[Battlemesh] Meshing with strong/near clients and weak/far nodes

fboehm fboehm at aon.at
Tue Feb 18 18:10:39 CET 2014

Am 18.02.14 17:40, schrieb Mitar:
> Hi!
> I think using TDMA would help here. Each client would reserve its time
> slot and it would not matter how strong they transmit in their time slot.
> Sadly open source drivers do not (yet) support TDMA. But Ubiquiti ones do.
> Mitar
>> I'm curious if list members have found clever approaches for operating mesh
>> nodes that must talk simultaneously to near/strong clients and far/weak
>> clients.  I've found that, at least with atheros / ath5k-based nodes
>> running OpenWRT AA r39154, which do single-radio meshing via multiple VIFs,
>> connecting a particular strong client to the AP VIF of one node can disrupt
>> that node's communication with a distant node on the adhoc VIF.  Admitted,
>> the ath5k driver is pretty suboptimal, but its weakness does at least
>> demonstrate the nature of the problem easily.
>> This problem is less pronounced with ar71xx-based nodes, e.g. UBNT Airmax
>> gear, and I do understand it is going to fundamental to single-radio
>> meshing applications anyway (i.e. hidden node problem).  Likewise, one
>> can't always control clients' TX strength, besides mounting nodes at
>> locations such that a client can never be physically too close, e.g. on a
>> rooftop or high on an exterior wall.
>> Acknowledging the limits of the radios, I'm curious if anyone has had
>> reasonable success in these situations with things the following:
>> - RF-Armor style shielding on the back of the mesh node, i.e. to reduce the
>> influence of stray noise or reflections
>> - Setting an RTS value
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>> http://ml.ninux.org/mailman/listinfo/battlemesh
It's quite a while since I read it but you might want to have a look at 
"JaldiMAC". It's kind of a 802.11 based polling protocol.


By the way. As far as I know AirMAX protocol from Ubiquiti Networks is 
also based on polling the clients. Although it seems to be a quite 
advanced and mature polling protocol.


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