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Bad Connections Dog Google's Mountain View Wi-Fi Network
itwbennett writes "Google launched its Mountain View, CA public public Wi-Fi network in August 2006. It was one of the first public wireless Internet services in the U.S. and was intended to provide free service across the city. But in 2012, one year after Google signed a 5-year agreement to continue the service, it started a slow decline to the point of being unusable. 'We started noticing it in very large files, things like operating system updates, but now it's on files as small as 500 kilobytes,' said Rajiv Bhushan, chief scientist of pharmaceutical startup Livionex and a long-time user of the network. A recent test by IDG News Service resulted in a total failure to get a working Internet connection at a dozen sites around Mountain View, including in the city's main downtown area and directly in front of Google's headquarters." I've had disappointing results trying to connect to several other public wireless nets around the U.S., both privately sponsored and municipal. Do you know of any that work especially well?
(These are general ideas and may not be technically accurate... feel free to correct me)
There are several problems with WiFi technology itself. First, there is no contention management for wireless. When you're wired in, collisions are detected quickly, so you can saturate the connection near its theoretical limits without too many errors. (There's a promotional video about this from Meru Networks, but it is fairly educational.) By contrast, WiFi will roll through a larger bit of data and then ask for confirmation of receipt, which can lead to a lot of problems as radios talk all over each other. This is not a problem in regular office environments, where walls, floors, and furniture can provide separation so the radios can "hear" things that are closer. However, get into an open air environment and add a bunch of devices at once, and everything flatlines as the access points attempt to orchestrate several hundred devices in range, including interference from other radios within "hearing" distance on the same channel.
The second issue is one of limited channels. Originally WiFi was designed to move a tiny amount, and I think you could actually split off 802.11b into 11 discrete channels. As data needs grew, they consolidated 11 channels into 3 discrete channels for 802.11g (4 in the EU, I believe) and that's where it stands: a 3 lane road for 2.4GHz. 5GHz has more channels, depending on where you are in the world, but right now they are unreliable as the requirement for many of them is to be compatible with DFS, which means that if there is a certain signal being broadcast, your access points are expected to abandon that channel immediately. I think there are changes in the works from the FCC and although it only introduces 30% or so of new spectrum, it happens to cross multiple channels, so it may be like going from 9-12 channels to 20 or so. Combined with the more limited range of the higher frequency, having 20 discrete channels opens up a lot of options for basic broadband in public spaces. (Well, it did until the new ac standard came out, and I haven't even bothered to read it because these massive spectrum widths are going to be a nightmare, and I'm in a different line of work these days.)
However, none of this solves the "microcell" design of WiFi, where the client makes the decision on what radio to connect to instead of the access point. Your cell service, for instance, works well because the tower instructs the client so it can perform handoffs, reduce the data rates, and make other adjustments to keep things from choking up. I have sat and watched an iPhone cross over multiple access points and hundreds of feet to connect across a stadium for no explicable reason. (That's true for every wireless device, but I'm picking on iOS because they are notoriously noisy, always flooding the air with useless beacons, trying desperately to connect to stored wireless networks even when they aren't around.)
I have deployed Xirrus, Aruba, Extricom, Unifi, and some other products in dense situations, but as far as I know, the only pseudo non-microcell options available are from Extricom and Meru. Although I haven't used Meru, I can say that Extricom has been the most reliable in very dense environments, since they use some tricks to keep the air quiet, and they do not introduce beacon traffic with the addition of more radios. (Disclaimer: I have worked with the guys from Extricom quite a few times, and I think they are very capable, so take that opinion with a grain of salt.) Xirrus works pretty well in corporate environments, and their reporting interfaces are great, but I was disappointed that their sales staff continued to deny problems in 2.4GHz long after it was obvious that they didn't have a workable solution for super dense deployments. But maybe they just didn't know.
Anyway, ignoring all of that technical garbage, the