Stanford Team Tries For Better Wi-Fi In Crowded Buildings 43
alphadogg writes "Having lots of Wi-Fi networks packed into a condominium or apartment building can hurt everyone's wireless performance, but Stanford University researchers say they've found a way to turn crowding into an advantage. In a dorm on the Stanford campus, they're building a single, dense Wi-Fi infrastructure that each resident can use and manage like their own private network. That means the shared system, called BeHop, can be centrally managed for maximum performance and efficiency while users still assign their own SSIDs, passwords and other settings. The Stanford project is making this happen with inexpensive, consumer-grade access points and SDN (software-defined networking)."
Re:How efficient is WiFi when crowded? (Score:4, Informative)
2.4ghz is still usable with 16 networks in the same area, but it's not a great experience. There are only three non-overlapping bands in the 2.4 GHz band, so you can see how there can be a rather lot of congestion.
The 5.8 GHz band, on the other hand, wouldn't have nearly as much of an issue. 802.11n in the 5.8GHz band devices can use 8 non-overlapping channels, significantly reducing the amount of interference.
802.11ac is kind of in a wierd spot. It's really 40MHz per channel minimum (twice the minimum for 802.11g or 802.11n), but many devices also support a whole whack of new frequencies that require the use of DFS to avoid interfering with radar (basically if the router detects radar on the channel, it blacklists the channel for a set amount of time and switches to another channel). That brings the total up to a possible 12 channels, even though they're twice as wide...
802.11ac also supports beam forming, which enables multiple simultaneous transmissions to happen on the same frequency at the same time without interfering. I believe that's more targeted at handling more users on a single network rather than letting multiple networks co-exist, though.