Published by Australian Academy of Science
Wireless but not clueless Box 1 | Hotspots and meshes

Each area in which WiFi is available is called a 'hotspot' or sometimes a 'node'. The problem for people in public places who want to use their laptops, palmtops or VoIP phones is finding out where these hotspots are, although they are becoming much more common. One 2006 survey found that the availability of WiFi in New York, USA, rose by 15 per cent in a one-year period; in London, UK, it grew by an even more impressive 73 per cent.

Some cities – such as London, UK, and Philadelphia, USA – are promoting the proliferation and 'meshing' of hotspots. Meshing, or mesh networking, is a way of joining hotspots together. The data can 'hop' from hotspot to hotspot, always looking for the best route to its destination (the internet, for example). This means that a user can connect to the network from a much greater number of places, or even while moving around. Setting up a city-wide WiFi mesh means a lot of antennae. One company in Paris, France, offers free internet access for life to people who make their rooftops available for the installation of WiFi antennae.

The idea of mesh networks is popular among community groups, who see them as a way of wirelessly connecting computer users in local neighbourhoods. In Melbourne, one group has set up a wireless regional area network (WRAN) using what it calls 'cheap, off-the-shelf WiFi hardware' such as computers or PDAs with WiFi adapters. Although this network doesn't yet provide unfettered access to the internet (due at least partly to licensing and compliance concerns), it does allow participants to interact amongst themselves by sharing files, speaking to each other using VoIP phones, and competing or co-operating with each other in computer games.

WiFi meshing technology might also have great appeal in developing countries, making the internet available cheaply and quickly, particularly in urban areas.

Other boxes

Box 2. Remote sensors and their applications

Box 3. Security and encryption

Box 4. Increasing speed

Box 5. Competition