dc transmission media final

8/3/2019 Dc Transmission Media Final

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PropertiesofMedi

a


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Figure 7.1 Transmission medium and physical layer


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Transmission media-parametersTransmission media-parameters

1. What kind of information it can carry ( Voice /

Data/ Video )?

2. What is the range / distance supported

without repeaters?

3. What topology it supports ?

1. Point-to-point ?

2. Point-to-multipoint ?


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4. Direction of transmission

1. unidirectional ?

2. bidirectional ?


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5. what is the bandwidth ( data

rate ) supported ?

6. Delays

7. Ease of installation ?

8. Ease of maintenance /



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8. up gradation capabilities?

9. Reliability Life?

10. Rights of way ?

11. Economics / cost benefit?



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Fundamental Issues in Transmission Media

Information bearing capacityAmplitude response & bandwidthdependence on distance

Susceptibility to noise &interferenceError rates & SNRs

t= 0t = d/c

Communication channel

dmeters

t


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un amenta ssues n ransm ss on

Media

Propagation speed of signalc = 3 x 108 meters/second in vacuum = c/ speed of light in medium

where >1 is the dielectric constant of

the medium = 2.3 x 108 m/sec in copper wire; =2.0 x 108m/sec in optical fiber

t= 0t = d/c

Communication channel

dmeters


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Communications systems &Electromagnetic Spectrum

Frequency of communications signalsAnalog

telephoneDSL Cell

phone

WiFiOptical

fiber

102 104 106 108 1010 1012 1014 1016 1018 1020 1022 1024

Frequency (Hz)

Wavelength (meters)

106 104 102 10 10-2 10-4 10-6 10-8 10-10 10-12 10-14

Powerand

telephon

e

Bro

adca

st

radio

Mic

rowave

r

adio

Infra

red

light

Visib

leli

ght

Ultraviol e

tlight

X-

rays

Gam

ma

rays


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Figure 7.2 Classes of transmission media


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Wireless & Wired MediaWireless Media

Signal energy propagates inspace, limited directionality

Interference possible, sospectrum regulated

Limited bandwidth Simple infrastructure:

antennas & transmitters

No physical connectionbetween network & user

Users can move

Wired Media

Signal energy contained &guided within medium

Spectrum can be re-used inseparate media (wires or

cables), more scalable Extremely high bandwidth

Complex infrastructure: ducts,conduits, poles, right-of-way


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Attenuation Attenuation varies with media

Dependence on distance of central importance

Wired media has exponential dependenceReceived power at d meters proportional to 10-kdAttenuation in dB = k d, where kis dB/meter

Wireless media has logarithmic dependenceReceived power at d meters proportional to d-n Attenuation in dB = n log d, where n is path loss exponent; n=2 in free

spaceSignal level maintained for much longer distancesSpace communications possible


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Twisted-pair cable


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Twisted-pair cable Physical description

Why it is twisted ?


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Effect of Noise on Parallel Lines

Figure 7-6

WCB/McGraw-Hill The McGraw-Hill Companies, Inc., 1998


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Noise on Twisted-Pair LinesFigure 7-7



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Unshielded Twisted-Pair Cable

Figure 7-8



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UTP ConnectorsFigure 7-9



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Shielded Twisted-Pair Cable

Figure 7-10



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Figure 7.5 UTP connector


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Figure 7.6 UTP performance


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Twisted PairTwisted pair Two insulated copper

wires arranged in a regularspiral pattern to minimizeinterference

Various thicknesses, e.g.0.016 inch (24 gauge) Low cost Telephone subscriber loop

from customer to CO Attenua

tion(d

B/mi)

f (kHz)

19 gauge

22 gauge

24 gauge

26 gauge

6

12

18

24

30

110 100 1000

Lower

attenuation rate

analog telephone

Higher

attenuation ratefor DSL


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Twisted PairTwisted pair Old trunk plant

connecting telephoneCOs

Intra-building telephone

from wiring closet todesktop In old installations,

loading coils added toimprove quality in 3

kHz band, but moreattenuation at higherfrequencies

Attenua

tion(d

B/mi)

f (kHz)

19 gauge

22 gauge

24 gauge

26 gauge

6

12

18

24

30

110 100 1000

Lower

attenuation rate

analog telephone

Higher

attenuation ratefor DSL


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Twisted Pair Bit Rates Twisted pairs can provide high

bit rates at short distances Asymmetric Digital Subscriber

Loop (ADSL) High-speed Internet Access Lower 3 kHz for voice Upper band for data 64 kbps inbound 640 kbps outbound

