Modul 2_LargeScaleFading - WCS

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WIRELESS COMMUNICATION. SYSTEM Modul 2 Large Scale Fading Faculty of Electrical Communication IT Telkom 2012 Modul 2 Large Scale Fading

Transcript of Modul 2_LargeScaleFading - WCS

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WIRELESS COMMUNICATION. SYSTEMModul 2 Large Scale Fading

Faculty of Electrical CommunicationIT Telkom

2012Modul 2 Large Scale Fading

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Subject

a. Path Loss Modelb. Model Okumura-Hatta, COST 231c. Model Walfish Ikegami, LEE

a. Path Loss Modelb. Model Okumura-Hatta, COST 231c. Model Walfish Ikegami, LEE

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IntroductionIn general, the received signal at the receiver point is the sum of thedirect signal and the number of signals reflected from various objects. Inmobile communications, reflection will be caused by:

• Environment• Buildings• Moving object, for example vehicles

Variation of the magnitude and phase of wave reflectiondepends on the reflection coefficient, the trajectory, and alsodepending on the angle of arrival. Thus, differences in the directsignal and reflected signal is:

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Variation of the magnitude and phase of wave reflectiondepends on the reflection coefficient, the trajectory, and alsodepending on the angle of arrival. Thus, differences in the directsignal and reflected signal is:

• Amplitude, depending on the magnitude of wave reflectioncoefficient

• Phase, depending on the phase variation of wave reflectionand path distance difference between the direct wave andreflecting wave

The worst condition occurs when the direct wave and reflection wavehas the same magnitude and different phases 180o. In such conditions, thedirect wave and its reflection will eliminate each other (completecancellation )

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Wireless Propagation Radio

Free Space LossDiasumsikan terdapat satu sinyal langsung (line of sight path)sangat mudah memprediksi dengan free space formula

ReflectionTerdapat sinyal tak langsung datang ke receiver setelahmengalami pantulan terhadap object. Mungkin terdapat banyakpantulan yang berkontribusi terhadap besarnya delay.

DiffractionPropagasi melewati object yang cukup besar seolah-olahmenghasilkan sumber sekunder, seperti puncak bukit dsb.

ScatteringPropagasi melewati object yang kecil dan/atau kasar yangmenyebabkan banyak pantulan untuk arah-arah yang berbeda.

Free Space LossDiasumsikan terdapat satu sinyal langsung (line of sight path)sangat mudah memprediksi dengan free space formula

ReflectionTerdapat sinyal tak langsung datang ke receiver setelahmengalami pantulan terhadap object. Mungkin terdapat banyakpantulan yang berkontribusi terhadap besarnya delay.

DiffractionPropagasi melewati object yang cukup besar seolah-olahmenghasilkan sumber sekunder, seperti puncak bukit dsb.

ScatteringPropagasi melewati object yang kecil dan/atau kasar yangmenyebabkan banyak pantulan untuk arah-arah yang berbeda.Modul 2 Large Scale Fading

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Radio Propagation Mechanisms

R

S

transmitterStreet

Building Blocks

D

S

R: ReflectionD: DiffractionS: Scattering

receiver

D

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Efek propagasi multipath pada kanal wirelessmobile adalah:– Large scale fading Large scale path loss– Small scale propagation

Large scale path loss– Large attenuation dalam rata-rata– Daya sinyal terima menurun berbanding terbalik dengan

pangkat- terhadap jarak , dimana umumnya 2 < < 5(untuk komunikasi bergerak). disebut Mean PathlossExponent

– Sebagai dasar untuk metoda prediksi pathloss Small scale

– Flukstuasi sinyal yang cepat disekitar nilai rata-rata(large scale) - nya

– Doppler spread berhubungan dengan kecepatan fading(fading rate)

– Penyebaran waktu berhubungan dengan perbedaan delaywaktu kedatangan masing-masing sinyal multipath.

Efek propagasi multipath pada kanal wirelessmobile adalah:– Large scale fading Large scale path loss– Small scale propagation

Large scale path loss– Large attenuation dalam rata-rata– Daya sinyal terima menurun berbanding terbalik dengan

pangkat- terhadap jarak , dimana umumnya 2 < < 5(untuk komunikasi bergerak). disebut Mean PathlossExponent

– Sebagai dasar untuk metoda prediksi pathloss Small scale

– Flukstuasi sinyal yang cepat disekitar nilai rata-rata(large scale) - nya

– Doppler spread berhubungan dengan kecepatan fading(fading rate)

– Penyebaran waktu berhubungan dengan perbedaan delaywaktu kedatangan masing-masing sinyal multipath.

