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IT Shops Coping With Overloaded 2.4GHz WiFi Band 165

alphadogg writes "Of the 470,000 Wi-Fi connections made on a recent day at Abilene Christian University, fully 94% used the 2.4GHz band, representing an extreme example of how today's surging number of Wi-Fi clients is crowding the band least able to accommodate them. At ACU, this is not considered a problem, at least not yet. In part, that's because of careful wireless LAN design and capacity planning. And partly because a goodly percentage of mobile devices that can run on the alternative 5GHz band, do so: on that same day, 47% of the school's laptops and desktops, and two-thirds of its iPads cruised on 5GHz, via either 802.11a or 802.11n. Yet relatively few of today's Wi-Fi clients support 5GHz."
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IT Shops Coping With Overloaded 2.4GHz WiFi Band

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  • Channel 14 (Score:4, Interesting)

    by snsh ( 968808 ) on Monday October 24, 2011 @03:23PM (#37822210)

    Anyone knowledgeable about the conflict is 2.5GHZ that led the US FCC to limit wifi from using channel 14 (2.484 GHz)?

    According to the FCC spectrum chart [] the top of the 2.4 wifi band abuts the "Standard Frequency and Time Signal" Band at 2.5 GHz. What is that used for?

  • Re:5 GHz sucks (Score:5, Interesting)

    by Miamicanes ( 730264 ) on Monday October 24, 2011 @04:22PM (#37823258)

    The main problem is that 802.11A/N is totally the wrong kind of protocol for crowded environments where you have lots of individual users who need reliable and robust connectivity that doesn't necessarily have to be individually fast. 802.11N in particular was optimized for the questionable use case of making your neighbors hate you so you can avoid running cat5 between your living room and den, instead of enabling lots of adjacent users to peacefully coexist. Hand-offs are still kludgy, and it's rare to find someone who doesn't do wireless networking for a living who can literally walk from the back yard down to the basement and upstairs, then out to the front yard without having his connectivity break (and break *hard*) at some point along the trip.

    What do I propose? "802.11u" (as in, "UMTS"), running on unlicensed 5.8GHz. Stick private picocells in every room, hallway, and area. Multiple ones, in large areas. Wire them together with ethernet, or optionally create a peer to peer mesh network for the backhaul (5.8GHz where good links are possible, 2.4GHz for links between floors or "difficult" walls). Then take more or less canonical UMTS, and implement it as micro cell sites in devices with the approximate form factor of a smoke detector.

    The nice thing about UMTS is that it's CDMA, just like 1xRTT (and ironically, unlike EVDO). You don't have to do local spectrum planning. If an area has poor throughput, just buy and add more femtocells or picocells to the congested area, let the devices negotiate lower power levels, and watch CDMA work its magic. By linking the PicoFemto/cells together, they'll magically work the same way a real cellular network does (sharing their bitstreams, and allowing them to reinforce each other and cancel out local/directional noise).

    5.8GHz private UMTS wouldn't be fast (it would probably max out around 2.5mbit/sec at the cheap end, and max out around 10 or 20mbit/sec for a high-end corporate network where cost was no object), but it would be perfect for places like college campuses, offices, etc. where you have lots of people who need mainly internet access, but no single user necessarily needs GIGANTIC amounts of individual bandwidth. In other words, the exact places that are a total clusterfuck mess today, because you have hundreds or thousands of users stomping all over each other trying to use a wireless protocol optimized for streaming HD media from a point source to a single hungry consumer.

    It might even be possible to make a cheaper "home" version that ran with uplink & downlink sprayed across the entire existing 2.4GHz wifi band -- the idea being that if Qualcomm has a chip designed to do 1900 & 2150MHz uplink/downlink UMTS, extending it to add ~2.4-2.5GHz would probably just be a straightforward next-gen upgrade that would be easy to add to any Android phone (or iPhone) that already had UMTS capabilities.

    I have no idea whether this could possibly be cheap enough to justify doing at home, but I suspect the costs would be fairly competitive to what businesses, colleges, and hotels spend kludging around with high-end enterprise WiFi *anyway* today.

"For a male and female to live continuously together is... biologically speaking, an extremely unnatural condition." -- Robert Briffault