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Phone calls clear as a bell

New technology developed at U de Sherbrooke will give cell phones FM-radio sound quality


It’s not just the exponential growth of the global cell phone market from 50,000 to five billion users in just 20 years that impresses Roch Lefebvre. It’s also the fact that technology developed by the small group of researchers he leads at Université de Sherbrooke is inside more than 90 percent of those devices.

“It’s really amazing,” said the engineering professor and digital communications expert about the world’s use of ACELP – for Algebraic Code Excited Linear Prediction – an advanced speech-encoding algorithm, or digitizing technique, developed by the university’s Groupe de recherche sur la parole et l’audio. ACELP has been the international gold standard for speech and audio applications (in other words, sound quality) on both narrow-band or digital wireless networks and the Internet since 1995. “For a researcher, it doesn’t get any better
that that.”

Or maybe it does. Later this year, when the next generation of cell phones featuring wideband multimedia is expected to hit the market, the Sherbrooke researchers will again witness their work be part of an expected worldwide communications revolution. As with ACELP, their speech compression technique for wideband applications (known as Adaptive Multi Rate – WideBand, or simply AMR-WB) has been adopted as the world standard. Developed in 2001, it is now being licensed for use in a new wave of wireless devices and will provide previously unheard-of sound quality.

“It’ll be a very significant change,” he told University Affairs. “It’ll be like going from black-and-white to colour TV [or] from current phone sound to FM-radio quality.”

That improvement, he explained, is the result of many years of mathematical research and investigation into human speech and hearing by a small group of determined academics at the Université de Sherbrooke looking to develop ground-breaking audio compression technologies.

The goal in audio compression is to break down, transmit and rebuild bits of information. “It’s really pretty simple,” said Dr. Lefebvre. “It’s like folding a tent, then transporting it and putting it up again when you get it where you want it. The trick is in the doing.”

It was the group’s discovery of a solution for masking – when sounds with higher frequencies drown out those with lower ones – that led to the development of AMR-WB. The technology is contained in next-generation cell phones that are expected to be rolled out in the third quarter of 2009 by some European service providers, including British multimedia giant Orange.

Dr. Lefebvre expects the new devices will take the world by storm – and add to the $100 million that ACELP is reported to have generated in royalties for the university. That revenue, according to Dr. Lefebvre, is the second-biggest research windfall for a university after Gatorade for the University of Florida.

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