Cellphone calls

Friday, July 20th 2007 - 11:24 CEST - Comments: 0

T hose annoying “dropped” cellphone calls that have been largely attributed to atmospheric disturbances, high humidity and heavy vegetation may actually have a more celestial origin: A Queen’s-led team suggests instead that a large percentage are caused by solar activity. Investigating the mystery of communications satellite failures in the 1990s led Mathematics and Statistics professor David Thomson - then working at Bell Laboratories in Murray Hill, NJ - to an unexpected discovery with implications for millions of cellphone users around the world. Both the satellites and the phones seemed to be affected by changes in solar gravity modes.

 

 

Cellphone calls

Dr. Thomson, who came to Queen's in 2002 as Canada Research Chair in Statistics and Signal Processing, has continued to work on this complex problem with a team of colleagues from Queen's and several US universities. Their latest findings will be reported in the international journal, Proceedings of the IEEE (Institute of Electrical and Electronics Engineers). Using data from solar radio telescopes, Dr. Thomson tracks radio-frequency energy bursts emitted by the Sun. Then he and his students will try to correlate these pulses to dropped calls and other interruptions in cellphone activity. He hopes that data from Queen's new $600,000 solar radio telescope located on the roof of the university's mathematics building will help identify how the modes cause calls to drop.

 

Dropped cellphone calls - Blame the sun

"What we have discovered is surprising and very different from the explanations that appear in most engineering textbooks," says Dr. Thomson, who is cross-appointed to the Faculty of Applied Science. When a solar radio flare occurs and cell-site antennae are facing the sun, the number of dropped calls that go away for no apparent reason increases dramatically, the researchers found. In one well-studied example this figure reached nine per cent, while some systems have dropped more than 20 per cent of their calls during flares. The mystery is why calls drop in the absence of flares. "We believe that this is caused by the Sun radiating energy into the Earth's magnetic field," says Dr. Thomson. "It's one of those things that people look at and say, ‘It can't possibly be,' but a lot of experts have now given a thumbs-up to this theory."

 

Cellphone & Telecommunication studies

Other members of the international research team include: Louis Lanzerotti from the New Jersey Institute of Technology, Marc Lessard from the University of New Hampshire, and Frank Vernon and Lindsay Smith - whose fourth-year Math and Engineering thesis at Queen's contributed to the findings - from the University of California at San Diego. "Understanding our Sun's more than 10 million normal modes and their interactions with engineering systems on Earth is a challenge that we are just beginning to undertake," says Dr. Thomson. "While many of the studies on telecommunications and cellphone system failures arose between the 1970s and the 1990s, it's now timely to generate a synthesis of this knowledge and apply it to the problems that prompted the research in the first place!"

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