Cognitive Radios Could Increase Wireless Spectrum
schliz writes to tell us that a new intelligent radio technology, dubbed "cognitive radio," is being developed that adjusts operation based on input from its surroundings. Consumers wont likely see practical implementations of this tech for another five years, but it could have wide reaching applications from wireless networking to public safety devices. "Adaptive, cognitive radios could enable techniques such as dynamic frequency sharing, in which radios automatically locate unused frequencies, or share channels based on a priority system. In public safety, cognitive radios also could be used to provide interoperability between various signals and automatically adjust radio performance."
But as with any system of resource sharing (especially bandwidth), some devices/users will simply ignore the rules to improve their own performance: flag every transmission as ultra-high-priority and so forth. You can't expect users, or even manufacturers, to "play fair." And I'm not convinced that regulation can force people to play fair. Unlike objective measures like antenna transmission power, things like "priority" are more open to interpretation (or misinterpretation, if you prefer). I suppose the same solution as for cell-phones could be applied: if you charge someone for every transmission, they are forced to conserve bandwidth.
I love technology... but when it comes to safety and emergency systems, it's usually best to use the lowest-tech solution possible: cheaper, easier to repair/maintain, more robust, more reliable, and better understood. I don't know if I want my emergency call negotiating interoperability with other devices to reach someone (since any such operation is error-prone). The simplest solution (e.g. full-power transmission on a reserved channel) is probably better in such a case.
Motorola have been working on this for years and I suspect so have all the other mobile handset makers. Frequency agile, power agile systems are used in all cell phones, base stations can direct and use a focused beam to reach a faint handset - this is in service stuff. Walk through hand off from a handset that uses DECT, then dials out and goes cellular seamlessley has been demonstrated, as have handsets that can ask others to dial power down etc. The only thing holding this back has been market forces - customers just haven't wanted it. Yet.