WiFi Explained

What is WiFi

WiFi is a technology that allows data transfer over specified radio frequencies, this in turn removes the need for cabled connections making device portability possible. The WiFi revolution has been trumpeted on a number of occasions but has stalled each time on security fears or cost, but as mobile hones have driven the publics understanding of wireless communication the consumer appetite for WiFi products has grown steadily to a point where it became commercially viable.

How does it work

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 are 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 effect 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 Variants

The accepted wifi standards are set by the Institute of Electrical and Electronics Engineers or IEEE, 802.11b was the first to market and is the slowest in terms of raw bandwidth but is also the cheapest to produce equipment for, with speeds up to 11mbits this is the format that is most prevalent in today's electronics marketplace.

Then there is 802.11a which strangely came second, this can handle up to 54mbits and runs in the 5 Ghz band, this has until recently been the domain of the corporate network as 802.11a equipment costs more to purchase and gives greater range.

The most recent entry is 802.11g which is back on the 2.4 Ghz band but can achieve the 54mbps of 802.11a and brings the benefits of the cost reduction in technology, if you are buying networking equipment 802.11g is the best option today as it is also backwards compatible with 802.11b although your connection will run at the speed of the slowest technology used.

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!.

WiFi Uses

So that's how so the next logical question is why and perhaps how to implement wireless networking?

In the Home

Home networking is not fun, that is reflected in the number of homes that have cabled CAT5 networks today, 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. Its 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

This is the area that has seen the wifi explosion the home is leading the take up of wireless equipment and coupled with the rapid uptake of broadband wifi growth is assured for the next few years.

For home networking it is important to understand the components, each device will need a wireless card or dongle, they in turn connect to the hub which can be one of 3 devices.

The Wireless Access point is simply a translation device that sits connected to your main PC and allows any wireless device to talk to it, this means that if that PC is off then so is everyone's internet connection. Next a Wireless router, this is similar to the access point but allows routing around the home network so 2 laptops can network even if the main PC is off, but again if the internet connection is through the main PC if its off then so is you web connection.

By far the most popular choice is a wireless router / modem, be careful to get the right modem either dial up, DSL or ADSL these allow you to network all of your devices and as long as the wireless hub is on any device can access the internet, commonly these will have an inbuilt firewall and some cabled connections.

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, so what benefits are there for wireless? 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 centrino technology for Intel means every laptop shipped has embedded wifi.

So of course it makes sense to use wifi, but security conscious businesses are not happy with the level of encryption offered by WEP alone and are layering extra security on top far beyond rolling updates of keys, this makes networks a nightmare to manage and thus restricts growth in this area.

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, then there are issues of where to site access points to work most efficiently. Its 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.

A number of providers in the UK are already out there, BT openzone, Costa Coffee and even McDonalds wifi with a big Mac, but how many of us, even the technically savvy ones have actually use the service?

So what about a nationwide service provider of WiFi, well arguably that's what BT hope open zone will become, but many more ambitious plans have been muted, broadband balloons lurking in the lower atmosphere and more recently broadband wifi lampposts in every street. Great ideas but hugely capital intensive to get going and in this market you come directly head to head with mobile operators who hope to sell 3G data services, they already have the networks and the subscriber base so perhaps its fair to say hotspots will stay just that "spots"

Next Steps for Wifi

While many industry pundits (of whom we do not claim to be one) talk of hot spots and longer ranges it seems likely that the next 12 months will bring wifi into new devices, first mobile phones will have wifi alongside Bluetooth then add wifi to MP3 players allowing them to stream. Longer term Wifi may become the defacto standard for connecting household electronics and automating your home, heard this before? well yes that was Bluetooth.

What's different about wifi, well its cheap, commonly available and understood and if you don't have it in your home maybe you should, this is a consumer led growth you should be part of it.