Device stuck at 64QAM DL, not using 256QAM anymore

4G LTE
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1

Hi there,

This is my first post here so I hope I’m doing this correctly.

I found this forum by accident and wanna try.

Since some time my device isn’t able to use 256QAM for DL. It just uses 256QAM for UL and only 64QAM for DL. The device does know 256QAM since it made 256QAM some days ago, now it doesn’t. I’m confused and I don’t know what to do.

Someone said a high BLER is causing the eNb to keep 64QAM. The BLER is between 12-17% - depending on the used LTE Band. Is this correct? If so, what can I do to reduce the BLER to get 256QAM DL back?

Thanks in advance.

IMG_20220121_173440
IMG_20220121_1734401080×1953 184 KB

2

May be 256 QAM disabled at eNodeB that’s why UE is not getting in DL

3

This eNb can 256QAM. Like every other eNb I was but just the UE doesn’t use 256QAM DL. Other devices do 256QAM on the same eNb and the UE that doesn’t use 256QAM there, uses 256QAM on other provider networks.

4

Is this eNB broken because also SISO? Or some shared DAS? Something looks wrong so maybe you should contact to provider to fix this?

5

I contacted the provider and they said this eNb is working fine. There are no known issues in this area. (which I don’t trust tbh)

1 Like
6

Could this be due to higher interference?
What is RSRQ here, could be high interference as RI1 TM4?

7

User need to check intra site/inter site overlapping to check why so high BLER if BLER can be reduced by physical optimization it will be best solution.

Apart from this check value of dltargetbler set it around 10%.