Patent-holding Aussies make 6 Gbit/s wireless link
By Peter Judge, Techworld
Scientists achieved a world record 6 Gbit/s over a wireless link at CSIRO, an Australian government lab which also owns key Wi-Fi patents.
The scientists sent 16 simultaneous DVD-quality streams, over a 250m link, using 85GHz radio signals, in a demonstration at the Commonwealth Scientific and Industrial Research Organisation (CSIRO), Australia's national science agency in Mansfield Australia last week.
At 2.4bit/s/Hz, this is the most efficient radio signal ever sent, claimed Dr Jay Guo, director of the Wireless Technologies Laboratory at CSIRO, who plans to go on to 12 Gbit/s om future demonstrations. It also used very low transmission power, sending the signal as a point-to-point beam: "The transmit power was 250 microW," said Ian Davis,
project leader in cognitive wireless communications.
The 85GHz band has good international possibilities, as the US regulator, the FCC, has licensed it for line-of-sight communications, and this band could easily be extended to useful distances, said Davis: "I know of no particular problems with this band."
"For the demonstration we were running our link over 250m and had a 20 dB margin," he said. Using another link, the team has been measuring "rain fade" to determine how far it could be extended, he went on. The rain fade in Sydney's atmosphere is 36 dB/km, still allowing annual availability of 99.999%.
In practical terms, this means the link "could be extended to 530m, operating in Sydney's semi-tropical atmosphere, and still would have 99.999% availability [equivalent to fibre]," he explained. This could offer a replacement for fibre, in congested environments and across valleys and rivers, or to meet short term needs such as emergencies, said Dr Guo.
"What stands out for me is that other technologies have gone faster with lower efficiency or slower with higher efficiency but CSIRO has achieved both speed and efficiency in the one technology," said Helen Coonan, minister for communications, IT and the arts.
No-one we spoke to at CSIRO would comment on the progress of the lab's ongoing bid to claim royalties on virtually all wireless LAN equipment. CSIRO has a US patent on "wireless LANs" that can combat multipath interference, and Buffalo has already been ordered to pay a royalty.
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