Re: [10GBT] Discussions on ...
Gottfried,
Please publish the detailed bit-to-symbol mapping of the Double Square
constellation so that we have a chance to analyze the technical implications
for our presentation, which is due to Brad in two days time.
Thanks,
Sailesh.
srao@phyten.com
>From: Gottfried Ungerboeck <g.ungerboeck@BLUEWIN.CH>
>Reply-To: "IEEE P802.3an" <STDS-802-3-10GBT@listserv.ieee.org>
>To: STDS-802-3-10GBT@listserv.ieee.org
>Subject: Re: [10GBT] Discussions on ...
>Date: Mon, 20 Sep 2004 15:57:44 +0200
>
>Sailesh,
>
>128-point checkerboard constellation = 128-point Double Square
>constellation
>(128-DSQ). The designation "Double Square" alludes to an algorithmic symbol
>construction and labeling method for this type of constellations.
>
>When I concentrated on the question of the optimum modulation rate for
>10GBASE-T, which I found in the 800 Mbaud range (ungerboeck_1_0504.pdf,
>Long
>Beach; see also takatori_1_0504.pdf), I said nothing about specific
>modulation & coding to accomplish the "achievable bit rates" vs modulation
>rate.
>
>This time I am speaking about a particular modulation & coding scheme
>(namely 128-DSQ + LDPC), which I find best suited for transmission at the
>around 800 Mbaud rate. I would appreciate if the notions of "12PAM" or
>"8PAM" camp would disappear from our 10GBASE-T discussions. Instead let's
>concentrate on the various not necessarily connected technical issues and
>the proposals made on this issues.
>
>The specific issues at hand are: (a) in what range should the 10GBASE-T
>modulation rate be; then (b) what modulation & coding should be used to
>accomplish transmission at a modulation rate within this range.
>
>Regards, Gottfried
>
>-----Original Message-----
>From: stds-802-3-10gbt@IEEE.ORG [mailto:stds-802-3-10gbt@IEEE.ORG] On
>Behalf
>Of sailesh rao
>Sent: Mittwoch, 15. September 2004 20:07
>To: STDS-802-3-10GBT@listserv.ieee.org
>Subject: Re: [10GBT] Discussions on precoder decisions
>
>Gottfried,
>
>Is the "Double Square" constellation the same as the "Checkerboard"
>constellation you were telling me about last week? If not, this would be
>the
>5th constellation I've heard about from the PAM12 camp.
>
>Here's the list so far:
>
>1. Original PAM-12 "donut" constellation.
>2. PAM-12 Compapiano-Glazer "cross" constellation.
>3. PAM-12 multi-dimensional "Kabob" constellation.
>4. Checkerboard constellation.
>5. PAM8/16 Double Square constellation.
>
>A general observation is that instead of researching PAM12 constellations,
>the task force would be well served if we can converge around the PAM-8
>proposal and conduct a working session on the standards draft at the
>interim
>meeting.
>
>Regards,
>Sailesh.
>srao@phyten.com
>
> >From: Gottfried Ungerboeck <g.ungerboeck@BLUEWIN.CH>
> >Reply-To: "IEEE P802.3an" <STDS-802-3-10GBT@LISTSERV.IEEE.ORG>
> >To: STDS-802-3-10GBT@LISTSERV.IEEE.ORG
> >Subject: Re: [10GBT] Discussions on precoder decisions
> >Date: Wed, 15 Sep 2004 10:56:34 +0200
> >
> >George,
> >
> >the 128DSQ constellation ("double square") is the natural go-in-between
> >8 PAM and 16 PAM, much more so than 12PAM. Contrary to 12PAM, all
> >encoding, decoding, and precoding operations are based on powers-of-two
>arithmetic.
> >128DSQ has been known for a long time in the literature and its good
> >fit with precoding has been well described.
> >
> >On precoding, please see ungerboeck_1_0704.pdf (Portland). One fixed
> >IIR-type precoder is enough. If the group cannot agree on a single
> >fixed precoder, then let it be a very small set (2?) of fixed
> >precoders, one being selected preferrably during auto negotiation.
> >
> >Regards, Gottfried
> >
> > _____
> >
> >From: stds-802-3-10gbt@IEEE.ORG [mailto:stds-802-3-10gbt@IEEE.ORG] On
> >Behalf Of George Eisler
> >Sent: Mittwoch, 15. September 2004 06:03
> >To: STDS-802-3-10GBT@listserv.ieee.org
> >Subject: Re: [10GBT] Discussions on precoder decisions
> >
> >
> >Hugh,
> >
> >Thanks again for taking the badly needed lead on urging along the
> >decision making. The precoder definition is clearly in need of
> >consideration, although I think it will take simulation work to really
> >nail it down. Of course you can't finish it if you don't get started.
> >
> >On last week's call, I was surprised by the "double square"
> >contribution, with it's sort of 16/8 PAM flavor. It seems to open the
> >case up rather than converging, but I wonder what's your take on it? I
> >was going to call you, only to realize that I don't have your phone
>contact.
> >
> >George Eisler
> >310 459-9225
>
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