History

History

Wi-Fi uses both single carrier direct-sequence spread spectrum radio technology (part of the larger family of spread spectrum systems) and multi-carrier OFDM (Orthogonal Frequency Division Multiplexing) radio technology. These regulations then enabled the development of Wi-Fi, its onetime competitor HomeRF, and Bluetooth.
Unlicensed spread spectrum was first made available by the Federal Communications Commission in 1985 and these FCC regulations were later copied with some changes in many other countries enabling use of this technology in all major countries.[11] The FCC action was proposed by Michael Marcus of the FCC staff in 1980 and the subsequent regulatory action took 5 more years. It was part of a broader proposal to allow civil use of spread spectrum technology and was opposed at the time by main stream equipment manufacturers and many radio system operators.
The precursor to Wi-Fi was invented in 1991 by NCR Corporation/AT&T (later Lucent & Agere Systems) in Nieuwegein, the Netherlands. It was initially intended for cashier systems; 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, who held the chair of IEEE 802.11 for 10 years and has been named the 'father of Wi-Fi,' was involved in designing standards such as IEEE 802.11b, and 802.11a.

WI-FI

WI-FI

Wi-Fi (pronounced wye-fye, IPA: /ˈwaɪfaɪ/) is a wireless technology brand owned by the Wi-Fi Alliance intended to improve the interoperability of wireless local area network products based on the IEEE 802.11 standards. Common applications for Wi-Fi include Internet and VoIP phone access, gaming, and network connectivity for consumer electronics such as televisions, DVD players, and digital cameras.
The Wi-Fi Alliance is a consortium of separate and independent companies agreeing to a set of common interoperable products based on the family of IEEE 802.11 standards.[1]
The Wi-Fi Alliance certifies products via a set of established test procedures to establish interoperability. Those manufacturers that are members of Wi-Fi Alliance whose products pass these interoperability tests can mark their products and product packaging with the Wi-Fi logo.[2]
Wi-Fi technologies have gone through several generations since their inception in 1997. Wi-Fi is supported to different extents under Microsoft Windows, Apple Macintosh and open source Unix and Linux operating systems.

Uses

Uses

A Wi-Fi enabled device such as a PC, game console, cell phone, MP3 player or PDA can connect to the Internet when within range of a wireless network connected to the Internet. The area covered by one or more interconnected access points is called a hotspot. Hotspots can cover as little as a single room with wireless-opaque walls or as much as many square miles covered by overlapping access points. Wi-Fi has been used to create a mesh networks, for example, in the City of London.[3] Both architectures are used in community networks.[citation needed]
Wi-Fi also allows connectivity in peer-to-peer (wireless ad-hoc network) mode, which enables devices to connect directly with each other. This connectivity mode is useful in consumer electronics and gaming applications.
When the technology was first commercialized there were many problems because consumers could not be sure that products from different vendors would work together. The Wi-Fi Alliance began as a community to solve this issue so as to address the needs of the end user and allow the technology to mature. The Alliance created the branding Wi-Fi CERTIFIED to show consumers that products are interoperable with other products displaying the same branding.
Many consumer devices use Wi-Fi. Amongst others, personal computers can network to each other and connect to the Internet, mobile computers can connect to the Internet from any Wi-Fi hotspot, and digital cameras can transfer images wirelessly.
Routers which incorporate a DSL or cable modem and a Wi-Fi access point are often used in homes and other premises, and provide Internet access and internetworking to all devices connected wirelessly or by cable into them. Devices supporting Wi-Fi can also be connected in ad-hoc mode for client-to-client connections without a router.
Business and industrial Wi-Fi is widespread as of 2007. In business environments, increasing the number of Wi-Fi access points provides redundancy, support for fast roaming and increased overall network capacity by using more channels or creating smaller cells. Wi-Fi enables wireless voice applications (VoWLAN or WVOIP). Over the years, Wi-Fi implementations have moved toward 'thin' access points, with more of the network intelligence housed in a centralized network appliance, relegating individual Access Points to be simply 'dumb' radios. Outdoor applications may utilize true mesh topologies. As of 2007 Wi-Fi installations can provide a secure computer networking gateway, firewall, DHCP server, intrusion detection system, and other functions.
In addition to restricted use in homes and offices, Wi-Fi is publicly available at Wi-Fi hotspots provided either free of charge or to subscribers to various providers. Free hotspots are often provided by businesses such as hotels, restaurants, and airports who offer the service to attract or assist clients. Sometimes free Wi-Fi is provided by enthusiasts, or by organizations or authorities who wish to promote business in their area. Metropolitan-wide WiFi (Mu-Fi) already has more than 300 projects in process.[4]

