At 10:23 AM 12/6/2002 -0500, Tyler Durden wrote:
Now I guess the question is, as users come on line, does the lack of a centralized "wavelength authority" mean significantly decreased performance, or is there some kind of self-regulation that will occur as, perhaps, users try one wavelength, find out its crowded, and then try another? (Or does some WiFi hardware automatically do this? Or, can it operate at 3 or 4 channels simultaneously, using multilink PPP or something equivalent?)The simple answer is a centralized frequency coordinating authority can significantly improve geographic spectral reuse. This has been the topic of technical numerous papers on cellular communication over the past 30 years or so. IMHO, one of the shortcomings of 802.11 is that there is insufficient provision for code division/data rate fall back as channel conditions deteriorate when the noise floor moves up. In busy locations the radius of effective communication may shrink until the devices are little more than wireless cable replacements.
I and several committee members raised this issue early on at 802.11 but the implied design changes (e.g., longer correlators) were considered too expensive. If the considerations had been taken to heart devices would have been free to negotiate markedly lower data rates in order to improve jam margin and interference. Of course, there is nothing technical or legal to prevent competing 2.4/5.7 GHz devices from emerging which can inter-operate with existing 802.11x while having improved jam margin capabilities when talking among themselves.
steve
