Re: [8023-10GEPON] Ad hoc on 10GEPON channel model - definitions
Dear Mike,
The FC-PI-2 and FC-PI-4 are inherently the same in terms of the definitions I quoted but I will change the reference for the sake of using only stabilized and released specifications. Thank You for that comment.
Regarding the receiver sensitivity, there are two definitions provided. Number one is quoted after FC-PI-2 and says "The minimum acceptable value of re-ceived signal at point γR to achieve a BER < 10-12.". The alternative is quoted after T1.523-2001 and says "The minimum value of average received power to achieve a 1 x 10–10 bit error ratio. It includes power penalties caused by use of a transmitter under standard operating conditions with worst-case values of extinction ratio, pulse rise and fall times, optical return loss, receiver connector degradations, and measure-ment tolerances." Is that clear right now ? Sorry for the wording in the original document. I will try to clarify that ...
Thank You also for the suggestion on the power budget estimation based on OMA - it was also suggested by Piers to have a look in that direction and that is what I am doing right now. I am afraid that I am still a little bit confused with the spreadsheet but I will figure it out with time. I will have to look into which terms require proper definitions in order to have the power budget defined in the way You mentioned before. I will try to have a look at it today and come back to You tomorrow.
Thank You for Your time
Best wishes
Marek Hajduczenia (141238)
SIEMENS Networks S.A. - IC COM D1 R
Rua Irmãos Siemens, 1
Ed. 1, Piso 1
Alfragide
2720-093 Amadora
Portugal
* Marek.Hajduczenia@siemens.com
http://marekhaj.easyisp.pl/index.php
(+351.21.416.7472 4+351.21.424.2082
-----Original Message-----
From: Mike Dudek [mailto:mike.dudek@PICOLIGHT.COM]
Sent: quarta-feira, 13 de Dezembro de 2006 16:43
To: STDS-802-3-10GEPON@listserv.ieee.org
Subject: Re: [8023-10GEPON] Ad hoc on 10GEPON channel model - definitions
A few comments on these definitions.
I would caution the use of FC-PI-4. This is a draft standard that is in development, and therefore is likely to contain errors. That said the definitions are unlikely to change and are mostly copied (maybe all copied) from the released document FC-PI-2. At this point however I would recommend that FC-PI-2 is used.
I know that this is not easy to incorporate into a matrix, but it is fairly common practice in the datacom world to create the exact definitions of what is meant by a particular term through the use of a test procedure. Eg. Transmitter and Dispersion penalty (TDP) for the 1G EPON clause 60 (which is in 802.3 2005) is defined by reference to the test procedure of clause 58.8.9.
As you noted there are significant differences between link penalties (IEEE) and Optical Path penalty (ITU) and lumping them into the same row in the matrix may add to confusion. However as these use different names it is not that confusing. More of a problem is "receiver sensitivity" AKA "intrinsic sensitivity". As normally used in the IEEE and Fibre Channel context (including it's use in the various link budget spreadsheets) this is the performance of the receiver when tested with a perfect transmitter. I don't see the definition you have provided in the matrix stated as coming from FC-PI-4 in FC-PI-4. I would be grateful if you would provide the exact page reference for it, because in the FC-PI-4 document this would be an incorrect definition and needs to be corrected if it exists. The definition as stated I think is more like how ITU defines sensitivity including the effect of transmitter impairments, (the definition may have come from FDDI which is a much older A!
NSI standard).
Note that in my opinion the budgeting method used in 802.3 Clause 52 (10G serial) is probably the best method to achieve plug and play operation for a system which has a challenging budget to meet.
In summary this method is as follows.
The budget is based on Optical Modulation Amplitude at both the Tx and Rx, (So variations in extinction ratio don't affect the budget).
The difference between the sensitivity measured with a reference receiver between a near perfect Tx with a short fiber, and the device under test Tx with a long fiber with a worst case dispersion characteristic is measured and called Transmitter and Dispersion penalty (TDP). (hence TDP includes all Transmitter and Dispersion penalties relative to a near perfect Tx.).
The Receiver is tested with a signal that emulates the worst case signal at the end of a worst case dispersive fiber. (ie emulating a Tx with the worst case Transmitter and Dispersion penalty.). This is the Receiver's Stressed receiver sensitivity.
The link budget closes (ie system is OK) provided the loss in the link is less than "minimum Tx OMA -TDP" - Rx stressed receiver sensitivity. Note that the key Tx parameteter specified is the (Tx OMA - TDP).
-----Original Message-----
From: Hajduczenia, Marek [mailto:marek.hajduczenia@SIEMENS.COM]
Sent: Wednesday, December 13, 2006 5:39 AM
To: STDS-802-3-10GEPON@LISTSERV.IEEE.ORG
Subject: Re: [8023-10GEPON] Ad hoc on 10GEPON channel model - definitions
Dear Frank,
Attached please find an updated matrix list. It contains several new definitions, which - being unable to find them in the 802.3, I went to ANSI standards to find the respective terms defined. Some of them are still missing and I am trying to find some comprehensive and yet recognized defnitions for such parameters.
I also added a wish list, which would probably need to be added if we want to go into details with the channel impairments and penalties.
Feel free to modify/add/change ...
Best wishes
Marek Hajduczenia (141238)
SIEMENS Networks S.A. - IC COM D1 R
Rua Irmãos Siemens, 1
Ed. 1, Piso 1
Alfragide
2720-093 Amadora
Portugal
* Marek.Hajduczenia@siemens.com
http://marekhaj.easyisp.pl/index.php
(+351.21.416.7472 4+351.21.424.2082
-----Original Message-----
From: EffenbergerFrank 73695 [mailto:feffenberger@HUAWEI.COM]
Sent: quarta-feira, 13 de Dezembro de 2006 8:09
To: STDS-802-3-10GEPON@listserv.ieee.org
Subject: Re: [8023-10GEPON] Ad hoc on 10GEPON channel model - definitions
> All,
>
> Marek offers a good starting point of a definition cross-reference
> matrix.
> I have taken this, and filled in the ITU side.
>
> We should probably make more items in this matrix, to include at
> least the Tx min and max, and Rx sensitivity and overload. Those
> are somewhat different between the two systems, too.
>
> Regards,
> Frank E
>
>