selecting transmission medium for sharing e

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Selecting Transmission Medium for sharing E-Resources:

A Comparative Study Report

R. Prabu

Ph.D. Scholar, Dept. of Library & Information Science, Bharathidasan University,

Trichy -24.

[email protected]

S. Ketheeswaren

Assistant Librarian, University of Jaffna, Sri Lanka

Dr. S. Srinivasa Ragavan,

Librarian and Head, Bharathidasan University, Trichy 24

Abstract

Transmission media are the physical pathways (guided or unguided) that connect

computers, other devices, and people on a network. Computers and telecommunication

devices use signals to represent data. These signals are transmitted from a device to

another in the form of electromagnetic energy. Examples of Electromagnetic energy

include power, radio waves, infrared light, visible light, ultraviolet light, and X and

gamma rays. All these electromagnetic signals constitute the electromagnetic

spectrum. Each portion of the spectrum requires a particular or unique transmission

media for the transfer of data such we call as Twisted Pair, Coaxial cable, Optical

fibber, Satellite, and Wireless etc.

In the paper, The Guided (Twisted Pair, Coaxial cable, Optical fiber) and the Unguided

Microwaves (Satellite, wifi, wimax, bluetooth) transmission mediums are compared

with help of relative plots in terms of their networking capabilities (e.g., speed,

damping length, Bandwidth, Cost and Get connection).

Optical fibber in the guided media outperforms other medias in better networking

performance but optical fibber cable connection is sensitive than twisted Pair and

Coaxial cable connections and require higher cost than the same. Twisted pair

outperforms coaxial cable. Here it is also notable that coaxial cable can be connected

easily without order, but twisted pair not like that. Among Unguided; wimax

outperforms other medias in better networking performance in long range even though

wi-fi is a substitute for providing a greater power of access than wimax in short range.

Here all unguided mediums are better for ease of access than guided.

Keywords: Transmission Medium, Guided Media, Unguided media, Data channel,

Data transfer

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mailto:[email protected]:[email protected]


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1. Introduction

Making an appropriate network for a service of library and information science is now

common over the world, when such network is to be established or maitained we need

much information on neworks and for chosing the appriopriate network particulary

considering library envinments, comaprative ideas of different data tansmission medias

are very essentially needed, here we make an initial step to compare different

tarasmission medias such as the Guided (Twisted Pair, Coaxial cable, Optical fiber) and

the Unguided Microwaves (Satellite, wifi, wimax, bluetooth) transmission mediums.

1.1 Data transmission medium

In order for data transmission to occur, there must be a transmission line, also called

transmission channel between the two isolated data machines.

These transmission channels are made up of several segments that allow the data tocirculate in the form of electromagnetic, electrical, light or even acoustic waves. So, in

fact, it is a vibratory phenomenon that is propagated over the physical medium.

Transmission media are the physical pathways (guided or unguided) that connect

computers, other devices, and people on a network. Computers and telecommunication

devices use signals to represent data. These signals are transmitted from a device to

another in the form of electromagnetic energy. Examples of Electromagnetic energy

include power, radio waves, infrared light, visible light, ultraviolet light, and X and

gamma rays. All these electromagnetic signals constitute the electromagnetic

spectrum. Each portion of the spectrum requires a particular or unique transmission

media for the transfer of data such we call as Twisted Pair, Coaxial cable, Opticalfibber, Satellite, and Wireless etc.

Figure 1.1.1 Electromagnetic Spectrum

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1.2 Transmission Medias

1.2.1 Guided Transmission MediaGuided Transmission Media uses a "cabling" system that guides the data signals along

a specific path. The data signals are bound by the "cabling" system.Examples

Twisted Pair (multi-pair cables), Coaxial cable, and Optical fiber

1.2.1.1 Twisted Pair (multi-pair cables)

Pair of twisted pair multi conductors

Commonly used for communication networks within library buildings and in

wired telephone networks.

Produced in unshielded (UTP) and shielded (STP) forms, and in different

performance categories as in the figure 1.2.1.1 below.

Figure 1.2.1.1.1 Twisted Pair cables in unshielded (UTP) and shielded (STP) forms

Each neighbour pairs is typically twisted to reduce crosstalk.