Much higher rates possible atshorter distances Strategy for telephone companies is

to bring fiber close to home & thentwisted pair

Higher-speed access + video

Table 3.5 Data rates of 24-gauge twisted pair

StandardData Rate Distance

T-1 1.544 Mbps 18,000 feet, 5.5 km

DS2 6.312 Mbps 12,000 feet, 3.7 km

1/4 STS-1 12.960 Mbps 4500 feet, 1.4 km

1/2 STS-1 25.920 Mbps 3000 feet, 0.9 km

STS-1 51.840 Mbps 1000 feet, 300 m


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Ethernet LANs Category 3 unshielded twisted pair(UTP): ordinary telephone wires Category 5 UTP: tighter twisting to

improve signal quality Shielded twisted pair (STP): to minimize

interference; costly 10BASE-T Ethernet

10 Mbps, Baseband, Twisted pair Two Cat3 pairs Manchester coding, 100 meters

100BASE-T4FastEthernet

100 Mbps, Baseband, Twisted pair Four Cat3 pairs Three pairs for one direction at-a-time 100/3 Mbps per pair; 3B6T line code, 100 meters

Cat5 & STP provide other options

T i i di li i


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Transmission media-application summary

LAN

Telephone-Local loop

Internet access network- DSL


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Coaxial cable


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Coaxial Cable Cylindrical braided outerconductor surrounds

insulated inner wireconductor

High interference immunity

Higher bandwidth thantwisted pair

Hundreds of MHz Cable TV distribution

Long distance telephonetransmission Original Ethernet LAN

medium

35

30

10

25

20

5

15

Atte

nuation(d

B/km

)

0.1 1.0 10 100

f (MHz)

2.6/9.5 mm

1.2/4.4 mm

0.7/2.9 mm


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Coaxial cable-Physical description

Fi 7 8 BNC


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Figure 7.8 BNC connectors

Fi 7 9 C i l bl f


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Figure 7.9 Coaxial cable performance


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Categories of coaxial cables-applicationsCategories of coaxial cables-applications

Category Impedance Use

RG-59RG-59 75 Cable TVRG-58RG-58 50 Thin Ethernet

RG-11RG-11 50 Thick Ethernet

also used in long distance telephone transmission

Transmission media application summary


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LAN Thin Ethernet-Thick Ethernet

Telecom carrier-back haul links

Cable TV


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Optical fiber


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Optical Fiber

Light sources (lasers, LEDs) generate pulses of light that aretransmitted on optical fiber Very long distances (>1000 km) Very high speeds (>40 Gbps/wavelength)

Nearly error-free (BER of 10-15) Profound influence on network architecture

Dominates long distance transmission Distance less of a cost factor in communications

Plentiful bandwidth for new services

Optical fiber

Optical

source

ModulatorElectricalsignal

Receiver Electricalsignal


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Core

Cladding JacketLight

c

Geometry of optical fiber

Total Internal Reflection in optical fiber

Transmission in Optical Fiber

Very fine glass cylindrical core surrounded by concentric layer of glass (cladding) Core has higher index of refraction than cladding Light rays incident at less than critical angle c is completely reflected back into

the core

Propagation modes


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Propagation modes

Basic principle Light wave communication


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Basic principle- Light wave communication

Figure 7-19


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Single Mode

Figure 7 19


Figure 7-17


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Multimode Step-Index

g


Figure 7-18


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Multimode Graded-Index

g


Figure 7.13 Modes-Summary


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Figure 7.13 Modes Summary

Figure 7-20


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Fiber Construction

g



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Multimode: Thicker core, shorter reach Rays on different paths interfere causing dispersion & limiting bit rate

Single mode: Very thin core supports only one mode (path) More expensive lasers, but achieves very high speeds

Multimode fiber: multiple rays follow different paths

Single-mode fiber: only direct path propagates in fiber

Direct path

Reflected path

Multimode & Single-mode Fiber


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Optical Fiber Properties

Advantages Very low attenuation Noise immunity Extremely high

bandwidth

Security: Very difficultto tap without breaking

No corrosion More compact & lighter

than copper wire

Disadvantages New types of optical signal

impairments & dispersion Polarization dependence Wavelength dependence

Limited bend radius If physical arc of cable too high,light lost or wont reflect

Will break

Difficult to splice

Mechanical vibration becomessignal noise


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100

50

10

5

1

0.5

0.1

0.05

0.010.8 1.0 1.2 1.4 1.6 1.8 Wavelength ( m)

Loss(d

B/km)

Infrared absorption

Rayleigh scattering

Very Low Attenuation

850 nm

Low-cost LEDs

LANs

1300 nm

Metropolitan Area

Networks

Short Haul

1550 nm

Long Distance Networks

Long Haul

Water Vapor Absorption

(removed in new fiber

designs)


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Wavelength-Division Multiplexing Different wavelengths carry separate signals Multiplex into shared optical fiber

Each wavelength like a separate circuit

A single fiber can carry 160 wavelengths, 10 Gbps per

wavelength: 1.6 Tbps!

