Wireless Spectrum Gets Crowded

The use of multiple radios, or wireless transmitters, will push the adoption of mobile technologies, but will require industry coordination and careful construction, an Intel executive said Monday in Beijing.

"Radios are everywhere and yet we do very little with them," said Kevin Kahn, Intel senior fellow and director of its Communications Technology Lab, in a speech at the Intel Developer Forum (IDF). "If anyone other than the geeks among us are going to use this stuff, then it means that we need ease of use."

By 2009, each mobile platform will handle six or more radios for applications such as Wi-Fi, WiMax, 3G cellular, UWB (Ultra Wide Band), Bluetooth, digital TV and GPS (Global Positioning System).

Kahn said that the biggest problem is interference between the different radios, which exist on chips that are measured in square millimeters and sometimes use adjacent spectrum.

"Simultaneous operations are a fairly widespread problem," he said.

For example, this kind of spectrum conflict led to the Bluetooth standard being adjusted so that it Bluetooth could coexist with Wi-Fi, he said. Cooperation between different technology standards in different spectrums would be critical to their development. "We're going to have to work across the industry to put the hooks in to coordinate and provide this kind of advanced performance."

Kahn believes the solution lies in creating parallel modules for each radio standard, such as Wi-Fi and WiMax.

On the device level, the problem is solved by timing the use of the radios "so that they are never physically doing operations at the same time, even though the user never notices."

Looking to the future, Kahn said "Sixty GHz is the next chunk of unlicensed spectrum," and predicted that it would come into wide use by 2011 or 2012. He described it as likely being used for a "next generation personal area network (PAN)."

It is a "very large piece of spectrum," but "the difficult part is that 60GHz is very high frequency. Not surprisingly, building radio to run up there is more difficult. Doing that cost effectively will take a little while," Kahn said.

"Because it is so high, it tends to be very directional. We deal mostly with omnidirectional radio systems. When you get to very high frequencies, the signals in order to get good performance typically become much more directional, and we may have to use antenna steering techniques."

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