Wi Fi & Wi MAXWi Fi & Wi MAXBRBRAITTBRBRAITT

What is Wi fi ?What is Wi fi ?• Cables are required to connect more Cables are required to connect more

number of computers.number of computers.• Locating the individual cable of Locating the individual cable of

computer is difficult.computer is difficult.• To avoid this kind of problem only To avoid this kind of problem only

one solution .i.e. Wi fi.one solution .i.e. Wi fi.• Wi fi gives freedom to connect PC to Wi fi gives freedom to connect PC to

Internet from any room.Internet from any room.

Meaning of Wi fi.Meaning of Wi fi.• Wi fi means wireless fidelity, i.e. Wi fi means wireless fidelity, i.e.

freedom which allows a person to freedom which allows a person to connect to Internet, from any room connect to Internet, from any room without wires.without wires.

Features of Wi fi.Features of Wi fi.• Wi fi enabled computers send and Wi fi enabled computers send and

receive data indoor and outdoor receive data indoor and outdoor within the range of base station.within the range of base station.

• Wi fi allows to access Internet while Wi fi allows to access Internet while on move.on move.

• Wi fi is a set of product compatibility Wi fi is a set of product compatibility standards for wireless LANs.standards for wireless LANs.

Components required for Wi Components required for Wi fi.fi.• PC or Laptop running windows 98 or PC or Laptop running windows 98 or

above versions.above versions.• Wireless PCMCIA card.Wireless PCMCIA card.• Access Point, essentially a compact Access Point, essentially a compact

radio transmitter with antenna.radio transmitter with antenna.

Components required for large Components required for large environment.environment.• Multiple access points.Multiple access points.• Network switch.Network switch.• Authentication and Billing server.Authentication and Billing server.• Wireless access gateway.Wireless access gateway.

Description of components.Description of components.• MAPS: Many Radio Transmitters.MAPS: Many Radio Transmitters.• Network Switch: Switch through which Network Switch: Switch through which

many radio transmitters are connected.many radio transmitters are connected.• Authentication & Billing server: gives Authentication & Billing server: gives

access to the subscriber by conducting access to the subscriber by conducting authentication and perform billing.authentication and perform billing.

• Wireless gateway: a device which connects Wireless gateway: a device which connects wireless subscribers to the wired network.wireless subscribers to the wired network.

Wireless Standards.Wireless Standards.• 802.11b (First standard)802.11b (First standard)• 802.11a (Faster, more expensive 802.11a (Faster, more expensive

than the above).than the above).• 802.11g (New standard which 802.11g (New standard which

combines above two).combines above two).

Comparison of wireless Comparison of wireless standards.standards.

802.11b802.11b 802.11g802.11g 802.11a802.11a

FrequencyFrequency 2.4 to 2.4 to 2.4835Ghz2.4835Ghz

2.4 to 2.4 to 2.4835Ghz2.4835Ghz

5.725 to 5.725 to 5.850Ghz5.850Ghz

Speed Speed (max)(max)

11Mbps11Mbps 54Mbps54Mbps 54Mbps54Mbps

ApplicatioApplicationn

Home N/WsHome N/Ws Larger N/Ws Larger N/Ws , Small , Small BusinessBusiness

Larger N/Ws Larger N/Ws , Large , Large Business Business with securitywith security

Working modes of Wi fi.Working modes of Wi fi.• Adhoc: Allows wireless devices to Adhoc: Allows wireless devices to

communicate directly.communicate directly.• Infrastructure : Allows wireless Infrastructure : Allows wireless

devices to communicate via central devices to communicate via central node.node.

BillingBilling• Time based billing.Time based billing.• Support for secure online credit card Support for secure online credit card

payments.payments.• Configurable plans and TariffsConfigurable plans and Tariffs• A/C renewal through online payment A/C renewal through online payment

or recharging with prepaid coupons.or recharging with prepaid coupons.

Terminology.Terminology.• Hot spot: geographical region covered Hot spot: geographical region covered

by one APby one AP• BSS(Basic Service Set): when two or BSS(Basic Service Set): when two or

more stations come together to more stations come together to communicate with each other, they communicate with each other, they form BSS.form BSS.

• IBSS (Independent BSS): A BSS that IBSS (Independent BSS): A BSS that stands alone and not connected to stands alone and not connected to central node.central node.

Limitations of Wi fi.Limitations of Wi fi.• Hot spots are very small.Hot spots are very small.• Because this spectrum is unlicenced, Because this spectrum is unlicenced,

chance of interference is more.chance of interference is more.• Do not support non-line of sight.Do not support non-line of sight.• Wi fi range is about 30Mts.Wi fi range is about 30Mts.• Transmit power is between 15mws Transmit power is between 15mws

and 200mws.and 200mws.

Wi fi channels.Wi fi channels.• Channel 1 : 2412MhzChannel 1 : 2412Mhz• Channel 2 : 2417MhzChannel 2 : 2417Mhz• ……• Channel 11: 2462MhzChannel 11: 2462Mhz

BSNL’s Wi fi services.BSNL’s Wi fi services.• Authentication only to some APsAuthentication only to some APs• Allow users to view predefined sites Allow users to view predefined sites

before authenticationbefore authentication

Wi Max.Wi Max.• Provide Universal Internet Access.Provide Universal Internet Access.• Automatically connect the user to the Automatically connect the user to the

closest available antenna.closest available antenna.

Parts of Wi Max.Parts of Wi Max.• Wi Max towerWi Max tower• Wi Max receiver.Wi Max receiver.

Wi Max towerWi Max tower• A single tower provide coverage of A single tower provide coverage of

8000 sq.km.8000 sq.km.

Wi Max receiver.Wi Max receiver.• PCMCIA Card that can be built in PCMCIA Card that can be built in

Laptop.Laptop.

Forms of service.Forms of service.• Line of sight Line of sight • Non-line of sight.Non-line of sight.

Line of sight.Line of sight.• Able to send lot of data with few Able to send lot of data with few

errors.errors.• Use High frequencies appx. 66GHz.Use High frequencies appx. 66GHz.

Non-Line of Sight.Non-Line of Sight.• A small antenna on computer A small antenna on computer

connects to tower.connects to tower.• Use frequencies range 2GHz to Use frequencies range 2GHz to

11GHz.11GHz.• Because these are low wave lengths, Because these are low wave lengths,

the transmitted signals bend around the transmitted signals bend around obstacles.obstacles.

Features of Wi Max.Features of Wi Max.• Coverage area 50kms.Coverage area 50kms.• Use licensed spectrum.Use licensed spectrum.• Better quality of service.Better quality of service.