Wifi mesh networking for emergencies

I know we have some talented computer folks here, as well as some very well prepared folks..... I'd like to hear your thoughts on wifi mesh networking for emergencies and disaster recovery



I was just thinking about the issue, after a major incident, cellphone towers could get wiped out, backhauls are easily damaged, and a lot of the expensive, centralized infrastructure we depend on could just as easily fall apart.



Of course, critical needs such as food, water and shelter must be addressed as the utmost priority, but once they have been, connectivity would help recovery efforts. How would you folks put together a wifi mesh in the aftermath of an incident as part of the rebuilding process? What technologies and hardware would you use to maximize coverage and resiliency? What topologies would you lay it out in?



I am aware that there will of course be challenges such as marginal power, so it would be good if you could share your ways of dealing with the above.



Cheap, affordable mesh nets could also be useful for adhoc events under less trying circumstances too, so it's not all about doom and gloom

mesh networking is going to be essential, not just for emergencies but also as part of eliminating the fragility and control issues of centralized communications.
even the most basic mesh network that simply bundled texts and redistributed them (and returned a delivery notification) would be so useful.
I'm not a tech guy but as I understand it the main problem is that cell phones are designed so that they send on a set of frequencies that are listened for by the cell towers and the phones receive on a band that is sent by the towers... in other words the phones hardware is not designed to allow them to send and receive directly even if software was written to allow it.
the exception right now is with WiFi, but the range is not nearly as good as it could be if the phones were built to mesh from the start.

KevinL said:

What technologies and hardware would you use to maximize coverage and resiliency?

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A HAM radio with a fold-away antenna; Wifi is unnecessarily complex for emergency communication, especially compared to amateur radio.

ham would be great if it were taught in schools... maybe if a basic UHF licence were needed for graduation. ;-)
with mesh the idea is that every user routes information and the more users there are the better the information flows.

it should function like the traveling salesman problem in a neural network.

IMHO the range on wifi equipment is just too short for much of a mesh network. Too many hops to get a decent distance. On the other hand, if cell phone radios could be meshed instead of being locked to a tower, then we are getting somewhere.

Your basic 100-watt HAM transceiver works in a 300+ mile range during the day, 1000+ miles at night, no extra equipment, local or distant, needed. Experienced HAM operators bounce signals off the Moon for entertainment.

Ive been dealing a lot with wireless networking, mesh networks, wifi repeater stations, and wide coverage wifi over the past few years...

Since budget has always been a concern, I have been buying hardware almost all from Ubiquity Networks. At the price level, it allows even the common enthusiast to play, experiment and own carrier style gear.

http://www.ubnt.com/airmax

My first project using this stuff was a simple point to point bridge between my office and a friends house 6 miles away. I used the Nanostation 2.4ghz product which ended up costing me $79 per radio. It was basically a transparent IP Network bridge. But then the project evolved into supplying my office with a 2nd WAN connection to my firewall for automatic failover since our DSL line was far less than reliable.

http://www.ubnt.com/nanostation

Their new AirMax stuff is pretty amazing, high speeds, long distance, and still decent prices.

You can flash aftermarket firmware to do whatever you need it to, also supports DD-WRT, but the packaged firmware is pretty feature rich. Ive never flashed one since the stock stuff takes care of what I need it for.

Im also a HAM, love it, but its hard to get other friends and family on the wagon due to licence requirements.

StarHalo said:

Your basic 100-watt HAM transceiver works in a 300+ mile range during the day, 1000+ miles at night, no extra equipment, local or distant, needed. Experienced HAM operators bounce signals off the Moon for entertainment.

Click to expand...

My dad's done it tons of times. There's also meteor scatter, where they bounce it off shooting stars!

But yes, if your concern is communication rather than accessing the Internet, then ham radio is the way to go. You don't need to know code anymore (which many folks lament as lowering the bar to entry), and as StarHalo points out, the range is excellent.

As your thread title suggests, for emergenices, this is the way to go. The Internet is great, but when the grid goes down, I would stick to the amateur bands. First hit on Google here.

A little off topic, but this is what one of my customers builds. I'm sure these guys cost a couple of pennies. Full on mobile stand-alone communications stations. If you've seen the latest Die Hard movie it's basically like what they've got on there.

http://www.nomadgcs.com/news/Mobile_Inspection_Station/Mobile-Inspection-Station.html