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Last Updated: Wednesday, 8 March 2006, 20:17 GMT
Q&A: Wi-fi explained
Wireless hotspots are spreading across the world's cities, with blanket wi-fi zones now being rolled out in many city centres. Operators are promising wireless surfing at the touch of a button from the park, the bus or the street corner. So what does the wireless future have to offer and will it live up to the hype?

What is wi-fi?

Wi-fi is the acronym for Wireless Fidelity, essentially a set of standards for transmitting data over a wireless network.

Wi-fi allows you to connect to the net at broadband speeds without cables, as long as you have the right equipment and, in most cases, a regular internet service provider and a wi-fi account.

To understand the technology behind wi-fi, imagine using a walkie-talkie. Your voice is picked up by a microphone, encoded onto a radio frequency and transmitted with the antenna to another walkie-talkie, which decodes your voice.

Wi-fi works in broadly in the same way, but using a better radio that is capable of handling a lot more data per second.

wi-fi graphic
1: Wi-fi uses antennas around which wi-fi "hotspots" are created. The hotspots are outlets equipped to receive the radiowaves that power wireless networking. Until recently, wi-fi has been confined to more than 10,000 hot-spots in cafes, bars and airport lounges. But various projects are under way to set up city-wide zones, where a series of antennas are installed in the streets, on lampposts or street signs. The hotspots around them together create a much wider area of coverage. Norwich has a mesh network which links each lamppost antenna to the next creating a seamless wi-fi hotspot around the centre of the city.
2: The source internet connection is provided by a PC or server to which the antennas are connected either wirelessly or via a cable.
3: Some mobile phones and personal digital assistants (PDA) now have wi-fi chips installed. With mobile phones, this means conventional networks can be bypassed and inexpensive long-distance calls made over the web (using Voice over Internet Protocol, VoIP).
4: Many laptops and handheld computers now come with built-in wi-fi connectivity; it is also possible to add wi-fi to your computer with a special card that plugs into a port on your laptop.

How do I use a giant wi-fi zone?

In the UK, there are already more than 10,000 wi-fi hotspots in public places such as restaurants, hotels, cafes, libraries and airports.

Wi-fi-enabled laptops and phones can be set up to connect to these hotspots automatically; usage is generally paid through a credit card at a login page on a web browser. Frequent users may even have accounts with service providers such as T-Mobile, BT Openzone, O2, SkypeZones and Nintendo wi-fi.

Will it catch on?

So far, wi-fi has been a service that is most useful for business people who need to work on the move; but operators want to make it available to all.

However, some analysts warn that wi-fi could be the "next dotcom crash", mainly because of patchy hotspot coverage, lack of enabled hardware and uncertainty over how to make money.

There are still a few big challenges ahead for wi-fi. Finalising interoperability and standards is one, and the concern over security is another.

Just because there are more than 10,000 wi-fi hotspots in the UK does not mean that a pass to use one means you can use all of them. Currently wi-fi hotspots are divided by who controls them.

In Norwich the local authority and regional development agency are pioneering a free wi-fi service. This model could catch on, if successful. More than 3,000 connections are being made to the city's wi-fi network each week

Logging on to the internet via wi-fi in different locations brings the risk (just as it does at home or in the office) of your computer being infected by computer viruses and worms. Experts advise you to install security software and update it regularly.

Who stands to profit?

Some critics argue that wireless hotspots can be a rip-off - the price of installing a wireless router in, say, a coffee shop, involves a one-off cost of a few hundred pounds but customers may be charged upwards of 5 an hour.

Users of the new city-wide wi-fi networks will be required to pay access charges to an account provider, such as BT Openzone or T-Mobile.

The revenues will be shared between the owners of the street furniture on which the equipment is installed (usually local councils), wi-fi hotspot suppliers and the internet service providers.

See how wi-fi zones work

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