[Commotion-dev] Serval Mesh Helper Device / ISM long-range meshing work

[Paul Gardner-Stephen]

Hello,

On Fri, Feb 8, 2013 at 12:42 AM, Seamus Tuohy <s2e at opentechinstitute.org> wrote:
> Hey Paul,
>
> This sounds great. I would be quite interested in seeing what kind of
> QOS and energy consumption you get running various types of traffic over
> this device. Having some clearer idea of the throughput, jitter, and
> delay would be a great starting point for conversations around use cases.

Our focus at present is on long-range communications, in particular
for Rhizome bundle-oriented traffic.  As such we have done nothing as
yet to minimise latency and jitter.  Nonetheless, MDP pings have been
as low as a few hundred milliseconds.

>From a Commotion perspective, I would imagine that some of the more
interesting use-cases that come immediately to mind include (all
sitting on top of Serval Rhizome):

1. Distribution of updates to Commotion project and related software
2. A Twitter-like mesh-based micro-blogging service (possibly with a
gateway to Twitter itself)
3. Distribution of either introduced or locally produced news/content
4. Delivery of voicemail and SMS traffic between commotion OpenBTS's
and mesh nodes

Essentially it is best to think of it as a courier service between
nodes, like an inter-campus mail service, rather than a bulk real-time
transport. Of course, in many instances it can do better than that,
but this perspective will, I think, help with the exploration of the
kind of service that it can enable.

Paul.

> s2e
>
> On 02/07/2013 12:00 AM, Paul Gardner-Stephen wrote:
>> Hi All,
>>
>> Just a heads up on some stuff we are doing at Serval that I think will
>> be of interest to Commotion deployments more generally.
>>
>> We are now actively working on what we call our "Mesh Helper Device",
>> the prototype of which will consist of a TP-LINK WR703N running
>> Commotion OpenWRT + servald, connected to an RFD900 ISM 915MHz band
>> packet radio and a rechargeable battery.
>>
>> This gives the potential for much greater range than just WiFi, as
>> well as offering some resistance for 2.4GHz jamming in places where
>> that is a problem.
>>
>> The RFD900s with current firmware in urban settings offer 5x to 10x
>> range compared with WiFi.  For example, I could receive a decent
>> signal with one radio sitting on my lounge, and the other radio with
>> me walking around the block, up to about 150m away -- with the signal
>> path obliquely through perhaps 8 or 10 houses, fences, cats, dogs,
>> trees and everything else.
>>
>> With good clear line of sight, and a low noise floor, ranges of 10km
>> or more are possible, with some evidence pointing to the actual limit
>> being around 80km - 120km in very ideal conditions.
>>
>> We have already managed to get Serval Mesh traffic, including some
>> Rhizome transfers (but not yet voice) running over one of these links:
>>
>> servalpaul.blogspot.com.au/2013/02/breaking-wifi-barrier-serval-mesh.html
>>
>> We think a complete Mesh Helper Device, including these really nice
>> radios could be built and sell for <US$200.  It may also be possible
>> to use a cheaper compatible (but slightly lower performance) radio and
>> get the price down to <US$100.
>>
>> The RFD900 firmware only does point-to-point communications, but it is
>> entirely possible to make it do "ad-hoc" point-to-multipoint
>> communications.  Perhaps this is something for us to look at as a
>> follow on after our current work block is complete.
>>
>> We are hoping to have a couple of these with us in New Zealand in a
>> couple of weeks for the KiwiEx field trial. General outline of our
>> thinking for KiwiEx at present is at:
>>
>> http://developer.servalproject.org/dokuwiki/doku.php?id=content:exercises:kiwiex2013
>>
>> If there are other things people would like tested while we are there,
>> let me know, and we will endeavour to cover them.
>>
>> Paul.
>>
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>>