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• Fading didefinisikansebagai fluktuasi daya dipenerima

• Karena perilaku sinyalpada kanal multipathadalah acak, makaanalisis fadingmenggunakan analisisprobabilitas stokastik

• Fading terjadi karenainterferensi atausuperposisi gelombangmultipath yang memilikiamplitudo dan fasa yangberbeda-beda

Definisi Fading

Fading

Large Scale Fading

Small Scale Fading

TerdistribusiLognormal

Terdistribusi Rayleigh / Rician

• Fading didefinisikansebagai fluktuasi daya dipenerima

• Karena perilaku sinyalpada kanal multipathadalah acak, makaanalisis fadingmenggunakan analisisprobabilitas stokastik

• Fading terjadi karenainterferensi atausuperposisi gelombangmultipath yang memilikiamplitudo dan fasa yangberbeda-beda

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Definisi : local mean ( time averaged) dari variasi sinyal

Large Scale Fading disebabkankarena akibat keberadaan obyek-obyek pemantul serta penghalangpada kanal propagasi sertapengaruh kontur bumi,menghasilkan perubahan sinyaldalam hal energi, fasa, serta delaywaktu yang bersifat random.

Sesuai namanya, large scalefading memberikan representasirata-rata daya sinyal terima dalamsuatu daerah yang luas.

Statistik dari large scale fadingmemberikan cara perhitunganuntuk estimasi pathloss sebagaifungsi jarak.

Kuat sinyal (dB)

Jarak

Definisi : local mean ( time averaged) dari variasi sinyal

Large Scale Fading disebabkankarena akibat keberadaan obyek-obyek pemantul serta penghalangpada kanal propagasi sertapengaruh kontur bumi,menghasilkan perubahan sinyaldalam hal energi, fasa, serta delaywaktu yang bersifat random.

Sesuai namanya, large scalefading memberikan representasirata-rata daya sinyal terima dalamsuatu daerah yang luas.

Statistik dari large scale fadingmemberikan cara perhitunganuntuk estimasi pathloss sebagaifungsi jarak.Modul 2 Large Scale Fading

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Equal level main & reflected pathLower level reflected path

Rx Level

WidebandChannel

NarrowbandChannel

Frequency

Channel Frequency Responset

t

t

t

Channel PulseResponse

Direct Wave

Reflected WaveResultant

Sinyal multipath juga akan menyebabkan distorsi sinyal / cacat sinyal.Problem ini secara khusus berkaitan dengan bandwidth sinyal yangdigunakan dalam komunikasi mobile, dan juga karena respon pulsayang berbeda dari sinyal multipath

Equal level main & reflected pathLower level reflected path

Rx Level

WidebandChannel

NarrowbandChannel

Frequency

Channel Frequency Responset

t

t

t

Channel PulseResponse

Direct Wave

Reflected WaveResultant

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KANAL MULTIPATH FADINGKANAL MULTIPATH FADINGFADING :Fenomena fluktuasi daya sinyal terima akibat adanyaproses propagasi dari gelombang radio.

Pengaruh fading terhadaplevel sinyal terima adalahdapat menguatkan ataupunmelemahkan tergantungphasa dari sinyal resultanmasing-masing path.

CA

D

BR eceiverTransm itter

Pengaruh fading terhadaplevel sinyal terima adalahdapat menguatkan ataupunmelemahkan tergantungphasa dari sinyal resultanmasing-masing path.

CA

D

BR eceiverTransm itter

A: direct pathB: reflectionC: diffractionD: scattering

PR

PR_thres

t0Modul 2 Large Scale Fading

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Multipath dalam kanal radio menyebabkan :

Lingkungan kanal radio mobile ( indoor / outdoor ) seringkalitidak terdapat lintasan gelombang langsung antara Tx danRx, sedemikian daya terima adalah superposisi dari banyakkomponen gelombang pantul masing-masing memilikiamplitudo dan fasa saling independen

Multipath Fading , atau Short Term Fading

• Perubahan yang cepat dari amplituda kuat sinyal• Modulasi frekuensi random berkaitan dengan efek

Doppler pada sinyal multipath yang berbeda-beda• Dispersi waktu (echo) yang disebabkan oleh delay

propagasi multipath

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IntroductionWhy is it important to understand the characteristicsof wireless channel ?

– To determine the most appropriate signal design (source, channelcoding, and modulation)

– To develop new technologies in the radio signal transmitters andreceivers

– In multiuser communications, channel access scheme must bedone as efficiently as possible.

– In cellular systems, coverage of the desired signal is computed asaccurately as possible excess power would result in excessiveinterference as well.

– In cellular communication systems, to ensure the communicationconnection from cell to cell, then the lowest allowable level to bedetermined.

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– To determine the most appropriate signal design (source, channelcoding, and modulation)

– To develop new technologies in the radio signal transmitters andreceivers

– In multiuser communications, channel access scheme must bedone as efficiently as possible.

