Our actual deployment density is very low at the moment, but that isn't very important. The design is quite scalable.
Our network consists of a backbone, distribution layer, and client endpoints. Our backbone is dedicated to primarily point to point links. These are generally long links making use of mountain tops (currently one at the moment) and take advantage of the FCC's fixed point-to-point rules. These point-to-point rules pretty much give us the ability to shoot anywhere we can see and have plenty of power to spare for a reasonable SOM (system operating margin). Our distribution point is a midpoint between our backbone and client connectivity. Since we do not allow clients to tie directly into our backbone (and for really big reasons), they must connect though these points. These sites are typically point-to-multipoint radios, and fall under the point-to-multipoint FCC regulations. The regulations dictate that P2MP radios use a lower level of EIRP...36dBm to be exact. This works just fine for short links (up to 10 miles or more line of sight, and near line of sight in some special cases). The distribution point radios typically are non-directional or perhaps sectorized. (In our network deployment, we have yet to make use of the last type) The client end points can really be quite a few things. A sole station, a group of stations sharing the same radio, a group of stations on a local wireless network sharing the same radio, etc. Assuming one had the resources, a network could be created as needed to lower gain devices such as magmount antennas on vehicles and handheld PDAs and laptops. A mobile unit located in a high position could connect into our distribution point (say Puyallup, ~10 miles away from Tacoma), and provide wireless coverage to this particular valley area for several miles on end -- assuming mobile units made use of 5dBi magmount antennas, which are slightly smaller than cellular antennas. People could roam away from these mobile units making use of more localized access points, maybe providing several thousand feet of range at most. It might be good to keep some of this a flat network (bridged) due to the complexity and mobility required. Another key piece in this network is the use of routed architecture as opposed to building one flat, bridged network. This isolates broadcast-based protocols and chatter, prevents broadcast storms from destroying the network, and provides a lot of control to the operator. All of this means scalability. Blanketing the world with 802.11b for any laptop to obtain a usable signal within 1000 square miles isnt going to happen. Plus, why waste money on infrastructure when you can practically pack it up and take it with you -- build it instantly as needed? I know this is a lot of babble, but I feel that wireless technology could play a very important, and relatively inexpensive, role in disaster relief. We have no arrangements with local/state/federal government for our system, and we are just building it because we love to experiment and play, but it definately has some exciting applications. FYI, our mountain top radio has decent battery backup power, i believe 2200 watts. Our radio gear draws, at most, 10 watts. We have provisions to tie into an 80kW battery bank at the facility, but have not done this yet. Our urban sites do not currently make use of battery backup yet, but i suspect that we'll do that soon. >-----Original Message----- >From: Douglass Turner [mailto:[EMAIL PROTECTED] >Sent: Tuesday, July 15, 2003 3:39 PM >To: Casey Halverson; [EMAIL PROTECTED] >Cc: Douglass at home >Subject: RE: [BAWUG] WiFi for disaster relief : Is complete untethering >possible? > > >Hi Casey, > >Could you say a bit about the density and range of APs you are >deploying? >What power source are you using for them? > >-Doug > >> >> -----Original Message----- >> From: Casey Halverson [mailto:[EMAIL PROTECTED] >> Sent: Tuesday, July 15, 2003 7:21 PM >> To: Douglass Turner; [EMAIL PROTECTED] >> Subject: RE: [BAWUG] WiFi for disaster relief : Is complete >untethering >> possible? >> >> >> Yes, we are building this network in the puget sound region--- >> the system is called "SnowNet". There is plenty of work to be >> done, but the system is quite useable at the moment if the >> circumstances arose. > > -- general wireless list, a bawug thing <http://www.bawug.org/> [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless
