Model Tuning Process on Aircom Asset

ASSET WORKSHOP Model Tuning MOBILINK-PAKISTAN

AGENDA

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Aim of Model Tuning

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CW Measurement - Site Selection - CW Drive Route Definition - Equipment configuration

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Model Tuning Process

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Model Calibration Analysis

ASSET WORKSHOP-2007, Rajendra

AIRCOM INTERNATIONAL Limited

2

Aim of Model Tuning

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Determine model parameters in accordance to realistic propagation effects existing within proposed regions.

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Minimise Standard Deviation Error.

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Make sure calibrated model corresponds well with the collected data is essential.

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Provide cost efficient Nominal Plan

ASSET WORKSHOP-2007, Rajendra

AIRCOM INTERNATIONAL Limited

3

CW Measurements and Model Calibration Process

Propagation Model Requirements Identification

Drive Route Definition

Site Selection

CW Survey Campaign Data Post Processing Data Data Validation Validation

Calibration

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YES Report

ASSET WORKSHOP-2007, Rajendra

Pass Model?

AIRCOM INTERNATIONAL Limited

4

CW MEASUREMENT z

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More or 10 sites per model. Less number of sites can be considered if modelled geographical area is fairly small. Within geographic region of model Spread of site heights representative of network sites heights within modelled region

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Allow measurements in all clutter types

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Rooftop sites are preferred in a case test transmitter has to be mounted

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Ease of access

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No blocking objects in close vicinity

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Nothing unusual, we are characterising the majority of the network not the minority

ASSET WORKSHOP-2007, Rajendra

AIRCOM INTERNATIONAL Limited

5

CW MEASUREMENT Distance z z

Must account for expected coverage propagation Must account for expected interference propagation

Clutter z

Sufficient measurement in all local clutter types ( >1000 )

Roads z z

Avoid street canyons, tunnels, elevated roads, cuttings etc Mix of radial and tangential roads

Miscellaneous z z z z z z

Do not plan a map along the roads with ground height above the transmitter antenna. Good balance between measurements taken in LOS and NLOS situations Do not plan a route across a big water surface, if site is on the one side of the lake, do not drive other lake side Avoid large blocking objects as high building or long roof Long enough to ensure sufficient data is captured Check map data validity

ASSET WORKSHOP-2007, Rajendra

AIRCOM INTERNATIONAL Limited

6

CW MEASUREMENT Spectrum clearance z During CW survey allocated test frequency shouldn’t be use for other purposes z 10-15KHz bandwidth monitoring z Check restrictions on test frequency TX EIRP Equipment configuration z Accurate Radiated Power setting, EiRP should be greater than 40dBm z Raw/Averaged data z Use Omni antenna with minimum vertical beam width of 12 degrees z Directional antenna can be used but in post processing everything beyond 3dBm should be dismissed Driving z z z

Do not drive out of RX noise floor Avoid street canyons, tunnels, elevated roads, cuttings etc Distance/Time triggering

ASSET WORKSHOP-2007, Rajendra

AIRCOM INTERNATIONAL Limited

7

DATA REQUIREMENT z

In order for model to be realistic, statistically sufficient number of data need to be collected.

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Common practice is to take 50 samples which gives one sample every 0.8λ.

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50 samples should be averaged and give the local mean.

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Common practise is to have at least 30000 data.

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30000 data gives total driven distance of 30000x40λ=198km or 20km per site for 1800MHz range. If this distance is not achievable due to limitation in drivable roads it is recommended to have more than 10 sites per model. As stated before, in a case of modelling small geographical area with 3 sites, tuning can be performed with 10000 data or 22km per site. The more data the model is more realistic

ASSET WORKSHOP-2007, Rajendra

AIRCOM INTERNATIONAL Limited

8

VALIDATION DATA z

Compare the site data (photographs, surrounding clutter and terrain profile) to the Clutter and DTM layer of the map data provided.

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Check the driven routes against vectors within the map data.

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Filter out any invalid data that may cause anomalies in the calibration process

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Make sure that details relating to a site (EIRP, Location, Height, Antenna file) correspond to reports from CW Survey. Use Asset utilities to get visual representation of the received signal vs distance.

ASSET WORKSHOP-2007, Rajendra

AIRCOM INTERNATIONAL Limited

9

VALIDATION DATA z

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Filter clutter types that have less than 500 bins. Clutter offsets or them will be estimated later in the model tuning process. Filter out any file which shows extreme in signal level. Unusually high signal level at far distance can be caused by reflection over big water surface, or driving along route which is higher than antenna.

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Unusually weak signal level can be caused by driving behind blocking object.

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Okumura –Hata can’t model above situations, therefore these data must be filtered out.

ASSET WORKSHOP-2007, Rajendra

AIRCOM INTERNATIONAL Limited

10

K PARAMETERS z

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K3 and K4 are not altered. This is because they relate to mobile height which in a typical cellular system is constant making these coefficients redundant. K7 is the diffraction parameter. It can be determined by tuning just NLOS data. All K parameters must keep the same polarity as in the original Okumura Hata model K1, K2, K7 >0 K3, K5, K6