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KARNATAK UNIVERSITY DHARWAD


What is Wi-Fi?

The standard for wireless local area networks (WLANs). It’s like a common language that all the devices use to communicate to each other. If you have a standard, people can make all sorts of devices that can work with each other.
It’s actually IEEE 802.11, a family of standards. The IEEE (Eye-triple-E, Institute of Electrical and Electronics Engineers Inc.) is a non-profit, technical professional association of more than 360,000 individual members in approximately 175 countries. The Wireless Ethernet Compatibility Alliance started the Wi-Fi--wireless fidelity--certification program to ensure that equipment claiming 802.11 compliance was genuinely interoperable.
The technical term "IEEE 802.11" has been used interchangeably with Wi-Fi, however Wi-Fi has become a superset of IEEE 802.11 over the past few years. Wi-Fi is used by over 700 million people, there are over 750,000 hotspots (places with Wi-Fi Internet connectivity) around the world, and about 800 million new Wi-Fi devices every year. Wi-Fi products that complete the Wi-Fi Alliance interoperability.
Certification testing successfully can use the Wi-Fi CERTIFIED designation
And trademark.
Not every Wi-Fi device is submitted for certification to the Wi-Fi Alliance. The lack of Wi-Fi certification does not necessarily imply a device is incompatible with Wi-Fi devices/protocols. If it is compliant or partly compatible the Wi-Fi Alliance may not

Object to its description as a Wi-Fi device though technically only the CERTIFIED designation carries their approval.
Wi-Fi certified and compliant devices are installed in many personal computers, video game consoles, MP3 players, smart phones, printers, digital cameras, and laptop computers.


When Wi-Fi Originated?

The precursor to wi-fi was invented in 1991 by NCR Corporation in Nieuwegein, the Netherland.
The first wireless products were brought on the market under the name WaveLAN with speeds of 1 Mbit/s to 2 Mbit/s.
Vic Hayes has been named as father of “Wi-Fi’’.

Wi-Fi network services
Distribution and integration
o This service is used by mobile stations in an infrastructure network every time they send data
o Integration is a service provided by the distribution system; it allows the connection of the distribution system to a non-IEEE 802.11 network
Association, re-association, and disassociation
o Delivery of frames to mobile stations is made possible because mobile stations register, or associate, with access points
o When a mobile station moves between basic service areas within a single extended service area, it must evaluate signal strength and perhaps switch the access point with which it is associated.
o To terminate an existing association, stations may use the disassociation service
Authentication and Deauthentication
o Authentication is a necessary prerequisite to association because only authenticated users are authorized to use the network. Deauthentication terminates an authenticated relationship

Threats of security
Wi-Fi works with no physical wired connection between sender and receiver by using radio frequency. The most common wireless encryption standards, wired equivalent privacy has been shown to be using breakable even when correctly configured.
Advantages of Wi-Fi
Wi-Fi can make access publicly available at Wi-Fi hotspots.
Does not require regulatory approval for individual.
Wi-Fi network can support roaming.
Wi-Fi allows local area network to deploy without wires for client devices.

Limitations
Spectrum assignments and operational limitations are not consistent worldwide: most of Europe allows for an additional two channels beyond those permitted in the U.S. for the 2.4 GHz band (1–13 vs. 1–11), while Japan has one more on top of that (1–14). Europe, as of 2007, was essentially homogeneous in this respect.
A Wi-Fi signal occupies five channels in the 2.4 GHz band; any two channels whose channel numbers differ by five or more, such as 2 and 7, do not overlap. The oft-repeated adage that channels 1, 6, and 11 are the only non-overlapping channels is, therefore, not accurate; channels 1, 6, and 11 do, however, comprise the only group of three non-overlapping channels in the U.S.

Capabilities and Uses
High data transmission rate and high reliability in all weather conditions and an always available (95% Uptime) network makes wifi a robust solution suitable for high bandwidth applications
Online video-conferencing with greater clarity
Telephony, using VoIP
Revenue-model for budding start-up ISPs
Broadband in the true sense
Easier reach into far-flung rural areas
Ability to add more nodes as and when required
Less maintenance overheads, especially in Rural areas where technical manpower is scarce.

WIMAX

What is WiMAX?
Worldwide Interoperability for Microwave Access (WiMAX) is the common name associated to the IEEE 802.16a/REVd/e standards
These standards are issued by the IEEE 802.16 subgroup that originally covered the Wireless Local Loop technologies with radio spectrum from 10 to 66 GHz

How WiMAX Works?

Think about how you access the Internet today. There are basically three different options:
 Broadband access - In your home, you have either a DSL or cable modem. At the office, your company may be using a T1 or a T3 line.

 Wi-Fi access - In your home, you may have set up a Wi-Fi router that lets you surf the Web while you lounge with your laptop. On the road, you can find Wi-Fi hot spots in restaurants, hotels, coffee shops and libraries.

 Dial-up access - If you are still using dial-up, chances are that either broadband access is not available, or you think that broadband access is too expensive.
The main problems with broadband access are that it is pretty expensive and it doesn't reach all areas. The main problem with Wi-Fi access is that hot spots are very small, so coverage is sparse.
What if there was a new technology that solved all of these problems? This new technology would provide:
 The high speed of broadband service
 Wireless rather than wired access, so it would be a lot less expensive than cable or DSL and much easier to extend to suburban and rural areas
 Broad coverage like the cell phone network instead of small Wi-Fi hotspots
 Short for Worldwide Interoperability for Microwave Access and it also goes by the IEEE name 802.16. ¬
WiMAX has the potential to do to broadband Internet access what cell phones have done to phone access. In the same way that many people have given up their "land lines" in favor of cell phones, WiMAX could replace cable and DSL services, providing universal Internet access just about anywhere you go. WiMAX will also be as painless as Wi-Fi -- turning your computer on will automatically connect you to the closest available WiMAX antenna.

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