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Australian Agency Unveils Wireless Broadband Via TV Channels

Australia's national science agency, the Commonwealth Scientific and Industrial Research Organization (CSIRO) has unveiled a new technology that it says will allow re-use of old analog TV channels--including VHF channels--to provide Internet linkage at up to 20 bits per second per Hertz of spectrum. The CSIRO system allows six users to use one seven MHz wide Australian TV channel (a bit larger than the U.S. six MHz TV channels) to upload data at 12 Mbps without reducing the data bandwidth available to other users. CSIRO is currently completing the research and testing the downlink part of the system, which will also run at 12 Mbps per user.

CSIRO has dubbed the technology "Ngara," which is a word in the Darug dialect of indigenous Australians, which means to listen, hear and think. Wireless Research Director for Gartner, Robin Simpson said the most promising aspect of Ngara is that it aims to re-use old analog TV channels.

"This means any rural property or business that can currently receive TV signals could in future connect to high-speed internet just by using a new set-top box," said Simpson.

The CSIRO news release was short on technical data but a Computerworld article from last April CSIRO developing 100Mbit wireless broadband indicates that the system uses OFDM. An article in Computerworld this week, CSIRO wireless broadband over TV becoming a reality says that the technology could serve up to 1,000 homes in a roughly 15 to 20 km radius around a broadcast tower. As the system would use existing broadcasting towers, the cost to roll out the technology is expected to be substantially less than for an LTE system.

A system that serves 1,000 people using 7 MHz of spectrum within a 15 to 20 km radius obviously wouldn't be of much value in densely populated areas, but in rural areas of Australia--and possibly in rural parts of the United States--it could be a way to provide high speed Internet service to homes, farms and small communities where DSL and cable service is not available, and without the latency present in geostationary satellite links.

Doug Lung is one of America's foremost authorities on broadcast RF technology. He has been with NBC since 1985 and is currently vice president of broadcast technology for NBC/Telemundo stations.