Bills would boost unlicensed Wi-Fi

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compared WiFi and TV ranges: Rmember that WiFi is first targetting
* mobile applications (including in cars) so it will require enough intervalguard timeto support varying speed (due to additional Doppler frequency effect): the protection ofsurrounding channels would need limiting the bandwidth in mobile channels. The same will be true for mobile receptors for TV channels from fixed TV stations (but they can't limit their bandwidth because these emittors are ALSO targetting fixed and portable receptors in homes). The interaction between mobile WiFi and surrounding TVchannels should not be neglected, even if there's enough time guards between channels (something unlikely to be performed correctly with analog TV signal, and being more accute with numeric TV signal as it has a lower emission power which means that the dB attenuation differential will be lower and that it will more difficult to adapt the WiFi receptors against intermodulations.
* portable TV sets at home with a range that ALSO are in the same distance range as WiFi devices. Such proposal would mean the end of portable TV, requiring only cabled installations with shield protection in cables, and a antenna outside, protected from interaction by home WiFi devices AND by mobile WiFi devices outdoor (this second issue being even more difficult to avoid, unless the FCC demands that customers change their antenna installation, which means additional costs for customers).

Don't forget also the channels that have been allocated in the TV band for radars in airports, and for civil air navigation systems: there are critical security measures to protect their frequencies, including for small ranges (notably for approach and landing/takeoff, which occurs within small distance ranges, compatible with the distance of many classic WiFi transmitters, even at low power!)

This means that WiFi in the TV band would require a completely different standard for its emission profile, the only accurate and interoperable profile there being the standard created for numeric TV broadcasts and NOT the one created for the 802.11a/b/g and BlueTooth standards, and not even the one created for WiMax (which has a much wider range in power, distance, and bandwidth), and not the same standard as used in GSM cellular telephony.

With such required adaptations, do you still call it "WiFi"? What is the bonus brought there by using a band that will likely cause problems to many existing applications (and not only analog or numeric TV broadcasts)?

Such FCC proposal is ill unless the FCC regulator finances the rearrangement of critical applications that remains in the lower TV bands to a higher UHF band. But customers that still only receive TV through the VHF band will have to tune again their receptors, andpossibly buy a new antenna for the higher UHF frequencies, or get into satellite reception (renting a decoder for channels that he dis not intend to receive). Otherwise, the covered population will be reduced and it will harm the finances of broadcast TV channels due to reduction of the target population for advertizing.

The FCC should not regulate suchthings too fast: before freeing a band, it must FIRST ensure that this band is effectively free throughout the territory, and permitted for use by US neighbors(notably Canada and Mexico, which have necessarily different frequency allocation plans, taking the US needs into account). The situation may be even morecritical with Cuba, or within Antilllas (Porto Rico) due to many more surrounding countries that need protection of their frequencies.; Posted by: PhilippeV Posted on: 02/22/06 You are currently: a Guest | Members login | Terms of Use