Conquering that 'last mile'

Pioneering work by physicists and engineers at ANU to build a cheap, simple and robust wireless communication system may soon see regional Australia getting a workable connection to the Internet. The system is called BushLAN, and it's all about bridging that last mile.

Regional Australia has never had adequate access to the Internet. It's either not available, too expensive or unreliable. A major part of the problem is the last mile of access.

This last mile is the connection between the central communications hub in a local town to individual residences and businesses. Unfortunately, the 'last mile' is usually much more than just a mile. In rural areas such as Cowra, for example, the last mile has been measured to be anywhere from three to 100 kilometres from the town centre. In more isolated areas it can be much greater.

The cost of cabling to only a few customers over these distances is prohibitive and current wireless solutions aren't practical. Satellite connections are expensive and usually require a cable connection for a user to send information out (ie, they receive downloads from a satellite but send information out via the telephone).

There are ground-based wireless connections commercially available but these operate in microwave frequencies using directional antennas that require a clear line of sight to function. Given Australia's sparse population and frequently hilly terrain this would require a large number of repeater stations.

Dr Gerard Borg is a plasma physicist at the Research School of Physical Sciences and Engineering. His work with radio transmission has convinced him that the last mile could be effectively bridged using the low-VHF radio spectrum. This part of the radio spectrum has much longer wavelengths than the microwave frequencies used by other wireless systems and this allows signals to be transmitted further without the need for expensive repeaters or satellites. What's more, it doesn't depend on line of sight as the signal has the ability to go around mountains and other large obstacles in the landscape.

At the moment, the low VHF radio spectrum is used to transmit TV signals but with the decommissioning of some analog TV bands in 2008 (digital TV uses higher frequency radio) there's an opportunity to switch this unused spectrum over to data connections for regional Australia.

BushLAN (Bush - local area network), as the system is called, has the potential to provide remote users in regional Australia with a permanent, high-quality Internet connection (at more than 100 Kbps) at an affordable price. However, to get BushLAN up and running, many technical and marketing aspects of this multi-faceted system have to be developed first.

To achieve his goal, Dr Borg has enlisted the assistance of a wide range of students from the Faculty of Engineering and Information Technology who have taken on the various jobs associated with the system as part of their Honours, Masters or Doctoral projects.

"The practical nature of BushLAN and its relevance to regional Australia really attracts the students," says Dr Borg. "Once they're involved, they become highly motivated about what we're trying to achieve. Quite often they finish the formal part of their work for their thesis, but then they stay on working on the project through the Christmas vacation."

The next step for BushLAN is to set up local trials to test transmissions, and then work with interested Internet service providers to see how BushLAN can be integrated into existing information systems. The hope is that with BushLAN as part of the system, the 'final mile' will no longer be an unbeatable hurdle.

Reproduced from the ANU Reporter, Vol 34 No 4.