– In cellular systems, coverage of the desired signal is computed asaccurately as possible excess power would result in excessiveinterference as well.

– In cellular communication systems, to ensure the communicationconnection from cell to cell, then the lowest allowable level to bedetermined.

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• Ideal Channel

• Ideal channel passed all the spectrum of the signal without distortion(called BW infinite channel with a 'flat' frequency response for allfrequencies)

• signal attenuation and the error is only caused by the AWGN (AdditiveWhite Gaussian Noise).

• Received signal is a deterministic quantity which the characteristicsexpressed by using the statistical properties of the AWGN (Gaussiandistributed).

Transmitted bit

Ideal channel

AWGN

detection

Introduction

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• Ideal Channel

• Ideal channel passed all the spectrum of the signal without distortion(called BW infinite channel with a 'flat' frequency response for allfrequencies)

• signal attenuation and the error is only caused by the AWGN (AdditiveWhite Gaussian Noise).

• Received signal is a deterministic quantity which the characteristicsexpressed by using the statistical properties of the AWGN (Gaussiandistributed).

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Introduction

• Real channel (Physical Channel) :

• Physical channel always has a limited bandwidth• Only a significant component of the signal spectrum that passed

through the physical channel, in other words the signal isdistorted

• Signal bandwidth must be smaller or equal to the coherencebandwidth of the channel for relatively no distortion. The questionis: How to obtain the BW signal is smaller than coherentbandwidth of the channel?

Transmitted bit

PhysicalChannel

AWGN

detection

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• Real channel (Physical Channel) :

• Physical channel always has a limited bandwidth• Only a significant component of the signal spectrum that passed

through the physical channel, in other words the signal isdistorted

• Signal bandwidth must be smaller or equal to the coherencebandwidth of the channel for relatively no distortion. The questionis: How to obtain the BW signal is smaller than coherentbandwidth of the channel?

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Introduction

2m

2

2)mm(

m

e2

1)m(p

Probability Distribution Function (PDF) of a lognormal distributedrandom variable is represented as follows :

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wherem = normal random variable signal strength(dBm)

= Average (mean) signal strength (dBm)m = standard deviationm

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Introduction (Free Space Prop. Model)

Isotropic antenna: power is distributedhomogeneously over surface area of a sphere.

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Isotropic antenna: power is distributedhomogeneously over surface area of a sphere.

Received power is power through effective antennasurface over total surface area of a sphere of radius d

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(Free Space Prop. Model), continued

The power density w atdistance d is

where PT is the transmitpower.

24 dPw T

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The power density w atdistance d is

where PT is the transmitpower.

R TP AdP

4 2

The received power is

with A the `antenna aperture' orthe effective receiving surface area.

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(Free Space Prop. Model), continued

The antenna gain GR isrelated to the aperture Aaccording to

Thus the received signalpower is

G RA 4

2

2

d4GGP=P

d41

4GP=P

RTTR

2

2

RTR

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The antenna gain GR isrelated to the aperture Aaccording to

Thus the received signalpower is

2

d4GGP=P

d41

4GP=P

RTTR

2

2

RTR

Received power decreases with distance,PR :: d-2

Received power decreases with frequency, PR :: f -2

Cellular radio planning: Path Loss in dB:Lfs = 32.44 + 20 log (f / 1 MHz) + 20 log (d / 1 km)

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Microwave and Satellite Communications ....• Friis transmission formula,

• Assumption: there is only a direct wave from the sender to the receiver• Radio link designed for local Fresnell I (R1) are free of obstructions. High

antenna tower at the transmitter and the receiver is determined in such away as to guarantee the line of sight conditions

)Km()MHz(P Dlog20flog2045,32L

22 Introduction

• Friis transmission formula,

• Assumption: there is only a direct wave from the sender to the receiver• Radio link designed for local Fresnell I (R1) are free of obstructions. High

antenna tower at the transmitter and the receiver is determined in such away as to guarantee the line of sight conditions

Fresnell_Iradius

21

1hh4R

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Plain Earth Propagation Model…. (Egli’s Model)

• As the basic theory of wave trajectory analysis inmobile communication

• Key words: there are multiple paths (multipath): 1direct wave and a wave reflection.

• Analysis of the signal path in mobilecommunications is much different from the LOSmicrowave communications because signals havediffraction, much obstructed, and a lot of reflection.

23 Introduction

• As the basic theory of wave trajectory analysis inmobile communication

• Key words: there are multiple paths (multipath): 1direct wave and a wave reflection.

• Analysis of the signal path in mobilecommunications is much different from the LOSmicrowave communications because signals havediffraction, much obstructed, and a lot of reflection.