Advantages of Wi-Fi

Advantages of Wi-Fi

Wi-Fi allows LANs to be deployed without cabling for client devices, typically reducing the costs of network deployment and expansion. Spaces where cables cannot be run, such as outdoor areas and historical buildings, can host wireless LANs.
As of 2007 wireless network adapters are built into most modern laptops. The price of chipsets for Wi-Fi continues to drop, making it an economical networking option included in ever more devices. Wi-Fi has become widespread in corporate infrastructures, which also helps with the deployment of RFID technology that can piggyback on Wi-Fi.[5]
Different competitive brands of access points and client network interfaces are inter-operable at a basic level of service. Products designated as "Wi-Fi Certified" by the Wi-Fi Alliance are backwards inter-operable. Wi-Fi is a global set of standards. Unlike mobile telephones, any standard Wi-Fi device will work anywhere in the world.
Wi-Fi is widely available in more than 250,000 public hotspots and tens of millions of homes and corporate and university campuses worldwide. WPA is not easily cracked if strong passwords are used and WPA2 encryption has no known weaknesses. New protocols for Quality of Service (WMM) make Wi-Fi more suitable for latency-sensitive applications (such as voice and video), and power saving mechanisms (WMM Power Save) improve battery operation.

Ramon Magasaysay Award for 2007, has made us Nepalis proud

Ramon Magasaysay Award for 2007, has made us Nepalis proud

Mahabir Pun, the recipient of the prestigious Ramon Magasaysay Award for 2007, has made us Nepalis proud. I salute him. I also look forward to the day when there will be a thousand more Mahabir Puns who will come up with such exemplary deeds.

I had the good fortune of interacting with Pun last year when we were in a workshop making midterm review presentations on various projects funded under the World Bank assisted Poverty Alleviation Program. Pun was there to make a presentation on his wireless internet system, and I was there to make a presentation on Solar Tuki.

While talking with him at that time, it became clear that the wireless internet system and network he was setting up in the villages in Myagdi was actually against the telecom laws in Nepal at that time. The parabolic antennas and other hardware needed for the wireless internet system had entered Nepal as accompanied luggage items of Pun's numerous Nepali and foreign well-wishers and volunteers. These items could not have entered Nepal legally as Pun did not have the license to either import the wireless hardware, or install and operate the wireless internet system. Unlike in other developed countries, the frequency for operating the wireless network was neither free for use nor available in the public domain. So Pun had to use the wireless network without proper authorisation.

Pun, the brave visionary, was so highly motivated and driven to improve the lives of his village folks in Myagdi that he worked selflessly and tirelessly to establish internet access to the villages even though he knew that he was breaking the law. He got away without being punished probably because the arm of the law enforcement agency was either too short or did not feel it worth the trouble to reach out for him in Myagdi. If Pun had waited for the "proper" procedures to be set in place and for the full cooperation of the government and its agencies, he probably would still be waiting endlessly, and the villages in Myagdi would still be as isolated from the worldwide web and the global village.

HISTORY

History
The term "wireless" came into public use to refer to a radio receiver or transceiver (a dual purpose receiver and transmitter device), establishing its usage in the field of wireless telegraphy early on; now the term is used to describe modern wireless connections such as in cellular networks and wireless broadband Internet. It is also used in a general sense to refer to any type of operation that is implemented without the use of wires, such as "wireless remote control", "wireless energy transfer", etc. regardless of the specific technology (e.g., radio, infrared, ultrasonic, etc.) that is used to accomplish the operation.
Early wireless work
David E. Hughes, eight years before Hertz's experiments, induced electromagnetic waves in a signalling system. Hughes transmitted Morse code by an induction apparatus. In 1878, Hughes's induction transmission method utilized a "clockwork transmitter" to transmit signals. In 1885, T. A. Edison uses a vibrator magnet for induction transmission. In 1888, Edison deploys a system of signalling on the Lehigh Valley Railroad. In 1891, Edison attains the wireless patent for this method using inductance (U.S. Patent 465,971 ).
In the history of wireless technology, the demonstration of the theory of electromagnetic waves by Heinrich Rudolf Hertz in 1888 was important.[3][4] The theory of electromagnetic waves were predicted from the research of James Clerk Maxwell and Michael Faraday. Hertz demonstrated that electromagnetic waves could be transmitted and caused to travel through space at straight lines and that they were able to be received by an experimental apparatus.[3][4] The experiments were not followed up by Hertz and the practical applications of the wireless communication and remote control technology would be implemented by Nikola Tesla.
The electromagnetic spectrum
Light, colors, AM and FM radio, and many popular electronic devices all work on the electromagnetic spectrum. In the US the frequencies that are available for use for communication are treated as a public resource and are regulated by the Federal Communications Commission (FCC). This determines which frequency ranges can be used for what purpose and by whom. In the absence of such control, chaos might result if, for example, airlines didn't have specific frequencies to work under and a ham radio operator was interfering with the pilot's ability to land an airplane. Wireless communication spans the spectrum from 9 kHz to 300 GHz.

