Ask Slashdot: Ad-Hoc Wireless Mesh Network For Emergency Vehicles?

First time accepted submitter Texaskilt writes "I am looking to put together a mobile mesh network for my volunteer fire department and would like some recommendations from the Slashdot crowd. Ideally, the network would consist of cheap wireless routers (Linksys WRT-type) mounted on each vehicle. From there, tablets or other wireless devices could connect to the router. When the vehicles are in the station, the routers would auto-connect to the WiFi network to receive calls for service and other updates. When out on a call, the router would form an ad-hoc network with other vehicles on the scene. If a vehicle came into range of an Internet 'hotspot,' it would notify other vehicles and become a gateway for the rest of the 'ad-hoc' networked vehicles. I've looked at Freifunk for this, but would like some other options. Recommendations please?"

Comments

Project Byzantium?

[Intrepid imaginaut]

http://project-byzantium.org/

I have to wonder though, what's wrong with good old fashioned radios.

Re:Project Byzantium?

[slimjim8094]

I am an emergency responder, and frankly I can't come up with much I'd use internet for. Medical history databases? Like what? Even at the hospital they need it sent from other hospitals if they don't already have it , there's no world-wide database of medical history, and even if there was can you imagine the nightmare of hooking every EMS agency up to it? And the security involved in handling patient data on such a scale? No thanks. In any case, it doesn't do me much good. Either the patient can tell me their medical history, or we've got much bigger problems. If they're unconscious, their history is secondary to keeping them alive, and you've got plenty to do on that front.

As for conferencing with doctors - that's crazy. We already have medical directors (physicians) we can call on the phone or over the radio, and it works fine when we need it. Plus, it won't give them any more information than what you can tell them over the phone anyway. I don't much want to fidget with Skype and a webcam when we're supposed to be deciding on a course of action. They can't interact with the patient anyway, and crappy wireless webcam video wouldn't be sufficient to notice something subtle that we missed.

The paramedics that I work with have CAD for tracking status, location, nature, etc - but they don't use it past dispatch. They can also send telemetry (specifically EKGs) from their monitors via their cellphones to the receiving hospital, so a heart attack can be diagnosed from the trace before we get there. That's pretty cool, but it's about the limit of what we've ever felt like we needed.

Have a look at Mikrotik

[Jimbookis]

http://www.mikrotik.com/ devices might have what you want. They are inexpensive, very flexible and have interesting mesh modes I have yet to try out and will run directly off your fire engines battery system with some power filtering and clamping. Whatever you do in general you should have a play, write a clear specification with all sorts of test cases and run a small trial for a while. Make the devices/solution meet your requirements, not the other way around or you will be sorry.

Good ol' HAM radio?

[guruevi]

It works well, it won't give you much throughput but if all you need is some text and voice-based systems this should be plenty (it's about 300-9600 baud for IP so a slow serial link).

The issue I see with your approach is that when the vehicles are within range of each other they will also be within range of the same hotspot. So mesh is simply overkill. Mesh is intended for lots and lots of nodes in dense areas to connect to each other to a single (large?) uplink for either anonymizing or places where you cannot place (either due to economic or ecologic reasons) multiple antenna's. This works well for the GSM range because they are intended to cover literally miles (2W) at a frequency that is licensed to cooperate with each other and able to penetrate a lot of structures so two cell phones can technically talk to each other and extend the range of the original tower another mile or so (given the battery usage to do so is acceptable).

The 100 mW you get out of a WiFi router close to the hydrogen resonance frequency is simply not enough to cover a mile of random area which may have other compatible and incompatible broadband sources (microwaves, garage door openers, bluetooth ...) that could overpower the signal.

You're better off using the professional systems for this. WiMax base stations can be had for $1500 and a receiver is ~$200 and it will cover about 50km. Otherwise get a free cell phone plan for your volunteer fire department (I mean, some local corporate overlord MUST be benevolent enough) or set up your own transmitter (HAM or otherwise).

Since it's been posted before...

[sbrown7792]

Here's the article from less than 2 weeks ago about the same thing. They had a few interesting ideas.

VANET

[ArhcAngel]

So you want to set up a VANET (Vehicular Ad-Hoc Network)...a subset of the MANET (mobile ad-hoc network). There's even a proposal for a secure fire truck communication protocol via VANET. Perhaps you can find more information by reaching out to some of the agencies working on this protocol.

