A seismic shift in radio design could break the spectrum-availability bottleneck, proponents say, and open up a new frontier of opportunities for radio designers and wireless application developers. Cognitive radio — one that can sense its environment and location and then alter its power, frequency, modulation and other parameters so as to dynamically reuse available spectrum — is emerging, but some are already calling it the holy grail of wireless design.

Derived from a doctoral thesis submitted in May 2000 by Joseph Mitola, who is now at work on the military's cognitive-radio initiative, CR could in theory allow multidimensional reuse of spectrum in space, frequency and time, obliterating the spectrum and bandwidth limitations that have slowed broadband wireless development in the United States and elsewhere.

President Bush has set a goal of broadband access for all Americans in three years to boost competitiveness with other nations and create new business opportunities at home.

"We ought to have a universal, affordable access for broadband technology by the year 2007, and then we ought to make sure as soon as possible thereafter, consumers have got plenty of choices when it comes to purchasing the broadband carrier," Bush said during a recent campaign swing through the Southwest.

The first in a series of eagerly anticipated nationwide studies has concluded that the use of mobile phones poses no increased risk of brain cancer - at least not for the first 10 years.

Despite this caveat, the Danish study is likely to carry more weight with health authorities and scientists than many previous studies because of its large sample size and careful design. Earlier studies that claimed to find evidence of a health risk have been criticised for weaknesses in these areas.

More than two-thirds of American adults were users of the Internet in 2003, according to a poll published by market research company Harris Interactive.

The figure of 69 percent of those polled represents around 146 million people.

Internet use among adults is growing constantly, Harris Interactive said, noting that the figure had risen from 67 percent in 2002, 64 percent in 2001, and 56 percent in 1999.

The safety of cellphones has been called into question, again. This time the scientific community is paying very close attention.

Last summer neurosurgeon Leif Salford and colleagues at Lund University in Sweden published data showing for the first time an unambiguous link between microwave radiation emitted by GSM mobile phones (the most common type worldwide) and brain damage in rats. If Salford's results are confirmed by follow-up studies in the works at research facilities worldwide, including one run by the U.S. Air Force, the data could have serious implications for the one billion-plus people glued to their cellphones.

Yesterday's earthquake shook us all along the coast of California. I was in Santa Barbara when the quake hit, with the epicenter about 150 miles north. When the ground stopped rolling my first thought was to contact family and coworkers to assess what damage may have occurred. Apparently that's what many other people thought too, and all I got on my mobile phone was "network busy" and dropped connections for the next half hour or so.

This earthquake served as another reminder that as we continue to build up our technical infrastructure and enjoy its benefits, we're also adding complexity and increased potential for unforseen problems.

Design for robustness, as well as features, is increasingly recognized as important but I'm pretty it's still not getting the attention it deserves, even in the military and space programs. Just as no significant software project can be fully tested, any system complex enough to be interesting is likely to exhibit emergent properties that are unexpected, and often unwelcome.

Maybe I should go ahead and get that ham radio license after all.

Scores of wireless networking transmitters are popping up atop public buildings, traffic lights and other structures in a bid to bring high-speed Internet access to virtually every corner of this Southern California city.

Encryption schemes that hide messages in chaotic signals have attracted attention in recent years as a means to transmit information securely but most work has been either theoretical or strictly limited to laboratory experiments. Now a group of researchers in Beijing have managed to demonstrate chaotically encrypted, two-way voice transmission through the Beijing Normal University computer network.

Quantum cryptography keys encoded in photons of light have been transmitted more than 23 kilometres through air, British researchers have announced. They say the breakthrough is an important step towards a global communications system that is completely secure.