[Freedombox-discuss] Serval Mesh Extenders

[Paul Gardner-Stephen]

Hello,


On Mon, Jul 15, 2013 at 6:58 AM, Jack Wilborn <jkwilborn at gmail.com> wrote:

> Are you saying we need to drop to lower frequencies?
>

Dropping the frequency gains a few dB from improved progagation
characteristics.
The rest of the gains are slightly increased power (+24dBm in the current
prototypes) and low data rates (128kbit, that gives at least +8dB compared
with Wi-Fi @ 1mbit based on a simplistic energy-per-bit perspective).
 Altogether these give about +20dB versus 2.4GHz WiFi.


>   I don't follow all of your arguments, but I have knowledge about RF
> characteristics.  I have communicated with ships in storms in the Atlantic,
> Red Sea, and Bering Sea from Arizona over HF Packet.  Is this what you are
> saying?  What about some of the little used HF bands, I think there are
> some after the TV went to HD that maybe the FCC would allow this type of
> testing over?  Just a question, that I though was the direction you were
> going, as this would make it a very wide wifi....
>

We are using the ISM band at 915MHz, because it is available on reasonable
terms in USA, Canada, Australia and New Zealand.  HF is interesting, but
the data rates are likely too low, unless one of the old analog TV channels
down there were made available, which is not a realistic hope.  Of course
for Europe, some alternative would be required, because the 915MHz band is
not available there.

Paul.

>
> Jack
>
>
> On Sun, Jul 14, 2013 at 6:18 AM, Paul Gardner-Stephen <
> paul at servalproject.org> wrote:
>
>> (also appologies to all for delays in responding, I was somewhat
>> ironically left incommunicado by a 24 hour blackout over the weekend).
>>
>>
>> On Fri, Jul 12, 2013 at 7:30 PM, macbroadcast <marc at let.de> wrote:
>>
>>>  Am 11.07.2013 23:45, schrieb Paul Gardner-Stephen:
>>>
>>> Hi All,
>>>
>>>  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.
>>>
>>>
>>>  Awsome progress Paul , i am following your progress for some time,
>>> what you think about this " bug/ feature"
>>>
>>> However, some mesh proponents say Google is unnecessarily hampering
>>> their efforts because it does not support the device-to-device mode of
>>> Wi-Fi chips in its Android software (a complaint registered with Google as “Android
>>> bug #82 <https://code.google.com/p/android/issues/detail?id=82>”). That
>>> means before a device can become an active part of a mesh network, a user
>>> must bypass Android’s security controls, or “root” the device, by
>>> installing special software. Unrooted devices can use connectivity provided
>>> by a mesh network, but they can’t help expand its coverage.
>>>
>>>
>>>
>>> http://www.technologyreview.com/news/516571/build-your-own-internet-with-mobile-mesh-networking/
>>>
>>
>> I am not quite sure exactly what you are asking here.  If it is "what do
>> I think about the lack of action on bug82?" then my answer is
>> disappointment, and that with the Mesh Extender concept we have engineered
>> our way around it.
>>
>>>
>>>
>>> Is it possible to run it  in a virualized enviroment ? i see debian and
>>> openwrt directorys in there.
>>>
>>> https://github.com/servalproject/serval-dna
>>>
>>
>> Well, I run it on debian VMs on my laptop, so yes.
>>
>>
>>> *<http://developer.servalproject.org/dokuwiki/doku.php?id=content:tech:meshms><http://developer.servalproject.org/dokuwiki/doku.php?id=content:tech:rhizome>
>>> *Rhizome and MeshMS is very interesting too ;)
>>>
>>
>> We think so, too.  As a store-and-forward protocol, Rhizome avoids a lot
>> of the traditional problems that mesh networks face, in particular
>> exponentially increasing probability of packet loss over multiple hops.
>>  Rhizome turns out to be at times annoyingly reliable in its delivery,
>> delivering data at the first opportunity sometimes months after it was
>> sent, in the event of networks that have been partitioned for that long.
>>
>>
>>> Good luck
>>>
>>
>> Thanks,
>> Paul.
>>
>>
>>> Marc
>>>
>>> --
>>> Les enfants terribles / Marc Manthey
>>> 50823 Köln, germany
>>> Vogelsangerstr.97
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>>>
>>>
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>>
>>
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>
>
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