Empirical Model….• Derived from measurements and intensive research in an area• Attenuation curves are plotted and the results made formulations• Popular attenuation formula : Okumura-Hata, dan Walfish Ikegami• Another path attenuation models developed by: Lee, Egli, Carey,

Longley-Rice, Ibrahim-Parson, etc

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Karakteristik propagasi pada jaringan bergerak (seluler)berbeda dibandingkan dengan karakteristik propagasipada jaringan tetap. Pada jaringan bergerak fading yangterjadi lebih hebat dan fluktuatif dibandingkan denganjaringan tetap.

Untuk menghitung path loss pada propagasi jaringanseluler telah banyak dilaakukan percobaan dan penelitian.Beberapa diantaranya yang sering dipakai adalah

Untuk menghitung path loss pada propagasi jaringanseluler telah banyak dilaakukan percobaan dan penelitian.Beberapa diantaranya yang sering dipakai adalah

Model Hata Model Walfisch-Ikegami ( COST-231 ) Model Okumura dll

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Macrocells In early days, the models were based on emprical

studies Okumura did comprehesive measurements in

1968 and came up with a model. Discovered that a good model for path loss was a simple power

law where the exponent n is a function of the frequency, antennaheights, etc.

Valid for frequencies in: 100MHz – 1920 MHzfor distances: 1km – 100km

PROPAGATION MODEL

In early days, the models were based on empricalstudies

Okumura did comprehesive measurements in1968 and came up with a model. Discovered that a good model for path loss was a simple power

law where the exponent n is a function of the frequency, antennaheights, etc.

Valid for frequencies in: 100MHz – 1920 MHzfor distances: 1km – 100km

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Okumura Model L50(d)(dB) = LF(d)+ Amu(f,d) – G(hte) – G(hre) – GAREA

– L50: 50th percentile (i.e., median) of path loss– LF(d): free space propagation pathloss.– Amu(f,d): median attenuation relative to free space

Can be obtained from Okumura’s emprical plots shown in the book (Rappaport),page 151.

– G(hte): base station antenna heigh gain factor– G(hre): mobile antenna height gain factor– GAREA: gain due to type of environment

G(hte) = 20log(hte/200) 1000m > hte > 30m G(hre) = 10log(hre/3) hre <= 3m G(hre) = 20log(hre/3) 10m > hre > 3m

hte: transmitter antenna height hre: receiver antenna height

L50(d)(dB) = LF(d)+ Amu(f,d) – G(hte) – G(hre) – GAREA

– L50: 50th percentile (i.e., median) of path loss– LF(d): free space propagation pathloss.– Amu(f,d): median attenuation relative to free space

Can be obtained from Okumura’s emprical plots shown in the book (Rappaport),page 151.

– G(hte): base station antenna heigh gain factor– G(hre): mobile antenna height gain factor– GAREA: gain due to type of environment

G(hte) = 20log(hte/200) 1000m > hte > 30m G(hre) = 10log(hre/3) hre <= 3m G(hre) = 20log(hre/3) 10m > hre > 3m

hte: transmitter antenna height hre: receiver antenna height

Cellular radio planning: Path Loss in dB:Lfs = 32.44 + 20 log f (MHz) + 20 log d (km)

LdPPdBPLr

t22

2

4log10log10)(

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Hatta Model Valid from 150MHz to 1500MHz A standard formula For urban areas the formula is:

– L50(urban,d)(dB) = 69.55 + 26.16logfc - 13.82loghte – a(hre) +(44.9 – 6.55loghte) log d

wherefc is the ferquency in MHzhte is effective transmitter antenna height in meters (30-200m)hre is effective receiver antenna height in meters (1-10m)d is T-R separation in kma(hre) is the correction factor for effective mobile antenna height which

is a function of coverage area

a(hre) = (1.1logfc – 0.7)hre – (1.56logfc – 0.8) dB

for a small to medium sized city

Valid from 150MHz to 1500MHz A standard formula For urban areas the formula is:

– L50(urban,d)(dB) = 69.55 + 26.16logfc - 13.82loghte – a(hre) +(44.9 – 6.55loghte) log d

wherefc is the ferquency in MHzhte is effective transmitter antenna height in meters (30-200m)hre is effective receiver antenna height in meters (1-10m)d is T-R separation in kma(hre) is the correction factor for effective mobile antenna height which

is a function of coverage area

a(hre) = (1.1logfc – 0.7)hre – (1.56logfc – 0.8) dB

for a small to medium sized city

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Daerah urban

Model Hata pada daerah urban berlaku rumus sbb :

L50(u) = C1+ C2 log ( f ) - 13,82 log (hb) – a (hm) + { 44,9 – 6,55log (hb) } log (d).

