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Add documentation for the roadm impairment feature
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Signed-off-by: EstherLerouzic <[email protected]>
Change-Id: Ief7e79ef10edf098c49ab1a0164284e5ae604961
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EstherLerouzic committed May 18, 2024
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Expand Up @@ -243,6 +243,10 @@ The user can only modify the value of existing parameters:
+-------------------------------+-----------+----------------------------------------------------+
| field | type | description |
+===============================+===========+====================================================+
| ``type_variety`` | (string) | Optional. Default: ``default`` |
| | | A unique name to ID the ROADM variety in the JSON |
| | | template topology input file. |
+-------------------------------+-----------+----------------------------------------------------+
| ``target_pch_out_db`` | (number) | Default :ref:`equalization strategy<equalization>` |
| or | | for this ROADM type. |
| ``target_psd_out_mWperGHz`` | | |
Expand Down Expand Up @@ -270,6 +274,184 @@ The user can only modify the value of existing parameters:
| | | insert a ``Fused`` node on the degree |
| | | output. |
+-------------------------------+-----------+----------------------------------------------------+
| ``roadm-path-impairments`` | (list of | Optional. List of ROADM path category impairments. |
| | dict) | |
+-------------------------------+-----------+----------------------------------------------------+

In addition to these general impairment, the user may define detailed set of impairments for add,
drop and express path within the the ROADM. The impairment description is inspired from the `IETF
CCAMP optical impairment topology <https://github.com/ietf-ccamp-wg/draft-ietf-ccamp-optical-impairment-topology-yang>`_
(details here: `ROADM attributes IETF <https://github.com/ietf-ccamp-wg/draft-ietf-ccamp-optical-impairment-topology-yang/files/4262135/ROADM.attributes_IETF_v8draft.pptx>`_).

the ``roadm-path-impairments`` list allows the definition of impairments list per internal path category
(add, drop or express). several add-path drop-path or expresss-path can be defined. They are indexed and the impairments defined per band.

each item should contain:

+--------------------------------+-----------+----------------------------------------------------+
| field | type | description |
+================================+===========+====================================================+
| ``roadm-path-impairments-id`` | (number) | A unique number to ID the impairments. |
+--------------------------------+-----------+----------------------------------------------------+
| ``roadm-express-path`` | (list) | List of the impairments defined per frequency |
| or | | range. The impairments are detailed in the |
| ``roadm-add-path`` | | following table. |
| or | | |
| ``roadm-drop-path`` | | |
| (mutually exclusive) | | |
+--------------------------------+-----------+----------------------------------------------------+

Here are the parameters for each path category and the implementation status:

+----------------------------+-----------+-----------------------------------------------------------+-------------+-------------+---------------------+
| field | Type | Description | Drop path | Add path | Express (thru) path |
+============================+===========+===========================================================+=============+=============+=====================+
| ``frequency-range`` | (list) | List containing ``lower-frequency`` and | | | |
| | | ``upper-frequency`` in Hz | | | |
+----------------------------+-----------+-----------------------------------------------------------+-------------+-------------+---------------------+
| ``roadm-maxloss`` | (number) | In dB. Default: 0 dB. Maximum expected path loss on this | Implemented | Implemented | Implemented |
| | | roadm-path assuming no additional path loss is added = | | | |
| | | minimum loss applied to channels when crossing the ROADM | | | |
| | | (worst case expected loss due to the ROADM). | | | |
+----------------------------+-----------+-----------------------------------------------------------+-------------+-------------+---------------------+
| ``roadm-minloss`` | | The net loss from the ROADM input, to the output of the | Not yet | N.A. | N.A. |
| | | drop block (best case expected loss). | implemented | | |
+----------------------------+-----------+-----------------------------------------------------------+-------------+-------------+---------------------+
| ``roadm-typloss`` | | The net loss from the ROADM input, to the output of the | Not yet | N.A. | N.A. |
| | | drop block (typical). | implemented | | |
+----------------------------+-----------+-----------------------------------------------------------+-------------+-------------+---------------------+
| ``roadm-pmin`` | | Min per carrier power levels expected at the output of | Not yet | N.A. | N.A. |
| | | the drop block. | implemented | | |
+----------------------------+-----------+-----------------------------------------------------------+-------------+-------------+---------------------+
| ``roadm-pmax`` | | (Add) Maximum (per carrier) power level permitted at the | Not yet | Not yet | N.A. |
| | | add block input ports. | implemented | implemented | |
| | | | | | |
| | | (Drop) Best case per carrier power levels expected at | | | |
| | | the output of the drop block. | | | |
+----------------------------+-----------+-----------------------------------------------------------+-------------+-------------+---------------------+
| ``roadm-ptyp`` | | Typical case per carrier power levels expected at the | Not yet | N.A. | N.A. |
| | | output of the drop block. | implemented | | |
+----------------------------+-----------+-----------------------------------------------------------+-------------+-------------+---------------------+
| ``roadm-noise-figure`` | | If the add (drop) path contains an amplifier, this is | Not yet | Not yet | N.A. |
| | | the noise figure of that amplifier inferred to the | Implemented | Implemented | |
| | | add (drop) port. | | | |
+----------------------------+-----------+-----------------------------------------------------------+-------------+-------------+---------------------+
| ``roadm-osnr`` | (number) | (Add) Optical Signal-to-Noise Ratio (OSNR). | implemented | Implemented | N.A. |
| | | If the add path contains the ability to adjust the | | | |
| | | carrier power levels into an add path amplifier | | | |
| | | (if present) to a target value, | | | |
| | | this reflects the OSNR contribution of the | | | |
| | | add amplifier assuming this target value is obtained. | | | |
| | | | | | |
| | | (Drop) Expected OSNR contribution of the drop path | | | |
| | | amplifier(if present) | | | |
| | | for the case of additional drop path loss | | | |
| | | (before this amplifier) | | | |
| | | in order to hit a target power level (per carrier). | | | |
+----------------------------+-----------+-----------------------------------------------------------+-------------+-------------+---------------------+
| ``roadm-pmd`` | (number) | PMD contribution of this roadm path. | Implemented | Implemented | Implemented |
+----------------------------+-----------+-----------------------------------------------------------+-------------+-------------+---------------------+
| ``roadm-cd`` | | | Not yet | Not yet | Not yet |
| | | | Implemented | Implemented | Implemented |
+----------------------------+-----------+-----------------------------------------------------------+-------------+-------------+---------------------+
| ``roadm-pdl`` | (number) | PMD contribution of this roadm path. | Implemented | Implemented | Implemented |
+----------------------------+-----------+-----------------------------------------------------------+-------------+-------------+---------------------+
| ``roadm-inband-crosstalk`` | | | Not yet | Not yet | Not yet |
| | | | Implemented | Implemented | Implemented |
+----------------------------+-----------+-----------------------------------------------------------+-------------+-------------+---------------------+

