Issue with the Intra cell Beam Switching in a 5G network

5G NR
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1

Hello Experts.

There is a problem with the Intra cell Beam Switching in a Huawey 5G network.

We see in Drive Test that the UE does not change the Serving Beam when the Drive Test is done with a car, still when the others beams are 10 dBs better, dropping the SINR.

But when we do a walk test, the Serving Beam switch betwen Cells beams correctly.

Some ideas of what is happening?

Thank You

2

Beam level CSI reporting configured properly?

3

In walk test beams are changed very slow while in drivetest needs to be changed fast.

What is your CSI reporting periodicity?

4

The CSI reporting configured is 80 slots (40ms).

5

filtercoeffrsrprsindex → what value you set?

6

So you have PMI based weights or SRS beam weights?

There is a UL SINR threshold for this.

Also, did you involve Huawei into this?

They have lot of internal traces and can quickly grasp the issue and fix it.

7

I will check it, thank you.

I checked another UE of the DT and this UE change Serving Beam correctly between beams.

This UE is newer, the other one with the problem is older.

Could it be a problem of UE capabilities?

No, Huawey is not involved in this part yet.

8

If one UE is OK, then you can exclude RAN.

I would say likely no RAN issue, but UE issue!