.. _dec-turbo_db-decoder-parameters:

Turbo |DB| Decoder parameters
-----------------------------

.. _dec-turbo_db-dec-type:

``--dec-type, -D``
""""""""""""""""""

   :Type: text
   :Allowed values: ``TURBO_DB`` ``CHASE`` ``ML``
   :Default: ``TURBO_DB``
   :Examples: ``--dec-type CHASE``

|factory::Decoder::p+type,D|

Description of the allowed values:

+--------------+---------------------------+
| Value        | Description               |
+==============+===========================+
| ``TURBO_DB`` | |dec-type_descr_turbo_db| |
+--------------+---------------------------+
| ``CHASE``    | |dec-type_descr_chase|    |
+--------------+---------------------------+
| ``ML``       | |dec-type_descr_ml|       |
+--------------+---------------------------+

.. |dec-type_descr_turbo_db| replace:: Select the standard Turbo decoder.
.. |dec-type_descr_chase| replace:: See the common :ref:`dec-common-dec-type`
   parameter.
.. |dec-type_descr_ml| replace:: See the common :ref:`dec-common-dec-type`
   parameter.

.. _dec-turbo_db-dec-implem:

``--dec-implem``
""""""""""""""""

   :Type: text
   :Allowed values: ``STD``
   :Default: ``STD``
   :Examples: ``--dec-implem STD``

|factory::Decoder::p+implem|

Description of the allowed values:

+-----------+--------------------------+
| Value     | Description              |
+===========+==========================+
| ``STD``   | |dec-implem_descr_std|   |
+-----------+--------------------------+

.. |dec-implem_descr_std| replace:: Select the |STD| implementation.

.. _dec-turbo_db-dec-sub-type:

``--dec-sub-type, -D``
""""""""""""""""""""""

Please refer to the |RSC| |DB| :ref:`dec-rsc_db-dec-type` parameter.

.. _dec-turbo_db-dec-sub-implem:

``--dec-sub-implem``
""""""""""""""""""""

Please refer to the |RSC| |DB| :ref:`dec-rsc_db-dec-implem` parameter.

.. _dec-turbo_db-dec-crc-start:

``--dec-crc-start``
"""""""""""""""""""

   :Type: integer
   :Default: ``2``
   :Examples: ``--dec-fnc-crc-ite 1``

|factory::Decoder_turbo_DB::p+crc-start|

.. note:: This parameter requires the Turbo code to be concatenated with a |CRC|
   to work, see the :ref:`crc-crc-parameters`.

.. _dec-turbo_db-dec-fnc:

``--dec-fnc``
"""""""""""""

|factory::Flip_and_check::p+|

.. note:: The |FNC| post processing technique is detailed in
   :cite:`Tonnellier2016a`.

.. note:: This parameter requires the Turbo code to be concatenated with a |CRC|
   to work, see the :ref:`crc-crc-parameters`.

.. _dec-turbo_db-dec-fnc-ite-min:

``--dec-fnc-ite-m``
"""""""""""""""""""

   :Type: integer
   :Default: ``3``
   :Examples: ``--dec-fnc-ite-m 2``

|factory::Flip_and_check::p+ite-m|

See the :ref:`dec-turbo-dec-fnc` parameter.

.. _dec-turbo_db-dec-fnc-ite-max:

``--dec-fnc-ite-M``
"""""""""""""""""""

   :Type: integer
   :Default: ``10``
   :Examples: ``--dec-fnc-ite-M 6``

|factory::Flip_and_check::p+ite-M|

See the :ref:`dec-turbo-dec-fnc` parameter.

.. _dec-turbo_db-dec-fnc-ite-s:

``--dec-fnc-ite-s``
"""""""""""""""""""

   :Type: integer
   :Default: ``1``
   :Examples: ``--dec-fnc-ite-s 2``

|factory::Flip_and_check::p+ite-s|

See the :ref:`dec-turbo-dec-fnc` parameter.

.. _dec-turbo_db-dec-fnc-q:

``--dec-fnc-q``
"""""""""""""""

   :Type: integer
   :Default: ``10``
   :Examples: ``--dec-fnc-q 6``

|factory::Flip_and_check::p+q|

See the :ref:`dec-turbo-dec-fnc` parameter.

.. _dec-turbo_db-dec-ite:

``--dec-ite, -i``
"""""""""""""""""

   :Type: integer
   :Default: ``6``
   :Examples: ``--dec-ite 8``

|factory::Decoder_turbo_DB::p+ite,i|

If the Turbo code is concatenated with a |CRC| and if the |CRC| is checked, the
decoder can stop before making all the iterations.

.. _dec-turbo_db-dec-sf-type:

``--dec-sf-type``
"""""""""""""""""

   :Type: text
   :Allowed values: ``ADAPTIVE`` ``ARRAY`` ``CST`` ``LTE`` ``LTE_VEC``
   :Examples: | ``--dec-sf-type ADAPTIVE``
              | ``--dec-sf-type CST 0.5``

|factory::Scaling_factor::p+type|

This is especially useful with the max-log-|MAP| sub-decoders (|BCJR| with the
:math:`\max` approximation): the |SF| helps to recover a part of the decoding
performance loss compare to the |MAP| algorithm (|BCJR| with the :math:`\max^*`
operator).

.. note:: The |SF| technique is detailed in :cite:`Vogt2000`.

Description of the allowed values:

+--------------+---------------------------------------------------------------+
| Value        | Description                                                   |
+==============+===============================================================+
| ``ADAPTIVE`` | Select the adaptive |SF|, for the first and second iterations |
|              | a |SF| of 0.5 is applied, for the other iterations the |SF|   |
|              | is 0.85.                                                      |
+--------------+---------------------------------------------------------------+
| ``ARRAY``    | Select an hard-coded array of |SFs| (c.f.                     |
|              | :numref:`tab_turbo_dec_sf_array`).                            |
+--------------+---------------------------------------------------------------+
| ``CST``      | Set the same |SF| to be applied for each iterations.          |
+--------------+---------------------------------------------------------------+
| ``LTE``      | Select a 0.75 |SF|.                                           |
+--------------+---------------------------------------------------------------+
| ``LTE_VEC``  | Select a 0.75 vectorized |SF| (faster than ``LTE``).          |
+--------------+---------------------------------------------------------------+

.. _tab_turbo_db_dec_sf_array:

.. table:: Hard-coded array of |SFs|.

   +-----------+--------+
   | Iteration | Value  |
   +===========+========+
   | 1         | 0.15   |
   +-----------+--------+
   | 2         | 0.25   |
   +-----------+--------+
   | 3         | 0.30   |
   +-----------+--------+
   | 4         | 0.40   |
   +-----------+--------+
   | 5         | 0.70   |
   +-----------+--------+
   | 6         | 0.80   |
   +-----------+--------+
   | 7         | 0.90   |
   +-----------+--------+
   | 8         | 0.95   |
   +-----------+--------+

.. _dec-turbo_db-dec-sub-max:

``--dec-sub-max``
"""""""""""""""""

Please refer to the |RSC| :ref:`dec-rsc_db-dec-max` parameter.

References
""""""""""

.. bibliography:: references.bib
   :labelprefix: Trdb-