Serval "Mesh Extender" (WiFi to UHF packet)
I'm a bit of a fan of mesh networking devices and we are now introducing the Village Telco "Mesh Potato" wireless telephony/data device to our county EMA.
That said, I ran across this on the FreedomBox mailing list. The Serval Project is a cousin to the Mesh Potato and uses open software to connect Android devices without the commercial infrastructure. The note below relates to the addition of 900 MHz UHF devices as range extenders for the 2.4 GHz mesh network. This is all Part 15 but I found the mix of 2.4 GHz WiFi and UHF to be interesting and something that might be relevant to this group. The bottom line of the note is an appeal for funding but there's enough meat to make it interesting.
FreedomBox, FYI, is a personal server development project intended to provide privacy.
Date: Tue, 9 Jul 2013 04:37:04 +0930
From: Paul Gardner-Stephen <paul@...>
To: freedombox-discuss <freedombox-discuss@...>
Subject: [Freedombox-discuss] Crowd-funding the Serval Mesh Extender
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As some of you may already be aware we have been working on what we call the Mesh Extender at the Serval Project.
The Mesh Extender is a combined battery powered embedded Linux router and UHF packet radio running the Serval Mesh software (which is all GPL, see github.com/servalproject for the source).
It is intended for mobile and truly ad-hoc deployment where the end user just turns it on and uses it.
The idea is that it uses the UHF packet radio to mesh over greater
distances than is possible with Wi-Fi, the trade-off being lower bandwidth.
In general, we find that the UHF packet radio has a range of about 10x that of Wi-Fi when deployed indoors with omni-directional antennae. This means it has a range of about a block in a suburban or urban setting compared with Wi-Fi's range of about one house or apartment.
For example testing it in Boston recently we had coverage over much of the MIT campus from a single Mesh Extender in my room at a nearby hotel:
Extending the range in this way is a critical enabler for the adoption of mesh communications because it removes the need for skilled installation and lowers the required penetration rate from near 100% in a local area if using un-aimed Wi-Fi to below 1%:
Combined with the always-on end-to-end encryption of voice calls and text messages of the Serval Mesh we think that this device has the potential to play a significant role in enabling distributed, resilient and private communications for people in a wide variety of situations.
We also see that the close alignment of what the Freedom Box and Serval Project are trying to achieve means that any device like this that we create could easily be adapted to being both a Mesh Extender and Freedom Box by adapting the included software inventory.
The necessity of a portable and trivial to deploy enabler of mesh
communications, and the need for this to be completely open, has led us to the current point where we have setup a crowd funding campaign to develop this technology, taking it from the prototype stage and to develop an actual manufacturable product, and do further testing with our humanitarian partners.
This is the point that our campaign at igg.me/at/speakfreely will take us to if fully funded.
But to realise the full potential of this we not only need to make an
attractive manufacturable device, but also to improve the open-source
firmware of the packet radios we are using to support true "ad-hoc packet radio" within the complex regulatory requirements of the ISM 915MHz band, in particular the need to frequency hop which presents interesting technical challenges for a fully distributed mesh that does not rely on GPS timing for synchronisation.
Achieving "ad-hoc packet radio" will require us to not only meet our
current funding goal, but stretch it by a factor of two.
We are conscious that achieving this will require promoting the campaign far and wide, possibly wider than the Serval team can achieve alone.
Therefore it would be tremendously helpful if as many of you as are willing and able would assist us in spreading the word as far and wide as possible. We would love to get slash-dotted and reddited off the net. Repeatedly.
So please take a look at our campaign, use the words below if they are
helpful, and help us to get the word out, and ultimately let's make
effective and private long-range mesh communications not only possible, but practical and easy for the general public so that they can enjoy the resilient backup communications capability that they need to keep connected, no matter what disaster may befall them.
Thanks in advance,
Dr. Paul Gardner-Stephen
Founder, Serval Project.
Serval crowd-funding Mesh Extenders to make mesh & disaster telephony go the next mile http://igg.me/at/speakfreely
Serval Project has been working for three years with New Zealand Red Cross on free and open technology, called the Serval Mesh, which can keep mobile phones operating when mobile networks fail, such as during disasters. We now want to take this technology out of the lab and get it into peoples hands. Find out more at http://igg.me/at/speakfreely