied, reproduced, stored in a retrieval system or transmitted without prior written permission from Vodafone Australia.



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Document ControlTitle: ActixOne Optimisation Processes

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11-05-2012 0.1 Doc. Outline

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Table of Contents

Document Control......................................................3

Table of Contents.......................................................4

1. Purpose & Scope............................................5

2. Customer.........................................................6

3. RTWP Analysis................................................73.1 Tool Access.....................................................................................................73.2 Analysis...........................................................................................................73.3 Actions & Outcomes........................................................................................73.4 Tracking...........................................................................................................7

4. Coverage Analysis – PCHR Analysis..............84.1 Tool Access.....................................................................................................84.2 Analysis...........................................................................................................84.3 Actions & Outcomes........................................................................................84.4 Tracking...........................................................................................................8

References.................................................................9

Definitions/Glossary.................................................10

Appendices...............................................................11

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1. Purpose & ScopeThe scope of this document is to describe process of Day to Day Performance Management & Optimisation conducted by the Regional MSP Engineering teams as it relates to methods and procedures that can be used by the ActixOne Tool



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2. CustomerInternal - GNOC, MSP

External - VHA



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3. RTWP AnalysisHigh RTWP in 3G cells impacts on user throughput as well as accessibility for UL RABs. Based on current VHA network setting there is no accessibility will be observe due to high RTWP, but user experience from throughput point of view and also retainabililty will be impacted directly.

3.1 Tool AccessTools are used for troubleshooting are:

i. PRSii. Nastariii. NodeB LMT

PRS usually is used to monitor network performance and extract the list of all cells with high RTWP issue.

Nastar is used to perform history check and identify affected spectrum

NodeB LMT is the main tool used to analyse antenna branch performance and identify defected part. Also this tool will help to check TMA configuration and attenuation setting.

High RTWP measured via 3 counters in PRS (Report Kordia 3G KPI);

VS.MaxRTWP VS.MinRTWP VS.MeanRTWP

These counters represent Max/Min/Average RTWP during measurement period and the value is average of all receive path for measured object.

Min value of this counter captures minimum during measurement period and running this report in daily bases will give the minimum RTWP which is captured during minimum network load and it will be included all external load apart from 3G internal load. Normal range for min RTWP is between -101 and -108 dbm and values higher and lower than this needs attention.

Low value for min RTWP like -115dbm represents disconnected RX path or faulty antenna, TMA or any other element of antenna branch.

Other reason for low value can be wrong setting of TMA attenuation.

Higher value for this counter will be results of external interference of wrong setting of TMA attenuation.

http://localhost:7890/pages/31184925/06/31184925/06/resources/mbsc/m-perf/Mt-29435.html





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Nastar is used to identify real time RTWP level for each antenna branch as well as identify main and diversity difference.

RTWP captured from Nastar “UMTS Uplink Interference Analysis Task” is cell bases. Nastar keeps record on RTWP (based on setting) for up to 2 weeks and can be used to check RTWP situation during busy hour and midnight to distinguish between 3G internal interference and external interference.

LMT of NodeB has the same functionality as Nastar Uplink interference Analysis but only in real time bases. Output of LMT shows RTWP for multiple carrier as well as antenna branches in the same window and troubleshooting will be easier.

LMT of NodeB also is used to track RTWP situation during technicians visit from the site and any type of work on antenna branch as it is real time measurement.



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NodeB LMT is the best tools to adjust TMA attenuation setting as well.

In summary, LMT is used to:

- Monitor RTWP for different carrier and branch in radio unit - Monitor RTPW during tech work in site on antenna side to detect faulty,

swap and etc.- Configure TMA setting correctly to avoid incorrect RTWP measurement and

main diversity issue.

NodeB LMT Rx Frequency Scanning is related to spectrum measurement which scans frequency in 200 kHz steps to identify polluted range in case of external source.



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3.2 AnalysisSteps to analyse RTWP issue is explained in attached slide

VS.MinRTWP is the main trigger point for RTWP work in the 1cell; VS.MeanRTWP also will be impacted in case of any physical of setting issue but is not the main trigger point. Mean value of RTWP can be affected by high load in the cell and optimization steps for this issue are different than this guideline.




