actix radioplan vodafone case study slides

Rikard SlungaNetwork Optimisation, Nice 0

Ensuring the reliability of

RF field optimisation

Roger Rüland, Vodafone Netherlands

Dietrich Hunold, Actix


Overview

Vodafone Netherlands network optimisation project

Importance of using measurements throughout the optimisation process

Time efficient and reliable RF field optimisation method

Successful verification of optimised network by measurements


Vodafone Netherlands

Part of the Vodafone Group

3.4 million customers

3500 employees

Mobile phone penetration in NL: 81%

55% UMTS population coverage

Highly competitive market (5 Operators, several MVNOs)


UMTS Optimisation Project

VF live! UMTS launch in June 2004

Need for optimisation of parts of the VF-NL radio network topology on very short term

Network covers all major Dutch cities

Due to size and timeframe of the project external help was necessary


UMTS Coverage

Maastricht

Amsterdam

Rotterdam

The Hague Utrecht


Optimisation Targets

Rollout of a new network is focussed on coverage, not capacity

Maximise the area with good CPICH Ec/Io and decrease the pilot pollution without decreasing the area with good RSCP

Downlink based optimisation

Only downtilt changes allowed


UMTS Optimisation Project

Deadline was strict so the external party had to absolutely deliver within timeframe

Lots of existing drive test measurements which should be used in the optimisation

Radioplan selected as one of the delivering companies


Optimisation Workflow

Deliver planning data (Quantum) and measurements to Actix

Verify consistency and completeness based on delivered data

Find logical errors (swapped sectors, down sites, etc.)

Pathloss tuning to increase reliability and accuracy

Receive and discuss optimisation results from Actix

Implement changes in the network

Evaluate optimisation predictions with measurements


Pre Optimisation / Rollout Process

Planning data must reflect network data

Check sites when handovered from contractor

Done by VF-NL drive test team using TEMS equipment

Handover test

Pathloss test


RF Network Check in Actix Radioplan

Compare measurements with planning data

VF-NL site assessment procedure works well, only 1 site found with logical errors (exchanged feeder)

Measured RSCP level in line with predicted RSCP level; good fit of propagation model (Std. Dev.: 6 to 8 dB)

Improve accuracy of pathloss matrices even more by pathloss tuning

One drive test route rejected for pathloss tuning due to obvious unrealistic offset


One Occurrence of Exchanged Sectors

Sector 3 measured

Sector 2 measured


Pathloss Prediction Accuracy

Pilot RSCP error (measurement – prediction):

Avg. -2.9dB

Std.Dev. 8.0dB


Optimisation and Change Implementation

Work orders for optimisation delivered by Radioplan

Implementation of downtilt proposals in clusters and prioritised

Installing Remote Electrical Tilt unit during site visit

1

2

3

4


Assess Improvement by Measurements

Measurements show good improvement of KPIs

Ec/Io strongly increased, cell overlap reduced

RSCP coverage maintained

Measured improvements in the order of predicted improvements

Ec/Io measurements


Drive Test Verification in Central Rotterdam

-0.2 cells97.8%94.9%meas.

-0.5 cells90.2%79.2%predict.

improv.afterbefore

+1.0dB98.1%90.5%meas.

+0.9dB91.5%81.1%predict.

improv.afterbefore

Ec/Io >= -8dB improvement

Cell overlap <= 3 cells

cell overlap measurements


Optimisation Workflow with Actix Radioplan

Data import

Data consistency/correctness check

Pathloss tuning

Optimisation

Result analysis

Deliver work orders

Evaluate improvements with measurements

Actix Radioplan

PlanningData

Measurement Data

Optimised Network


Pathloss Tuning

Direct use of drive test measurements

Goal: Improve planning data accuracy

Very efficient (1 town in < 5 sec)

Example:Shifting sand dunes at coast line

No reliable clutter data possible

Uncertainty in pathloss prediction

Shifting sand dunes

DEM


Pathloss Tuning Example

Low measured pilot RSCP

Effect of Pathloss Tuning


Actix Radioplan Optimisation Approach

Reconfigurationof the

network setup

DEM map clutter map

Objectivefunction

network setup pathloss maps

Pre-Analysis Verification

constraints

traffic maps

Planning Data /Measurements

Planning Data /Measurements

High-speed iterative process


Result AnalysisGraphical analysis of network KPIs

Pilot RSCP

Pilot Ec/Io

Pilot pollution areas / cell overlap

KPI statistics report

Coverage percentage of RSCP, Ec/Io per clutter class

Number of cell/site changes, cost overview

Improvement analysis

Graphical clustering of site changes


Ec/Io Before Optimisation


Ec/Io After Optimisation


Cell Overlap Before Optimisation


Cell Overlap After Optimisation


QoS Validation

Network simulations before/after optimisation with same traffic:

Ec/Io rejections reduced by 70%

SHO users reduced by 5%

UL load reduced by 16%

Throughput increased by 11%

At same GoS (5% outage):at least 25% more traffic possible!

Simulated Ec/Io80% Speech, 20% WWW


Summary

Make sure that the planning data reflects the actual situation in the network

Do not merely rely on predictions, use measurements when optimising a radio network

Consistent network improvements within short time

actix radioplan vodafone case study slides

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