[OpenWrt-Devel] IEEE 802.11 TDMA mode support in OpenWRT

[Fernando Frediani]

Hi all,

Is anyone aware of any implementation of TDMA mode support in OpenWRT
(similar to Ubiquiti's AirMAX, Deliberant's iPoll or MikroTik's NV2, etc)

Would that have to be implemented having in mind the radio driver or
could it possible also be implemented in any router ?
This is certanlly something significant for more throughput demanding
and crowded environments.

Best regards,

Fernando

[Ben West]

In an old thread on the Battlemesh listserv about strategies for dealing
with a mix of strong / weak clients for PtMP, someone offered this pointer
for JaldMAC, an open 802.11 polling implementation in ath9k:

http://matthias.vallentin.net/papers/nsdr10.pdf
https://github.com/shaddi/jaldimac/commits/master

Unfortunately, that repo has sat idle for over 2 years, and I believe it it
was more a proof of concept rather than a usable implementation.

Also, i believe TDMA requires very tight synchronization between all
radios, hence the inclusion of GPS modules on proprietary implementations.

Post by Fernando Frediani
Hi all,
Is anyone aware of any implementation of TDMA mode support in OpenWRT
(similar to Ubiquiti's AirMAX, Deliberant's iPoll or MikroTik's NV2, etc)
Would that have to be implemented having in mind the radio driver or could
it possible also be implemented in any router ?
This is certanlly something significant for more throughput demanding and
crowded environments.
Best regards,
Fernando
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openwrt-devel mailing list
https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel

[Russell Senior]

Ben> [...] Also, i believe TDMA requires very tight synchronization
Ben> between all radios, hence the inclusion of GPS modules on
Ben> proprietary implementations.

Ubiquiti AirMax hardware does not have GPS, so it must be possible to
do without.

When we were stripping some SkyPilot hardware that we salvaged from a
dead muni-wifi project, they included a GPS in each device. It is a
shame the operator (MetroFi) didn't use the GPS to report the device
locations, as cleaning up after them would have been much easier. We
were told the primary purpose of the GPS was for timing.

[Fernando Frediani]

Hi Ben,

TDMA doesn't require synchronization between the radios. This would be
Ubiquiti's AirSync technology and that's for another usage. When you
have two or mode radios colocated in a tower receiving and transmitting
at the same time so it avoids them do it at the same time and
synchronizes Receive and Transmit.

TDMA is more to be used in PtMP environments where you have multiple
customers talking to the AP and they don't see each other, so the AP is
able to organize more correctlly the time each one sends data. That's
probably why it was only implements on proprietary systems usede by
WISPs with different names.

Regards,

Fernando

Post by Ben West
In an old thread on the Battlemesh listserv about strategies for
dealing with a mix of strong / weak clients for PtMP, someone offered
http://matthias.vallentin.net/papers/nsdr10.pdf
https://github.com/shaddi/jaldimac/commits/master
Unfortunately, that repo has sat idle for over 2 years, and I believe
it it was more a proof of concept rather than a usable implementation.
Also, i believe TDMA requires very tight synchronization between all
radios, hence the inclusion of GPS modules on proprietary implementations.
On Thu, Jul 3, 2014 at 11:02 AM, Fernando Frediani
Hi all,
Is anyone aware of any implementation of TDMA mode support in
OpenWRT (similar to Ubiquiti's AirMAX, Deliberant's iPoll or
MikroTik's NV2, etc)
Would that have to be implemented having in mind the radio driver
or could it possible also be implemented in any router ?
This is certanlly something significant for more throughput
demanding and crowded environments.
Best regards,
Fernando
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openwrt-devel mailing list
https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel
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Ben West
http://gowasabi.net
314-246-9434