.

Applications of wireless technology

Applications of wireless technology

Security systems
Wireless technology may supplement or replace hard wired implementations in security systems for homes or office buildings. The operations that are required (e.g., detecting whether a door or window is open or closed) may be implemented with the use of hard wired sensors or they may be implemented with the use of wireless sensors which are also equipped with a wireless transmitter (e.g., infrared, radio frequency, etc.) to transmit the information concerning the current state of the door or window.
Television remote control
Some televisions were previously manufactured with hard wired remote controls which plugged in to a receptacle or jack in the television whereas more modern televisions use wireless (generally infrared) remote control units.
Cellular telephones
Perhaps the best known example of wireless technology is the cellular telephone. These instruments use radio waves to enable the operator to make phone calls from many locations world-wide. They can be used anywhere that there is a cellular telephone site to house the equipment that is required to transmit and receive the signal that is used to transfer both voice and data to and from these instruments. (For more information see mobile phones).
Wireless communication
Wireless is a term used to describe telecommunications in which electromagnetic waves (rather than some form of wire) carry the signal over part or the entire communication path. Common examples of wireless equipment in use today include:
• Cellular phones and pagers: provide connectivity for portable and mobile applications, both personal and business.
• Global Positioning System (GPS): allows drivers of cars and trucks, captains of boats and ships, and pilots of aircraft to ascertain their location anywhere on earth.
• Cordless computer peripherals: the cordless mouse is a common example; keyboards and printers can also be linked to a computer via wireless.
• Cordless telephone sets: these are limited-range devices, not to be confused with cell phones.
• Satellite television: allows viewers in almost any location to select from hundreds of channels.
Wireless networking is used to meet a variety of needs. Perhaps the most common use is to connect laptop users who travel from location to location. Another common use is for mobile networks that connect via satellite. A wireless transmission method is a logical choice to network a LAN segment that must frequently change locations. The following situations justify the use of wireless technology:
• To span a distance beyond the capabilities of typical cabling,
• To avoid obstacles such as physical structures, EMI, or RFI,
• To provide a backup communications link in case of normal network failure,
• To link portable or temporary workstations,
• To overcome situations where normal cabling is difficult or financially impractical, or
• To remotely connect mobile users or networks

Wireless Internet
The wireless Internet is defined by access to the Internet on any wireless or mobile device. The wireless Internet encapsulates a variety of wireless Internet access alternatives including wide-area networks (WANs), wireless local area networks (WLANs), and wireless personal area networks (PANs).
Wide area networks - WANs
Wide-area networks (WANs) are essentially the cellular networks maintained by major carriers, including in the U.S. Verizon Wireless, Sprint PCS, and Cingular Wireless. Wireless internet access over wide-area networks is still slow and is conducted mostly through what are currently known as 2G or 2.5G wireless networks. Data speeds are slow (averages run between 20 and 60 Kbps), but coverage is nearly ubiquitous. 3G, the next generation of wireless wide-area networks, promise greater data speeds (up to 384 Kbps) with the same level of nearly ubiquitous coverage as current wireless networks.
Wireless local area networks - WLANs
Wireless local area networks (WLANs) are smaller-scale wireless networks with a typical radius of several hundred feet. The most prevalent form of Wireless Local Area Network technology is called WiFi, which includes a host of standards including 802.11a, 802.11b, and 802.11g. Wireless Internet via WiFi offers blazing fast data speeds (11Mbps at the low end with 802.11b and 54 Mbps at the high end for 802.11a and 802.11g). While WiFi technology does not offer the degree of ubiquity as wide area networks, the WLAN's data speeds and relatively cheap costs have spurred it ahead in the popular market as a wireless internet solution.

The Cellular Explosion
Probably the most important factor in the birth of wireless Internet has been the proliferation of digital cell phones in the last few years. The expanding network of digital cellular and personal communication services (PCS) has created a solid foundation for wireless Internet services. It is estimated that there are more than 50 million Web-enabled cell phones in use. In 1997, Nokia, Motorola, Ericsson and Phone.com came together to create the WAP because they believed that a universal standard is critical to the successful implementation of wireless Internet. Since then, more than 350 companies have joined them in the WAP Forum.

