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Re: [8023-10GEPON] Define TDP values



Ken,
just a quick comment on the faulty links in version 2.1.
When changing from 2.0 to 2.1 I expected the links to updated automatically - Excel does not do that apparently.
It will be corrected in the new release of the spreadsheet.
Thanks
 

Marek Hajduczenia (141238)
NOKIA SIEMENS Networks S.A. – COO BBA DSLAM R&D
Rua Irmãos Siemens, 1, Ed. 1, Piso 1
Alfragide, 2720-093 Amadora, Portugal
* marek.hajduczenia@nsn.com
(+351.21.416.7472  4+351.21.424.2082

 


From: mariconk@gmail.com [mailto:mariconk@gmail.com] On Behalf Of ext Ken Maricondo
Sent: quinta-feira, 29 de Novembro de 2007 5:47
To: Hiroshi Hamano
Cc: STDS-802-3-10GEPON@listserv.ieee.org; Hajduczenia, Marek
Subject: Re: [8023-10GEPON] Define TDP values

Dear Hamano-san and Hajduczenia,

From the research that I have found so far, three values that have an influence on the TDP value are the laser spectral width, RIN and link distance.  A narrower laser spectral width or lower RIN value will trend toward lowering the TDP value, while a longer link will increase the TDP.   The TDP values (as pointed out already) have not been entered into the draft that is currently posted; but the extinction ratio has been entered into the draft (9dB, min for the DS and 6dB, min for the US), but I am not sure of these values.   I would like to see an extinction ratio formula in the spreadsheet, such as the one I found in the optical fiber telecommunications IIIB on page 75 (see attached PDF for the formula).  The formula takes into account the laser slope efficiency and can allow the user to calculate different values of non-zero values.  I feel that the use of this formula will not omit the OMA value, but enhance the integrity of the OMA.   Just as a point of clarification, the laser spectral width, RIN, and link distance will ultimately have an effect on the IEEE_Rx_Sen_OMA.   I will be happy to send you links to OMA and extinction ratio application notes I found so far.  I'm not sure if I can post links on this thread.

At this point, I think that a discussion of what should be included in the TDP and the dispersion penalty value is in order.  I found a word document that started this task (doc00008, also attached), but did not seem to be completed.   I also think that if the 802.3av taskforce uses ITU, Fiber Channel, other standards, etc, then these values and standards should be documented within the draft.   Let me be clear, I am not opposed to using other standards as a reference, but it would be a help to the reader of the 802.3av standard in the future to understand where values have come from; I believe that the references can be placed in the draft as informative notes.

Hajduczenia - can you please clarify how TDP field includes conditional formatting to check the TDP value against ITU_Optical_Path_Penalty under the Version 2.2 section in the Revision notes Tab on the excel spreadsheet 3av_0711_hajduczenia_5 is calculated and where?  I tried to use the link next to the revision note, but it points me to cell B36 in the Version 2.2 Tab, Dispersion_D_Max.  Also (FYI), some of the other link values in the Version 2.1 section are not valid.

Best regards,

Ken Maricondo



 
On Nov 28, 2007 9:55 PM, Hiroshi Hamano <hamano.hiroshi@jp.fujitsu.com> wrote:
Dear Dr. Maricondo,

Thank you very much for your explanations, and I apologize for my late reply.

Now, I understand that, in your E-mail, (Dispersion_Penalty+TDP) means
the dispersion penalty value using a realistic transmitter with worst case TDP,
in contrast to that using an ideal or perfect transmitter with small or no TDP.

I am not sure, whether (Dispersion_Penalty), in the Spreadsheet, is figured out
based on such an ideal transmitter or not, but I agree that the result should
indicate the worst case value in order to decide the fail/pass condition.

But I am not sure either, how TDP should be counted into such transmitter parameters
for calculating (Dispersion_Penalty+TDP), in the Spreadsheet, and how big its
impact will be.  If you have any suggestions, that will be quite helpful.

If TDP value should be derived from the measurement results, not from Spreadsheet
calculations, some penalty value may remain only assumed and uncalculated,
unless the relationship between the measured TDP and Dispersion_Penalty is justified.

Any comments or discussions will be highly appreciated.

Best regards,
Hiroshi Hamano

%% "Ken Maricondo" <kmaricondo@ieee.org>
%% Re: [8023-10GEPON] Define TDP values
%% Fri, 23 Nov 2007 17:07:53 -0500

