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WCDMA RNPCW Test and Propagation Model Tuning

Prepared by WCDMA RNP

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Introduction

CW test (Continuous Wave test) is an important

step of Propagation Model Tuning. According

to the CW test data (including latitude/longitudeand received level) and corresponding Digital

maps, we can get the accurate Propagation

Model through tuning.

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Table of Contents

Training.huawei.com

Chapter 1 Principle and Purpose of CW

Test

Chapter 2 CW Test Flow

Chapter 3 Analysis of CW Test Data

Chapter 4 Propagation Model Tuning

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Principle and Purpose of CW test

Section 1 Basic Principle of

Radio Propagation

Section 2 Principle of

Propagation Model Tuning

Section 3 Purpose of CW Test


CW Test

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Radio Waveband Classification

Frequencies in different bands have different propagation characteristics.

Waweband Frequency WavelengthExtremely long wave

(EFL, extremely low frequency) 330Hz 105104 kmSpecial long wave

(SLF, special low frequency) 30300Hz 10410

3km

Ultra long wave

(ULF, ultra low frequency 3003000Hz 10310

2km

Very long wave

(VLF, very low frequency) 330kHz 10210 km

Long wave

(LF, low frequency 30300kHz 101 km

Medium wave

(MF, medium frequency) 3003000kHz 10310

2m

Short wave

(HF, high frequency) 330MHz 10210m

Very short wave

(VHF, very high frequency 30300MHz 101 m

Decimetric wave

(UHF, ultra high frequency)300

3000MHz 10

210 cm

Centimeter wave

(SHF, special high frequency)330GHz 101 cm

Millimeter wave

(EHF, extremely high frequency) 30300GHz 101 mm

Microwave

Submillimeter wave

(ultra extremely high frequency) 3003000GHz 10.1 mm

Note: The above table is from Electromagenetic, Antenna and Electric Wave Propagation, written by Pan Zhongying.

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Electric field Electric fieldElectric field

Oscillator

Transmission direction of electric wave

Magnetic fieldMagnetic field

Generation of Electromagnetic Wave

Based on Maxwell equations set:

The variable magnetic field can excite eddy electric field and variable electric field can also

excite eddy magnetic field.

Continuous electromagnetic oscillation (electromagnetic wave) forms due to mutual

excitation of alternating electric and magnetic field.

The speed of electromagnetic wave only varies with electric and magnetic characteristics of

medium. The propagation speed of electric microwave in vacuum equals that of light invacuum.

Light and electromagnetic wave are essentially the same. Light is electromagnetic wave of a

certain wavelength.

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Propagation of Electromagnetic Wave

Ripple in the pond: Energy is propagated around from the source point

and gradually weakens.

Electromagnetic wave is similarly propagated except that (when the

radiation source is isotropically effective ideal point source):

It is propagated in the form of spherical wave in three-dimension space.

The propagation media are different, including air, obstacle and reflector.

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Theory of Radio Propagation

In the free space, sine wave emitted by point source radiates

spherical waves in all directions. This point source is called

isotropically effective radiation one.

Suppose transmitted power of point source is Prad (W), the power of

unit area d (m) away (namely, Poynting vector) is:

For actual antennas, if radiated power is Pt (W) and antenna gain is Gt

(dBi) , Poynting is:

)(W/m4

2

2d

PP radfs

)(W/m4

2

2d

GPP ttfs

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Theory of Radio Propagation

Suppose effectively received area of the Rx antenna is Ae

(m2) and the

gain is Gr (dBi), they satisfy the following equation:

)(mG4

2

r

2

eA

Therefore, the received power at the place d (m) away is:

)(WGGPd)(44

4

rtt2

22

2

rttefsr

G

d

GPAPP

Radio network planning and design are based on propagation loss.

Free space propagation loss is:

)(dB)d4

log(20)GG

1log(10

rt

t

rfs

P

PL

)(dBlog20log204532 )(f)(d.L MHzkmfs

Other propagation models are developed on the basis of free space

propagation model.

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Reflected wave of buildiDiffracted waveDirect waveReflected wave on the g

Characteristics of Radio Propagation

Electric wave propagation system

of Land Mobile Communications

Radio

propagation in

actual

environment

LOS and NLOS

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Characteristics of Radio Channels

d (m)

Pr (dBm)

10

20

30

-20

-40

-60

Slow fadin

Fast fadin

Radio channels vary with

users position and time.

Multipath scattering and

obstruction result in

acute changes to

received power.

Slow fading

Attenuation: Pr is in direct proportion to

1/dn.

