cw test and propagation model tuning(fileminimizer)

8/12/2019 Cw Test and Propagation Model Tuning(FILEminimizer)

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HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential

CONFIDENTIAL

www.huawei.com

CW Test andPropagation Model

TuningISSUE 4.0

RNP Staff Training Dept.



HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 4

After this course, you will Know principle of propagation modeltuningKnow the procedure of CW testKnow the procedure of tuningpropagation model

Objectives




1 Principle of Model Tuning

2 CW Test Flow3 Pre-processing of CW Test Data

4 Propagation Model Tuning

Contents




Radio Propagation Model

Propagation model is used to predict the effect ofterrain, obstacle and artificial environment on thepath loss.

WCDMA common propagation models




Common Radio Propagation Models

Okumura/Hata modelFor: 900M 1500MHz

COST231-Hata model

For: 1500-2000MHz COST231 Walfish-Ikegami model

For: 800M-2000MHz

Keenan-Motley modelFor indoor propagation

SPM model in U-NetFor macro cell on 300M 2000M

Based on Statistics

Ray Tracing modelVolcano modelWaveSight model

WinProp model

Based on theory analyses




Radio Propagation Model in U-NetSPM model (Standard Propagation Model):

PathLoss = K1 + K2 log (d ) + K3 log (HTxeff ) + K4 *Diffraction loss +K5 log (d )× log (HTxeff ) + K6*(HRxeff ) + Kclutter *f (clutter)

K1 : constant (dB)K2: multiplier factor of log(d)d : distance between Tx antenna and Rx antenna (m)K3: multiplier factor of log(H Txeff )HTxeff : effective height of Tx antenna (m)K4: multiplier factor of diffraction loss, which must be a positive numberDiffraction loss : diffraction loss through the path with barriers (dB)K5 : multiplier factor of log(H Txeff )log(d)K6 : multiplier factor of HRxeff

HRxeff : effective height of Rx antenna (m)Kclutter : multiplier factor of for f(clutter)f(clutter ): average weighted loss caused by clutter

With a set of K parameter, we can make prediction for the planning area.




Typical Radio Propagation Environment

Name Description

Dense Urban There are dense buildings in the city, normally most of thebuildings are more than 10 floors high.

UrbanNormal area in cities. Buildings are not so dense. Normallythere are streets or planting areas between them. And fewbuildings are more than 10 floors high.

Sub-Urban Buildings are sparsely distributed, and mainly low buildings.

Country Village. Buildings are distributed very sparsely, and mainlyhouses.

Special Including mountain area, sea surface, highway, indoor,tunnel, etc.

Different radio scenario adopts different propagation model.




Principle of Propagation Model Tuning

Huawei take GENEX U-Net toperform propagation model tuning.

Y

Target PropagationEnvironment

Setup a Model

Collect datafrom field test

Actual PathLoss

Set the modelParameter

Prediction PathLoss

Compare

End

NMeet the precision request?




Propagation Model Tuning working flow

1. Decide the propagation environment2. Acquire site, setup the simulation site,

transmitting continuous wave (CW)signal

3. Drive test on the pre-planned route,collecting enough data

4. Post process the data, compare testresults with prediction results, and thentune the propagation parameters (K1,K2, …Kclutter)

GPS Satellite




Basic Principle of CW Test

TypificationThe CW test data must represent the characteristic ofelectromagnetic wave in this area.

Balance

The CW test data must represent the characteristic ofelectromagnetic wave by the proportion of different clutters inthis area.







Contents




2.1 Decide the Propagation Environment

Firstly, decide if it’s necessary to separate the planning area toseveral propagation environments, such as Dense Urban,Urban, Sub-Urban or Rural Area, etc.

Then for each environment, set proper initial propagation modelparameter, and perform dedicate CW test and propagation

model tuning.




2.2 Site Selection – Standards

1. Antenna height of the CW transmitter should be greater than 20m.

2. Antenna of the CW transmitter should be at least 5m higher than theobstacle objects nearby within 50m far.

Note: Here the obstacle mainly refers to the highest building on therooftop where the antenna is installed. The building where the site is

located should be higher than average height of surrounding buildings.

5 m




2.3 Setup Test Platform (2)

MobilityPower

Supplier

CWTransmitter

TX Antenna

CWReceiver




2.3 Setup Test Platform (3)

Record the gain or loss of all the RF parts:a) TX power of the CW transmitter

b) Loss of the RF cables

c) Gain of TX antenna

d) Loss of the connectors

e) Gain of Rx antennaThen with a, b, c and d, we can get the EIRP.




2.4 Plan the Drive Test route (1)

Rules to plan the routeLandform: The route must cover all main landforms in the area.

Height: The test route must cover landforms with different height inthis area if the landforms are up-and-down.

Distance: The route must cover near and far to the site. Butnormally no need to test in areas more than 2R far away to the site.

– R: Future cell radius in this area.

Direction: The route must be consistent on the horizontal andvertical route.