Dimana :f = frekuensi (MHz)hb = tinggi antena BTS (m)hm = tinggi antena MS (m)d = jarak antara BTS – MS (km)C1 = 69,55 untuk 400 f 1500

= 46,3 untuk 1500 < f 2000C2 = 26,16 untuk 400 f 1500

= 33,9 untuk 1500 < f 2000

f = frekuensi (MHz)hb = tinggi antena BTS (m)hm = tinggi antena MS (m)d = jarak antara BTS – MS (km)C1 = 69,55 untuk 400 f 1500

= 46,3 untuk 1500 < f 2000C2 = 26,16 untuk 400 f 1500

= 33,9 untuk 1500 < f 2000

a(hm) = {1,1log (f) - 0,7} hm – {1,56 log(f) – 0,8 }

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Daerah dense urbanModel Hata pada daerah urban berlaku rumus sbb :

L50(du) = C1+C2 log ( f )-13,82 log (hb) – a (hm)+{ 44,9 – 6,55log (hb) } log (d)+Cm

Dimana :f = frekuensi (MHz)hb = tinggi antena BTS (m)hm = tinggi antena MS (m)d = jarak antara BTS – MS (km)C1 = 69,55 untuk 400 f 1500

= 46,3 untuk 1500 < f 2000C2 = 26,16 untuk 400 f 1500

= 33,9 untuk 1500 < f 2000Cm = 3 dB

f = frekuensi (MHz)hb = tinggi antena BTS (m)hm = tinggi antena MS (m)d = jarak antara BTS – MS (km)C1 = 69,55 untuk 400 f 1500

= 46,3 untuk 1500 < f 2000C2 = 26,16 untuk 400 f 1500

= 33,9 untuk 1500 < f 2000Cm = 3 dB

a(hm) = 3,2{ log(11,75hm) } 2 – 4,97

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Daerah suburban

L50(su) = L50(u) – 2{log(f/28)}2 – 5,4

Daerah rural terbuka

L50(rt) = L50(u) – 4,78{log(f)}2 + 18,33log(f) – 40,94

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Kelebihan : mudah digunakan ( langsung dimasukkan pada rumus jadi )Kekurangan: tidak ada parameter eksak yang tegas antara daerah kota,

daerah suburban, maupun daerah terbuka

Lu = 69,55 + 26,16log fC – 13,83log hT – a(hR) + [44,9 – 6,55 log hT ] log dLu = 69,55 + 26,16log fC – 13,83log hT – a(hR) + [44,9 – 6,55 log hT ] log dDimana ,

150 fC 1500 MHz30 hT 200 m , 1 hr 10 m1 d 20 kma(hR) adalah faktor koreksi antenna mobile yang nilainya adalah sebagaiberikut :

Daerah kota

Okumura-Hata Prediction ModelPrediction Model

150 fC 1500 MHz30 hT 200 m , 1 hr 10 m1 d 20 kma(hR) adalah faktor koreksi antenna mobile yang nilainya adalah sebagaiberikut :

• Untuk kota kecil dan menengah,a(hR) = (1,1 log fC – 0,7 )hR – (1,56 log fC – 0,8 ) dB, dimana, 1 hR 10 m• Untuk kota besar,

a(hR) = 8,29 (log 1,54hR )2 – 1,1 dB fC 300 MHza(hR) = 3,2 (log 11,75hR )2 – 4,97 dB fC > 300 MHz

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Daerah Suburban

4,528flog2LL

2C

usu

Daerah Open Area

94,40flog33,18)f(log78,4LL c2

cuo

Okumura-Hata Prediction Model

94,40flog33,18)f(log78,4LL c2

cuo

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Merupakan formula pengembangan rumus Okumura Hata untuk frekuensi PCS ( 2GHz)

COST-231 ( PCS Extension Hata Model)

MTRTcu C)logd6,55logh(44,9)a(hlogh13,82logf33,946,3L

dimana , 1500 MHz fC 2000 MHz30 m hT 200 m ,1 m hR 10 m1 d 20 kma(hR) adalah faktor koreksi antena mobile yang nilainya sebagai berikut :

Prediction Model

• Untuk kota kecil dan menengah,a(hR) = (1,1 log fC – 0,7 )hR – (1,56 log fC – 0,8 ) dBdimana, 1 hR 10 m

• Untuk kota besar,a(hR) = 8,29 (log 1,54hR )2 – 1,1 dB fC 300 MHza(hR) = 3,2 (log 11,75hR )2 – 4,97 dB fC 300 MHz

dan,CM =

0 dB untuk kota menengah dan kotasuburban3 dB untuk pusat kota metropolitan

1500 MHz fC 2000 MHz30 m hT 200 m ,1 m hR 10 m1 d 20 kma(hR) adalah faktor koreksi antena mobile yang nilainya sebagai berikut :

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COST231 Walfish Ikegami Model

Cost231 Walfish Ikegami Model digunakan untuk estimasi pathloss untuklingkungan urban untuk range frekuensi seluler 800 hingga 2000 MHz.