Shadow: obstructed by barriers

Fast fading

Multipath effect Fast changes to signal strength at small

distance and time interval

Doppler frequency shift Delay spread

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Diversity Technology

Measures against fast fading- diversity technologies

Explicit diversity

Space diversity

Polarization diversity

Frequency diversityGSM-frequency hopping; WCDMA-

spread spectrum

Others: directional diversity, field diversity and transmit

diversity

Implicit diversity

Implicit diversity uses signal processing technologies tohide diversity functions into signals under transmission,

such as RAKE reception technology, channel interlacing

and error code correction.

Regarded as time diversity

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Delay Spread

Multipath propagation: Signals on different paths reach the

receiver at different time.

When the receiver fails to differentiate multipath signals, co-

channel interference (CCI) occurs. In the WCDMA system,

only the multipath delay larger than one chip period

(0.26s)can be recognized.

Typical value (s): Open < 0.2, Suburban = 0.5, Urban = 3

Solutions Equalization and RAKE technology

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Doppler Frequency Shift

Example of Doppler effect: A train is passing by you.

f1

f2

f3

V(km/h)

Doppler frequency shift in Mobile Communications

Vspeed of MS

angle where

signals arrives

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T

R

T

R

Diffraction loss Penetration loss

Clutter loss

Loss

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Characteristics:Electromagnetic wave is diffused around at the diffraction

point.

Diffracted wave covers all directions except for barriers.

Diffusion loss is the most serious.

Calculation formula is complicated, varying with differentdiffraction constants.

Diffraction Loss

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0 0 0 0

Dw1 w2

E1

E2

XdBmWdBm

Penetration loss=X-W=B dB Reflection and refraction of

electromagnetic wave through thewall

Indoor signals depend on penetration loss of building.

Signals are different at the indoor window and in the middle of room.

Building materials have great effect on penetration loss.

The reference angle of electromagnetic wave have great effect

on penetration loss.

Penetration Loss

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Obstacle/penetration loss is:Partition obstruction: 520dB

Floor obstruction:20dB

Indoor loss value is function of floor height: -1.9dB/floor

Obstruction of furniture and other barriers: 215dBThick glass: 610dB

Penetration loss of the carriage of the train: 1530dB

Penetration loss of lift: 30dB or so

Loss of thick leaves: 10dB

Penetration Loss

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Ground type Water Rice paddy Field City, mountain

and forest

Equivalent ground

reflection coefficient

0.91 0.60.8 0.30.5 0.10.2

Reflection loss (dB) 01 24 610 1420

Reflection Loss

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Radio Propagation Environment

Radio propagation environment determines the propagation

models directly. And propagation environment is impacted by the

following factors:

Landform: high mountain, hill, plain, waters, and vegetationClutter: building, road and bridge

Noise: natural noise and artificial noise

Climate: rain, snow and ice (tiny effect on UHF band)

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Type of radio environment

Radio environment is classified as follows, according to ITU-R P.1411-1and specific conditions in China.

Propagation

environment

Description

Dense urban Many tall buildings, signals fail to diffract from the roof

of building .

Urban Signals can diffract from the roof due to low buildings

and wide streets.

Suburban Low and sparse buildings

Rural Low and sparse buildings, but with lots of vegetation

Mountainous

areas

Road

Indoor

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Type of propagation environment

The corresponding cell type is as follows:

Cell type Cell type Typical antenna installation

Macro-cell >500 m Installed outdoors, higher than average height of

surrounding roofs

Micro-cell 100~500m Installed outdoors, lower than average height of

surrounding roofs

Pico-cell

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Principle and Purpose of CW Test


Radio Propagation

Section 2 Theory of


Section 3 Purpose of CW

Test


CW Test

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Radio Propagation Model

Propagation model is used to predict the effect of terrain,obstacle and artificial environment on the path loss.

WCDMA common propagation models

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Okumura/Hata modelFor: 900M2000MHz

COST231-Hata model

For: 1500-2000MHz COST231 Walfish-Ikegami model

For: 800M-2000MHz

Keenan-Motley model

For indoor propagationPropagation model in UNET

For macro cell on 300M2000M

Common propagation models


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L=K1 + K2log(d) + K3log(HTxeff) + K4 Diffraction

+ K5log(d) log(HTxeff) + K6(HRxeff) + Kclutterf(clutter)

K1: constant (dB)

K2: multiplier factor of log(d)

d: distance between Tx antenna and Rx antenna (m)K3: multiplier factor of log(HTxeff)

HTxeff: effective height of Tx antenna (m)

K4: multiplier factor of diffraction loss, which must be a positive valueDiffraction loss: diffraction loss through the path with barriers (dB)

K5: multiplier factor of log(HTxeff)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

Model in UNET:

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Principle and Purpose of CW Test


Radio Propagation

Section 2 Theory of



Test


CW Test

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Purpose of CW Test

Compare CW test data

with prediction results,

and then tune the

propagation parameters

to improve the accuracy

of coverage prediction.

