Child pages
  • #27: 1+1 HSB - Driving criteria in Adaptive Modulation
Skip to end of metadata
Go to start of metadata
Due date 
OwnerDaniela Spreafico


During discussions, it has been found that the underlying feature has been implemented only by a single vendor.
After rest of present vendors and also operators indicated limited interest in the feature, it has been rated a customer specific implementation with limited chances of a wider adoption in the industry.

Since it would not be possible to consolidate all attributes of customer specific implementations into a clear and easy to understand standard, it is proposed not to include the requested attribute, but to leave it for configuration with the proprietary element manager.


Proposal consisting in selection of the lowest or highest modulation format when 1+1 protection is configured

Details in the attached slide:




Content of the Mantis Bug Tracker:

DescriptionThe request is to allow on 1+1 HSB radio configuration the selection of wich Received Signal Level between the 2 receivers has to be considered for the Adaptive modulation shift up/down within the following:
o The lowest value
o The highest value

The proposal could be to add a new attribute ‘amDrivingCriteria’ with the allowed values:
o notRelevant (for radio configuration not 1+1
o lowestReceivedValue
o highestReceivedValue

On wich class? 3 options:
o on MW_AirInterfaceHsbFcSwitch_Pac
o on PureEthernetStructure_Pac (where the 2 airInterface_Pac involved are connected to)


  1. First discussion held on 18/4

  2. It is wrongly indicated on the description of the problem that the values to consider on local NE for the Adaptive Modulation are the RSLs related to the 2 receivers of the remote NE .

    Instead , the values to be considered on the local NE for the Adaptive modulation (up/down) are the MSE (Mean Square Error) of the remote receivers.

    The presentation is updated .

  3. First, I think we need to clarify whether the understanding to 1+1 HSB is the same for all of us. I think in attached pptx document there is illustrated 1+1 (working) standby (two active RAUs) and not 1+1 hot standby  while in the text there is mentioned 1+1 HSB (one ative RAUs).


    in 1+1 Hot standby, the modulation of active of receiver (RAU) should always be used (modulation of standby receiver should not be used even if higher modulation is reported)

    in 1+1 (working) standby (this was mentioned in the pptx), the highest/lowest modulation of both receivers can be used.





  4. The reference also on the .pptx is the 1+1 HSB described.

    On Far-end node both receivers calculate own MSE (MSE1, MSE2) .

    MSE1, MSE2 are sent to Near-end node that have to select which MSE (MSE1 or MSE2) will be input for ACM algorithm.

  5. Based on my understanding, I still think that in the attached slides and description is mentioned 1+1 space diversity (1+1 working standby) and not 1+1 HSB. In case of 1+1 HSB, it does not make sense to adapt modulation/power according to the received signal via redundant path (ODU) if primary path (ODU) works - the modulation should be adapt to active path (most of time primary path, in case of failure redundant path)


    1. You are right. The 1+1 HSB mentioned is an 1+1 HSB with space diversity (with 2 antennas and 2 receivers) but it is still defined as 1+1 HSB (with 2 receivers).

      It is up to operator to know that there are 2 antennas (space diversity) or 1 antenna.

      The need to adapt modulation/power according to the higher or lower MSE/RSL is in case of space diveristy.