Walter Yoong

Network Verification

RF Optimization

What is Network Verification?

ı Drive Test measurementsı To verify the quality after major network changes

like:� Network vendor swap� Introduction of new technology / frequency bands / devices� Roll-out of vendors new network software release

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What is typically measured?

ı Network Operator decides on � Services and RF� KPI selection and Pass criteria� Reporting format and content

ı Reported Cluster by Cluster� One cluster is a small city, or a part of a

larger cityı Also Meas files can be included in delivery

ı Example of Voice parameters:� Voice Quality� Call Setup time� Call Setup success Rate

ı Example of Data parameters:� Data setup time� Data setup success rate� DL Data rate� UL Data Rate� PING roundtrip times

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Who is performing the measurements

ı Infra vendor Service BUı Testing Service Providers

ı Optimization Teamsı Testing Service Providers

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Large ProjectsSmall Projects /

Regular Verification

March 2016

Large Small / Regular

Vendor Swap X

New Service Introduction (VoLTE)

X

New technology/feature introduction (SRVCC, CA)

X X

New RAN release verification

(X) X

Site Verification X

Network Verification Use Cases

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Use case summary

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Lab Engineering

Large scaleField

Trial pre-rollout

Network Verification

Optimization andtroubleshooting

(continuous process)

Service Monitoring

Quality/Benchmarking

FieldTrial

EngineeringField

Installation

Optimization Team

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Check KPIs Root cause analysiswith internal tools

(OSS, Actix) possible

Applysolution

Low KPIs

OSS

Quality/bechmarking

3rd leveltrouble ticket

Solution not found

solution found

Drive test andanalysis

Servicemonitoring

solution found

Prepare forConnect/Chip test

Regulatory complaint

synergies by having compatible benchmarking, monitoring and optimization solutions (in data collection and post-processing)

� There are two approachesA: Optimization Engineer goes to the field himself (not driving the car), analysing the data in realtime, working with network operations directlyto check improvements on siteB: Send „Drive Test Car Driver“ (or data collection service provider) tocollect measurement data, analyse in the office

� Trend: optimization engineers have increasingly less skills: requires thetool to do the analysis and assist in solution finding � NPA!

Optimization Team and Drive Testing

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Roles in Optimization

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Drive Test Car Drivers• Hired on temporary contracts (1 day .. 3 months)• Drive the car and ensure working data collection• Deliver the measurement files

Optimization Engineer Site focus (A)• Monitor KPIs in own cluster• Analyze all available logs

(OSS, Actix, ...)• Troubleshoot and Analyze on

the spot

Optimization Engineer Office focus (B)•Monitor KPIs in own cluster•Analyze all available logs (OSS, Actix, ...)•Send Drivetest car driver to collect data•Analyze data in Office

Network Operations Centre• Apply SW changes to network (parameters, tilt, site restart ...)

Field Service• Apply HW changes to network

ı Can be outsourced (infra vendor managed service, testing serviceprovider)ı Contribute to field trials for new features (see engineering)ı Keep up to date with planning and design guidelines from HQ� New features � umbrella topics (macro, small cells, new services:

VoLTE, ViLTE, …)� New settings/new RAN releases� Plan/Monitor/coach/involve in network verification

Additional comments

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Main levers of the optimization engineer to improve KPIs

ı Good planning (RF!) is prerequisite for good network quality: if RF is bad in the first place, you can never fix it

ı Possible Actions� Trigger BTS restart (sleeping cells)� Trigger capacity increase� Non-RAN issues: escalate to transport or core network� RAN issues

� Planning issues: Coverage and interference/missing dominance� HW issues: Twisted feeders, defective HW, broken antennas, corrosion, tilt, ...� Internal causes: incorrect DB parameters (neighbors, thresholds, timers, …)� External causes: interferers, changed environment (new buildings, …), cross border

coordination

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ı First Optimization Task is proper planning!� Optimize (maximize) Coverage� Minimize Interference (overlapping zones)

ı Challenges:� LTE 800/1800/2600 network rollout only based on existing GSM / UMTS sites� existing network grid is planned for GSM and UMTS in higher frequency bands causing

interference and overlapping for LTE 800� topology of terrain impacts network design

Brief Overview Optimization Tasks

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General Planning Recommendations

ı Focus on more homogeneous network grid regarding site to site distance and antenna heights (avoid overshooting sites)

ı Avoid overlapping areas (server >=3) close to the site in case of one or two sector solutions

ı Sites with huge tilt close to upper e-tilt limit should be avoided due to almost no further optimization potential within further roll-out � check possibility to reduce antenna height

ı Check for dominant server to avoid overlapping if required optimize azimuths in case lowest possible site density for additional sites has been reached

ı Use total e-tilt range especially for sectors pointing to rising terrain to ensure proper SINR conditions

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Example Overlapping

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Overlapping Area - Initial

0

5

10

15

20

25

30

>= 6 5 4 3 2 1

Are

a [%

]

INI

Overlapping Area - E-, M-Tilt & Azimuth Optimised

0

5

10

15

20

25

30

35

>= 6 5 4 3 2 1

Are

a [%

]

EMA

Example Coverage

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indoor outdoor

Example of Total Antenna Height Optimization

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height tilt

After the network is live…

ı Pre-Tests with test transmitter (only 3G) and Cluster Optimization based on drive-test was done in the beginning of UMTS or LTE

ı TODAY: Less people – less budget – less time…

ı Many tasks are outsourced to 3rd party or infrastructure vendors

ı Network is rather trouble-shot than optimized today �

ı In 2017, radio network optimization teams work different…

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Network Performance Testı Why another test?

� Subscriber� Verify the “speed” of the connection

� Mobile Operator� Deeper performance analysis for data service� Max “speed” in total with multiple connections� How much a single connection can typically bear� Interruptions during a continuous dataflow (e.g. streaming of audio/video/data)

ı Traffic Profile� Configurable “profile” of HTTP Transfer

� “Floor” level to detect interruptions� “Peak” level to detect max capacity

ı Valid in Uplink and Downlink directionı TCP roundtrip also calculated during the test

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Network Performance Test - Advantages

ı Everything in one test:� “Traditional” Capacity test� TCP Roundtrip

ı…and more:� Detects Interruptions� Changes in Capacity

ı Less data usage� Can run during the whole drive test

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Network Performance Tests - Results in NQDI

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Sustainability Throughput DL

Sustainability Throughput UL

Downlink Throughput

Uplink Throughput

Thank you!