Interesting People mailing list archives
Re: Harvard, BBN Use Streetlamps to Light Up Wireless Network
From: David Farber <dave () farber net>
Date: Mon, 14 May 2007 14:57:09 -0400
Begin forwarded message: From: Brett Glass <brett () lariat net> Date: May 13, 2007 4:18:47 PM EDT To: dave () farber net, Ip ip <ip () v2 listbox com>Subject: Re: [IP] Re: Harvard, BBN Use Streetlamps to Light Up Wireless Network
Bob Frankston writes:
First a technical detail. This assumes that the street lamps have power even when the lights are off. Many lights are run in series.
Actually, the lights are not run in series (the loss due to resistance would be too high). And standard industry practice is to put a separate photocell on each pole. This provides redundancy; if one light goes darkdue to a failed photocell, the rest don't. Metricom, which lost a billion
dollars trying to build similar networks, relied on knowledge of how these systems were wired and constructed.Unfortunately, mesh networks constructed in this way do not scale well due
to problems with spectrum usage. This is even more so with systems basedon 802.11b, which has too few non-overlapping channels to prevent interference
between mesh nodes. The most likely result of this project will be a semi-reliable network (with problems due to interference with consumerdevices) that covers a small area and disrupts private wireless broadband services in the area. (Those services should really be allocated their own
spectrum, but at the moment virtually all of them have been forced, by shortsighted policy, to use the same unlicensed spectrum as cordless phones and indoor Wi-Fi.) --Brett Glass ------------------------------------------- Archives: http://v2.listbox.com/member/archive/247/=now RSS Feed: http://v2.listbox.com/member/archive/rss/247/ Powered by Listbox: http://www.listbox.com
Current thread:
- Harvard, BBN Use Streetlamps to Light Up Wireless Network David Farber (May 13)
- <Possible follow-ups>
- Re: Harvard, BBN Use Streetlamps to Light Up Wireless Network David Farber (May 13)
- Re: Harvard, BBN Use Streetlamps to Light Up Wireless Network David Farber (May 14)
- Re: Harvard, BBN Use Streetlamps to Light Up Wireless Network David Farber (May 14)