Here is a ROADM example with two add-path possible impairments:

.. code-block:: json
"roadm-path-impairments": [
{
"roadm-path-impairments-id": 0,
"roadm-express-path": [{
"frequency-range": {
"lower-frequency": 191.3e12,
"upper-frequency": 196.1e12
},
"roadm-maxloss": 16.5
}]
}, {
"roadm-path-impairments-id": 1,
"roadm-add-path": [{
"frequency-range": {
"lower-frequency": 191.3e12,
"upper-frequency": 196.1e12
},
"roadm-maxloss": 11.5,
"roadm-osnr": 41
}]
}, {
"roadm-path-impairments-id": 2,
"roadm-drop-path": [{
"frequency-range": {
"lower-frequency": 191.3e12,
"upper-frequency": 196.1e12
},
"roadm-pmd": 0,
"roadm-cd": 0,
"roadm-pdl": 0,
"roadm-maxloss": 11.5,
"roadm-osnr": 41
}]
}, {
"roadm-path-impairments-id": 3,
"roadm-add-path": [{
"frequency-range": {
"lower-frequency": 191.3e12,
"upper-frequency": 196.1e12
},
"roadm-pmd": 0,
"roadm-cd": 0,
"roadm-pdl": 0,
"roadm-maxloss": 11.5,
"roadm-osnr": 20
}]
}]
On this example, this means that express channel will have at least 16.5dB loss when crossing this ROADM express path with this impairment id.

roadm-path-impairments is optional. If present, its values are considered instead of the ROADM general parameters.
For example if add-path specifies 0.5 dB PDL and general PDL parameter states 1dB, then 0.5dB is applied for
this roadm-path only.
If present in add and/or drop path, roadm-osnr replaces the portion of add-drop-osnr defined for the whole ROADM,
assuming that add and drop contribution aggregated in add-drop-osnr are identical:

.. math::
add\_drop\_osnr = - 10log10(1/add_{osnr} + 1/drop_{osnr})
add_{osnr} = drop_{osnr} = add_{osnr} + 10log10(2)
User can specify the roadm type_variety in json topology ROADM instance. If no variety is defined ``default`` ID is used.
User can defined the impairment type for each raodm-path using the degrees ingress/egress immediate neighbour elements and
the roadm-path-impairment-id defined in the library for this type-variety.
Here is an example:

.. code-block:: json
{
"uid": "roadm SITE1",
"type": "Roadm",
"type_variety": "detailed_impairments",
"params": {
"per_degree_impairments": [
{
"from_degree": "trx SITE1",
"to_degree": "east edfa in SITE1 to ILA1",
"impairment_id": 1
}]
}
}
It is not permitted to use a roadm-path-impairment-id for the wrong roadm path type (add impairment only for add path).
If nothing is stated for impairments on roadm-paths, the program identifies the paths implicitely and assign the first
impairment_id that matches the type: if a transceiver is present on one degree then it is an add/drop degree.

On the previous example, all «implicit» express roadm-path are assigned roadm-path-impairment-id = 0

Global parameters
-----------------
Expand Down Expand Up @@ -503,6 +685,9 @@ In the simplest case, homogeneous channel allocation can be defined via the ``Sp
+----------------------+-----------+-------------------------------------------+
| ``tx_osnr`` | (number) | In dB. OSNR out from transponder. |
+----------------------+-----------+-------------------------------------------+
| ``tx_power_dbm`` | (number) | In dBm. Power out from transceiver. |
| | | Optional. Default = power_dbm |
+----------------------+-----------+-------------------------------------------+
| ``power_dbm`` | (number) | In dBm. Target input power in spans to |
| | | be considered for the design |
| | | In gain mode |
Expand Down Expand Up @@ -585,6 +770,9 @@ In this approach, each partition is internally homogeneous, but different partit
| ``tx_osnr`` | (number) | In dB. Optional. OSNR out from |
| | | transponder. Default value is 40 dB. |
+----------------------+-----------+-------------------------------------------+
| ``tx_power_dbm`` | (number) | In dBm. Power out from transceiver. |
| | | Optional. Default value = 0 dBm |
+----------------------+-----------+-------------------------------------------+
| ``delta_pdb`` | (number) | In dB. Optional. Power offset compared to |
| | | the reference power used for design |
| | | (SI block in equipment library) to be |
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