Wallfisch/Ikegami model terdiri dari 3 komponen :• Free Space Loss (Lf)• Roof to street diffraction and scatter loss (LRTS)• Multiscreen loss (Lms)

LC =Lf + LRTS + Lms

Lf ; untuk LRTS + Lms < 0

Prediction Model

LC = Lf ; untuk LRTS + Lms < 0

• Lf = 32.4 + 20 log10 R + 20 log10 fc dimana R (km); fc (MHz)

• LRTS = -16.9 + 10 log10 W + 20 log10 fc + 20 log10 hm + L

di manaL =

-10 + 0.354 ; 0 < < 352.5 + 0.075( - 35) ; 35 < < 554.0 – 0.114( - 55) ; 55 < < 90

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Modul 2 Large Scale Fading

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Modul 2 Large Scale Fading

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Modul 2 Large Scale Fading

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• Lms = Lbsh + ka + kd log10 R + kf log10 fc - 9log10 bdimana Lbsh =

-18 + log10 (1 + hm ) ; hb < hr ; hb > hr

ka =54 ; hb > hr54 + 0.8hb ; d > 500 m hb < hr54 + 0.8 hb . R ; 55 < < 90

Catatan : Lsh dan ka meningkatkan path loss untuk hb yang lebih rendah.

COST231 Walfish Ikegami ModelPrediction Model

Catatan : Lsh dan ka meningkatkan path loss untuk hb yang lebih rendah.

kd =18 ; hb > hr18 – 15 (hb/hr ) ; hb < hr

kf =4 + 0.7 (fc/925 - 1

4 + 1.5 (fc/925 - 1)

; Untuk kota ukuran sedang dansuburban dengan kerapatan pohoncukup moderat

; Pusat kota metropolitan

Modul 2 Large Scale Fading

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Model ini valid ; d ≤ 5km, hb ≤ 50m, micro cell, data basegedung dan jalan yang lengkap

Pada prinsipnya model ini terdiri dari 3 elemen yaitu :- Free Space Loss,- Rooftop to Street Diffraction Scatter Loss,- Multi Screen Loss, seperti rumus berikut :

L50 = Lf + Lrts + LmsL50 = Lf + Lrts + Lms

L50 = Lf , jika Lrts + Lms ≤ 0

Lf = free space loss, Lrts = rooftop to street diffraction & scatterdan Lms = multi screen loss

Seperti disinggung di depan Lf dapat dihitung dengan rumus

Lf = 32,4+ 20log r + 20 log fc (dB)

Modul 2 Large Scale Fading

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Lrts dapat dihitung dengan rumus

Lrts = - 16,9 +10log W + 10log fc + 20log hm + L0 (dB)

Variable yang mendukung rumus di atas ditunjukan sepertigambar berikut

hb

R

hb

hr

hb

b w

hm

hm

W lebar jalan (m) dan hm = hr – hm (m)

Lrst = 0 jika hm ≤ 0

Modul 2 Large Scale Fading

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building

building building

building

building building

L0 = -10 +0,354 dB untuk 00 < 350

L0 = 2,5 + 0,075(-35) dB untuk 350≤ < 550

L0 = 4 - 0,114(-55) dB untuk 550≤ ≤ 900

Modul 2 Large Scale Fading

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Lms dapat dihitung dengan rumus

Lms = Lbsh + ka + kd log r + kflog fc – 9logb (dB)

Lbsh = -18log(1+ )hb Untuk hb

hb

> 0

= 0 Untuk ≤ 0

Ka = 54

Ka = 54 – 0,8 hb

Untuk hb > 0

Untuk r 0,5 dan hb ≤ 0Ka = 54 – 0,8 hb

Ka = 54 – 1,6 hb r

Untuk r 0,5 dan hb ≤ 0

Untuk r < 0,5 dan hb ≤ 0

Kd = 18 Untuk hb > 0

Kd = 18 -15 ( hbhr

) hbUntuk ≤ 0

Kf = -4 +0,7 ( f925 -1 ) Untuk urban dan suburban

Kf = -4 +1,5 ( f925 -1 ) Untuk dense urban

Modul 2 Large Scale Fading

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Tentukan loss propagasi dengan menggunakan model Hatadan COST 231 antara BTS dan MS pada daerah dense urbanjika diketahui data-data sbb :

f = 1887 MHz, hm = 1,5 m , hb = 30 m, r = 3km , hr = 30 m = 900 , b = 30 m, W = 15 m

Modul 2 Large Scale Fading

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ro = 1mil= 1,6 km

rPro

PrP P

rr

ffr ro

o o

n

o

. . .

