Page 1029 - 5G Basics - Core Network Aspects

Transport aspects 2

enters showtime, if DTA operation is enabled on the line and Act_min_Mds ≤ DTA_pref_Mds ≤ Act_max_Mds
(see clause T.2.7).

On lines where DTA operation is enabled, the DRA shall request a DTA update (using the DTA.request
primitive, see clause X.6.1) with the value of DTA_pref_Mds at the first opportunity after the FTU-O enters
showtime. DTA_pref_Mds shall be within the valid range specified for Mds in clause X.6.3. DTA_pref_Mds
shall be greater than or equal to DTA_min_Mds and less than or equal to DTA_max_Mds.

NOTE – The preferred Mds value (DTA_pref_Mds) may also be used by DTA control algorithms to return to that value in
case of low traffic.
The control parameter DTA_pref_Mds shall be set to the same value as the DPU-MIB configuration
parameter DTA_PREF_Mds.

T.2.4 Maximum step size for DTA changes (DTA_SMax)
The control parameter DTA_SMax represents the maximum step size for DTA changes and is the maximum
change in Mds that the DRA is allowed to request for a single DTA update (see clause X.6.2). The absolute
value of the difference between the number of downstream symbol periods Mds in a TDD frame just prior
to and immediately after any DTA update shall be less than or equal to DTA_SMax. The valid values for
DTA_SMax are all integers between 1 and 25 for MF = 36 and between 1 and 12 for MF = 23.
The control parameter DTA_Smax shall be set to the same value as the DPU-MIB configuration parameter
DTA_SMAX.

T.2.5 Minimum Mds for DTA (DTA_min_Mds)
See clause X.6.7.3.

T.2.6 Maximum Mds for DTA (DTA_max_Mds)
See clause X.6.7.4.

T.2.7 Minimum expected throughput for DTA (DTA_ETR_min)
The control parameter DTA_ETR_min represents the minimum expected throughput for DTA and provides a
target minimum ETR that the DRA should meet when DTA operation is enabled.

In order to meet the DTA_ETR_min configured value for the downstream direction, the DRA shall calculate
the number of downstream symbols min_Mds needed to provide an expected throughput of at least
DTA_ETR_min. This shall be done according to the derived framing parameters given in Table 9-21 such that
ETR would be greater than or equal to the downstream DTA_ETR_min assuming a downstream data symbol
rate of:
 1 
 min_M ds 1  
f D DS  f DMT   M M SF  

 F 
  .
For the upstream direction the DRA shall calculate the maximum value max_Mds such that at least an
expected throughput of the upstream DTA_ETR_min will be available. This shall be done according to the
derived framing parameters given in Table 9-21 such that ETR would be greater than or equal to the
upstream DTA_ETR_min assuming an upstream data symbol rate:
 1 
  M F 1  max_M ds 1  
f D US  f DMT    M M SF  
 F 
  .

The calculated minimum and maximum values min_Mds and max_Mds shall further constrain the dynamic
range of Mds given by DTA_max_Mds and DTA_min_Mds using the following definitions:

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