Time-of-flight positioning - Atheros

[Sergey Ryazanov]

Hi Monika,

2014-10-29 11:44 GMT+03:00 Graf  Monika <grafmon at student.ethz.ch>:
> Hello Everyone
>
> I am currently at a project where I am using Atheros Chipsets AR9590 with the ath9k driver.
>
It's a bit strange to ask questions about linux driver in
freebsd-wireless mailing list. Just in case, there are two mailing
lists for ath9k: ath9k-devel and linux-wireless.

> I am wondering how the time-of-flight information can be retrieved per packet in most recent Atheros chipsets. Is it required a proprietary HAL version ?
>
If you need a round-trip-time: take a tx timestamp from tx-complete
descriptor of data frame, then take a timestamp from received ACK
frame and then compute the time. To get received ACK frames from NIC
you should enable control frames receiving in Rx filter. If you need
more details about descriptor format or time of timestamp capture,
then may be Adrian could help.

BTW, a month ago or so, Lorenzo Bianconi added a dynamic ACK timeout
estimation to the ath9k, based exactly on round-trip-time computation.

-- 
BR,
Sergey