1

2

moptical

mux

1

2

moptical

demux

1 2. m

optical

fiber

Optical fiber-Physical description


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Optical fiber Physical description

LED /LaserPhoto detector


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Table 7.3 Fiber typesTable 7.3 Fiber typesType Core Cladding Mode

50/12550/125 50 125 Multimode, graded-index

62.5/12562.5/125 62.5 125 Multimode, graded-index

100/125100/125 100 125 Multimode, graded-index

7/1257/125 7 125 Single-mode

Fiber Optics-advantages


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Fiber Optics-advantages

1. Greater Capacity

1. up to 3.5 Gbps2. less signal attenuation

3. Longer range

1. 10s of KMs

2. AT&T has developed transmission systemover a distance of 318 KMs without anyrepeaters

4. Immunity to electromagnetic interference

5. Resistive to corrosive materials

6. Light weight

7. More immune to tapping

Fiber Optics-Disadvantages


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Fiber Optics-Disadvantages

1. Installation / maintenance complexity

2. Unidirectional3. Cost

not justifiable , if the bandwidth is low


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High Speed LAN

Backbone in Campus Network

Metropolitan Area Networks

Cable TV

Telecom carrier-back haul links

Inter-continental links


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Wireless

Wireless Media


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Wireless Media

Terrestrial

Satellite

E l Fi d Wi l P d t f M t l


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Example-Fixed Wireless Products from Motorola

F S O ti l C i ti E i t


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Free Space Optical Communication Equipment

Table 7 4 BandsTable 7 4 Bands


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Table 7.4 BandsTable 7.4 Bands

BandBand RangeRange PropagationPropagation ApplicationApplication

VLFVLF 330 KHz Ground Long-range radio navigation

LFLF 30300 KHz Ground Radio beacons andnavigational locators

MFMF 300 KHz3 MHz Sky AM radio

HFHF 330 MHz Sky Citizens band (CB),ship/aircraft communication

VHFVHF 30300 MHz Sky andline-of-sight

VHF TV,FM radio

UHFUHF 300 MHz3 GHz Line-of-sight UHF TV, cellular phones,paging, satellite

SHFSHF 330 GHz Line-of-sight Satellite communication

EHFEHF 30300 GHz Line-of-sight Long-range radio navigation

Note on wireless medium..


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As the frequency increases, need of line-of-sightincreases

Higher frequency links facilitate more bandwidth

which means higher data rate

provision for multiple types of info ( Voice,data, video )

ISM ( Industrial Scientific & Medical band ) is

made license free, in most of countries in India 2.4 GHz

5.7 GHz



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Range supported by a wireless link / network isdecided by key factors like :

Transmitted power Receiver sensitivity modulation technology

transmission technology terrain conditions

obstruction factors

attenuation weather conditions

Range supported is inversely proportional to thefrequency of operation

No e o w e ess ed u ..


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Radio Transmission

Radio signals: antenna transmits sinusoidal signal(carrier) that radiates in air/space

Information embedded in carrier signal usingmodulation, e.g. QAM Multipath propagation causes fading Interference from other users Spectrum regulated by national & international

regulatory organizations


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104 106 107 108 109 1010 1011 1012Frequency (Hz)

Wavelength (meters)

103 102 101 1 10-1 10-2 10-3

105

Satellite and terrestrial

microwave

AM radio

FM radio and TV

LF MF HF VHF UHF SHF EHF104

Cellular

and PCS

Wireless cable

Radio Spectrum

Omni-directional applications Point-to-Point applications


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ExamplesCellular Phone

Allocated spectrum First generation:

800, 900 MHz Initially analog voice

Second generation: 1800-1900 MHz Digital voice, messaging

WirelessLAN Unlicenced ISM spectrum

Industrial, Scientific, Medical

902-928 MHz, 2.400-2.4835 GHz,5.725-5.850 GHz IEEE 802.11 LAN standard

11-54 Mbps

Point-to-MultipointSystems Directional antennas at microwave

frequencies High-speed digital communications

between sites High-speed Internet Access Radio

backbone links for rural areasSatelliteCommunications Geostationary satellite @ 36000 km

above equator Relays microwave signals from

uplink frequency to downlinkfrequency

Long distance telephone Satellite TV broadcast

Wireless Media


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Wireless Media

Case Studies

Last mile Wireless Linksfacilitating

th ERP I l t ti f t bil i t


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(

(

((

Bandwidth

Provider

[ISP ] - POPBangalore

Main Manufacturing Unit

Sate #1

Remote Manufacturing unit

State #2

7 KMs approx

6 KMs approx

POP of the Bandwidthprovider

in District #2

Karnataka

Bandwidth providers POP in District

#1

EthernetPort

EthernetPort

G.703

G.703

Ethernet

Port

Wireless Link being built by CCIPL

Wireless Link being built by CCIPL

Ethernet Port

ISP

the ERP Implementation for an automobile giant

Wireless WAN in Hydarabad


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Main HUB

Raj Bhawan

Secretariate- C- Block

NIC-State Office

internetNICNET

Secretariate- K- Block

8.2KMs

Repeater (

2.69 KMs

(

1.19 KMs

8.2 Kms

Secretariate- L- BlockCIPR

Chief MinistersResidence

Institute

Of

Administration

(

Repeater

OU

CCMB

Repeater

5 KMs

1.8 KMs

Hyderabad


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Wireless Metropolitan Area Network for National Informatics Centre