Figure 1.2.1.1.2 Twisted Pair Cable Connectors

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1.2.1.2 Coaxial cable

Figure 1.2.1.2.1 Cross-section of a Coaxial Cable

Offers longer damping distances than of twisted pair, due to better shielding.

Used for cable TV and local-area networks. It has been widely used in telephone

systems, but optical fiber is now assuming this task.

Figure 1.2.1.2.2 Coaxial Cable Connectors

1.2.1.3 Optical fibber

Optical Fibers are glass fibers usually about 120 micrometers in diameter that are usedto deliver wave signals in the form of pulses of light over distances up to 50 km without

the using repeaters.

Three components: light source, transmission system, and a detector

The detector generates an electric pulse when hit by light

1-a pulse of light; 0-missing pulse of light.

optical rays travel in glass or plastic core

When light move from one medium to another as below it bend at the boundary.

The amount of bending depends on the properties of the media.

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Light at shallow angles propagate along the fibre, and those that are less than

critical angle are absorbed in the jacket

The cladding is a glass or plastic with properties that differ from those of the

core

Not affected by external electromagnetic fields, and do not radiate energy.

Hence, providing high degree of security from eavesdropping.

Reduction of the radius of the core implies less reflected angles. Single mode is

achieved with sufficient small radius.

Figure 1.2.1.3.1 Optical Fibre Cable Connectors

1.2.2 Unguided Transmission MediaUnguided Transmission Media now consists of a means for the data signals to travel

but nothing to guide them along a specific path. The data signals are not bound to a

cabling media and as such are often called Unbound Media.

Examples: Wi-Fi, Wimax, Bluetooth, and Satellite

1.2.2.1 Wi-Fi

The name Wi-Fi (short for "Wireless Fidelity", sometimes incorrectly shortened

to WiFi) corresponds to the name of the certification given by the Wi-Fi

Alliance, formerly WECA (Wireless Ethernet Compatibility Alliance).

With Wi-Fi, it is possible to create high-speed wireless local area networks,

provided that the computer to be connected is not too far from the access point.

In practice, Wi-Fi can be used to provide high-speed connections (11 Mbps or

greater) to laptop computers, desktop computers, personal digital assistants

(PDAs) and any other devices located within a radius of several dozen metres

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indoors (in general 20m-50m away) or within several hundred metres outdoors.

Figure 1.2.2.1.1 A sample Wi-Fi network in Library Buildings

Wi-Fi providers are starting to blanket areas that have a high concentration of

users (like train stations, airports, and hotels) with wireless networks. These

access areas are called "hot spots"

1.2.2.2 Wimax

What is WiMAX:

WiMAX is a short name for Worldwide Interoperability of Microwave Access.

WiMAX is described in IEEE 802.16 Wireless Metropolitan Area Network (MAN)

standard. It is expected that WiMAX compliant systems will provide fixed wireless

alternative to conventional Cable Internet.

Typically, a WiMAX system consists of two parts:

A WiMAX Base Station: Base station consists of indoor electronic systems

and a WiMAX tower. Typically, a base station can cover up to 10 km radius

(Theoretically, a base station can cover up to 50 kilo meter radius or 30 miles,

however practical considerations limit it to about 10 km or 6 miles). Anywireless node within the coverage area would be able to access the Internet.

A WiMAX receiver - The receiver and antenna could be a stand-alone box or a

PCMCIA card that sits inside the laptop or computer. Access to WiMAX base

station is similar to accessing a Wireless Access Point in a WiFi network, but

the coverage is more.

Important Wireless MAN IEEE 802.16 (WiMAX) Specifications

Range - 30-mile (50-km) radius from base station

Speed - Up to 70 megabits per second

Non-Line-of-sight (NLoS) between user and base station

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Frequency bands - 2 to 11 GHz and 10 to 66 GHz (licensed and unlicensed bands)

Figure 1.2.2.2.1 A sample Wimax network

1.2.2.3 BluetoothBluetooth is a short range, wire free, secure and international standardized wireless

technology that provides wireless communication system between the Bluetooth

enabled devices in a short ranged network. Bluetooth technology is a short range

wireless technology that was developed by the collaboration of mobile phones and IT

companies such as Nokia, Intel, Toshiba, Erickson and IBM. Bluetooth develops short

range wireless connections between the laptops, handheld pcs, wireless communication

devices and mobile phones. Bluetooth is only available to the personal area networks in

an office or a home network.

