Dear Experts,
Beam Switching in NR:
What is the message in MAC layer for it?
And mechanism how to report UE RSRP?
Will be helpful if you may explain bit detail…
UE Reports L1-RSRP as a PHY Message along with CSI-Report it will be either SSBRI or CRI.
NW sends MAC CE to UE for Beam change which contains TCI State ID , MAC DL TB Block(QXDM) message.
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Yes I saw this in Nokia log through CSI report SSB.
Is there any other way to report it ?
Because I can’t see the same msg in CSI report for Huawei.
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Actually the switch to the new beam is in the DCI not in the MAC CE.
But indeed it points to TCI state from MAC CE.
Yes Correct 
.
I gave at a high level.
Please check PUCCH schedule reports as these messages are send over PUCCH periodically.
So what is relation DCI with MAC CE to switch the beam?
As its not in the flow.
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Inside the MAC CE there are 8 possible TCIs.
The TCI inside the DCI will point to one specific TCI of those 8 possible TCIs.
That means MAC CE comes not so often but DCI to switch beams comes quite often as RF changes.
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Hi @samohiuddin, thanks for info.
Please tell if is it possible to see info in RRC connection reconfiguration whether UE meaure SSB or CSI-RS any parameter for same to control.
Is it linked to refined beam concept?
Yes, Network configures this in RRC Reconfiguration message (csi-ReportConfigToAddModList).
Message from RRC Reconfig:
Thanks @samohiuddin.
In my logs I am seeing the info below:
csi-ReportConfigToAddModList [ 0 ]
. . . . . . . . . . . . . . . . . . . . . . . . . . . .reportConfigId: 0
. . . . . . . . . . . . . . . . . . . . . . . . . . . .resourcesForChannelMeasurement: 0
. . . . . . . . . . . . . . . . . . . . . . . . . . . .csi-IM-ResourcesForInterference: 11
. . . . . . . . . . . . . . . . . . . . . . . . . . . .reportConfigType:- periodic
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .reportSlotConfig:- slots160: 15
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .pucch-CSI-ResourceList [ 0 ]
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .uplinkBandwidthPartId: 1
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .pucch-Resource: 11
. . . . . . . . . . . . . . . . . . . . . . . . . . . .reportQuantity:- cri-RI-PMI-CQI: null
Here report quantity: indicates measurement on basis of CSI-RS correct.
UE measurement reg SSBRI or CRI can be captured from CSF Info.
One example is here:
[ [0xB891] NR5G MAC LL1 CSF Indication
Chipset timestamp: 2020-03-18 18:12:11.998938, CFN : 75
Dual Mode Index : 1
SIM Index : 255
Version : 65537
Major.Minor Version : 1.1
log_fields_change
log_fields_change_bmask : 0x0000
sub_id : 0
num_records : 3
Records
Record[0]
report_ul_time
slot : 65
numerology : 120kHz
frame : 623
carrier_id : 0
report_id : 2
report_type : APERIODIC
num_bits_part1 : 35
num_bits_part2 : 0
is_rsrp : RSRP
num_bits_part2 : 0
debug_only : Result_from_WP
report_quanlity : RSRP , SSB_INDEX
resource1 : 5
resource2 : 2
resource3 : 4
resource4 : 1
resource_type : SSB
num_resource_bits : 4
pad : 0
rsrp1 : 61
rsrp2 : 59
rsrp3 : 58
rsrp4 : 51
valid_rsrp : 4
Record[1]
report_ul_time
slot : 65
numerology : 120kHz
frame : 623
carrier_id : 0
report_id : 0
report_type : APERIODIC
num_bits_part1 : 24
num_bits_part2 : 0
is_rsrp : RSRP
num_bits_part2 : 6
debug_only : Result_from_WP
report_quanlity : CRI , RSRP
resource1 : 0
resource2 : 1
resource3 : 2
resource4 : 0
resource_type : CSI_RS
num_resource_bits : 3
pad : 0
rsrp1 : 68
rsrp2 : 67
rsrp3 : 54
rsrp4 : 0
valid_rsrp : 3
Record[2]
report_ul_time
slot : 65
numerology : 120kHz
frame : 623
carrier_id : 0
report_id : 1
report_type : APERIODIC
num_bits_part1 : 24
num_bits_part2 : 0
is_rsrp : RSRP
num_bits_part2 : 6
debug_only : Result_from_WP
report_quanlity : CRI , RSRP
resource1 : 0
resource2 : 1
resource3 : 3
resource4 : 0
resource_type : CSI_RS
num_resource_bits : 3
pad : 0
rsrp1 : 73
rsrp2 : 56
rsrp3 : 52
rsrp4 : 0
valid_rsrp : 3
In above Record 0 is SSBRI measurement RSRP and Records 1 and 2 is of CSI-RSRP
Thanks dear. Is it valid for both FR1 and FR2?
I have seen it so far for mmW FR2 (28 & 39 GHz).
For FR1 (600, 850 or 2500) I have’nt seen yet. (Need to check 3GPP specs to confirm).