Wireless Fidelity (WiFi) technology.

ABSTRACT

The internet has been around for many years. When it first came about, people were used to using the big, old clunky computers with the forever slow dial up internet connection process. Many years have passed and new technology has made amazing things possible, especially the new Wireless Fidelity (WiFi) technology. The technology is used on everything from your typical laptop, to a next generation cell phone, enabling anyone who wishes to connect to the internet or a network they belong to at their own discretion, anywhere they are. In essence, one may see the world, from wherever they are

People may connect to a wireless network, and talk to the entire world.If you are using mostly desktop computers, a wired network may work fine. However, for mobility, modifications and growth (especially if you are running a small business), WiFi provides the best answer because it enables you to move the computers anywhere in the building where they can connect to the wireless network

Today's workforce, equipped with PDAs, laptops and other mobile devices, demand access to your network from wherever they are, without the hassle of a fixed network. WiFi allows your business to deploy a network more quickly, at lower cost, and with greater flexibility than a wired system. In this presentation we just give you a brief idea of what exactly is WiFi (wireless fidelity) technology, working of WiFi, its different types, its uses in various fields, and its future to what extent it is going to improve further.












Wireless Fidelity, the wave of the future. From cell phones to computers, its uses are endless

Wireless broadband can deliver fast Internet access by using radio waves instead of cables or wires. . If you or your company move to a new location, you don't need to leave your cables, cable drops and other network investments behind. The entire wireless network comes with you and takes only moments to set up in a new location.
Wireless Internet connections come in two forms.
WiFi (Wireless Fidelity) or 802.11

WiFi (Wireless Fidelity) is the latest data transmission technology using radiofrequency energy, which allows the user to enjoy wireless broadband Internet access. WiFi allows both companies and individuals alike to enter the world of high-speed, wireless Internet access, thus optimizing connection costs and generating sales through flexibility. Using laptops, desktops or PDAs, users can read their e-mail, access their corporate network, or simply browse the Internet without wires -provided that their devices feature WiFi technology - by means of special processors, PCMCIA WiFi cards or WiFi adaptors.
WiFi is designed for communication between devices such as computers, printers and scanners. It is typically used to set up private wireless networks in a home or office, allowing you to move your PC or laptop while still having access to the Internet and to your printer and other devices. WiFi has a range of about 90m. WiFi is also being used to provide public high speed Internet access in locations such as cafes, hotels and airport lounges, providing Internet access to users who are away from their normal place of work.

WiFi is a form of WLAN (wireless local area network) technology. Its radius is typically a few hundred feet, but may be cut down depending on interference (from walls, etc.). The standards of WiFi are called 802.11b, 802.11a, 802.11g, and the most recent is called A+G, which uses a combination of the 802.11a and 802.11g standards. When using the wireless internet through WiFi, you will get fast data speeds up to 11Mbps with 802.11b and up to 54Mbps for the 802.11a and 802.11g.

WiFi is the popular protocol that allows users to connect to a computer network wirelessly.WiFi, or its technical name, 802.11b, uses an unlicensed high-radio frequency to communicate with a computer network. This means that anyone has the right to broadcast in this unlicensed 2.1 GHz spectrum. Though not as fast as hardwired connections, WiFi reaches up to 11mbs-plenty of bandwidth for surfing the Internet or sharing files.


Of course, there are issues with WiFi. One is that there are different standards of WiFi. WiFi5, also known as 802.11a, uses a higher frequency than regular WiFi, and is able to transmit about 5 times as much data. Because of this greater data rate, businesses are more apt to use 801.11a for their wireless infrastructure. As the two technologies run at different frequencies, they do not interfere with each other's signal. However that also means that they are incompatible. That's where 802.11g fills in. 802.11g, which has no "WiFi" designation yet, runs at the same frequency as 802.11b, but provides the speed of 802.11a. That said, 802.11g can provide 55mbs and still is compatible with the existing WiFi networks-which are the most prevalent.


Another issue with WiFi is that it is easily interceptable-meaning, someone with a wireless computer notebook were to travel around a city, he would likely be able to see a number of open networks to which he could connect. The act of driving around with a wireless computer and an antenna to record all the wireless networks in an area is called "war driving." Of course, security becomes an issue with an open network, and there are protocols to protect ones wireless network.