Making a Web site accessible through a wireless device is quite a challenge. So far, only a small portion of the more than a billion Web sites, about 1.5 million, provide any wireless Internet content. As the use of WAP-enabled devices grows, you can expect that many more Web sites will be interested in creating wireless content.
WAP is designed to work on any of the existing wireless services, using standards such as:
Short Message Service (SMS)
Circuit Switched Data (CSD)
General Packet Radio Service (GPRS)
Unstructured Supplementary Services Data (USSD) For more information on these services, check out this page

Wireless Markup Language
WAP uses Wireless Markup Language (WML), which includes the Handheld Device Markup Language (HDML) developed by Phone.com. WML can also trace its roots to eXtensible Markup Language (XML). A markup language is a way of adding information to your content that tells the device receiving the content what to do with it. The best known markup language is Hyper Text Markup Language (HTML). Unlike HTML, WML is considered a meta language. Basically, this means that in addition to providing predefined tags, WML lets you design your own markup language components. WAP also allows the use of standard Internet protocols such as UDP, IP and XML.
There are three main reasons why wireless Internet needs a different protocol:
Transfer speed
Size and readability
Navigation
Most cell phones and Web-enabled PDAs have data transfer rates of 14.4 Kbps or less. Compare this to a typical 56 Kbps modem, a cable modem or a DSL connection. Most Web pages today are full of graphics that would take an unbearably long time to download at 14.4 Kbps. Wireless Internet content is typically text-based in order to solve this problem.

Wireless Application Protocol
Here's what happens when you access a Web site using a WAP-enabled device:
You turn on the device and open the minibrowser.
The device sends out a radio signal searching for service.
A connection is made with your service provider.
You select a Web site that you wish to view.
A request is sent to a Gateway Server using WAP.
The Gateway Server retrieves the information via HTTP from the Web site.
The Gateway Server encodes the HTTP data as WML.
The WML-encoded data is sent to your device.
You see the wireless Internet version of the Web page you selected.
To create wireless Internet content, a Web site creates special text-only or low-graphics versions of the site. The data is sent in HTTP form by a Web server to a WAP gateway. This system includes the WAP encoder, script compiler and protocol adapters to convert the HTTP information to WML. The gateway then sends the converted data to the WAP client on your wireless device.
What happens between the gateway and the client relies on features of different parts of the WAP protocol stack. Let's take a look at each part of the stack:

WAP protocol stack
WAE - The Wireless Application Environment holds the tools that wireless Internet content developers use. These include WML and WMLScript, which is a scripting language used in conjunction with WML. It functions much like Javascript.
WSP - The Wireless Session Protocol determines whether a session between the device and the network will be connection-oriented or connectionless. What this is basically talking about is whether or not the device needs to talk back and forth with the network during a session. A connection-oriented session means that data will be passed both ways between the device and the network. WSP would then send the packet to the Wireless Transaction Protocol layer. If the session is connectionless, commonly used when information is being broadcast or streamed from the network to the device, then WSP redirects the packet to the Wireless Datagram Protocol layer.
WTP - The Wireless Transaction Protocol acts like a traffic cop, keeping the data flowing in a logical and smooth manner. It also determines how to classify each transaction request:
Reliable two-way
Reliable one-way
Unreliable one-way
The WSP and WTP layers correspond to HyperText Transfer Protocol (HTTP) in the TCP/IP protocol suite.
WTLS - Wireless Transport Layer Security provides many of the same security features found in the Transport Layer Security (TLS) part of TCP/IP. It checks data integrity, provides encryption and performs client and server authentication.
WDP - The Wireless Datagram Protocol works in conjunction with the network carrier layer. WDP makes it easy to adapt WAP to a variety of bearers because all that needs to change is the information maintained at this level.
Network carriers - Also called bearers, these can be any of the existing technologies that wireless providers use, as long as information is provided at the WDP level to interface WAP with the bearer.
Once the information is received by the WAP client, it is passed to the minibrowser. This is a tiny application built into the wireless device that provides the interface between the user and the wireless Internet. Here's a look at the start page of a typical minibrowser:

The minibrowser offers streamlined functionality

The minibrowser does not offer anything more than basic navigation. Wireless Internet is still a long way from being a true alternative to the normal Internet. It is really positioned right now for people who need the ability to connect no matter where they are. The WAP Forum is continually working on the specifications of the WAP standard to ensure that it evolves in a timely and useful manner. For more information on wireless Internet and related topics, check out the links on the next page