It reduces the usage of power as compared to the Wi-Fi. Bluetooth is an international

standardized technology that is used for the wireless communication between the

Bluetooth held devices such as mobile phones, digital camera, laptops, desktop

computers, keyboard, mouse, mp3 players, video cameras and other devices

Bluetooth uses radio waves frequency as a medium and is suitable for the 1, 10 and 100

meters distance. Like the Bluetooth, Wi-Fi uses the same frequency but the power

consumption of the wi-fi is high so it produces more powerful signals

Bluetooth uses radio waves that operate at 2.4 GHz bands. Microsoft Windows XP withthe service pack 2 has the built-in support for the Bluetooth technology. The master

Bluetooth device can communication with the seven other Bluetooth enabled devices.

Different devices support different standards of the Bluetooth technology. The research

on the advanced Bluetooth is in progress for the Bluetooth version 3.0 to provide the

high-speed connections.

1.2.2.4 SatelliteIn 1962, the American telecommunications giant AT&T launched the world's first true

communications satellite, called Telstar. Since then, countless communications

satellites have been placed into earth orbit, and the technology being applied to them is

forever growing in sophistication

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1.2.2.4.1 Basic Elements

Satellite communications are comprised of following 2 main components:

1.2.2.4.1.1 The Satellite

The satellite itself also known as the space segment, and is composed of three separate

units, namely the fuel system, the satellite and telemetry controls, and the transponder.

The transponder includes the receiving antenna to pick-up signals from the groundstation, a broad band receiver, an input multiplexer, and a frequency converter which is

used to reroute the received signals through a high powered amplifier for downlink.

The primary role of a satellite is to reflect electronic signals. In the case of a telecom

satellite, the primary task is to receive signals from a ground station and send them

down to another ground station located a considerable distance away from the first.

This relay action can be two-way, as in the case of a long distance phone call. Another

use of the satellite is when, as is the case with television broadcasts and internet, the

ground station's uplink is down linked over a wide region, so that many different

customers possessing compatible equipment may receive it. Still another use for

satellites is observation, wherein the satellite is equipped with cameras or various

sensors, and it merely downlinks any information it picks up from its vantagepoint. l

1.2.2.4.1.2 The Ground Station.

This is the earth segment. The ground station's job is two-fold. In the case of an uplink,

or transmitting station, terrestrial data in the form of base band signals, is passed

through a base band processor, an up converter, a high powered amplifier, and through

a parabolic dish antenna up to an orbiting satellite. In the case of a downlink, or

receiving station, works in the reverse fashion as the uplink, ultimately converting

signals received through the parabolic antenna to base band signal

Figure 1.2.2.4.1 Network made up with satellite signals

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2. Tools and works of Comparative Performance

Definitions to the Key terms used in comparative Performance2.1 Damping Length

The length where an amplifier or repeater is needed to further propagate the data signalwithout the data loss and noise

2.2 Maximum Speed of Data Transfer

The optimal rate of data transfer at which the data possibly being propagated through a

Transmission medium in bit per second

2.3 BandwidthThe maximum amount of information that can be transferred over a network in a given

amount of time; when multiple devices are connected to the network, the bandwidth is

divided, depleting transfer rates and decreasing overall network reliability.

2.4 CostCost means the comparative ranks given to each media according to their basic network

implementing cost. Higher rank is given to a media for which the basic network

implementing cost becomes high.

2.5 Get Connection

Getting connection means the comparative ranks given to each media according to the

toughness for becoming networked. Higher rank is given to a media for which the

toughness becomes high.

3. Data CollectionsFor getting the current information on maximum speed, damping length, Bandwidth

which are assumed to important tools for evaluating the transmission medias the

relevant authenticated websites were searched for achieving data on maximum speed,

damping length, Bandwidth of each transmission medias with applied latest modern

technologies. The reference in the annex shows the URL on which the useful

information on such data taken.