Wireless technology can be disruptive as a new channel as well as can add value to existing channels by enabling both low cost access and growth in reach. WiFi, wireless Local Area Networks (LANs) over 802.11 networks, are a low-cost, relatively simple way to gain high-speed access to the Internet. WiFi hotspots—WiFi is one of the few bright spots on the technology landscape, the one that ought to have the telecommunications industry on its feet by sheer size of opportunity it points toward.

WiFi connects you to others and to the Internet without the restriction of wires, cables or fixed connections. WiFi gives you freedom to change locations — and to have full access to your files, office and network connections wherever you are. And WiFi can do this better than other technologies used to set up a home or SOHO (small office — home office) network. In addition WiFi will easily extend an established wired network.

How Does Wi-Fi Compare to Other Networking Methods?

No other networking technology used to set up a small home or SOHO network provides the convenience or mobility of a WiFi network. That's because other methods, including standard wired Ethernet networks and phone line- and power line-based networks, all require a connection via wire or cable. WiFi uses radio waves that travel through walls and floors and connect you anywhere, indoors or out. Networks based on phone lines, also called HomePNA, must have a phone jack close to the computer or peripheral that is to be networked with the rest of your system. Unfortunately, most homes have only two or three phone outlets — or even just one! — And these outlets may not be where you want to put your computer, printer or other device. You may have problems with this type of network based on the quality of your phone line installation and especially if you have numerous phone devices plugged into each wall jack. Networks based on power lines, also called Home Plug, have location problems, too.

Of course, there are many more power outlets in a home than there are phone plugs, but power plugs may not be where you need them when you need them, especially outdoors. Power line networks are often more expensive than WiFi based equipment. Power line networks can experience interference from transformers, large appliances, power strips, surge protectors and even common "wall warts" (DV power supplies). In addition, apartments and condominiums that share power lines may also inadvertently share access to confidential files and information on the computers that are attached to the power line network — even if users think they've established tight security protections Neither power line - nor phone line-based networks provide true mobility or portability. These technologies don't allow you to just pick up your laptop or PDA and go anywhere in your home or small office and begin working or continue working in another location without losing contact with your network. Working outside on your patio or next to the pool is impossibility. And since power-line — and phone line-based networks aren't available at "Hotspots" (e.g., airports, hotels and cafes), localized access networks or at the office, they can't be used when traveling or working in a corporate office.



Is a Wired, Wireless or Wireless/Wired Network Best For You?

If you are using mostly desktop computers, a wired network may work fine. However, for mobility, modifications and growth (especially if you are running a small business), WiFi provides the best answer because it enables you to move the computers anywhere in the building where they can connect to the wireless network. If you or your company moves to a new location, you don't need to leave your cables, cable drops and other network investments behind. The entire wireless network comes with you and takes only moments to set up in a new location. Obviously if you are using laptop computers and/or other kinds of mobile computing devices.


WiFi is the only answer for both home and business. If you already have a functioning wired network, it's easy to just keep it in place and add wireless components to extend your network's reach and give users more flexibility and convenience. Many home and SOHO access points and gateways allow you to easily connect to both wired and wireless equipment through their installed Ethernet ports. To see the variety of ways you can hook up a home or small office to create a wireless or combined wired/wireless network, go to SOHO — Small Office — Home Office Networking Configurations Corporations frequently extend their wired networks with WiFi networks. They connect wireless access points to their network backbone to provide Internet and network access in meeting rooms, lobbies, cafeterias and other common areas.

Companies also add wireless access points in their general office space to make it easy for staff to meet informally. For example, someone from marketing can carry his or her laptop to the sales manager's office two floors up and, via the wireless network there, make a presentation on the spot using their laptop. When employees are mobile, as in a large warehouse or shipping center, WiFi networks can easily cover the entire area: staff can operate anywhere in the building, not just at predetermined desktops and workstations.

WiFi is meeting a long overdue demand in the office environment where cabling and re-cabling to accommodate shifting seating arrangements or company growth is not only inconvenient but expensive. Initially installing a WiFi network in an office building or warehouse was a complex business, possibly requiring software development to integrate with existing technology and testing and site surveys to ensure optimal coverage.

