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PRESENTATION ON

WIRELESS COMMUNICATION

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TABLE OF CONTENTS

Overview

Current Wireless Systems

What is Wireless communication

Types of Wireless communication

The Wireless Spectrum

Why wireless communication ..?

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Overview

Wireless communications is the fastest growing segment of the communication industry. It has captured the attention of media and the imagination so of the public. Many new applications including wireless sensors networks, automated highways and factories, smart homes , factories , telemedicine are emerging research ideas to concrete the systems. The first wireless network was developed in the pre-industrial age.

In 1895 ,Marconi first developed the first RADIO transmission.

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Wireless Vision

The vision of wireless communication supporting information exchange between people or devices is the communication frontier of the next few decades. This vision will allow multimedia communication from any where in the world using a small handheld device or laptop. Wireless network will connect palmtop, laptop and desktop computers any where within an office building, campus as well as from the cafe corner.

Wireless sensors have an enormous range of both commercial and military applications. There have been many failures along the way, including the first generation wireless LANs, the Iridium satellite system ,wide area data services such as Metricom and fixed wireless access to the homes

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What is wireless communication ?

Wireless communication is transmitting/receiving voice and data using electromagnetic waves in open space.

The information from sender to receiver is carried over a well defined frequency band.

Each channel has a fixed frequency bandwidth and capacity ( bit rate).

Different channels can be used to transmit information in parallel and independently.

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Example

Assume a spectrum of 120 KHz is allocated over a base frequency for communication between station A and B . Each channel occupies 40 KHz ..?

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Types of wireless communication

Basic broad level classification of wireless communication :

Mobile

cellular phones (GSM /CDMA)

Portable

Wi-Fi , UWB

Fixed

wireless MAN

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Typical frequencies

FM radio 88 MHz

TV broadcast 200 MHz

GSM phones 900 MHz

GPS 1.2 GHz

PCS phones 1.8 GHz

Bluetooth 2.4 GHz

Wi-Fi 2.4 GHz

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Band width 2.4 is a free band also known as the ISM band , this band is given to the medicine industry , institution to the scientific establishment with and a lot useful appliances have come out in this frequency.

For instance , institutes like IIT in Delhi have laboratory where most of the experiments have been designed around 2.4 GHz simply because it is a license free band.

Lets not be limited ourselves to 2.4 GHz there are frequency working at 28 GHz , 32 GHz, 40 GHz and trial runs are being made at 100 GHz.

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Example

Suppose that if we pump in 1 mili watt of power at 20 KHz it might go certain distance before getting attenuated before reaching the receiver sensitivity, so wireless communication has work between A and B which are not co-located they are separated by a distance otherwise there is no need of wireless communication.

However if we need to communicate over large distance , one way is to increase the power but any increase in the power comes at two specific costs :

Money

Radiation hazard

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The Electromagnetic Spectrum

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Since we are looking at the electromagnetic magnetic spectrum another way of doing wireless communication is LIGHT . We can use simple visible light or infrared to do communication. All this is indeed wireless communications we do not need wires at all .

What is the need to go to such high frequencies where attenuation is high..?

Today we are getting into more band width hungry applications , we not only want a SMS but also MMS all these require a large band width . To go into a larger band width we have to translate ourselves to upward to larger frequency . A higher band width will give you a larger data rate . Therefore until the time we were using electromagnetic spectrum only for voice communication , lower frequencies were perfect .

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Why wireless communication..?

Freedom from wires

No cost of installing wires and no rewiring

No branches of wires here and there

“ Auto Magical “ instantaneous communications without physical connection ., Bluetooth , Wi-Fi

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Global coverage

Communication can reach where wiring is costly .,rural areas , old buildings , battlefields ,etc.

Stay connected

Roaming allows flexibility to stay connected anywhere and any time.

Rapid market growth

Flexibility

Services reach you wherever you go.

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Increasing dependence on telecommunication services for business and personal reason

Consumers and business are wiling to pay for it.

Basic Mantra : stay connected – anywhere , anytime .

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Challenges

Efficient hardware

low power Transmitters , Receivers

low power signal processing tool

Efficient use of finite radio spectrum

Integrated services

voice , data , multimedia over a single network services differentiation , priorities , resources sharing

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Network support for user mobility .

Maintaining quality of service over unreliable links

Connectivity and coverage

Cost efficiency

Fading

Higher probability of data corruption (hence need a stronger channel codes)

Need for stronger security mechanism

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Multimedia requirement

Voice Data video

Delay <100 mili sec __ <100 ms

Packet loss <1% 0 <1%

RFR 10 raised to power 3 10 raised to power 6 10 raised to power 6

Data range 8-32 Kbps 1-100 Mbps 1-20 Mbps

Traffic range continuous Bursty continuous

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Wireless vs Mobile

Wireless do not necessarily mean mobile.

Wireless systems may be:

- fixed

- portable

= mobile

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THANK YOUBY

SOMBARAN GUPTA

(R020112019)

4-SEMESTER