BANGALORE

Main HUB

Vidhana SoudhaKPCL

NIC-Visvesvaraya tower

Main Mini

NIC-Kendriya Sadan

Koramangala

internet

NICNET

6.76

KMs

( (

))) (

)

NIMHANS

HMT

CTO

0.53 KMs

High Court

CoffeeBoard

Election Commission

) ))

)M S Building

National Public

Education

Agriculture

11.2 Kms

Repeater Site

Repeater

UAS, Hebbal

GKVK

Repeater

Wireless Radio MA

Cell #3

Wireless Metropolitan Area Network in Delhi


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CAPAT

BARODA

HOUSESEVA

BHAVAN

HUB

NIC Head Office

CGO-Complex

and

Internet Point-Of-Presence

RPTR #1(2)

RPTR #2

(8)

RPTR #3(11)

SASTRYBHAVAN

R3IDRC

WFPR4

R5

R6UNDP

R7UNICEF

R9 ISDNR10R12ISM & H

R27

NESCO

R28

R29

NCERT

D S T

R13PFC

PATELBHAVAN

R14

R15

PARLIMENT

R16NIRMAN BHAVAN

R17N H A I

R18MIN.OF TORISM

R20K A B

UDYOG BHAVAN

SOUTH BLOCK

R22

R21

R23NORTH BLOCK

R24

KRISHI BHAVAN

R25

R26D O D

S S B

LEGEND:

R = REMOTE STATION

RPTR =REPEATER

STATION

R30

D H C

R31D S C

R32D P &T

R33WHO

R34

L N B R35

R36

R37

M N E R

M F P

L N B

R38CAA & A

NICNET5.95 KMs

3.43 KMs

1.56 KMsShared 2 MBPS Radio Network

Wireless Radio MAN

Cell #1

Wireless Radio MAN

Cell #2

Cell #3

Wireless Radio MAN

Cell #4

Wireless Optical [ Infrared ] Link[ 10 MBPS ]

Shared 2 MBPS Radio Network


2 MBPS RadioLink2 MBPS RadioLink


Links

mor

etha

n40

organi

satio

nsto

the

cent

ralNICS

iteat

CGO

Comp

lexfor

E-Mail

and

inter

neta

pplica

tions

Example Fixed Wireless Products from Motorola


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Example-Fixed Wireless Products from Motorola

Figure 7.17 Electromagnetic spectrum for wireless communication


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Radio Communication BandFigure 7-21


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Figure 7.18 Propagation methods


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Figure 7-23, 24


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VLF

LF


Figure 7-25, 26


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MF

HF


VHFFigure 7-27, 28


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VHF

UHF


Figure 7-29, 30


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SHF

EHF


Figure 7-31


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Terrestrial Microwave



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Antennae -at a glimpseAntennae -at a glimpse


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1.Omni Directional Antenna1.Omni Directional Antenna

2. Directional Antenna2. Directional Antenna

3. Sector Antenna3. Sector Antenna

Antenna types

Figure 7.20 Omnidirectional antennas


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Figure 7.21 Unidirectional antennas


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Horn AntennaFigure 7-33


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Application of sectoral antenna based wireless system


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Base station

System

AP 1

AP 2

AP 3

AP 4

AP 5

AP 6

600

600 600

600

600

600 Coverage upto

24 Kms

Example- Motorola Canopy Wireless products

Figure 7-36 Cellular System


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Cellular BandsFigure 7-37


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Cellular Bands




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Broadcast

Radio

TV

Citizen Band

Radio Mobile phones

Pager

Radio trunking



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Outdoor applications

Telecom carrier-Back haul links

Wireless Metropolitan Area DataNetworks

Next generation Wi-MAX networks Last Mile Access links / networks

Indoor applications

Wireless [ Wi-Fi ] LANs

Bluetooth



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Short RangeCommunication [ TV Remote control ]

Bluetooth devices

Input / Output deviceconnectivity Computer

High speed short rangelinks [ up to 4 KMs ] asalternative to Fiber optic

cables



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Infrared Communication for Campus Area Network

-Case study

High Speed Wireless Optical Communication Links

End user : M/s Aditi Technologies


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Palace View

M2

6 Mtrs

Park View

Manor House

500 Mtrs


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p p q p

dc transmission media final

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