Wireless Internet

Last updated: March 27, 2008.

Imagine for a moment if all the wireless connections in the world were instantly replaced by cables. You'd have cables stretching through the air from every radio in every home hundreds of miles back to the transmitters. You'd have wires reaching from every cellphone to every phone mast. Radio-controlled cars would disappear too, replaced by yet more cables. You couldn't step out of the door without tripping over cables. You couldn't fly a plane through the sky without getting tangled up. If you peered through your window, you'd see nothing at all but a cats-cradle of wires. That, then, is the brilliance of wireless: it does away with all those cables, leaving our lives simple, uncluttered, and free! Let's take a closer look at how it works.

Photo: A typical wireless router. This one can connect four different computers to the Internet at once. The white bar sticking out of the back is the wireless antenna. But note all the wireless wires I still need!

Wireless started out as a way of sending audio programs through the air. Pretty soon we started calling it radio and, when pictures were added to the signal, TV was born. The word "wireless" had become pretty old-fashioned by the mid-20th century, but over the last few years it's made a comback. Now it's hip to be wireless once again thanks to the Internet. By 2007, approximately half of all the world's Internet users were expected to be using some kind of wireless access—many of them in developing countries where traditional wired forms of access, based on telephone networks, are not available. Wireless Internet, commonly used in systems called Wi-Fi, WAP, and iMode, has made the Internet more convenient than ever before. But what makes it different from ordinary Internet access?

From radio to Wi-Fi

Radio is an invisible game of throw-and-catch. Instead of throwing a ball from one person to another, you send information, coded as a pattern of electricity and magnetism, from a transmitter (the thrower) to a receiver (the catcher). The transmitter is a piece of equipment that turns electrical signals (such as the sound of someone speaking, in radio, or a picture, in TV) into an oscillating electromagnetic wave that beams through the air, in a straight line, at the speed of light (300,000 km 186,000 miles per second). The receiver is a mirror-image piece of equipment that catches the waves and turns them back into electrical signals—so we can recreate the radio sounds or TV pictures. The more powerful the transmitter and receiver, the further apart they can be spaced. Radio stations use gigantic transmitters, and that's why we can pick up radio signals from thousands of miles away on the opposite side of Earth. Wireless Internet is simply a way of using radio waves to send and receive Internet data instead of radio sounds or TV pictures. But, unlike radio and TV, it is typically used to send signals only over relatively short distances with low-power transmitters.

Wi-Fi

If you have wireless Internet access at home, you probably have a little box called a router that plugs into your telephone socket. A router is a bit like a sophisticated modem: it's a standalone computer whose job is to relay connections to and from the Internet. At home, you might use a router to connect several computers to the Internet at once (saving on the need for several separate modems). In other words, the router does two jobs: it creates a wireless computer network, linking all your computers together, and it also gives all your machines a shared gateway to the Internet.

You can connect a router to all your different computers using ordinary network-connecting cables (for the technically minded, these are called RJ-45, Cat 5, or Ethernet cables). This creates what's called a LAN (local area network) linking the machines together. A computer network is a very orderly affair, more like an organized committee meeting, with carefully agreed rules of behavior, than a free-for-all cocktail party. The machines on the network have to be hooked up in a standard way and they communicate in a very orderly fashion. The rules that govern the network setup and the communication are based on an international standard called Ethernet (also known as IEEE 802.3).

Photo: If your laptop doesn't have a built-in Wi-Fi card, you can plug in a PCMCIA adapter card like this one.

A wireless router is simply a router that connects to your computer (or computers) using radio waves instead of cables. It contains a very low-power radio transmitter and receiver, with a maximum range of about 90 meters or 300 ft, depending on what your walls are made of and what other electrical equipment is nearby. The router can send and receive Internet data to any computer in your home that is also equipped with wireless access (so each computer on the wireless network has to have a radio transmitter and receiver in it too). Most new laptops come with wireless cards built in. For older laptops, you can usually plug a wireless adapter card into the PCMCIA or USB socket. In effect, the router becomes an informal access point for the Internet, creating an invisible "cloud" of wireless connectivity all around it, known as a hotspot. Any computer inside this cloud can connect into the network, forming a wireless LAN. Just as computers connected to a wired LAN use Ethernet, machines on a wireless LAN use the wireless equivalent, which is called Wi-Fi (or, more technically, IEEE 802.11). Wireless Internet is improving all the time, so better forms of Wi-Fi are constantly evolving. You may see wireless equipment marked 802.11a, 802.11b, 802.11g or 802.11n: these are all broadly compatible variants of 802.11, with 802.11g and 802.11a somewhat faster than 802.11b. The latest standard, 802.11n, will be even faster, but is currently still in development.

Wi-Fi is where the expression Wi-Fi hotspot comes from. A Wi-Fi hotspot is simply a public place where you can connect your computer wirelessly to the Internet. The hotspots you find in airports, coffee bars, bookshops, and college campuses use one or more wireless routers to create wireless Net access over a large area. The University of Twente in the Netherlands has one of the world's biggest hotspots. Using 650 separate access points, it has created a seamless hotspot that covers the entire 140 hectare (350 acre) campus. Cities like Philadelphia have also announced ambitious plans to turn huge areas into hotspots. Wi-Fi hotspots are now popping up all over the world. By 2007, there were estimated to be around 180,000 in the United States alone.

WAP

Photo: Web browsing on a cellphone. This phone is using WAP to browse breaking news on a website called Ananova.

Wi-Fi isn't the only way to access the Internet wirelessly. If you have a reasonably new cellphone (one made in the last five years or so), you'll probably find it has a rather crude, built-in Web browser that can haul up simplified, text-versions of web pages. This kind of wireless cellphone access to the Net uses a system called WAP (technically known as Wireless Application Protocol, though no-one ever calls it that). WAP has been pretty slow to take off, largely because cellphones in most European countries and the United States still use quite slow networks, which cannot send and receive data quickly enough to handle full-size web pages.

i-mode

In Japan, cellphone networks are newer and faster and handsets are more sophisticated than they are in countries like the United States. Japan has a much better version of cellphone Internet called i-mode and over a quarter of the country's people use it for browsing simplified web pages and sending emails. i-mode is much more popular than WAP and there are moves afoot to export it to Europe, the States, and other regions. But faster networks will be needed before i-mode can take off in those regions too.

Mobile broadband

If you want to find out more about high-speed mobile, wireless broadband (broadband Internet access using a USB modem to connect to a cellphone network ), please see our separate article on mobile broadband.

Photo: Mobile broadband with a USB modem is an increasingly popular form of wireless Internet.

A brief history of wireless

• 1888: German physicist Heinrich Hertz (1857-1894) made the first electromagnetic radio waves in his lab.
  
• 1894: British physicist Sir Oliver Lodge (1851-1940) sent the first message using radio waves in Oxford, England.
  
• 1899: Italian inventor Guglielmo Marconi (1874-1937) sent radio waves across the English Channel. By 1901. Marconi had sent radio waves across the Atlantic, from Cornwall in England to Newfoundland.
• 1940s: Taxi firms began using two-way radios.
• 1970s: First analog cellphones appeared, developed in Chicago by Illinois Bell and AT&T.
• 1980s: GSM (Global System for Mobile communications) digital cellphones appeared in Europe, followed by PCS (Personal Communications Services) phones in the United States.
• 1994: Nokia, Finnish cellphone maker, sent data over a cellphone network.
• 1994: Phone.com developed WAP in the United States.
• 1997: Wi-Fi standard (IEEE 802.11) was agreed internationally.
• 1999: Japanese telecommunications company NTT DoCoMo developed i-mode.