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Re: [10GBT] Symbol rate



Title: Message
 
Hi!
 
i just have one question.....i hope u guys can clear my doubts. Many thanks in advance.
I see that to calculate results for Model # 2, u have used anextcanc = -10.5, to get to 49.5 from 60.
Similarly for Models # 1 & 3 respectively, u are using -2.5 & -4.5.
 
i'm just wondering wouldnt they be +2.5 & +4.5 to get to +62.5 & +64.5 respecitvely from 60 ? i might be
wrong here, and hence, would appreciate ur reply.
 
thanks,
Samir.
 
 
----- Original Message -----
Sent: Tuesday, May 11, 2004 4:06 PM
Subject: Re: [10GBT] Symbol rate

You are right, Jose.  I used the 55m cat 6 case because that was what the presentations were pitching as the best case for PAM4 the situation IS even worse for longer lines, or worse for high frequency ANEXT.

 

By the way, Figure 7 is the one you want to look at to see the plots with the crossover of ANEXT & IL.

 

Jose, I think you meant the 100m models for Class F IL & Class E IL respectively, models 1 and 3 (2 is the 55m model).

To see the results for Model 1 (Class F IL, Class E other params, 100m, 60 dB ANEXT at 100MHz), run: solarsep_varlen7a(-2.5,650,4,100,6,1,7,2)

To see the results for Model 3 (Class E IL, Class E other params, 100m, 62 dB ANEXT at 100MHz), run: solarsep_varlen7a(-4.5,650,4,100,6,1,6,2)

 

-george

-----Original Message-----
From: stds-802-3-10gbt@IEEE.ORG [mailto:stds-802-3-10gbt@IEEE.ORG] On Behalf Of Jose Tellado
Sent:
Tuesday, May 11, 2004 3:45 PM
To: STDS-802-3-10GBT@LISTSERV.IEEE.ORG
Subject: Re: [10GBT] Symbol rate

 

 

I think the case you considered below is for 55m of cat6. The problem is even worse for 100m of channel model 1 or model 2 (see http://www.ieee802.org/3/an/public/mar04/kasturia_2_0304.pdf), where the SNR "pinching" happens around 500MHz,

 

Jose

 


From: stds-802-3-10gbt@IEEE.ORG [mailto:stds-802-3-10gbt@IEEE.ORG] On Behalf Of George Zimmerman
Sent: Tuesday, May 11, 2004 3:19 PM
To: STDS-802-3-10GBT@LISTSERV.IEEE.ORG
Subject: Re: [10GBT] Symbol rate

At the March meeting, some of the discussion on leaving the door open to the higher baud rates was aksing to have time to run simulations with the higher baud rates to validate the optimal DFE results presented.

The MATLAB code has been available on the 802.3an web site for a while now I assume others have now seen that the ANEXT model we agreed to (49.5-15log10(f/100)) is within a couple dB of the insertion loss at 650 MHz which means that the penalty for signaling at rates over 500 MHz, where the SNR gets pinched off, is extreme. (to run this case, use: parameters: solarsep_varlen7a(-10.5,650,4,55,6,1,6,2) ).

 

What these curves tell you is simply that at more than 1Gbaud, you are simply signaling faster than the channel can support, and thus starting out in an SNR hole in building a 10GBASE-T system.

 

Hopefully at the meeting we can agree to constrain the baud rates and begin to focus our analysis.

-george

 

-----Original Message-----
From: stds-802-3-10gbt@IEEE.ORG [mailto:stds-802-3-10gbt@IEEE.ORG] On Behalf Of Booth, Bradley
Sent: Tuesday, May 11, 2004 10:36 AM
To: STDS-802-3-10GBT@LISTSERV.IEEE.ORG
Subject: Re: [10GBT] Symbol rate

 

Sanjay,

 

The objectives do require that we provide one PHY that meets at least 100 meters on Class F and at least 55 to 100 meters on Class E.  A proposed PHY must meet both these distance requirements.  To take this a step further, a PHY or port type has traditionally referred to one PCS, one PMA and one PMD.  So this could be seen as one PHY which has only one PCS, one PMA and one PMD is required to meet both the distance objectives.

 

In the past, the Working Group has asked the Task Forces to make the tough decisions and to choose only one PCS, PMA and PMD to meet the objective.  If the Task Force chooses PAM5, then the decision is made.  If the Task Force chooses PAM10, then the decision is made.  If the Task Force chooses PAM5 and PAM10, then the Working Group will likely send the specification back to us to make a decision.

 

To quote the movie Highlander, "There can be only one."

 

Thanks,

Brad

-----Original Message-----
From: stds-802-3-10gbt@IEEE.ORG [mailto:stds-802-3-10gbt@IEEE.ORG] On Behalf Of Sanjay Kasturia
Sent: Tuesday, May 11, 2004 12:12 PM
To: STDS-802-3-10GBT@LISTSERV.IEEE.ORG
Subject: [10GBT] Symbol rate

At the March meeting, there was a motion to bound the range of symbol rates. The motion, moved by George Zimmerman, suggested  a symbol rate that would range from 714Msym/sec per pair to 1000Msym/sec per pair.

This motion failed to get the requisite 75% yes vote. Some of the people who voted against this proposal were in favor of schemes that would require higher symbol rates - e.g. 1250Msym/sec per pair but were probably not very familiar with 802.3 operation. With 802.3 voters in the room, the motion would have passed. See the vote tally appended below from the meeting minutes.

As I understand it, the PAM 4 type schemes that would use the much higher symbol rate would NOT meet our distance objectives but offered some value in that they could enable much lower power transceivers for shorter distances than called for in our objectives.

Should these schemes, which do not meet our distance objective, but could still be valuable for customers who want shorter reach and lower power be considered in separate class - possibly in a different forum than 802.3an?

Can our chair, Brad Booth, give us his opinion on this?

Vote count from minutes of March meeting

TF Voters Y: 24 N: 15 A: 19

802.3 Voters Y: 21 N: 5 A: 9

 

Sanjay Kasturia

Editor-in-chief

 

sanjay@teranetics.com

cell (650) 704-7686

office (408) 653-2235

 

Teranetics Inc.

2953 Bunker Hill Lane, Suite 204

Santa Clara, CA 95054