[Cerowrt-devel] [Make-wifi-fast] Will full-duplex be possible on 802.11 wired air?

Erkki Lintunen erkki.lintunen at iki.fi
Sat Mar 12 14:20:49 EST 2016

Last week or so I had a short peek on the lists and read something alike
'half-duplex makes wifi feel slow [in addition to the point in
discussion and when compared to wired]'. Now couldn't find the message
to reply to the sited one but going on with this one. 

Half-duplex brought me to a news item national IT press was buzzing
about few months ago: Taneli Riihonen's doctoral dissertation "Design
and Analysis of Duplexing Modes and Forwarding Protocols for OFDM(A)
Relay Links" [1].

1 http://taneli.riihonen.fi/ "Taneli Riihonen - List of Publications"

The fuss news media made out of the research was, that the methods
Riihonen found will solely speed up 5G cellular networks. Amusingly I
saw a picture a news outlet run out, where Taneli Riihonen was standing
and in the background a slide showed text "OFDM". I thought what the
heck, this isn't just about 5G, who cares about 5G. Then forgot the news
and now got flashback.

This might be old news/tidbits for the list, but one can't never be
sure, so passing on as in the back of my head are Dave Täht's words that
a lot of new research and reading old was made for accomplishment in
current state of bufferbloat in wired connections.

Getting to the on-the-air-timings spoken about below, the methods Taneli
Riihonen found in his dissertation used statistical methods for time
slotting the "shout out" and "listen to" for duplexing on the air.
Intuitively this brings me to expect that the dissertation might give
ideas how to measure timings for tx and rx, and, in the best case
readily usable, tools how they have proved their theory in the theses.

Sorry I haven't even glimpsed the 300 pages thesis. I'm only basing on
slides linked to in the same paragraph as the thesis on the above
web-page. Unfortunately the slides are in finnish.


* Aaron Wood <woody77 at gmail.com> [2016-02-09 06:17:57 +0800]:

> I've often wanted the same thing:  What's the time-length of given packets
> (using various transmission rates), and the inter-packet delays, etc.  What
> _is_ 100% channel utilization, in terms of packets per second of a given
> size/rate?
> From a pcap file full of radio-tap-level packets, can the channel usage be
> computed?  (none of the tools I looked at a few years ago could give me a
> channel usage indication from an analysis of actual packets (with rates and
> timestamps)).
> -Aaron
> On Tue, Feb 9, 2016 at 4:02 AM, Dave Täht <dave at taht.net> wrote:
> > Much more readable than the spec!
> >
> > http://chimera.labs.oreilly.com/books/1234000001739/ch03.html
> >
> > I still keep hoping for a comprehensive list (or a tool) for timings for
> > every possible operation across all the 802.11 standards. Trying to
> > figure out how long things take "on the wire" makes my brain spin.
> >
> > _______________________________________________
> > Cerowrt-devel mailing list
> > Cerowrt-devel at lists.bufferbloat.net
> > https://lists.bufferbloat.net/listinfo/cerowrt-devel
> >

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