iir network optimisation 2005 dickey

7/31/2019 IIR Network Optimisation 2005 Dickey

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Sergey Dickey, PCTEL RF Solutions GroupContributed to by Niallo Carrol, PCTEL Antenna Products Group

[email protected]

Using Measured Data and iVET toImprove Planning & Optimization


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Agenda

Evolution of Optimization: Getting Physical

Co-channel Interference: Ever More Ubiquitous

RET Antennae

Ways and Means of Optimization: Tools

Measurement versus Prediction: PMO

Importance of Measurement Dynamic Range: Case Study

Closing the (Control) Loop: High-Dynamic-Range Dual-

Technology Measurement Instruments



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Optimization is

Mobile Network Operators currently install asmuch as 30% more infrastructure than isrequired

Network adjustments are necessary inresponse to subscriber density changes

Experience to date suggests that clusters of

sites need to be adjusted between 3 to 7times in the course of a deployment

(Source: Sigma Wireless)


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2G 3G+: Interrelated Trends

Rising importance of co-channel interferenceDenser GSM networks in citiesFew or single frequency channel for the use by all sectorsInherent CCI in W-CDMA-based networks; pilot pollution

Breathing cells in W-CDMA

Fewer free network parameters used in optimization in 3G and3G+ systems

No frequency plans to optimizeTx power not dynamically controlled in HSDPA

Network performance is more difficult to predict due to the

complexity and dynamic behaviorDynamic link adaptation

Multiple traffic modes and QoS


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Co-channel Interference: OftenUnderappreciated


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Co-channel Interference: OftenUnderappreciated


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Co-channel Interference: Example


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E.g., One Sector Kills Another byShooting Him/Her in the Back:


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Three overlapping co-channel sites


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Antenna Physical ArrangementBecomes Critical for Optimization

Tilt:the one most important parameterleft to optimize

Azimuth: less important and probablyaffected by the future introduction ofintelligent antennae

Tilt changes are notoriously expensiveto implement, unless


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One Uses Antennae with RemoteElectrical Tilt

METS (Manual Electrical Tilt antennas)RETS (Remote Electrical Tilt)

Next stage, Networked Remote TiltAdjustment

Tilt adjustments are made over the Operation &

Management system or over a separate network layersuch as Sigma Wirelesss (now part of PCTEL Antenna

Products Group) Blustream system.


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RuralNo buildings, coverage is easy to predict

UrbanBuildings cause interference leading to blindspots, optimization is required

Optimization

Consists of changing the tilt of theAntenna to redirect its beam

Congestion IncreaseSubscriber density increases leading tocongestion

CapacityAdding a new Base Station requires neighboringcells to be adjusted

3G Need For Antenna Adjustments3G Need For Antenna Adjustments


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Patented Phase-shifter with closed loopcontrol system

Robust Slide Mechanism

Greater accuracy

Factory installed software settings

Superior Pattern ControlEssential for UMTS optimization

Antenna Interface Standards Group(AISG) and Ericsson-CompliantController

The iVETThe iVET ComponentsComponentsRemote Tilt as StandardiVET Antenna

Phase-Shifter

Microstrip Track

SlidingDielectric

OpticalSensor

Motor

Controller

Side Lobes Suppressed

Side Lobes

Main Beam 0 Tilt Main Beam 8 Tilt


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Traditional Approach to OptimizationAdjust or

Replace Antennas with Differing Tilt Angles

Alternative: Remote Tilt (iVET):

One Antenna, ROI after the second tilt change!

