WCA September 2012

From the americas

mitigation. This uses computer processors to take the signals from multiple antennas at each location and sorts the various signals out so they don’t interfere with one another. Smart antenna technology has been available for almost 20 years but is not yet used by cellular operators. Mr Chen : The presidential committee’s report concludes that the radio spectrum could be used as much as 40,000 times as efficiently as it is now. That sounds dramatic. Is it feasible? Mr Cooper : Cognitive radio, Smart antennas, and the other techniques all require computer processors. As the processors get more powerful they are capable of more spectrally efficient techniques. It’s a continuum. You add technologies, you improve the processing, you introduce a new technique, you get incremental improvement. Doubling every two and a half years is Cooper’s Law. You don’t have to double very much to get to 40,000. When they say 40,000 times, that’s a million times more spectrum. It’s going to take 20 years. Each time you put in new technology you get a big jump.

Mr Chen : The wireless operators contend that they need not just better-managed spectrum but additional spectrum, and they want the government to clear their access to it. Mr Cooper : How can 20 per cent more spectrum – which is as much as they’re ever going to get, in their wildest dreams – solve the problem when the need is for 20 times more spectrum? It can’t. They’ve got to push harder on technology. They’re not using technology that exists today and was demonstrated 10 years ago. Mr Chen : Where do we stand now on technology that makes more efficient use of spectrum? Mr Cooper : The technology that senses whether some free radio spectrum is available at that location is known as cognitive radio. This is still in the early stages of development but could be available in five to 10 years. The technology that allows cellular radios to use any of a large number of channels is called software-defined radio, or frequency-agile radio. All radios today are software-defined, but their agility is not yet adequate. That will take five years or longer. The technology that lets many people use the same radio channel at the same time is called smart antenna technology or adaptive array technology or interference

Dorothy Fabian Features Editor

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Wire & Cable ASIA – September/October 2012