P Prrn

ffr ro

o oo

. log . log10 10

Dalam persamaan linear,

Dalam persamaan logaritmik (dB),

Lee’s Prediction ModelPrediction Model

P Prrn

ffr ro

o oo

. log . log10 10

Pr = Daya terima pada jarak r dari transmitter.Pro = Daya terima pada jarak ro = 1 mil dari

transmitter.= Slope / kemiringan Path Loss

n = Faktor koreksi, digunakan apabila adaperbedaan frekuensi antara kondisi saateksperimen dengan kondisi sebenarnya.

o = Faktor koreksi, digunakan apabila adaperbedaan keadaan antara kondisi saateksperimen dengan kondisi sebenarnya.

Kondisi saat eksperimen dilakukan,1. Operating Frequency = 900 MHz.2. RBS antenna = 30.48 m3. MS antenna = 3 m4. RF Tx Power = 10 watt5. RBS antenna Gain = 6 dB over

dipole l/2.6. MS antenna Gain = 0 dB over

dipole l/2.

Modul 2 Large Scale Fading

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L0 and are obtained from table

where

hb in m

PT in W

Gb = BS antenna gain in scalar

hm in mfc = carrier frequency in MHzf0 = In an 900 MHz frequency referencen = 2 - 3

Lee Models00 log FdLLLee

543210 FFFFFF

2

1 5.30

bhF

Environment L0 [dB] Free Space 91.3 20Open (Rural) 91.3 43.5Suburban 104.0 38Urban:Tokyo 128.0 30Philadelpia 112.8 36.8Newark 106.3 43.1

Modul 2 Large Scale Fading

L0 and are obtained from table

where

hb in m

PT in W

Gb = BS antenna gain in scalar

hm in mfc = carrier frequency in MHzf0 = In an 900 MHz frequency referencen = 2 - 3

2

1 5.30

bhF

102TPF

43bGF

2

34

mhF

nc

ffF

05

Environment L0 [dB] Free Space 91.3 20Open (Rural) 91.3 43.5Suburban 104.0 38Urban:Tokyo 128.0 30Philadelpia 112.8 36.8Newark 106.3 43.1

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Pro and didapat dari data hasil percobaan

in free space,Pro = 10-4.5 mWattsg = 2

in an open area,Pro = 10-4.9 mWattsg = 4.35

in urban area (Philadelphia),Pro = 10-7 mWattsg = 3.68

in urban area (Tokyo),Pro = 10-8.4 mWattsg = 3.05

ao = faktor koreksi

o = 1 . 2 . 3 . 4 . 5

2

1 (m)48.30(m)riilstationbaseantenatinggi

v

(m)3(m)riilunitmobileantennatinggi

2

Lee’s Prediction Model

in an open area,Pro = 10-4.9 mWattsg = 4.35

in sub urban area,Pro = 10-6.17 mWattsg = 3.84

in urban area (Tokyo),Pro = 10-8.4 mWattsg = 3.05

v

(m)3(m)riilunitmobileantennatinggi

2

(watts)10(watts)riilpemancardaya

3

42dipoleantenatdhriilstationbaseantenagain

4

12dipoleantenathd.riilunitmobileantenagain

54

Modul 2 Large Scale Fading

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Lee’s Prediction Model

n diperoleh dari percobaan / empiris

dec/dB30ndec/dB20

Harga n diperoleh dari hasil percobaan yangdilakukan oleh Okumura dan Young

Berdasarkan eksperimen oleh Okumuran=30 dB/dec untuk Urban Area.

Correction factor to determine vin a2

v = 2,for new mobile-unit antenna heigh > 10 m

v = 1,for new mobile-unit antenna heigh < 3 mBerdasarkan eksperimen oleh Okumura

n=30 dB/dec untuk Urban Area.

Berdasarkan eksperimen oleh Youngn=20 dB/dec untuk Sub.Urban Areaatau Open Area

n hanya berlaku untuk frekuensi operasi30 sd. 2,000 MHz

v = 1,for new mobile-unit antenna heigh < 3 m

Modul 2 Large Scale Fading

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3Jarak dalam mil

2 4 5 6 7 8 9 101

-110

-100

-90

-80

-70

-60

-50

-120

Signa

l stre

ngth

in dB

m

12

22

32

42

52

62

72

82

Signa

l stre

ngth

in dB

(mikr

oVolt

)

New York City ( Po = - 77 dBm, = 48 dB/dec )

Tokyo, Japan ( Po= - 84 dBm, = 30.5 dB/dec )

Philadelphia ( Po = - 70 dBm, = 36.8 dB/dec )

Newark ( Po = - 64 dBm, = 43.1 dB/dec )