4. Test environmentThe collected data vary even among a transmission media with different applied

modern technologies. After collecting the data, the data were reviewed for gettingmaximum permissible values on speed, damping length, Bandwidth for each

transmission media with an applied modern technology for easily comparing each other

transmission medium with a unique value. The values found for satellite extreme

higher than the other media, so it was neglected in comparison.

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Mediums Damping Length Max speed Bandwidth Cost Get connected

Guided

Twisted pair

(multi-pair cables) 2 Km 100 Mbps 300 MHz Little High (rank 3)

Systematic Care needed

(rank 2)

Coaxial cable 9 Km 40 Mbps 35 MHz Medium (rank 4) Care needed (rank 3)

Optical fibber 60 Km 2.4 Gbps 2 GHz Very High (rank 1) Little tough (rank 1)

Ung

uidedWi-Fi 50 M (indoor) 54 Mbps 5 GHz High (rank 2) Easy (rank 4)

Wimax 10 Km (practically) 70 Mbps 11 GHz High (rank2) Easy (rank 4)

Bluetooth 10 M 0.72 Mbps 2.5 GHZ Low (rank 5) Very Easy (rank 5)Satellite 30000 Km 1.2 Gbps 60 GHz Extreme high Minute and tough

Relative percentage

Guided

Twisted pair

(multi-pair cables) 3.33 4.07 1.50 60.00 40.00

Coaxial cable 15.00 1.63 0.18 80.00 60.00

Optical fiber 100.00 100.00 100.00 20.00 20.00

UnguidedWi-Fi 0.08 2.20 25.00 40.00 80.00

Wimax 16.67 2.85 55.00 40.00 80.00

Bluetooth 0.02 0.03 12.50 100.00 100.00

Satellite Omitted as comparably very high valules

5. Table of Data Collections and plots

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11

0

10

20

30

40

50

60

Damping Length (Km)

0

500

1000

1500

2000

2500

Max speed (Mbps)

Twisted

pair

(multi-

pair

cables)

Coaxial

cable

Optical

fiberWi-Fi Wimax Bluetooth

0

20004000

6000

8000

10000

12000

14000

16000

18000

20000

Bandwidth (MHz)

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

Cost (Rank)

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

Get connected (Rank)

e at ve ercentages s e ecte e u

.00

.

0.00

0.00

.00

0.00

20.00

Twisted pair

-

Coaxial cable Optical fiber Wi-Fi Wimax Blue

Damping Length

Bandwidth

Cost

Get connected

6. Charts: Comparing Transmission Medias


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7. Result and Discussion

From charts in the paper, we see optical fibber posses the grater stages in

speed, damping length and bandwidth but optical fibber cable connection is

sensitive than twisted Pair and Coaxial cable connections and require highercost that the same.

Even coaxial cabling system has higher damping length than twisted pair

system; twisted pair has higher bandwidth and speed, so we can say twisted

pair outperforms coaxial cable. Here it is also notable that coaxial cable can be

connected easily without order, but twisted pair not like that.

Here we see from the charts, all unguided mediums are better for ease of

access than guided. Among Unguided; wimax outperforms other Medias in

better networking performance in long range (speed, damping length and

bandwidth), even though wi-fi is a substitute for providing a greater power of

access than wimax in short range. Even satellite performs with higher values

of speed, damping length and bandwidth, the implementing cost and minuteconnection control get demerits, so we do not choose satellite as an populated

outperforming media device for networking compared to other medias.

8. Findings Optical fibber in the guided media outperforms other Medias in better

networking performance but optical fibber cable connection is sensitive than

twisted Pair and Coaxial cable connections and require higher cost that the

same.

Twisted pair outperforms coaxial cable. Here it is also notable that coaxial

cable can be connected easily without order, but twisted pair not like that. Among Unguided; wimax outperforms other Medias in better networking

performance in long range even though wi-fi is a substitute for providing a

greater power of access than wimax in short range.

Here all unguided mediums are better for ease of access than guided.