Length: The total distance of one CW test route should be longer

than 60km.Number of test samples: The more, the better. (At least 10,000samples, and at least 4 hours test time)




2.4 Plan the Drive Test route (2)

Rules to plan the routeOverlap: Overlap the test route in different sites as much aspossible to enhance the reliability of models.

Obstacle: Shadow areas behind walls should be avoided whenantenna signals are obstructed by the wall.

Such areas as under viaducts or in tunnels should be avoided. Ifhave to pass through such areas, data should be filtered after test.

If a directional antenna is adopted for a CW transmitter, the testroute should be planned within the main lobe coverage area of theantenna (don’t plan route in area behind the antenna).




2.5 CW Drive Test – Limitation of the speed

CW drive test data contains results affected by slow fading(shadow fading) and fast fading (Raileigh Fading).

To tune a model, only the effect by slow fading will be accept,but not fast fading.

To get rid of the effect caused by fast fading, enough samples

are need in a certain distance.Lee criteria says the request for sampling:

At least 50 samples on 40λ range, then the difference betweenmean value of test data and actual value can be less than 1dB

– λ : wavelength of the RF signal

Then the maximum vehicle speed: V max = 0.8λ*f – f : samples per second of the receiver




2.5 CW Drive Test - Equipment

Scanner – DTI (GPS build in GPS antennaRF antenna of scannerCables for data and powerLaptop

Probe and Dongle

Huawei GENEX Probe hasthe function for CW test.







Contents




3 Pre-processing of CW Test Data

2.1 Data Filtering

3.2 Data Dispersion

3.3 Data Binning

3.4 Format Conversion

Contents




3.1 Data Filtering

Six kinds of data should be filtered:1. Data tested in places where GPS is unable to

locate accurately (such as under the viaduct,

in the tunnel)

2. Data obtained when the distance to antenna

is too near or too far

3. Data obtained with too weak signals

4. Error data caused by inexact antenna pattern

5. Data with a loss exceed over 15~30 dB but

no reasonable reason

6. Other data inconsistent with the requirements

during the route planning of CW test




● ● ● ●

● ● ● ●

…. ….

3.2 Data Dispersion (1)

Principle:Sampling speed of the receiver is much more higher than that of theGPS . So there are many receiver samples stored together on eachGPS sample. Actually these receiver samples should be distributedone by one in time sequence between every two GPS samples.

Between two GPS sample, vehicle speed is regarded uniform, so thetime intervals between every two adjacent receiver samples are same.

1 GPS Sample andn Receiver Samples

ReceiverSamples

Many Receiver samplesshare one geography data




3.2 Data Dispersion (2)

Data Process:Equally distribute the receiver samples to the route section betweentwo GPS points in time sequence so that there will be sufficientpoints in every 40λ range on test route.

● ● ●…. ….

1 GPS Sample andn Receiver Samples

Each receiver sample hasits own geography data

● ● ● ● ● ● ● ● ● ● ● ● ● ● ●…. ….

Original GPSsample

FittingGPS data

Disperse




3.3 Data Binning (1)

Objective:Keep the impact of slow fading but eliminate the fast fading

According to Lee criteria: At least 50 samples on 40λ range, then

the error between the mean value of the data on this 40λ range

and the actual value can be less than 1dB.

Methods:Method 1 (Grid Binning) : Divide the whole area into 40λ*40λgrids , take the average value for data located in each grid, andtake the center of each grid as the new location.




…. ● ● ● ● ….

…. ● …. ● ● …. ● ● …. ● ● …. ● ….

3.3 Data Binning (2)

Methods:Method 1 (Grid Binning) : Divide the whole area into 40λ*40λ grids ,take the average value for data located in each grid, and take thecenter of each grid as the new location.Method 2 (Distance Binning) : Divide the drive test route intosections with 40λ length, take the average value for data located

on each section, and take the center of each section as the newlocation.

Before Binning

After Binning

40λ

Tool: Huawei Genex Probe, or CW Data Editor




3.4 Format Conversion

The data exported by Genex Probe is a .txt file with format:

X (Longitude) Y (Latitude) Power (dBm)

Data imported to U-Net is a .dat file

Format conversion can be implemented manually (save as .datfile)







Contents





4.1 Basic Knowledge

4.2 Model Tuning by U-Net

Contents

P d f




Procedure ofModel Tuning

YES

YES

NO

NO

YES

Perform AppropriateFiltering

ErrorSatisfactorily

Low?

Goto Next

Parameter

Is FilteringNecessary Analysis Results

SPM Calibration

CW data SPM

Model

Set Model

Parameter

Original Data is

Unreasonable.

Need to retest.

All Parametersfinished

Calibration?

End

NO




][][][

)(dBm

predicted

dBm

measured

dB

P P i E

Criteria to evaluate the model (1)

The main idea to evaluate the model is to compare thepredicted value to the actual test value for a certain area,then get a statistics result of the errors.

