Boffins squeeze a mesh onto Android handsets Australian researchers have ported Wi-Fi mesh-networking onto the Android platform, potentially turning any Android handset into a relay able to extend network coverage into disaster areas. The newly-demonstrated project is called Serval, after a kind of cat, and enables a standard Android handset to make voice calls (VoIP), …
Wi-fi networks still require a radio frequency to broadcast.
If the Egyptian government wanted to, they could jam the wi-fi band and still stop all communications in an area.
So creating a 'mesh' really wouldn't be a good idea and it would probably let them know where you are....
But if your objective would be to get the word out... You'd want to set up a series of packet switched networks run by ham radio operators. Much harder to detect and jam.
If you're talking about disaster services... having the ability to create temporary base stations with up links to Satellite would have a larger impact. And then you'd want to restore SMS/Text services first since it would allow more people to communicate.
IMHO that would be a better solution.
Setting up a portable network means that the base station is known so it wouldn't be good to hide from authorities. But you're not doing that if you're in a disaster area and are looking for help....
Looking at what telco's do at sporting events... that's what you would need to do in the event of a disaster...
May I question some of your logic?
"If [a] government wanted to, they could jam the wi-fi band and still stop all communications in an area.
So creating a 'mesh' really wouldn't be a good idea and it would probably let them know where you are"
True in theory but it will prove difficult to jam a network that was designed /from the outset/ to cope with some relays going missing. Depending on the geographic area (and knowing that both the spectra and the antennas that are used for WiFi is, by nature, reasonably short-ranged) this could require a load of power in multiple locations. Not always easy to lay down.
"But if your objective would be to get the word out... You'd want to set up a series of packet switched networks run by ham radio operators. Much harder to detect and jam."
I'd disagree - 'ham' operators (an Americanism we prefer not to use over here, btw) are known to the authorities. To make matters 'worse', their PSN usually operates at 145 and 432MHz - and at high power (massive power compared to an Android) - using physically visible antenna systems. I know which chap I'd rather go hunting for...
Having said that, in a situation where there's been a disaster, the radio operator is usually first up and running with voice rather than data because it has less reliance on 3rd party components to decode, it can be used - if required - by non-trained, non-skilled operators and it's fast to relay messages in the voice modes. Give them a big enough disaster and they'll turn to morse code because it'll get through when nothing else does (frequently, there's nothing but 'make do' kit and antennas available) - but it's slow relative to voice and in practice there's nowhere near enough skilled proponents these days to be confident there'll be one on hand, as it were.
"you'd want to restore SMS/Text services first since it would allow more people to communicate"
I'd suggest the very last thing you want when you're passing priority or emergency traffic is a ton of regular users all trying to send messages of singular importance: one of the first acts of RAYNET (the UK's answer to this communications need) is to set up a net controller who's job is to manage the relaying of messages and that priority is given to - and bandwidth reserved for - urgent traffic. Allowing a precious resource like this to be (ab)used by the general public is inviting a communications collapse.
Sporting events? RAYNET 'do' the London Marathon (and other events) to hone their skills whilst offering a valuable service to the core emergency services. In the event of a serious disaster, I predict these guys would be up and running way before the phone network got off the ground.
First, you have a bounding problem.
Inside a city, you have lots of cell phones.
Yes, lose a cell phone and the mesh holds.
(You can imagine the drain on the batteries of running this mesh.)
Outside of a city, you have fewer cell phones so that you may not be able to create a viable mesh.
So your mesh is only good in an urban environment. Outside the urban environment you won't have a mesh.
Jamming a frequency isn't jamming a single phone or a small area. But you're jamming the frequency for a very large area. You can bet that military grade airborne equipment can jam a large area. So yes, its very possible that the Egyptian Military can in fact jam all of the cell phones in Cairo if they wanted. (Again assuming that they have the necessary equipment.)
With respect to 'ham' operators... in WWII you had hidden radios that got the word out... There are ways to hide the equipment and avoid detection...
As to your other point...
In a disaster... you can communicate video, voice, and text via a packet switched network. Yes you are correct that ham radios will communicate via voice, however if you have a packet switched network in place, you can fill a hole in the internet that is hard to shut down. All this in addition to voice.
At US sporting events where there is normally not enough cell traffic to require multiple cell towers, that get overwhelmed when the sporting venue is packed.... they bring in portable temporary cell towers.
In the event of an emergency the idea would be to erect a portable cell tower then tie it to an alternative network. (Microwave, Satellite, radio uplinks)
Thats the whole thing that people are missing with this mesh. You have hand set talking to handset. Yet if all of the cell towers are down in a region, the mesh then has to extend outside of that area.