Lost revenue due to delays

Expense of replacement antenna

Site Access logistics

Lose coverage during swap out

Rigging and logistics expensesRisk of getting it wrong

Why iVETWhy iVET for UMTSfor UMTS

Early Deployment Urban Buildout Increased Congestion


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Frequency Bands : DCS, PCS andUMTS

Optimized Singleband

65or 33options

integrated Variable Electrical Tilt(iVET)

18dBi model at 1.3m

18.4dBi model at 1.5m

19dBi model at 1.7m

Minimum Visual Impact

Antenna only with iVET

Macrocell Variable TiltMacrocell Variable Tilt

Integrated Mast

Head Amplifier (MHA)

Fusion


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Remote Access Tilt ControlRemote Access Tilt Controland Optimizationand Optimization


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Tools of the Trade: Closing theLoop

Propagation ModelingCoverage and InterferenceMeasurements:

Drive Testing

Mobile measurements

Switch StatisticsAutomatic Cell Planning Tools


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Propagation Model orMeasurement: Both, actually (1)

Macro Models --Continuous functions suitable foroptimization, no gaps in coverage

Fast and easy to useVery inaccurate, unless calibrated bymeasurements

Ray-tracing Models accurate, but slowand expensive


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High accuracy

Fast

High dynamic range(Clarify)

Precise location info

But

Need to drive

Scanner and ClarifyRM

Measurements:


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Are the measurementsdispensable? -- NO

Any engineering system requires being tested andcalibrated periodically; one cannot rely on

predictions only without doing test and

measurement

Drive Test is an important tool of the optimization engineer:

Network audit

Model calibration

Troubleshooting

One of the inputs to ACP


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Why is Propagation ModelOptimization a Laborious and

Expensive Process?

Usually the data are gathered using theso-called CW measurement. Itrequires switching sites on and off

(keying up); every sector is drivenseparately

Because of the overwhelming expense,only a few sectors are used forcalibration; accuracy suffers


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Evolution of Optimization: Getting Physical

Co-channel Interference: Ever More Ubiquitous

RET Antennae

Ways and Means of Optimization: Tools

Measurement versus Prediction: PMO

Importance of Measurement Dynamic Range: Case Study

Closing the (Control) Loop: High-Dynamic-Range Dual-

Technology Measurement Instruments



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Dynamic Range Requirements

CPICH 1 CPICH 2

Rx Pwr

[dBm]DynamicRange

DynamicRange

Pilot Power [dBm]of CPICH1 Pilot Power [dBm]

of CPICH2cannot be detected

EC/Io


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Deleterious Effects of Limited Dynamic

Range of a Measurement Instrument:

Limited area where measurements areavailable

Positive bias of averaged (binned)measurements on the edges of a cell,even when points are present


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Deleterious Effects of Limited DynamicRange of a Measurement Instrument:


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Field Study: Comparison of CW datawith Scanner and Clarify for PMO

Two sets of drive-test data obtained with a Clarifymeasurement system (GSM version; -18 dB min C/ID.R.) a) taken in a clear-channel condition; b) withthe normal co-channel interference

Suburban area with flat terrainSlope-and-intercept (Lee) model used

Compared with the model produced by a standardscanner (0 dB min C/I)


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Study (continued)

Linear regression was used for fitting binned data

to the model


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Circular Binning:


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Gray: Scanner; Brown: Clarify; Red/pink: clear channel (CW)


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Results (1): Comparison between CW and

Clarify


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Results (2): Comparison between Clarify

and scanners


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Dual Network OperationsChallenges: Plan and manage inter-network handoff zones

Identifying where WCDMA handoff will betriggeredUnderstanding detail of underlay GSM networkManage parameters to move handoffs to desirable

locations

Solution: WCDMA/GSM Measured DataInter technology neighbor list planning and

managementWCDMA data identifies WCDMA handover zoneGSM provides detail of the GSM network andneighbors in that zone


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Dual Network Operations

Challenges: Sharing infrastructureCross optimization of shared antenna sites

Interference management

Solution: WCDMA/GSM Data enableTo more accurately predict impact of antenna tiltsand changes

See the propagation from multiple sitesIdentify sources of inter-network interference


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Conclusion

Using high dynamic range data in planning

and optimization solutions enhances resultsPropagation and resulting interference areissues in both WCDMA and GSM

CLARIFY

delivers CW-like Data with afraction of the effort

Collecting WCDMA/GSM datasimultaneously enables management of bothnetworks in a unified manner


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Thank You

www.pctel.com

iir network optimisation 2005 dickey

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