9. References

http://www.crutchfield.com/SLu3lQkqk5S/Learn/learningcenter/home/wireles

s_glossary.html#rate for introductory text and reviews Last accessed on 12

January 2009 http://www.crutchfield.com/Learn/learningcenter/home/bluetooth.html for

bluetooth Last Accessed on 15 January 2009

http://www.rfdesign.info/doc-desc/18/WiMAX-An-Introduction.html for

wimax, wi-fi and Bluetooth Last Accessed on 20th January 2009

http://searchmobilecomputing.techtarget.com/tip/0,289483,sid40_gci970933,0

0.html for wimax Last accessed on 26th January 2009

http://www.wtec.org/loyola/satcom/c2_s3.htm#f2_30 for satellite

Last accessed on 2nd February 2009

http://www.rap.ucar.edu/~djohnson/satellite/coverage.html for staellite

Last accessed on 5th February 2009

12
http://www.crutchfield.com/SL%EF%82%A7%09http:/www.crutchfield.com/SLu3lQkqk5S/Learn/learningcenter/home/wireless_glossary.html#rate%20for%20introductory%20text%20au3lQkqk5S/Learn/learningcenter/home/wireless_glossary.html%23rate%20for%20introductory%20text%20and%20reviewshttp://www.crutchfield.com/SL%EF%82%A7%09http:/www.crutchfield.com/SLu3lQkqk5S/Learn/learningcenter/home/wireless_glossary.html#rate%20for%20introductory%20text%20au3lQkqk5S/Learn/learningcenter/home/wireless_glossary.html%23rate%20for%20introductory%20text%20and%20reviewshttp://www.crutchfield.com/Learn/learningcenter/home/bluetooth.htmlhttp://www.crutchfield.com/Learn/learningcenter/home/bluetooth.htmlhttp://www.rfdesign.info/doc-desc/18/WiMAX-An-Introduction.htmlhttp://www.rfdesign.info/doc-desc/18/WiMAX-An-Introduction.htmlhttp://searchmobilecomputing.techtarget.com/tip/0,289483,sid40_gci970933,00.htmlhttp://searchmobilecomputing.techtarget.com/tip/0,289483,sid40_gci970933,00.htmlhttp://www.wtec.org/loyola/satco%EF%82%A7%09http:/www.wtec.org/loyola/satcom/c2_s3.htm#f2_30%20for%20satellite%20m/c2_s3.htmhttp://www.rap.ucar.edu/~djohnson/satellite/coverage.html%20for%20staellitehttp://www.crutchfield.com/SL%EF%82%A7%09http:/www.crutchfield.com/SLu3lQkqk5S/Learn/learningcenter/home/wireless_glossary.html#rate%20for%20introductory%20text%20au3lQkqk5S/Learn/learningcenter/home/wireless_glossary.html%23rate%20for%20introductory%20text%20and%20reviewshttp://www.crutchfield.com/SL%EF%82%A7%09http:/www.crutchfield.com/SLu3lQkqk5S/Learn/learningcenter/home/wireless_glossary.html#rate%20for%20introductory%20text%20au3lQkqk5S/Learn/learningcenter/home/wireless_glossary.html%23rate%20for%20introductory%20text%20and%20reviewshttp://www.crutchfield.com/Learn/learningcenter/home/bluetooth.htmlhttp://www.crutchfield.com/Learn/learningcenter/home/bluetooth.htmlhttp://www.rfdesign.info/doc-desc/18/WiMAX-An-Introduction.htmlhttp://www.rfdesign.info/doc-desc/18/WiMAX-An-Introduction.htmlhttp://searchmobilecomputing.techtarget.com/tip/0,289483,sid40_gci970933,00.htmlhttp://searchmobilecomputing.techtarget.com/tip/0,289483,sid40_gci970933,00.htmlhttp://www.wtec.org/loyola/satco%EF%82%A7%09http:/www.wtec.org/loyola/satcom/c2_s3.htm#f2_30%20for%20satellite%20m/c2_s3.htmhttp://www.rap.ucar.edu/~djohnson/satellite/coverage.html%20for%20staellite


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www.bsu.edu/web/ebleech/ppt/wk10_Satellite___Microwave.ppt for

fundamentals of satellite communication

Last accessed on 12th February 2009

http://en.wikipedia.org/wiki/Transmission_medium for introduction

Last accessed on 29 December 2008

http://en.kioskea.net/contents/transmission/transintro.php3 for introductionLast accessed on 15th March 2009

http://www.britannica.com/ebchecked/topic/524891/statellite- communication

Last accessed on 17th April 2009.

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