GPS

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Theory and Purpose of CW Test


Radio Propagation

Section 2 Theory of



Test


CW Test

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Basic Principle of CW Test

Typification

The CW test data must represent the characteristic of

electromagnetic wave in this area.

Balance

The CW test data must represent the characteristic of

electromagnetic wave by the proportion of different

clutters in this area.

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Table of Contents

Training.huawei.com

Chapter 1 Theory and Purpose of CW Test


Chapter 3 Analysis of Test Data


CW T t Fl

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CW Test Flow

Section 1 Site Selection

Section 2 Building Test

Platform in Networking

Section 3 Drive Test

Sit S l ti

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Site Selection

Principles of site selection

Number of sites: It is usually agreed that a minimum of 5 sites should be

tested in large and dense city, but one site is enough in the city, which

mainly depends on antenna height and EIRP.

Representation: Site selection should aim to cover all types of clutter

(from the digital map) in the coverage zone.

Multiple models: Define the corresponding zone of each model if the test

environment requires multiple models to describe its propagation

characteristics.

Overlap: Increase measurement overlap area between each site as

much as possible. But reasonable inter-site distance should be ensured.

Obstacle: The data should be filtered in the subsequent processing if

obvious obstacle exists.

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Site Selection

Standards of site selection

a. Antenna height should be greater than 20m.

b. The antenna should be 5m higher than the nearest obstacle.

c. The obstacle mainly refers to the highest building on the roof

where the antenna is installed. The building where the site is

located should be higher than average height of surrounding

buildings.

5m

CW T t Fl

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CW Test Flow


Section 2 Building Test

Platform in Networking


B ildi T Pl f i N ki

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Building Test Platform in Networking

Tx subsystem: Tx antenna, feeder, high-frequency signal sourceand antenna holder

Rx subsystem: test receiver, GPS receiver, test software and

laptop

High frequency signal

source

Signal source TMA

Power supply

Tx antenna

Rx antenna Drive testinstrument

Build-in GPS

Laptop

RF cable 1 RF cable 2

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Building Test Platform in Networking

Record the gain of the following parts on

signals during networking:

Tx power of signal source

Loss of RF cable

Gain of Tx antenna

Gain of Rx antenna

CW T t Fl

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CW Test Flow


Section 2 Building TestPlatform in Networking


D i T t

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Drive Test

Keep to the following standards to select a test path

Landform: The test route must cover all main landforms in the area. Height: The test route must cover landforms with different height in

this area if the landforms are up-and-down.

Distance: The test route must cover different positions from the site

in the area.

Direction: The test points must be consistent on the horizontal and

vertical route.

LengthThe total distance of one CW test should be longer than

60km.

Number of test points: The more, the better.

Overlap: Overlap the test route in different sites as much as

possible to improve the reliability of models.

Obstacle: Shadow areas behind this wall should be avoided when

antenna signals are obstructed by the wall at a side.

Drive Test

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Drive Test

Lee criteria for sampling: 50 samples by 40

The maximum vehicle speed: Vmax=0.8/Tsample

Delete test results from the sampled data under abnormal

conditions:

Fading over 15~30db without reasonable causes

In tunnels

Under the viaducts

Select test routes from the main lobe coverage area if

directional antennas are adopted for a CW test.

T bl f C t t

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Table of Contents

Training.huawei.com

Chapter 1 Theory and Purpose of CW Test




Analysis of Test Data

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Section 1 Data Filtering

Section 2 Data

Dispersion

Section 3 Data Binning

Section 4 Format

Conversion

Data Filtering

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Data Filtering

Data to be filtered is as

follows:

1. Data tested in the places where

GPS is unable to locate

accurately (such as under the

overhead rack, in the tunnel).

2. Data obtained when the distance

to antenna is too near or far.

3. Data obtained with too weaksignals.

4. Error data caused by inexact AP

(antenna pattern).

5. Other data inconsistent with the

requirements during the route

design of CW test.


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Section 2 Data

Dispersion


Section 4 Format

Conversion

Data Dispersion

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Data Dispersion

Propagation in mobile communications can be

indicated as follows:

r(x) = m(x)r0(x)

X: distance

r(x): received signals

r0(x): Raileigh Fading

m(x): local mean value, the combination of long-term fading

and space propagation loss

2L: average length between sampling areas, also called

intrinsic length

Lx

Lx

dyyrL

xm )(2

1)(

Data Dispersion

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Data Dispersion

The CW test is to obtain the local mean value of each geography

location in some areas as far as possible, i.e. the difference of r(x)

and m(x) should be the minimum value. In this sense, effect of

Raileigh Fading should be excluded.

