wifi ppt-ece(b)

8/3/2019 wifi ppt-ece(b)

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CONNECTION OF COMPUTERS OVER

WIDE RANGE USING WIRELESSFIDELITY(WI FI)

BY,K.SINDHU,

T.PRATHYUSHA,

N.BHANU CHANDER


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WiFi Introduction

Wi-Fi (Wireless Fidelity) is a generic term that refers to theIEEE 802.11 communications standard for Wireless LocalArea Networks (WLANs).

Wi-Fi Network connect computers to each other, to the internetand to the wired network.


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AGENDA:

Wifi

Wifi Technology

Wifi Network hotspotsOFDM

Network Topology

Initialisation of an Access point

Wifi UsesWifi Advantage

Conclusion


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What is Wireless LAN / WiFi


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Wi-Fi TechnologyWi-Fi Networks use Radio Technologies to transmit &receive data at high speed:

IEEE 802.11b

IEEE 802.11a

IEEE 802.11g


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IEEE 802.11b

Operates at 2.4GHz radio spectrum

11 Mbps (theoretical speed) - within 30 m Range

4-6 Mbps (actual speed) 100 -150 feet range

Most popular, Least Expensive

Interference from mobile phones and Bluetooth

devices which can reduce the transmission speed.


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IEEE 802.11a

Operates at 5 GHz

54 Mbps (theoretical speed) 15-20 Mbps (Actual speed)

50-75 feet range

More expensive

Not compatible with 802.11b


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IEEE 802.11g

Introduced in 2003

Combine the feature of both standards (a,b)

100-150 feet range 54 Mbps Speed

2.4 GHz radio frequencies

Compatible with b


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IEEE WLAN Standard 802.11n

y Currently under development.

y Compatible with 802.11b, 802.11a, and 802.11g.

y Potential transfer speeds range from 100 megabits persecond to 540 megabits per second.

y Uses orthogonal frequency division multiplexing

(OFDM).

y Single source, multiple signals.


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How a Wi-Fi Network (hotspots)works ?

A Wi-Fi hotspot is created by installing an access point toan internet connection.

An access point acts as a base station.

When Wi-Fi enabled device encounters a hotspot thedevice can then connect to that network wirelessly.

A single access point can support up to 30 users and canfunction within a range of 100 150 feet indoors and up to

300 feet outdoors. Many access points can be connected to each other via

Ethernet cables to create a single large network.


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Orthogonal Frequency Division Multiplexing

(OFDM)

Allows digital signal to be transmitted simultaneously onmultiple RF carrier waves.

Modulation technique of QAM

The signals are created so that they are orthogonal to oneanother, there by no interference to one another.

Able to deliver higher bandwidth efficiency.


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Wi-Fi Network Topologies

AP-based topology (Infrastructure Mode)

Peer-to-peer topology (Ad-hoc Mode)


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AP-based topology

The client communicate through Access Point.


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Peer-to-peer topology

AP is not required.

Client devices within a cell

can communicate directlywith each other.

It is useful for setting up ofa wireless network quickly

and easily.


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Initialization of a Access point:y Basically we have two modes in this process:-

Point point over net (PPPOE): Here we can store

name and password in modem & an automaticconnection is provided.

Bridge mode: The user name and password are typedmanually.


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Configuration of a Access

point:- To configure a Access point we need to know the

default IP addresses of the network & modem.

Default network: 192.168.1.245 Default gateway: 192.168.1.1

A specific key is provided for each password weregister.

In order to connect an access point for other devicethe same IP address as of the network can be used.


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Elements of a WI-FI Network

Access Point (AP) - The AP is a wireless LANtransceiver or base station that can connect one or many

wireless devices simultaneously to the Internet.

Wi-Fi cards - They accept the wireless signal andrelay information.They can be internal and external. (e.gPCMCIA Card for Laptop and PCI Card for Desktop PC)


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Wireless Adapter PCMCIA

(Personal Computer Memory Card International)


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Wi-Fi Users

Frequent Travellers

Businessmen and Corporate Managers

Students and AcademiciansAdministrators & Technocrats who

participate in Seminars & Conferences

Just about anybody with a laptop


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Advantages

Mobility

Ease of Installation

Cost Reliability

Security

Use unlicensed part of the radio spectrum

Speed


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Conclusion:-yWi-Fi is the technology which is used to connect

devices like laptops & computers without complexity .

We hope that its advanced technology 802.11 n whichhas a speed of nearly 540 Mbps will bring morechanges in future world of electronics.


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Thanks

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