WiFi is only one of many types of services that can be described by the term 'wireless networking.' Don't confuse WiFi with Wireless in general. You would use wireless LAN technology to provide access to shared resources in a small geographic area, like a warehouse, an office space full of cubicles, or a home. You might want to share your printer, a digital camera or connections to the Internet with more than one computer. A wireless LAN does not replace your connection to the Internet, just the wires in your house. This becomes more important as you add network enabled devices such as MP3 and video that might be stored on a computer somewhere in your house and played back on your A/V system.


Why adopt WiFi?


Today's workforce, equipped with PDAs, laptops and other mobile devices, demand access to your network from wherever they are, without the hassle of a fixed network. WiFi allows your business to deploy a network more quickly, at lower cost, and with greater flexibility than a wired system.


Productivity increases too, since workers can stay connected longer, and are able to collaborate with their co-workers as and where needed. WiFi networks are more fluid than wired networks. A network is no longer a fixed thing, networks can be created and ripped down in an afternoon instead of the days or weeks required to create a structured cable network.


Architecture
Wireless cards can operate in two modes,
Infrastructure and Ad-hoc.

Infrastructure mode: Most business systems use wireless in Infrastructure mode. This means that devices communicate with an access point. Typically the access point also has a connection to the company wired network, allowing user’s access to servers and files as if they were physically attached to the LAN.

Ad-hoc mode: Ad-hoc connections are direct connections between wireless cards. This type of connection is more common amongst home users, but if used by business users could have serious management and security implications.

Different Types of WiFi

· IrDA
· HomeRF (Swap)
· Bluetooth
· WECE(WiFi)
IrDA: IrDA stands for Infrared Data Association. This technology is the bases for communicating using direct infrared light. It is only good for short distances and requires no interfering object with the light beam. It is capable of transferring 4 megabits per second. HomeRF and Swap : This type is basically based on the digital enhanced cordless telecommunications standard and the 802.11 wireless - Ethernet specifications. A system or a swap system can transmit up to 1 Mbps while making 50 hops per second. Bluetooth : Bluetooth basically is the way that any electronic component to connect itself to a wireless network. The advantages of this type of WIFI are short and sweet ; it's wireless, cheap and can connect on it's own with no help from the user.
WECA & WiFi : WECE & WiFi type just means there is a "seal of approval" stating that a certain wireless product is usable with the IEEE 802.11 specification. This system can transfer data or information at a very fast rate, even up to 11 Mbps.
WORKING OF WIFI SYSTEM


WiFi operates using a credit-card sized wireless PC card, which plugs into your computer and communicates over the airwaves with a local access point. From there information is transmitted via a cable or ADSL link to your Internet service provider.

The above image is a wireless network card shown with antenna


WiFi LAN technology can be described simply by saying that it is the sending of a radio signal, and receiving that signal with a antenna, transforming it into a understandable media. WiFi radios work in the same way as a walkie-talkie almost, yet it has slight differences. They have the ability to convert radio signals into one’s and zero’s, and vice versa. The main advantage of a WiFi radio however is its ability to hop frequencies. A radio may transmit on more than one band, and can split it’s bandwidth between many frequencies. This allows for less of a chance of interference. For computers, WiFi is simple. Most computers are already set up with a WiFi capability or you may add a WiFi card to an older computer very easily. With more modern computers, if you have a WiFi system, and you are within a hot spot (an area with 802.11, which is a specific frequency, either 2.4 gig, or 5 gig) you will automatically be connect to the internet and be allowed to do anything you normally would on your home pc. The wide use of notebook and other portable computers has driven advances in wireless networks. The most common use for a wireless network is to connect a single notebook computer to a broadband internet connection. Wireless networks use either infrared or radio-frequency transmissions to link these mobile computers to networks. Wifi networks use radio technologies called IEEE 802.11b or 802.11a to provide a secure, fast, and reliable wireless connection. The international standard for wireless networking uses a frequency of 2.4-2.4835GHz. These frequencies are common in microwaves, and cord less phones.


