UE keeps sending measurements in uplink informing the gNodeB which is the best beam
So gNodeB just decides on which beam to send the PDSCH.
Based on UE reports.
Ok, So it can be like the Ue sents the strongest PCI-SSBidx to gNB and gNB sents data in the strongest one.
Still there is a handshake.
gNB selects the strongest finger from a hand offered from UE. 
Okay I do agree with this.
Then UE need to send any uplink data so UE have to send to same beam id right?
I mean how can UE know if gNB already used the updated one?
What I understand before: it should be like this.
What is important is the reportquantity inside the RRC Connection reconfiguration message.
This one dictates whether beam switching is done based on ssb or csi-rs.
Then all the other parameters (tci-presentindci, trs-info, repetition) are adjusted accordingly.
Do you see RSRP reported in Huawei Log?
Either SSB or CRI?
But it is Layer 1 reporting, how can you see it in DT logs?
It should be there in L3 as well.
Nope, Layer 3 is for HO, Layef 1 is for beam switching.
In CSF Indication all are defined in L3.
I know that csi-rs beams are transmitted periodically every 20 msec but don’t know how often UE reports the best 4 beams.
Okay, regarding report quantity, what UE need to report is already defined.
It’s defined in csi-ReportConfig.
Check following sample log:
Report id 0 report quantity just to report normal CSI (RI/PMI/CQI) without RSRP.
Nope. It says to report cri and pmi ri and cqi.
But this one is what we are discussing:
Cri means csi resource indicator.
Yes in this last case is ssb.
Do You mean CRI with RSRP?
No its not, in L1 there is a flag “Is RSRP” if this 1 the there will be RSRP report there.
In this case Is RSRP 0, so there is no CRI with RSRP as I said it reports only normal CSI.
Same case in Huawei log.
Exacly the same in this msg, you can see is_RSRP : RSRP (or in binary 1)
But that one is a different log than yours with other configuration.
You can’t expect same reporting type.
If there is CRI with RSRP the report quantity should be like this @RFSpecialist:
If the report quantity is reportQuantity:- cri-RI-PMI-CQI without RSRP, UE will not report RSRP in L1 as this is for CSI only.
SSB-RI and CSI-RI gives SSb-RSRP & CSI-RSRP.
Now whats the confudion here?