When the intrinsic length equals 40 wavelength and the number

of sampling points is 50, the difference of test data and actual

local mean value can be less than 1dB according to Lee criteria.

Intrinsic length is average length for binning (2G band is 6 m

long, namely, 40 wavelength)

Since the locating speed of GPS is far lower than the receiving

speed of the receiver, the dispersion processing is required

before the binning.

Data Dispersion

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Data Dispersion

The principle of dispersion processing is as follows:

Conditions:

There are many test records arranged under each locating

point in time sequence because the receiving speed of the

receiver is far higher than the locating speed of GPS.

The vehicle speed between two locating points is uniform.

The time interval between every two measurement records

is the same.

Processing:

Equally distribute these records to the route section between

two points in time sequence so that there will be sufficient

points in every 6m range on test route.


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Section 1 Data filtering

Section 2 Data

Dispersion


Section 4 Format

Conversion

Data Binning

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Data Binning

Objectives:

Reserve the impact of slow fading but eliminate the fast fading

Methods:

Method 1: make grids for the whole area with 6m side, perform

the arithmetic average for the data located in each grid, and thentake the grid center as the new location.

Method 2: divide the path into sections in equal interval with 6m

for each, and perform the arithmetic binning for the data in each

section to select some point for the location of mean value.

Tool: CW Data Editor


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Section 2 Data

Dispersion


Section 4 Format

Conversion

Format Conversion

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Format Conversion

The data format exported by Agilent E74xx Series is

Data format imported to UNET is

Format conversion can be implemented manually

(saved as .dat file)

X Y CW_Power_List_

_Freq__Hz

CW_Power_List__

Ampl__dBm

Time Date

X Y CW_Power_List__Ampl__dBm

Table of Contents

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Table of Contents

Training.huawei.com

Chapter 1 Principle and Purpose of CW Test




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Preparations

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Preparations

Installing network planning software: UNET is powerful planning and optimization software and

model tuning is only one of its functional modules.

Creating a project In UNET, perform planning and optimization model tuning

based on each project.

Importing antenna pattern file

Correctly import the antenna pattern varying with different

manufacturers


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Section 1 Preparations

Section 2 Propagation

Model Tuning

Propagation Model Tuning Flow

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Propagation Model Tuning Flow

YES

NO

NO

YES

Change Model Parameter

Perform Appropriate

Filtering

CW Data

SPM Model

Document

Change

SPM CELIBRATION

Analysis Results

ErrorSatisfactorily

Low?

Goto Next

Parameter

Is Filtering

Necessary


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Establishing a model

Establish a standard macrocell model to be tuned.

Select the effective antenna height.

Select a calculation method of diffraction loss.

Importing data

Import CW test data file into the project.


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Map correction

GPS locating in CW test usually adopts WGS84 and UTM

projection. However, digital maps in China do not use such

projections and reference plane. Correct digital maps if CW test

data does not correspond to them.

Correction method:

Correct four parameters on rectangular coordinates in a

digital map to realize the optimal match with the test data.


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Setting Filtering

Distance filtering:

Filter the data of which r is less than 150m or r is greater

than 3000m.

Signal strength filtering:

Filter the data of which Signal is greater than -40dBm orSignal is less than -121dB.

Clutter filtering

Filter the Clutter in which sampling points are less than 300.


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Parameter tuning

L=K1 + K2log(d) + K3log(Heff) + K4 Diffraction

+ K5log(d) log(HTxeff) + K6(HRxeff)

+ Kclutterf(clutter)

Tune such parameters as log(d), log(Heff), Diff,

log(d)log(Heff), Hmeff and Klutter to finally tune SPM

propagation model.


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calculatedvalues for thevariable

ERROR (measurement prediction)

Regression line


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opagat o ode u g


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p g g

Correction of propagation model parameters in a city

Parameter

K

Reference value

K1 23.2

K2 44.90

K3 5.83

K4 0.5

K5 -6.55

K6 0


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p g g

Analysis of correction results

Analyze correctness of the acquired model after correction.

Evaluate the correctness of the model with Std Dev, which refer

to the binding degree of the acquired model and actual test

environment.

Make Std Dev less than 8 as much as possible in actual modeltuning, which indicates that the tuned model and actual test

environment are well bound.

Summary

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y

After completing this course, you should be

able to master:

Principle and purpose of CW test

Process of CW test

Process of propagation model tuning

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Than

kyou!

huawe

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