Saw a presentation on MESH for emergency response

[bdwoolman]

Keven Whipp of the Montgomery [County Maryland] Amateur Radio Club gave a presentation last April on a very similar topic to the Columbia Area Linux User's Group (CALUG). The radio club has been working with Montgomery County to test various setups of MESH networks on Linksys WRT54GL routers running custom firmware to be used in emergency situations. They have been testing distances and reliability using different frequencies using high gain antennas (which require a license). As I recall the deployments they tested faced a lot of technical and regulatory obstacles. And they were looking at simple static deployments, not mobile. If, say the infrastructure went down after a flood, their objective was to provide basic internet services to Emergency Response Teams working in the area.

Anyway, here is a link to a PDF summary of the presentation. My take away was that even after pretty extensive testing the system was not ready for prime time, but was very promising. To be useful in the situations to which they aspired the Mesh had to be reliable and robust. It was not. I am sure they would be happy to share their experience with you. And I bet they made progress over the summer.

Re:Get ready for it!

[HangingChad]

But when lives are on the line, a more conservative approach is called for.

You know nothing about being a first responder, especially out in rural areas where radio coverage may be spotty to non-existent.

Lives are on the line whether you have working comm or not. There were times I would have settled for two tin cans and a string if I could call for mutual aid on it. During emergencies ad-hoc networks could be a lifesaver.

There is a big need for self-discovering networking between emergency response vehicles. You won't find any commercial solutions in the budget of most departments.

Maybe drag your fat butt out and pull some volunteer shifts before you start telling people in the field what they need.

There are standards for this.

[Animats]

It's not standardized across the US, but many states have standards for emergency radios. Find out what's standard and go with it.

One of the more useful projects of Homeland Security is to get all the agencies that have first responders connected in emergencies. It's hard, because each agency has their own system and they don't interoperate. Here's the Texas plan. And the Florida plan.

Most of the hard problems have to do with too many people on the air in urban areas. If you're a volunteer department, you're probably not in an urban area and don't have that problem. If you want something that will Just Work, get high-powered 700MHz public safety band capable VHF FM handhelds and vehicle radios for your own people and get them fitted into your state plan. A few Iridium satellite radios for command personnel and those who really need to talk to the outside world during an incident are helpful. Here's one suitable for fire truck installation. Iridium airtime costs are high, about $1.29 per minute, but in an emergency that's the least of your problems.)

The Serval Project

[complete loony]

The Serval Project on the Android Market.

Our focus is on providing useful services without any reliance on fixed infrastructure. Phone calls and text messaging via adhoc mesh, and even file distribution in the field.

Though you might find our next release more suitable than the version on the market. It's still in heavy development, but would also allow phone calls to be relayed to the PSTN via an asterisk PBX. We'd be happy to provide an alpha version and help you to get the most use out of it.

We're also working on a separate application that uses open street map data for situational awareness and collaborative mapping.

Commercial grade...not hobby grade

[ff1324]

Disclaimer: I work for a paid fire department but started as a volunteer. I understand the financial challenges for both m

Our metropolitan area uses InMotion OMG1000 or OMG1050 mobile routers. The cost just over $2000 each, but they create a man network for emergency equipment, have up to four different WAN connections, are remotely configurable and upgradable, and provide GPS services. They're almost bulletproof.

Wiring up WRT54Gs isn't the answer. You'll spend more time than your time is worth creating a solution than finding funding to implement one. Apply for a FIRE grant or cooperate with multiple agencies to access a larger program. Check with your county or state.

Realisitcally, an air card is all you need otherwise. If enough agencies want in on the project, see if the wireless provider will put you on your own APN.

Good luck.

Re:easiest solution

[DarthBart]

My old department got hand-me-down trucks from the Texas Forest Service that we converted to brush trucks. We also got a 5000 gallon flight-line fuel truck from them that we converted to a mobile hydrant. The one "new" truck we bought, we bought as a used truck from a department in Chicago and had to take out a loan to pay for it. The bi-annual fundraising BBQ we held covered operating expenses, but that was just about it. Everything else came from handouts from the government.

The radio system? Patched together with stuff my dad & I bought at hamfests.

And there was more than a few times during the summer and we were fighting multihundred acre brush fires that I wish I knew exactly where each truck was, how much fuel and water they had onboard, and be able to set a waypoint for them to drive to for their next task.

That may not have all been able to have been done with an ad-hoc wireless system, but that would have helped immensely.