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Cambridge's Streetlamp-Powered Wireless Network
Serpentegena writes "A joint research project by scientists at Harvard University and BBn Technologies may have spawned a new breed of Metronet. The wireless network, code-named CitySense, which will consist of 100 streetlamp-mounted nodes by 2011, will draw power off the Cambridge, Mass. public grid and be used at first for weather and pollution monitoring. The intention is to also allow 'academic researchers worldwide [...] to submit their own research programs to run on the network.' Sounds remarkably similar to the beginning of the ARPANET, except the network hosts will be running Linux."
56K modem speed (for their second generation network) was quite impressive in its day- considering most people were still connecting to the internet at 19.2 at the time. The first generation network was still impressive. Sure 14.4 and 56K sound slow nowadays, for the buck it really was amazing. I remember the first time I sat down at a barnes and noble with my laptop and got on IRC and I was just flat out blown away. I knew lots of people who had it and it seemed they were poised to do quite well. For some reason the died off before WiFi really was accessible, and I never understood quite why. They seemed to have little problem negotiating WAP placement deals. Anyway- that proprietary wireless network predated 802.11 (I think) and was the only way to go for wireless. Its not like they jumped on when wifi was already around and said 'hey try our slow network instead'.
EVDO can't support the subscriber density that Ricochet can/could. Get a dozen active users per square mile and EVDO gets pretty sluggish. Ditto with EDGE/HSDPA.
Wireless data is driven by the principle of geographic frequency reuse. If you can make short-distance transmissions, you can use less power, which means there can be someone else using the same channel just a short distance away. If you're far from your tower and need a lot of power, you tie up the channel for a wider area, meaning that fewer subscribers can be satisfied per unit of spectrum.
With a microcellular network like Ricochet, there are several poletops per square mile, and the same channel might be in use several times within a square mile. With cellular towers, a single sector usually serves several square miles, so a lower user density saturates the spectrum. Ricochet never achieved user density to come anywhere close to capacity, whereas many urban EVDO sites run maxed out for hours a day.
Metricom's Ricochet was ahead of its time, and not marketed effectively. They built a very dense, capable network, anticipating the internet growth that didn't materialize until many years later. They didn't have the financial resources of a giant cellular company to weather the lull, and their recurring costs killed them. Their assets were sold at auction, and have since changed hands several times. YDI/Proxim currently maintains Ricochet networks in the cities where they inherited contractual obligations, but the rest of the markets sit abandoned.
Ricochet's still relevant in areas where cable and DSL aren't available, because while not speedy by today's standards, it wipes the floor with dialup and is more than adequate for most uses. The deployment cost is dirt-cheap, and the modems can be had for a song. That's part of the problem though, because you can't sell a customer a $100 modem if they can get it for $5 on eBay.
The modems are also useful for peer-to-peer networking over distances that wifi can't touch. They do a mile in open space, and half a mile pretty reliably in an urban environment. The 900MHz band is wide open, and penetrates buildings much better than 2.4GHz. If you get 'em above the terrain, they'll do five or ten miles on the stock antennae. There's some user-driven research on the Ricochet Wiki if you're interested.
Google Wifi is deployed here in Mountain View and they're also posted on street lamps. Is it just me or does this plan just not sound very impressive. Google's system is quite interesting. Every now and then there's a very massive and obvious wifi AP up high on a pole. The rest of them would be hidden inside the street lamps and all they do is relay traffic back to the other ones. This saves them from having to actually wire every lamp post.
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