>
> Dear Hamano-san and Hajduczenia,
>
> I agree (from all that I have read) that the ITU_optical_path_penalty
> basically includes no transmitter penalty and that receiver sensitivity
> value in ITU formalism should share the TDP within the margin. The rationale
> as to why I suggested adding the TDP to *Dispersion_Penalty <=
> ITU_Optical_Path_Penalty* is as follows:
>
> 1.    Any penalty such as chirp, extinction ratio, MPN, etc., will require
> that the photodiode receiver to receive an increased proportional optical
> receive level in order to maintain the same BER verse a system without the
> same penalties. The *Dispersion_Penalty <= ITU_Optical_Path_Penalty* from
> what I can tell assumes an ideal transmitter and receiver over a given
> optical path and that only if the dispersion penalty exceeds the optical
> path penalty then the link fails.  If I use only dispersion penalty in a
> network calculation without the TDP, then I am not truly taking into account
> worse case/end of life network performance.  In my point of view, a network
> designed with a TDP of 3dB for example will have a shorter operational
> lifetime or be performance limited then an identical network with an ideal
> transmitter with no TDP or lower value of TDP.  So to compensate for the TDP
> a more robust FEC scheme or higher quality receiver might be in order.
>
> 2.    I do not discount or object to the TDP value from being subtracted
> from the *IEEE_Rx_Stressed_Sensitivity_OMA* to get *IEEE_Rx_Sen_OMA*, but I
> think that TDP should show up in the system margin as worse case/end of life
> calculation within the spreadsheet.  The fact that the receiver sensitivity
> has to go lower to compensate for the TDP only points out that I have to
> have a higher quality ideal receiver at first glance.
>
> I am acutely aware of the fact that 10GEPON standard will allow for degree
> of flexibility in the network design to compensate for network design short
> comings.  My suggestion for *(Dispersion_Penalty+TDP) <=
> ITU_Optical_Path_Penalty* to be changed is to make sure that there is no
> ambiguity in the standard (spreadsheet) and to point out to the adopter of
> the 10GEPON standard that *all* penalties have been accounted for, analyzed
> and documented.  At the end of the day it is up to task force as whole to
> adopt what they feel is appropriate for the standard.
>
> Best regards,
>
> Ken Maricondo
>
>
>
>
> On Nov 22, 2007 5:27 AM, Hiroshi Hamano <hamano.hiroshi@jp.fujitsu.com>
> wrote:
>
> > Dear Dr. Maricondo and Dr. Hajduczenia,
> >
> > Thank you for your quick response and discussion.
> > I am not sure how TDP values have been defined in the previous
> > specifications
> > such as IEEE 802.3ae and 802.3ah .  If they have also reflected the vendor
> > data
> > based on the transmitter measurement results, vendor feedbacks may be
> > quite
> > important similarly for 10GE-PON.
> >
> > > but should read *(Dispersion_Penalty+TDP)
> > > <= ITU_Optical_Path_Penalty* to insure all possible noise and penalties
> > are
> > > accounted for.
> >
> > Perhaps, I misunderstand the last sentence of Dr. Maricondo's E-mail.
> > But my understanding is that ITU_optical_path_penalty basically includes
> > no
> > transmitter penalty.  Receiver sensitivity value in ITU formalism should
> > share
> > the margin, instead, for possible transmitter penalty compared to the
> > ideal one.
> > Would you please explain again your intension about the sentence??
> >
> > Best regards,
> > Hiroshi Hamano
> > Fujitsu Labs. Ltd.
> >
> > %% "Ken Maricondo" <kmaricondo@ieee.org>
> > %% Re: [8023-10GEPON] Define TDP values
> > %% Wed, 21 Nov 2007 19:15:31 -0500
> >
> > >
> > > Dear Hamano-san,
> > >
> > > Although the TDP is a controversial value to be added to the 10GEPON
> > > standard, I have to agree with the previous committee ( 802.3ah) for
> > > assigning a TDP value; albeit not an apparent benefit, the TDP does set
> > a
> > > reference value/point for determining transmitter quality which does
> > impacts
> > > system performance.  I agree with your assessment that the lack of high
> > > power reference transmitter to make a TDP measurement at this time is a
> > > problem.  In the absence of such a reference transmitter/s, I think that
> > the
> > > TDP values you have chosen are a good reference point to start with and
> > I
> > > support you on this issue.
> > >
> > > I also think that the spreadsheet should reflect the impact of TDP on
> > the
> > > systems' overall performance.   From what I have been able to determine,
> > the
> > > TDP value is subtracted from the *IEEE_Rx_Stressed_Sensitivity_OMA* to
> > get *
> > > IEEE_Rx_Sen_OMA*, which does not readily translate into a system
> > performance
> > > impact/limitation.  The system pass/fail calculation is based on
> > > *Dispersion_Penalty
> > > <= ITU_Optical_Path_Penalty* only, but should read
> > *(Dispersion_Penalty+TDP)
> > > <= ITU_Optical_Path_Penalty* to insure all possible noise and penalties
> > are
> > > accounted for.
> > >
> > > Best regards,
> > >
> > > Ken Maricondo
---
-----------------------------------------
Hiroshi Hamano
Network Systems Labs., Fujitsu Labs. Ltd.
Phone:+81-44-754-2641 Fax.+81-44-754-2640
E-mail: hamano.hiroshi@jp.fujitsu.com
-----------------------------------------