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MinRTWP will trigger operation in two situations,

1- High RTWP2- Low RTWP

High RTWP triggers whenever external interference is impacting network as well as faulty or wrong setting related to TMA, attenuation and etc.

Report to identify low high RTWP is based on daily resolution and needs to be available for couple days and any continues high RTWP for MinRTWP (higher than -100dbm for more than 3 days) .

Report is used to extract KPI in PRS located in “root\kordia\Kordia 3G KPI “. Report need to be run in Ucell level and daily resolution and any cell with RTWP >-100dBm will be subject to this procedure.

Next step is to monitor RTWP situation from LMT.



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Identify Radio unit related to Ucell:

RTWP Monitoring function of LMT is located under Real-time Specific Monitoring folder

Based on location of radio unit , apply setting (in case of reporting to ACMA is needed, it is possible to record all measurement by checking box next to “Auto Save” and specify the location of log file).

Base on number of carrier have been configured on this board, the output will be displayed in output window



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Information which will be extracted from this chart is:

- Level of RTWP for different carrier and antenna branch, so in case of 2 carrier, there will be 4 chard. Carrier 0 and 1 and for each carrier Primary (which is TX/RX port) and also Secondary (top port in RU which is RX)

- Difference between main and diversity to conclude possible setting / plumbing issue of attenuation and splitter existence.

In case of high Min RTWP, the best troubleshooting is to turn OFF TMA and remove all attenuations (if TMA exists), in the meantime monitor RTWP from LMT for any changes (TMA can be powered from the same RU or other unit as well other NodeB in the location or external source.so for this operation is necessary to have site STD handy for double check the solution in the site.

After removing all these setting and turn OFF TMA, if RTWP come back to acceptable level, this is the results of wrong attenuation setting of TMA(in very rare situation this can be sign of swap feeders) , and after reviewing of STD , it can be corrected. (Refer to TMA setting section) and trouble shooting is over for this case.

After turning OFF TMA and removing all attenuations, still Min RTWP stays higher than normal level, in this case trouble shooting continues in LMT.

As it can been seen from procedure flow, 3 different situations can be identified from RTWP chart;

- One carrier has high RTWPo Usually this is the results of narrow band external interference on the carrier

and further analysis can be done by scanning RX frequency from LMT tools “RX Frequency scan” function . this tool will show impacted spectrum range for reporting to ACMA.



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- One branch has high RTWPo Usually this is result of wrong connection (plumbing error) or wrong TMA

and parameters setting for attenuation. For analyses this, it is important to make sure TMA is OFF and attenuations are set to zero, so any difference in branches will be the result of connection error in the site (internal of external error)

- All carriers and branches belong to sector have issue o Wide band external interference o Interference from G900 in case U900 and interference from U850 in case

U900o Structural issue like existence of external object in the front of antenna or

any kind of antenna faulty.

As it can be seen from the charts, difference between main and diversity is 6dbm for this cell which is the results of wrong setting.

Setting related to attenuation available in command “LST RXBRANCH”



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Low RTWP is the result of mainly wrong setting as well as plumbing issue (faulty splitter, TMA, disconnected jumper and so on) in the site.

For Low RTWP issue the first step is to monitor both antenna branch for the cell and compare RTWP level both period of time.

Here is the example of cell with both antenna branch RTWP level fixed to 112dbm during all hours

Main reason for this kind of behaviour is connection issue as well as TMA faulty. Monitoring VSWR alarm in the same time will give better idea regarding



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eliminating connection loss reason as both branch act in the same way, and the site is carrying traffic with very high drop, so TMA faulty will be highlighted .For this specific example as it can be seen Mean , Max and Min value for RTWP is same and this implies both branch have the same issue and this cannot be due to connection loss as for this specific example there is no VSWR issue, so high possible reason can be TMA faulty.

For some of site low RTWP come from wrong configuration as diversity supposed to be in non-operation mode (e.g. IBC cells). For this kind of cells, diversity branch from LMT RTWP monitoring will be displayed as fix -112 or -115dbm and main branch with variable RTWP.

3.3 Actions & Outcomes<likely outcomes and changes (parameter, tilt, etc.) that can be made to drive optimisation>

3.4 Tracking<where changes need to be tracked, Opti Tracker, etc.>



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4. Coverage Analysis – PCHR Analysis<high level view of pilot pollution causes.