With respect to the situation in Egypt, the government has the ability to shut down the entire network. You get out of the city, your population declines and the distance between points in your theoretical mesh increase.
You create the 'mesh' you can only communicate to others within the mesh. However if jammed, you're SOL...
It would be hard to jam a mesh. You'd need an awful lot of power to disrupt comms between lots of small devices relaying signals to each other. If you can determine where the jamming signal is coming from it's possible to be shielded from that signal but not from nearby devices. The beauty of an auto-mesh is that the user doesn't need to do much other than wander about until it works.
Your other point - how would they know where you are? If they're transmitting some kind of megawatt jamming signal they won't be able to pick up your transmissions, they'd be blinding themselves. Ham radio is easier to detect because typically operators are licensed so you know who they are in the first place and they're transmitting over longer distances which makes it much easier to jam.
Lets make this simple..
Suppose you have a mesh of 10 phones. What's the square area covered by the mesh?
Suppose your enemy has an airborne transmitter. What's the square area that they can cover at oh lets say 10,000 feet?
I realize that its not a fair comparison, but you get the idea. How much power do you need at 40,000 feet?
As to jamming ham radios... you're going to jam all of the frequencies in the usable range? Isn't that going to be a bit harder?
This post has been deleted by its author
It's likely to need a rooted android handset, so not likely to be in the Market. Rooting is needed because Android doesn't provide a native method to enable AdHoc WiFi. You can find more details here:
http://permalink.gmane.org/gmane.org.freifunk.batman/2407
http://www.itu.dk/pit/index.php?n=Main.AndroidBatphone
http://www.servalproject.org/
"The newly-demonstrated project is called Serval, after a kind of cat, and enables a standard Android handset to make voice calls (VoIP), which are relayed though one or more handsets back to the cellular network"
While I think this is a great idea, I do think it's a bit unfortunate for the poor sod who foots the bill for everyone else who is not in range of the base-station (or the poor sod who's connection is used for up/downloading who knows what).
"More recently, we have Peep Wireless, which...is now busy raising money on the back of promises to make every phone a relay using...the entire electromagnetic spectrum."
Well, there's a region of the EM spectrum around 600 THz that's not well regulated. And every mobile phone comes equipped with the hardware necessary to generate and receive these signals.
Does it even have to get out of the mesh? Here's this thing you download on your phone, it lets you connect with anyone else who has also downloaded it (where there is a path of hops available), totally avoiding any commercial network at all. Free communication with anyone on the mesh locally (which could cover a lot of square kms in heavily populated areas), attractive, leading to the mesh getting a higher and higher thread count, making it more and more attractive...
I would wager that the people in Egypt were more concerned with communicating with each other than they were with getting sound bytes out to western media. Mesh doesn't need to be a means to an end, it could be an end in itself.
It's nice to see this capability spreading to smart phones, you can already set your house up to be part of a wireless mesh. Even if only used for communicating with people in your local area, it can still lower your costs in these hard times. It's not just another way to get access to an existing network, it can be a whole new network all by itself, useful on its own. Plus no huge treasure trove of data centrally stored for security forces and their puppet masters to comb through. Double plus good!
Many many large authoritarian organizations would dislike this sort of thing becoming mainstream, not just cell phone companies - so full steam ahead!!
Android is pretty much the only place where this kind of thing would even be allowed to be possible (as far as mobile phones), yet another reason to go this route.
Pretty much a non-starter. Every unit forwarding in the mesh has to turn on its transmitter, probably on high power (note that the range at the moment is only a few hundred metres). In a disaster zone, you can hardly keep your phone plugged into a wall socket. The whole mesh would be dead in a couple of hours.
I've thought for a while that mesh might me a good way to get WiFi and voice on the underground or in buildings with poor mobile reception, with no need to install expensive WiFi hotspots (expensive for both users and the provider).
It might not work well at the edges of the transport network, but on a city like London, every stations in Zone 1 is often has thousands of people whose phones could form a daisy chain to the surface, and these are never turned off, even when they're out of cover. The actual cost per user would be tiny because there are lots of them and they're copnstantly moving. It might even work in the tunnels when trains are sufficiently close to each other during rush hour.
Far from being a money loser for the network operator, this could be a siginificant value-add for a low outlay - they might just need to put a bundle of WiFi hotspots in easy-to-reach places near the station entrance. In London, for instance, the Tube WiFi trials are being conducted by O2, leaving 3, Voda, Orange et al with no benefit.
I take no responsibility for the social consequences of filling every tube carriage with idiots barking into their phones.
The Register 
Biting the hand that feeds IT
Copyright. All rights reserved © 1998–2024
