Adaptive Target BLER for better Spectral Efficiency and Throughput

RAN
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Hello Everyone,

To all workin Ericsson RAN (Ericsson and Huawei).

Traditionally HARQ BLER Target of 10% is used in Ericsson RBS.
Also the same value is used in Huawei as the Initial BLER Target Value (10%)

But Huawei provides the Adaptive Target BLER Functionality that helps then gain better spectral efficiency and throughput.
As per my knowledge and the Sw Release we have 18.Q4 Ericsson do not have such flexibility. Plus no possibility to change that 10% target BLER as it is Hard Coded I believe.

Do you know if Ericsson has any equivalent available (Hidden Parameters or System constants) to the Huawei flexibility?

1 Like
2

Hello LTE Experts.

Huawei has a feature “Adaptive Target BLER”, a functionality that helps then gain better spectral efficiency and throughput.
Anyone know about that feature and its functionality?
Is it same the link adaptation?

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This feature allows to schedule with higher MCS because required BLER can be increased.

4

Isn’t it the same as Link Adaptation feature?
Is it something else?

5

What about RLC retransmissions?

6

No change. It only control HARQ retransmission.
I am telling in general, not Huawei specific.

7

Yes so its not same link adaptation feature (ulla/dlla).

So how this feature work?
I mean its functionality/description of that feature?
Because I’m still not getting the idea of using it.

8

Yes, sorry, my bad.
I meant to ask if anyone saw the benefit of increasing target bler >10%?
MCS would be higher but overall gain want because of higher retransmission rate.

9

Spectral efficiency / throughput increases after changing it from 10 to 15%.

10

Realy? Thanks for the info, I will test it. :wink:

11

Do you know the exact name of this feature in Ericsson?
I’ve not seen it before.
It is hardcoded to increase BLER in Ericsson greater than 10%
Don’t belong to a feature…

12

Bler target switch or something like… enhancement bler target?

You mean by default target bler isn’t fixed around 10%?

Generally what used is like target bler around 10% (not adaptive)

13

As deafault since one enodB launched , target BLER is 2% but we can increase it to 10 % .
But I did not see that feature your mentioned in Ericsson

Use this command to find out which value it is set:
hget . pdcchTargetBler$|pdcchTargetBlerPCell

14

I think Ericsson has something related to Adaptive Target BLER feature…

Is it range from 2% to 30%?

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Maxmimum 10 %

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So this target bler is adaptive?
I mean target bler value is chosen which range from 2% to 10% adaptively by eNB situation/case?

17

No it is not adaptively changed, we as operator of system should change it.

18

Maybe Ericsson still use fixed target bler around 10%?

19

Yes maximum 10 % in order

Parameter Current Value Proposed Value
dlBlerTargetEnabled FALSE TRUE
pdcchTargetBler 24 200
pdcchTargetBlerPCell 22 180

See we have three option for bler.
dlBlerTargetEnabled this one related to ericsson lean carrier feature so please skip it.
But for two other remaiend MO you can set it to 200/180 and see the result.
In scheduling algorythm the enodeB will elimiate those users which consuming more resources because of the retransmisson.
So you will see after modification DL THR improvement but a bit active users reduction.
Active users will be reduced because less users will be remained in buffer.
But no change in payload generation because most users working like before.

20

Sounds Ericsson isn’t using Adaptive Target Bler feature/switch.