[Make-wifi-fast] deep wifi

[Dave Taht <dave.taht@gmail.com>]

taking all the other lists off the cc.

and changing the thread title to something else that's less depressing.

On Mon, Aug 27, 2018 at 6:56 PM Bob McMahon <bob.mcmahon@broadcom.com> wrote:
>
> Hmm, not sure I understand the distinction.   CTS per the AP informs those other transmitters to stay quiet per the CTS NAV.  I may be misunderstanding things.  Thanks for the continued discussions.  It helps to better thoroughly understand the issues.
>
> Bob
>
> On Mon, Aug 27, 2018, 6:52 PM David Lang <david@lang.hm> wrote:
>>
>> On Mon, 27 Aug 2018, Bob McMahon wrote:
>>
>> > I thought that RTS/CTS would handle the case of hidden nodes, i.e. a device
>> > that fails to successfully transmit can resort to RTS/CTS to get the
>> > receiver to reserve time for it.  Also, lack of a RX ack seems ok to
>> > trigger MAC level retransmits.
>>
>> the problem isn't getting the receiver to reserve time for it, it's getting the
>> other transmitter(s) to not step on it when it transmits. Those other
>> transmitters may belong to different people, sharing a channel with your system
>> and nothing else.
>>
>> David Lang
>>
>> > It seems the LBT bug is the collision avoidance overheads when it isn't
>> > needed, i.e. no other energy would cause the RX PHY to fail its decode and
>> > the EDCA backoffs had no benefit, stochastic or otherwise.   Optimizing
>> > that out is said to be not possible from local information only and per
>> > "shared" spectrum.
>> >
>> > Bob
>> >
>> >
>> > On Mon, Aug 27, 2018 at 3:33 PM David Lang <david@lang.hm> wrote:
>> >
>> >> On Mon, 27 Aug 2018, Jonathan Morton wrote:
>> >>
>> >>> 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.
>> >>
>> >> Also, there may be other transmitters that the recipient of the packets
>> >> can hear
>> >> that you cannot hear, so it's not possible to detect colliding
>> >> transmissions
>> >> directly in all cases.
>> >>
>> >> This is another trap that digital/wired people fall into that doesn't
>> >> really
>> >> apply in the analog/radio world.
>> >>
>> >> David Lang
>> >>
>> >
>
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-- 

Dave Täht
CEO, TekLibre, LLC
http://www.teklibre.com
Tel: 1-669-226-2619