Suburban ( Po = - 61.7 dBm, = 38.4 dB/dec )

Open Area ( Po = - 49 dBm, = 43.5 dB/dec )

Open Area ( Po = - 45 dBm, = 20 dB/dec )

Lee’s Prediction Model

3Jarak dalam mil

2 4 5 6 7 8 9 101

-110

-100

-90

-80

-70

-60

-50

-120

Signa

l stre

ngth

in dB

m

12

22

32

42

52

62

72

82

Signa

l stre

ngth

in dB

(mikr

oVolt

)

New York City ( Po = - 77 dBm, = 48 dB/dec )

Tokyo, Japan ( Po= - 84 dBm, = 30.5 dB/dec )

Philadelphia ( Po = - 70 dBm, = 36.8 dB/dec )

Newark ( Po = - 64 dBm, = 43.1 dB/dec )

Suburban ( Po = - 61.7 dBm, = 38.4 dB/dec )

Open Area ( Po = - 49 dBm, = 43.5 dB/dec )

Open Area ( Po = - 45 dBm, = 20 dB/dec )

Modul 2 Large Scale Fading

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ro = 1mil= 1,6 km r1

Pro

Pr

r2

area 1 area 2

r

r1 r2r

area 1 area 2

1.6 km

Lee’s Pathloss Formula Untuk Berbagai Jenis KondisiLingkungan

r1 r2r1.6 km

o

n

o1o1

ror .ff.

rr.

rr.PP

21

o = 1 . 2 . 3 . 4 .

5

o

n

o1N12

o1

ror .ff.

rr.....

rr.

rr.PP

N21

persamaanumum,

Modul 2 Large Scale Fading

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MOBILE

Building

IncidentWave = incident angle relative to streetBuilding

Building

Building

R

Diagram Parameter

w

b

Mobile

R

hb

hb

hrhmhm

Cell siteGROUND

Modul 2 Large Scale Fading

Page 63: Modul 2_LargeScaleFading - WCS

L [dB]=L (d0)+10 log (d/d0)

from table 3.2 (Rappa, pp 104)

Log Distance Path Loss Model

Environment Pathloss Exponent

Free Space 2Urban 2.7 - 3.5Shadowed Urban 3.0 - 5.0in building LOS 1.6 - 1.8in building Obstructed 4.0 - 6.0in factories Obstructed 2.0 - 3.0

Modul 2 Large Scale Fading

Environment Pathloss Exponent

Free Space 2Urban 2.7 - 3.5Shadowed Urban 3.0 - 5.0in building LOS 1.6 - 1.8in building Obstructed 4.0 - 6.0in factories Obstructed 2.0 - 3.0

Page 64: Modul 2_LargeScaleFading - WCS

L [dB]=L (d0)+10 log (d/d0) + X Shadowing effect + fading margin + availability

(Rappa, pp 104)

Log-normal Shadowing

Modul 2 Large Scale Fading

L [dB]=L (d0)+10 log (d/d0) + X Shadowing effect + fading margin + availability

(Rappa, pp 104)

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Modul 2 Large Scale Fading

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The measurement method with Regression Methods

• Select multiple locationsat distances d1 and takethe measurement ofpath loss

• Repeat for thedistance d2 and d3, etc.

• Plot of themean pathloss asa function of distance

Cell site(Tx)

d1 d2

d3

Modul 2 Large Scale Fading

• Select multiple locationsat distances d1 and takethe measurement ofpath loss

• Repeat for thedistance d2 and d3, etc.

• Plot of themean pathloss asa function of distance

Cell site(Tx)

Page 74: Modul 2_LargeScaleFading - WCS

Getting Mean and Standard Deviation

• Measurement isusually done for some typesof areas: Urban, suburban, andopen areas

• Measurements at constant radius from the BTS to producedifferent pathloss

• With the linear regression method,we can obtain the meanpathloss trend and standarddeviation around the average value

• Example for urban: path loss Slope = 33.2 dB / decade and Std dev. = 7 dB

Path loss [dB

]

urban

xxx

x x

x x x

x x

x x

x x

x x

o o o

o o o

o o

o o

o o

o o

o

o o

79

85

75

Modul 2 Large Scale Fading

• Measurement isusually done for some typesof areas: Urban, suburban, andopen areas

• Measurements at constant radius from the BTS to producedifferent pathloss

• With the linear regression method,we can obtain the meanpathloss trend and standarddeviation around the average value

• Example for urban: path loss Slope = 33.2 dB / decade and Std dev. = 7 dB Distance d [km]

Path loss [dB

]

suburban

open

xxx

x x

x x x

x x

x x

x x

x x

o o o

o o o

o o

o o

o o

o o

o

o o

# #

# #

# #

#

3 4 6

75