Ciao Mike
Please note that, as Brian pointed out, Pete’s tables do show changed unstressed RX sensitivities.
If the power budget is not really changing, I would deem preferable to leave the unstressed RX sensitivity as it is (at the end of the day the SRS of the RX is not changing either, since the RX is the same) with
the note that, even if ideal, the reference TX has SECQ = 0.9dB (pending Jonathan confirmation, see below).
My reasoning is as follows: under the assumption that both RX and – of course - reference TX are not changing (what is changing is the methodology for TDECQ and SECQ calculation: let me call the new one TDECQ’/SECQ’),
to me it seems you cannot at the same time do the following:
1)
apply the usual link budget calculations:
(Launch power in OMAouter minus TDECQ) - Channel IL (- MPI) = unstressed RX sensitivity
2)
keep the unstressed RX sensitivity unchanged
3)
assume SECQ’ of the reference TX (let me call it SECQ’ref_TX
) equal to 0dB
I see a couple of options. Let me rewrite the link budget calculation as follows:
(Launch power in OMAouter minus TDECQ) - Channel IL (- MPI) = unstressed RX sensitivity - SECQref_TX
When the original definitions applies (where SECQref_TX= 0), you end up with the following numbers
-3.5dBm – 3dB (- 0.1dB) = -6.6dBm -0dB = -6.6dBm
With the new TDECQ’/SECQ’ methodology the max TDECQ’ is 0.9dB higher, so you may have:
a) SECQ’ref_TX
= 0dB Þ (-3.5-0.9) - 3 (- 0.1) = -7.5 - 0
b) SECQ’ref_TX
= 0.9dB Þ (-3.5-0.9) - 3 (- 0.1) = -6.6 - 0.9
Option a) requires an improved RX performance and is consistent with the fact that a zero stress TX has 0dB SECQ’. But I find this extra requirement not justified, given the fact that the same considerations
in Jonathan’s presentation regarding ‘SRS remaining unchanged’ should also apply here.
Option b) leaves the RX requirement unchanged but assumes that SECQ’ref_TX
is actually 0.9dB, something that I am leaving Jonathan to confirm/reject (is the 0.9dB increase constant with stress amount? If not it would be difficult to do the usual elementary math).
Of course we’ll face the drawback/paradox that a TX with ideal properties has a SECQ’ ≠ 0dB.
Please correct me if I am wrong…maybe I did not correctly catch what is being proposed.
Thanks and regards
Carlo
“…non men che saver, dubbiar m'aggrata…” (Inferno - Canto XI)
.:|:.:|:. | Carlo
Tosetti |
CISCO | TMG Technical Leader|
From: Brian Welch [mailto:bwelch@xxxxxxxxxxx]
Sent: mercoledì 21 giugno 2017 21:02
To: STDS-802-3-400G@xxxxxxxxxxxxxxxxx
Subject: Re: [STDS-802-3-400G] [PossibleSpam] Re: [STDS-802-3-400G] IEEE P802.3bs 200 Gb/s and 400 Gb/s Ethernet SMF Ad Hoc conference call
Mike,
The presentation that Pete referenced (prepared for next weeks Ad Hoc) is proposing to make the unstressed RX sensitivity more stringent by 0.9 dB, and increasing the SECQ for the SRS value by 0.9 dB.
Brian
From: Dudek, Mike [mailto:Mike.Dudek@xxxxxxxxxx]
Sent: Wednesday, June 21, 2017 11:03 AM
To: STDS-802-3-400G@xxxxxxxxxxxxxxxxx
Subject: [PossibleSpam] Re: [STDS-802-3-400G] IEEE P802.3bs 200 Gb/s and 400 Gb/s Ethernet SMF Ad Hoc conference call
The definition for unstressed receiver sensitivity has always been with zero stress. Saying that SECQ = 0dB clarifies what is meant by zero stress. It is harder for the Rx to achieve the BER with a SECQ
of 0.9dB rather than SECQ of 0dB and we aren’t changing the Unstressed sensitivity so I don’t understand why you are saying this makes the Rx unstressed sensitivity test harder.
From: Carlo Tosetti (ctosetti) [mailto:ctosetti@xxxxxxxxx]
Sent: Wednesday, June 21, 2017 1:53 AM
To: STDS-802-3-400G@xxxxxxxxxxxxxxxxx
Subject: Re: [STDS-802-3-400G] IEEE P802.3bs 200 Gb/s and 400 Gb/s Ethernet SMF Ad Hoc conference call
Ciao Peter
I have a question related to the added text in the notes on unstressed receiver sensitivity “…and is defined for a transmitter with SECQ of
0dB”.
Based on such value, the proposed change in TDECQ has an impact on the RX side, as it is captured by the corrections in
unstressed sensitivity values: the same RX which was OK with the reference TX when using the old TDECQ definition is now not working anymore with the new TDECQ definition and needs an improvement of 0.9dB in the unstressed sensitivity.