WiFi functions through a transmitting antenna which is usually linked to a DSL or high-speed land-based Internet connection and uses radio waves to beam signals. Another antenna, which is in the laptop or PC, catches the signal. The signal, usually l, has a range of about 300 feet for most home connections. The farther the user is from the signal, the slower the connection speed. Wireless LANS have capacity speeds from less than 1 Mbps to 8 Mbps. WiFi can easily be expanded in the home or business with the simple step of plugging in a card or a USB connection to the new computer or other WiFi certified product. No cords or cables, or wires are necessary.


WiFi - wireless fidelity - is mainly centered around the 802.11b standard using the unlicensed 2.4GHz band to transmit data across the radio spectrum normally occupied by cordless phones, garage door openers and a growing number of Bluetooth products designed for device connectivity.

A transmitting antenna, usually linked to a DSL or high-speed land-based internet connection, uses radio waves to beam signals to PCs, laptops, PDAs and mobile devices. A client antenna, a PC card ( PCI or USB connected) , removable PCMCIA card or chip embedded into the remote device, picks up the signal. The client device can receive strong signal within a 100 metre range of the transmitter. The further from the signal the slower the data rate - although additional transmitters can boost that rate.

Moving data using radio frequency is nothing new, in fact the first Morse code radio transmission has a lot in common with today's WiFi technology, after sending what is in effect the first binary wireless transmission mankind spent the next 20 years perfecting the reproduction of the human voice in an analogue format.

The telephone while revolutionary did mask the ability of data transmission, this was not left to rot as militaries around the world continued to develop the sending of data via RF transmissions. WIFI of today is a distant cousin of that Morse signal, although instead of a low bandwidth dot and dash being sent thousands of bits of data is sent every second and we are now measuring in kilobits per second and with newer technologies even megabits.


WiFi as a standard uses the 2.4 GHz range which is largely unused by the European military and other RF users like mobile communications, this frequency band is then broken down into channels which a wireless device can use to transmit data and in order to avoid interference the devices can frequency hop or jump between them mid data stream. So we have a method of moving data over RF but each device needs to be connected and enabled to work with WiFi, this is in effect like giving each device in your network a handheld radio (except they work at much high frequencies). Over this radio link the binary DataStream carries your data for example a webpage back to the device that requested it. A laptop for example would have a wireless access card or dongle this is both a transmit and receive device, this could connect to another laptop with the same setup and create a point to point connection. It is far more likely that the laptop and any other client device will connect to a router or access point to join a much larger wireless network.


Performance of any wireless link is limited by the same factors that affect your radio or TV signal, weather, distance, power and walls or objects, again an example if you use an indoor aerial for your TV your signal is weaker and therefore the picture quality drops. With a WiFi network if the signal strength or quality drops the effective data rate is reduced as more packets are re sent to counteract the errors, so it is important to bear in mind the maximum achievable range of a WiFi enabled device may be at the minimum sustainable speed.


WiFi Uses


In the Home:


Home networking is not fun, that is reflected in the number of homes that have cabled CAT5 networks today, and few homeowners want to run cabling under floors and have unsightly connection boxes in each room that you might use a device. So wireless is a real answer offering the ability for a broadband internet connection to be shared between users in the home, perhaps mum using the PC, dad on a laptop in the garden while the kids hook up their playststaion upstairs. It’s only a small step from sharing your internet connection to a full network, sharing a printer and even a music server with all your collection stored as MP3's


In the Workplace

The workplace on the other hand is far more cautious, most offices already have a perfectly good and fast (at least 100mbits) network in place in strict terms for desktop PC's there are few, but more and more workers are issued with laptops as standard. Those laptops will almost certainly have a wireless access card as standard and the new centurion technology for Intel means every laptop shipped has embedded WiFi.


We must also consider the number of devices in an office network there could be hundreds of devices trying to share the limited number of channels, and then there are issues of where to site access points to work most efficiently. It’s not all doom and gloom with good planning these can be overcome to fully extract the business benefits of wireless networks but it takes some guts to get started.


In Public

When is a hotspot not a hotspot? When no one knows about it!
And there lies the dilemma, while there is a market for those who wish public internet access on their mobile devices there are rarely enough users concentrated in one location to make it pay. Even when there are at airports or stations getting the average user to understand how to connect and pay for the time they will be using the service is a tough job.

