As the GSM Association and the Wimax Forum lobby for LTE and Wimax as the top option for bringing wireless broadband to areas underserved by DSL (or not served at all), there is at least one other option in the works: converting old analog TV antennas into wireless data receivers capable of 12-Mbps download speeds.
Australian government research body CSIRO - one of the pioneers in Wi-Fi that won a patent battle last year over the 802.11 wireless standard against IT heavyweights such as Microsoft, Intel and Dell - last month unveiled a wireless technology that does just that. It's called Ngara, and it combines OFDM-based Wi-Fi and beam-forming transmission techniques.
CSIRO says any rural property capable of receiving an analog television signal today would be able to use the technology through a new set-top box and a slightly modified version of their existing TV aerial.
Ngara enables multiple users to transmit simultaneously without compromising individual transfer rates of 12 Mbps, as the beamforming technology allows the towers to focus beams on individual homes, explains CSIRO ICT center director Ian Oppermann.
"Someone who doesn't live near the fiber network could get to it using our new wireless system," Oppermann said in a statement. "They'd be able to upload a clip to YouTube in real time and their data rate wouldn't change even if five of their neighbors also started uploading videos."
Ngara offers more than ten times the spectral efficiency of the industry's minimum standard, Oppermann says. Six users can be served with 12-Mbps connections in the space of one 7-MHz television channel, representing an efficiency of 20 bps per Hz.
CSIRO developed the technology under its Broadband In The Bush project with the proposition that it could be used to provide connectivity to the 7% of Australia's population that are too remote to reach via fiber via Australia's NBN rollout. NBN Co plans to use both wireless and satellite technologies to connect these places.
Analog television services in Australia are currently being switched off in phases, with the last signal due to go off in late-2013. That process will free up a contiguous block of spectrum from 694 MHz to 820 MHz.
However, regulator ACMA plans to follow ITU guidelines and use most of this frequency range for LTE.
The GSM Association is pushing hard to have digital dividend spectrum worldwide allocated for LTE usage. Its latest argument for "spectrum harmonization" cites a report co-authored by Boston Consulting Group (BCG) that projects that turning digital-dividend frequencies over to mobile could increase Asia-Pacific GDP by $729 billion and tip $131 billion in taxes into government coffers by 2020.
CSIRO acknowledges that most digital dividend spectrum will be used for mobile networks but says it's developing Ngara "on the reasonable assumption that, in regional and rural areas, these services are not likely to take up all the available spectrum."
Meanwhile, wireless access is just the first phase of Ngara's development; CSIRO is also developing wireless backhaul using the same technology, aiming to combine isolated available channels into a single link ten times faster than the current 150-Mbps microwave backhaul links serving Australia's rural towns.
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