[Bloat] [Make-wifi-fast] [Cerowrt-devel] closing up my make-wifi-fast lab

Bob McMahon bob.mcmahon at broadcom.com
Mon Aug 27 15:59:17 EDT 2018

ok thanks, that's helpful.  I guess I thought if astrophysicists can direct
image exoplanets
a WiFi device should be able to detect superposition  - though, talk about
some giant hand waving! ;)


On Mon, Aug 27, 2018 at 12:45 PM Jonathan Morton <chromatix99 at gmail.com>

> > On 27 Aug, 2018, at 10:11 pm, Bob McMahon <bob.mcmahon at broadcom.com>
> wrote:
> >
> > I guess my question is can a WiFi transmitting device rely on primarily
> energy detect and mostly ignore the EDCA probability game and rather search
> for (or predict) unused spectrum per a time interval such that its digital
> signal has enough power per its observed SNR?   Then detect "collisions"
> (or, "superposition cases" per the RX not having sufficient SINR) via
> inserting silent gaps in its TX used to sample ED, i.e. run energy detect
> throughout the entire transmission?  Or better, no silent gaps, rather
> detect if there is superimposed energy on it's own TX and predict a
> collision (i.e. RX probably couldn't decode its signal) occurred?  If
> doable, this seems simpler than having to realize centralized (or even
> distributed) media access algorithms a la, TDM, EDCA with ED, token buses,
> token rings, etc. and not require media access coordination by things like
> APs.
> The software might be simpler, but the hardware would need to be
> overspecified to the point of making it unreasonably expensive for consumer
> devices.
> Radio hardware generally has a significant TX/RX turnaround time, required
> for the RX deafening circuits to disengage.  Without those deafening
> circuits, the receivers would be damaged by the comparatively vast TX power
> in the antenna.
> So in practice, it's easier to measure SNR at the receiver, or indirectly
> by observing packet loss by dint of missing acknowledgements returned to
> the transmitter.
>  - Jonathan Morton
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.bufferbloat.net/pipermail/bloat/attachments/20180827/bcce10ba/attachment-0002.html>

More information about the Bloat mailing list