Suppose the error of sample i is:




Standard Deviation

dB E dB 22

dB8

8.0.. Coeff Corr

Criteria to evaluate the model (3)

A model is reasonable if the statistics of the error between thepredicted results and the actual results meet the followingrequests:

Mean Deviation

CorrelationCoefficient





4.1 Basic Knowledge

4.2 Model Tuning by U-Net4.2.1 Establish a Project

4.2.2 Establish a Propagation Model

4.2.3 Create the Transmitter

4.2.4 Import the CW test data &

Digital Map correction4.2.5 CW data Filtering

4.2.6 Implement the Tuning

4.2.7 Evaluate the Turned Model

Contents




Model Tuning Operation flow on U-Net

Establish a Project

Establish a Model

Create Transmitter

Import CW data &Map correction

Implement Tuning

Evaluate the Model

CW data Filtering




4.2.1 Establish a Project for Model Tuning

Create a new projectSelect ―UMTS in the dialog of ―Project type selection

Set the coordinate system

Set the coordinate system according to the digital map.

―WGS84 UTM Zones is widely used.

Import digital map

Import antenna pattern data




4.2.2 Establish a Model to be turned (1)

Create a new SPM model by duplicateCreate a new ―copy of standard propagation model by

duplicating on a exist ―standard propagation model . Then

rename is if necessary.

Set initial parameters for the new model

General Parameter

Common Parameter

– Select the effective antenna height. – Select calculation method of diffraction loss

Clutter Parameter




4.2.2 Establish a Model to be turned (2)

Initial K parameters of SPM model in normal Urban city

Frequency (MHz)

450 900 935 1805 2110K1 4.3 12.1 12.6 22 24.3K2 44.9K3 5.83K4 0.5K5 -6.55

K6 0




4.2.3 Create the CW Transmitter

Two way to create CW transmitter:By head file —— Suitable for batch importing the transmitters

Head file is a text file with extension name .hd , it contains basicinformation for a CW transmitter

e.g. test.dat DATE test 741790 32 54 0 0 0 23.04499751 113.7509966 Survey 0GPS 0 0 0 0 hard

Be aware to import the antenna before the head fileBe aware to import the CW data manually after the head file

Manually create —— It is more flexible for single CW transmitter As normal U-Net project, one by one set the antenna, site andtransmitter, etc. Pay attention to the latitude and longitude, EIRP, allthe feeder loss and connecter loss.




4.2.4 Import the CW data

Pre-process on the CW test data

For model tuning, U-Net only need latitude, longitude ant the

corresponding measurement power. Combine all data for one transmitter

to one .txt file, then import to U-Net or by copy and paste

Import the CW data

Method 1: Right click on the “ CW measurements in “ Explorer then

select ―New , then paste the CW data into the sheet. (By this method

there should not any blank tail in each row, otherwise U-Net will give a fail

result.)

Method 2: Similar to method 1, select ―Import from the context menu,

then browse to the CW data file. By this method, we can import several

files simultaneously.




4.2.4 Digital Map correction

Reason:GPS locating in CW test usually adopts WGS-84 and UTM projection.However, some digital maps in some country (e.g. China) do not usesuch projections. Correct digital maps if CW test data does notcorrespond to them.

Correction method:Correct four parameters on rectangular coordinates in a digital map torealize the optimal match with the test data.The four rectangular coordinates parameters are stored in files“ index.txt




4.2.5 CW data Filtering (1)

Data filtering:By distance:

– Recommended delete data in range r<0.1r or r>2r ( typically r = 1500m)

By signal strength:

– Recommended: delete data with Signal>-40dBm Signal<-110dBm

By Clutter:

– Recommended: delete clutters with number of samples less than 300





Select ―Filtering Assistant... on properties of the data.





In the clutter list, the un-checked clutter will be deleted.




4.2.6 Implement Tuning (1.1)

U-Net 2.1 (Build 2050) Right click on the model, select ―Automatic Calibration




4.2.6 Implement Tuning (1.2)

U-Net 2.2.1 Build2613 Right click on the model, select ―Calibration… , then select

―Automatic Calibration




Select the parameters to be tuned. Normally only tune K1 and K2must be tuned.

4.2.6 Implement Tuning (2)




Check if the Standard Deviation less than 8dB

4.2.6 Implement Tuning (result)




4.2.7 Evaluate the model (1)

Check if any K parameter exceed out of the scope.

Parameter Minimal Typical Maximum

K2 20 44.9 70

K3 -20 5.83 20

K4 0 0.5 0.8K5 -10 -6.55 0

K6 -1 0 0




Calculateprediction with

the tuned model


• Compare the test resultsto the prediction ones.

• Red is test value, blueone is prediction value.

U-Net 2.1Bulid 2050




4.2.7 Evaluate the model (2)CW

CW

Calculateprediction with

the tuned model

U-Net2.2.1 Bulid

2613

• Compare the test resultsto the prediction ones.

• Red is test value, blueone is prediction value.





1. Create a link budget project by RND to estimatethe cell radius

2. Compare the result to radius in similar cities3. If they are quite different, it means something is

wrong with the tuned model, we must find thereason.




Summary

Principle of model tuningProcedure of CW testProcedure of model tuning by U-Net



Thank youwww.huawei.com

cw test and propagation model tuning(fileminimizer)

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