I am wondering – but honestly I am not sure if this is physically sound and consistent with the new proposed TDECQ methodology: shouldn’t the note say instead “…and is defined for a transmitter with SECQ of
0.9dB” (admittedly this looks pretty ugly…)?
Thanks and regards
Carlo
“…non men che saver, dubbiar m'aggrata…” (Inferno - Canto XI)
.:|:.:|:. | Carlo
Tosetti |
CISCO | TMG Technical Leader|
From: Anslow, Peter [mailto:panslow@xxxxxxxxx]
Sent: martedì 20 giugno 2017 21:47
To: STDS-802-3-400G@xxxxxxxxxxxxxxxxx
Subject: Re: [STDS-802-3-400G] IEEE P802.3bs 200 Gb/s and 400 Gb/s Ethernet SMF Ad Hoc conference call
Matt,
I think that the file I have generated for next week’s SMF Ad Hoc should answer your question:
http://www.ieee802.org/3/bs/public/adhoc/smf/17_06_27/anslow_02_0617_smf.pdf
Regards,
Pete Anslow |
Senior Standards Advisor
43-51 Worship Street
| London, EC2A 2DX,
UK
Direct +44 2070 125535 |
From: Matt Traverso (mattrave) [mailto:mattrave@xxxxxxxxx]
Sent: 20 June 2017 04:16
To: Anslow, Peter <panslow@xxxxxxxxx>;
STDS-802-3-400G@xxxxxxxxxxxxxxxxx; Jonathan King <jonathan.king@xxxxxxxxxxx>
Subject: RE: [STDS-802-3-400G] IEEE P802.3bs 200 Gb/s and 400 Gb/s Ethernet SMF Ad Hoc conference call
Hi Jonathan,
I’m sorry to have missed the most recent ad hoc where you presented
king_01a_0617_smf. I find myself confused as to what you mean by: “a similar decrease in the OMAouterminus TDECQ spec”. Can you show
an example with what would happen for the TX or RX table for any of the clause 122 PMD’s?
I think this all stems from a mixing of terms increase/decrease with negative numbers…
Thanks
--matt
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Matt Traverso PRINCIPAL ENGINEER.ENGINEERING |
Cisco Systems, Inc. 3700 Cisco Way |
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From: Anslow, Peter [mailto:panslow@xxxxxxxxx]
Sent: Tuesday, June 13, 2017 1:12 AM
To: STDS-802-3-400G@xxxxxxxxxxxxxxxxx
Subject: [STDS-802-3-400G] IEEE P802.3bs 200 Gb/s and 400 Gb/s Ethernet SMF Ad Hoc conference call
Hi,
As previously announced, there is an SMF Ad Hoc meeting starting at 8:00 am Pacific today, Tuesday 13 June.
Attendees names and affiliations will be taken from the Webex participants list. Please use an e-mail address indicating affiliation when signing in. If you attend via phone only, or if your employer and affiliation are
different, please send me an e-mail.
I currently have requests for 1 presentation so the draft agenda is:
- IEEE patent policy reminder:
http://www.ieee802.org/3/patent.html
- IEEE 802 participation policy:
http://www.ieee802.org/devdocs.shtml
- Approval of the agenda
- Approval of the draft minutes from 16 May 2017 call
- Presentations
- TDECQ changes and consequent spec limits Jonathan King, Finisar
- TDECQ changes and consequent spec limits Jonathan King, Finisar
- Discussion
The presentation for this call is on the P802.3bs
SMF Ad Hoc web page.
If you have any questions for the presenter(s) after the call, please ask the Ad Hoc Chair for contact details.
Peter Anslow from Ciena has invited you to join a meeting on the Web, using WebEx. Please join the meeting 5-10 minutes early so we may begin on time.
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Topic: "P802.3bs SMF Ad Hoc"
Date & Time: Every 2 weeks on Tuesday, from Tuesday, 13 June 2017, to Tuesday, 27 June 2017 at 16:00, GMT Summer Time (London, GMT+01:00)
To join web meeting click here: https://ciena.webex.com/ciena/j.php?MTID=m8af2937bfb4b6fd299ccb5ee317895fb
Meeting password: IEEE (please note passwords are case sensitive)
Teleconference: Provide your phone number when you join the meeting to receive a call back. Alternatively, you can call:
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Conference Code: 765 992 3550
Meeting number: 632 000 521
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Additional Notes:
- To add this meeting to your calendar program click the following link, or copy the link and paste it into your Web browser:
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Regards,
Pete Anslow |
Senior Standards Advisor
43-51 Worship Street
| London, EC2A 2DX,
UK
Direct +44 2070 125535 |