4.1 Tool Access<How and where to access the tool and how to activate the relevant modules>

4.2 Analysis<How to conduct the analysis, what to look for, symptoms, evidence>

4.3 Actions & Outcomes<likely outcomes and changes (parameter, tilt, etc.) that can be made to drive optimisation>

4.4 Tracking<where changes need to be tracked, Opti Tracker, etc.>



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ReferencesProvides references to other documents or processes applicable to this procedure.

Optionally provides references to supplementary documents that support or provide additional information to make the Procedures document effective.

Reference Detail



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Definitions/GlossaryThe following introduces some of the terms and acronyms used in this document:

MSP Managed Service Providers

GNOC Global Network Operations Centre

VHA Vodafone Hutchinson Australia

PM Performance Management

ITIL Information Technology Information Library

VAS Value Added Service

RAN Radio Access Network

MTTR Mean Time To Repair

NPO Network Planning & Optimization

RIC

RASCI Responsible, Accountable, Support, Contribute, Information



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Appendices TMA configuration guideline

Requested tools and information to perform TMA configuration:

- Access to NodeB LMT- Site detail design file- MML command access

Setting of attenuation and power switch for TMA is based on site STD and any miss-match between STD and actaul configuration may cause performace issue or alarm generation.

TMA unit based on STD power up from connected RU or 2G RU or external source. This operation will explain the setting for different situations.

3G RU:

1- Log in to NodeB LMT and start monitoring RTWP for specific board. 2- Run command “LST ANTENNAPORT” to make sure ALD power switch is OFF for

both ports in RU

3- Run Command “LST RXBRANCH” to make sure all attenuation parameters value is 0 for all ports

4- Record the value for RTWP for both ports from LMT RTWP monitoring window.5- Turn ON power swith based on site STD (only one port power needs to be set to ON

for most of TMA type).6- Monitor RTWP for any step change. The delta value between RTWP value before

activation and after is the gain of TMA in RU port which will help to set accurate attenuation value. If step change in RTWP obseved go to step 11

7- In case no step change is observed, this can be the results of wrong implementation of site vs. STD or TMA faulty.

8- List alarms in site and check for alarm number 26530 and 26531.in case of TMA faulty or wrong activating of power from wrong port, these alarms will apear in the list.



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9- Turn OFF port again with command SET ANTENNAPORT and activate for the other port in RU and perform all steps from number 6.

10- In case non of port in RU can create step change in RTWP, trying to power up from 2G RU will help to identify the issue(prabably wrong configuration), otherwise site visit is needed to rectify possible issue. This operation is terminates here.

11- Set ports attenuation based on the value of step change in RTWP with command “MOD RXBRANCH” and parameter “ATTEN” . please note steps are 0.5dBM.

12- RTWP value must be reduce back to the value before activating TMA, fine tuning of parameter “ATTEN” is needed otherwise.

13- Monitor alarms in the site. 14- Attenuation setting is needed for other antenna braches are sharing the same

antenna system. This can be identify from site’s STD.

2G RU

Depends on TMA type , GSM bypass or not, the TMA setting may vary. For GSM bypass TMA which is the most common setting, the procedure will be:

1- Open LMT of 3G cell which will use TMA and monitor RTWP.2- Make sure TMA power is OFF for 3G RU (check step 2 and 3 of procedure for “3G

RU” mentioned above)3- Make sure TMA power setting is OFF from 2G RU. Use command “LST

BTSRXUBP” and check parameter “ANT_A ALD Power Switch” or “ANT_B ALD Power Switch “

4- Make sure TMA attenuation is 4 for 2G RU with command “LST BTSRXUBP” and parameter “Antenna Tributary 1 Factor “

5- Tune ON TMA power by setting “ANT_A ALD Power Switch” to ON and monitor RTWP for 3G cell and observe any step change in RTWP.

6- Set attenuation setting properly based on step change in RTWP and apply to 3G RU as explained in step 11 of procedure for “3G RU”

7- If TMA is used for 2G as well, then idle channel measurement is needed to adjust attenuation for 2G with command “LST BTSRXUBP” and parameter “Antenna Tributary 1 Factor”



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