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Etisalat AcademyAnand Alexander Page 1 of 25

PREDICTION MODELS

Anand Alexander

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By the end of this session, the participants will be able to:

Choose appropriate prediction models for different propagation

environments, topography, morphology and frequency ranges.

Objectives

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Okumura- Hata Model

Empirical Models:

- Okumura- Hata model

- Hata-Cost 231 model

- Walfisch-Ikegami model

- Keenan Motley model

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Okumura- Hata Model

HATA Model based upon 4 Environment Types and applies to:

Large Cells normally > 3km - High Sites Frequency, f: 150 - 1,000 MHz

Base Station Antenna Height, Hb: 30 - 200 m Mobile Antenna Height, Hm : 1 - 10 m

Transmission Path Length, d: 1 - 20 km

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Okumura- Hata Formula: Loss for Urban

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Land Cover Correction Factors (RACE Project)

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Okumura- Hata Model: Path Loss vs. Distance

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COST 231- Hata Model

900MHz GSM networks and other UHF/VHF services were modeled

successfully with the Hata formulae

1800MHz GSM frequencies became available within Europe, however

much less research had been carried out investigating the propagation of

higher frequencies. Empirical formula such as Hata was not available

The European Co-Operation in the field of Scientific and Technical

research (COST) developed the Hata formula further to include higher

frequencies (up to 2GHz)

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COST 231- Hata Model

COST 231 HATA Model is based upon the 4 Environment Types of Hata and applies to:

Large Cells normally > 3km

Frequency, f: 1,500 - 2,000 MHz

Base Station Antenna Height, Hb: 30 - 200 m

Mobile Antenna Height, Hm: 1 - 10 m

Transmission Path Length, d: 1 - 20 km

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COST 231- Hata Model: Loss Urban

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Exercise

Urban Environment

D = ?

Max Propagation Loss = 150dB

Given a UMTS Macro Urban Cellcalculate the Maximum Cell Uplink

Range given the following

parameters:

Base Station Height = 30m

Mobile Height = 1.5m

Frequency = 2GHz Maximum Loss (from a Link

Budget calculation) = 150dB

No in-building penetration

Use COST231 Hata Model

assuming a medium sized city

and/or sub-urban centres with

moderate tree density

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BTS Height and Path Loss Coefficient

Note that both Hata and COST 231 Hata have distance decay factors as:

[44.9 - 6.55 log 10 (Hb )] log 10 (d)

Base Station Height has the effect of varying decay rate

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Okumura Hata (Ericsson Variant)

A variant of the Okumura-Hata model has been developed by Ericsson. This

model can be used for rough estimations of the size of macro cells,

Lpathloss= A 13.82 log hb a(hm) + (44.9 6.55 log hb) log R

The cell range is the distance, R, corresponding to maximum allowed pathloss, Lpathmax. According to equation, the cell range is given by:

R =10 where

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Relationship between Path loss and Range

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Relationship between Path loss and Range

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Walfisch Ikegami Model

Hata and COST 231 Hata suited to cells having moderately high

base stations with cells in excess of 3km

For cells < 3km, and base station heights below 20m, particularly

microcells Hata models break down

Use of Walfish-Ikegami model for dense urban environments where

cell coverage is severely limited by clutter as with dense urban areas

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Macrocellular Modelwhere Base Station height

> Average Rooftop Height,

but might be < highest

rooftop height

Based upon MultipleDiffractions from Rooftops

Diffraction and Reflection

mechanics dominate

Input variables relate to

geometry of environment

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Frequency, f: 800 - 2,000 MHz

Base Station Antenna Height, Hb: 4 - 50 m

Mobile Station Antenna Height, Hm : 1 - 3 m

Transmission Path Length, d: 0.02 - 5 km

Also Considers

Height of buildings, HroofWidth of roads, wBuilding separation, bRoad orientation w,r.t to direct radio path, f( )

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Line of Sight exists between base and mobile antennas:

Lb = 42.6 + 26logd + 20logf ; d > 20 m

Lb = Lo (free space loss)

Line of Sight exists between base and mobile antennas:

Lb = LFS + LMSD + LRSDS

(1) LFS free space loss

(2) LMSD multi-screen diffraction loss

(3) LRSDS roof-top-street diffraction loss

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Without free Line-of-Sight between Base Station and Mobile Station:L

b= L

o+L

rts+ L

msd

Free space loss,

Lo

= 32.4 + 20.Log10(dkm) + 20.Log10 (fMHz)

Roof-top to street diffraction and scatter loss,

Lrts

= -16.9 - 10.Log10 (w) + 10.Log10 (f) + 20.Log10 (Hroof - Hm) + Lcriwith

Lcri

= -10 + 0.354. for 0

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Exercise

Calculate using the Walfish -Ikegami model, the path loss for UMTS working in

the 2GHz band:

a. For the NLOS conditions over a distance of 3 km, given f = 900 MHz, base

station antenna height is 31.5 m, mobile station antenna height is 1.5 m, building

height is 21.5 m, street width is 30 m, width of building is 20 m. The street

orientation is on the average 15 with respect to the radio path.

b. For the LOS conditions over a distance of 3 km

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Pico cell Models

Used when micro and macro cell networks cannot cope

with either signal strength or capacity requirements.

There are two types of Radio propagation in a pico cell:

LOS following a Rician distribution

NLOS following a Rayleigh distribution

Path Loss:

pWkFc

dL dB

4log20

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Suggested values of F and W in dB (IEEE report)

Building Type F(dB) W(dB)

Airport 15 4.0

Conference center 30 3.7

Hospital 11 3.6

Office 15 2.2

Parking garage 12 4.3

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General Planning Software Model (usedby Huawei)

Lp = K1 + K2logd + K3(hm) + K4log(hm) + K5log(Heff) + K6log(Heff) logd + K7diffn + Kclutter

The general planning software model expressions is:

K1-Constant related with the frequency (MHz);

K2-Constant related to the distance (km);

K3, K4-MS antenna height (m) correction factor;

K5, K6-BS antenna height (m) correction factor;

K7-Diffraction correction factor;

Kclutter-Ground fading correction factor;d-Distance between the BS and MS (km);

hm, Heff-Valid heights of the MS antenna and BS antenna (m)

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Clutter and K Parameters

0Urban

5Dense urban

-2.90Village

-2.50Parallel low build ings

-2.50Suburban

16High building

5.00Industrial & commercial area

13.00Forest

-1.00Rangeland

-2.00Open areas

-3.00Watery land

-3.0Inland water

Attenuatio

n

Clutter

0Urban

5Dense urban

-2.90Village

-2.50Parallel low build ings

-2.50Suburban

16High building

5.00Industrial & commercial area

13.00Forest

-1.00Rangeland

-2.00Open areas

-3.00Watery land

-3.0Inland water

Attenuatio

n

Clutter

-0.8K7

-6.55K6

-13.82

0.00

-2.49/800(urban)

-2.93/2000 (urban)

0/800 (large city,-

2.93/2000 (large city )

K3

44.9K

149/800 (urban),

162.5/2000 (Urban)

145/800 (big city)

165.5/2000 (big city)

K1 (MHz)

Parameter valueK parametername

-0.8

-6.55

-13.82K5

0.00K4

-2.49/800(urban)

-2.93/2000 (urban)

0/800 (large city,-

2.93/2000 (large city )

44.9K2

149/800 (urban),

162.5/2000 (Urban)

145/800 (big city)

165.5/2000 (big city)

Parameter valueK parametername

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Question and Answers

Discussion

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