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Wireless Fidelity (WiFi)

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asma mushtaq

on 2 January 2014

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Transcript of Wireless Fidelity (WiFi)

Wireless Fidelity (WiFi)
WiFi Technologies
Wi-Fi Networks use Radio Technologies to transmit & receive data at high speed

WiFi Network Topologies
Peer-to-peer topology (Ad-hoc Mode)

AP-based topology (Infrastructured Mode)

Wireless Technology is an alternative to Wired Technology, which is commonly used, for connecting devices in wireless mode.
Wi-Fi (Wireless Fidelity) is a generic term that refers to IEEE 802.11 standard for Wireless Local Area Networks (WLANs).

Wi-Fi Networks connect computers to each other, to the internet and to the wired network.

IEEE 802.11b
Appeared in late 1999
Uses 2.4GHZ ISM(Industrial, scientific and medical) band
11Mbps(theoretical speed)
4-6Mbps(actual speed)
100-150 feet range
DSSS modulation
Signal range is good and not easily obstructed
Most popular, least expensive
Unlicensed radio frequency band
Interference from microwave ovens, mobile phones and Bluetooth devices which can reduce the transmission speed.

IEEE 802.11n
Newer IEEE standard for wifi
Uses multiple wireless signals and antennas (MIMO technology) instead of one
Operates on both 2.4GHz and 5GHz bands
Supports data rates of over 100 Mbps
OFDM modulation
Better range due to increased signal intensity
Fastest maximum speed
Totally backward compatible-supports 802.11a, b and g standards
Costs more than 802.11g
The use of multiple signals may greatly interfere with nearby 802.11b/g based networks
IEEE 802.11a
Introduced in 2001
Operates at 5 GHz U-NII (Unlicensed National Information Infrastructure) band
54 Mbps (theoretical speed)
15-20 Mbps (Actual speed)
50-75 feet range
OFDM modulation
fast maximum speed
Regulated frequencies prevent signal interference from other devices
Not compatible with 802.11b
More expensive (found in business networks)
Shorter range signal that is more easily obstructed

WI-FI Network Elements
Access Point (AP)
- The AP is a wireless LAN transceiver or “base station” that can connect one or many wireless devices simultaneously to the Internet.

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

- Firewalls and anti-virus software protect networks from uninvited users and keep information secure.
Asma Mushtaq 370
Rashiqa Faiz 381

Wi-Fi Technologies
Wi-Fi Architecture
Wi-Fi Network Elements
Wi-Fi Network Topologies
How a Wi-Fi Network Works
Applications of Wi-Fi
Future of WiFi

WiFi standards:
IEEE 802.11

IEEE 802.11b
IEEE 802.11a
IEEE 802.11g
IEEE 802.11n
IEEE 802.11ac
IEEE 802.11ad
First WLAN standard appeared in 1997
Maximum bandwidth 2Mbps
DSSS, FHSS modulation
too slow for most ofthe applications
IEEE 802.11g
Introduced in 2002 and 2003
Attempts to combine the best of both 802.11a and 802.11b
54Mbps(theoretical speed)
20-25Mbps(actual speed)
50-75feet range
Supports DSSS modulation
Uses OFDM moduation for higher transmission rates
Fast maximum speed
Signal range is good and not easily obstructed
Cost more than 802.11b
Appliances may interfere on the unregulated signal frequency

Peer-to-peer Topology
AP is not required
Client devices within a cell can communicate with each other directly.
It is useful for setting up a wireless network quickly and easily.

Infrastructured Network
The client communicate through Access Point.
Any communication has to go through AP.
If a Mobile Station (MS), like a computer, a PDA, or
a phone, wants to
communicate with another MS, it needs to send
the information to AP first, then AP sends it to the destination MS.

A Hotspot is any location where wifi network is made publicly available
Hotspots are equipped with Broad band Internet connection and one or more Access points that allow users to access the internet wirelessly
Hotspots can be setup in any public location that can support an Internet connection.

How a Wi-Fi Network Works?
A wifi connection works through a transmitting antenna, which is usually connected to DSL or cable internet connection. The antenna on the router will then beam radio signal through a specific range. Another antenna which is on the laptop or personal computer will receive the signal

Wi-Fi Configurations
Wi-Fi Applications
Small Businesses
Large Corporations & Campuses
Health Care

No Wires- A truly wireless networking solution
No Waiting- Fast, easy deployments
Ease of Installation- Quick easy setup
Security-Wi-Fi Protected Access encryption (WPA2) protocol
Fast data transfer rate

Interference from other devices e.g. telephones and microwave devices for wifi networks
Degradation in performance
Speed – Slower than cable
High power consumption
Limited range-Affected by various medium

Wi-Fi is a simple and cost effective way to connect to internet without the need of wires.The 802.11 standards have been growing like mushrooms after the rain in order to address the needs of the consumers
Hotspot is a geographic area setup in any public location and has a readily accessible wireless network.
Wifi networks have a several limitations that should be concerned

Future of WiFi

The future of wifi is very bright. It is growing in popularity because of decreasing costs and the fredom it gives to users
WiFi standards Summary
Full transcript