Advantages of Wireless

· Some wireless technology allows users the flexibility to physically move while using a device such as a computer.
· New nodes can be added to a wireless network.
· Wireless can be used in places where it is not possible to run cables or drill holes, such as within historic buildings.
· Wireless technology can give users broadband access even when they are away from their home or office.
· Wireless is sometimes available where ADSL and cable are not.

Disadvantages of Wireless

· Wireless has a relatively high initial outlay, compared to ADSL or cable.
· Some wireless technology may require line-of-sight between the transmitting and receiving points. This can be a problem in some areas.
· Wireless suffers from potential security risks. As radio waves travel in all directions, anyone within range can access an unsecured wireless network, be they in the next office, the next building or even out in the street. However, security measures for wireless networks are continually being updated.
· Bandwidth can be limited in a congested network. WiFi shares the airwaves with devices such as microwaves and cordless phones, which can use up valuable bandwidth, or cause interference on occasions.


Security

So we intend to send data through the airwaves, well its not long before someone raises the security card and its right they should, data sent on computer networks is always private be it a web surfing session or email. Use of the industry standard triple DES encryption was deemed too slow for wireless networks which had limited bandwidth to cope with encryption overheads. So WEP the wireless encryption protocol emerged as the preferred method of securing the wireless connections, the 128bit WEP standard is not bombproof but would take a few months with a high powered server to crack, this of course assumes you don't change the key which of course you will!.

Security is the bane of everybody who puts together a wireless network. access points, using factory default settings, are not secure at all. So, if security is such a concern does that mean I shouldn't deploy WiFi? No, it doesn't. But it is something that you should bear in mind when in the planning stage. When talking about security there is no such thing as having a completely secure system. Everything is insecure to some degree or other. The degree of security you require is dictated by the sensitivity of the information you possess. If you require very high levels of security then you cannot rely on the built in security measures of a WiFi network alone. On the other hand, most small to medium sized companies do not require very high levels of security.
If you already have a wireless network you may be concerned about whether it is secure. There are four things you can do to ensure that you are secure.
· Make sure that your access point(s) are not broadcasting the SSID (identifier for N/W)
· Make sure that your access point(s) are encrypting the wireless traffic using Wireless Equivalent Privacy (WEP)
· Buy a wireless intrusion detection system.
· A number of products are available designed to help you monitor the security of your WiFi network as well as who is using it.
If you have a high security requirement, then you should either ensure your network people are appropriately trained or hire a wireless consultant. You may also need to buy proprietary, non-standard access points from the likes of Cisco (although even some proprietary standards from the likes of Cisco have their problems). Unfortunately, this will substantially increase the cost of your wireless network.
The Future of WiFi

With the spread of this new technology the future will provide fasterWiFi Protected Access (WPA) offers confidence and privacy to authorized users.WPA is a level of security that greatly increases the authentication and encryptionof your wireless system. The system works by using an access point to block LAN access until the user can be identified by entering a pass code. Once the correct pass code is entered the user can then begin surfing the net. This process will keep unauthorized users from accessing the authorized users account and keep all data safe and secured. WiFi telephones are also on the rise and soon will be widely available.
With the continuation of this progress more and more internet users will feel confident enough to upgrade from the out-dated dial up connection to the powerful WiFi network. With these high quality performance products, the future will only become more functional for everyone, everywhere.

There may also be potential problems that could occur in the future with WiFi. With more people connected to WiFi, the signals sent can become weaker causing a slow connection. Analysts are worried that the growing population of WiFi users could possibly slow down the signals making WiFi inconvenient.

Conclusion

With the increasing popularity of WiFi, several communities and businesses are setting up wireless communities that allow users to roam around the area while connected. Hotels, airports, and coffee shops are setting up more networks as the demand increases for this low-cost service. Globally, this wireless local area networking (LAN) technology is springing up in airports, cafes, and along city streets, creating ubiquitous broadband access in public and private spaces. One of the reasons for extensive growth of WiFi is the promotion of technology by collaborative group of vendors making WiFi gear, and referred as WiFi Alliance. WiFi Alliance also works on certification, standardization and interoperability of WiFi gear from all the vendors. WiFi has improved a lot since it was first introduced. Basically, the price and performance of WiFi is now at a point where it makes sense for a wider group of users