Hello Experts,
Anyone worked over refined beam for 5G FR1 if enabled in any network?
In that scenario does UE select best refined beam on the basis of CSI-RS or any change in mechanism?
Hi there,
Beam refinement mechanism is based on SSB (mandatory) or CSI-RS(optional) up to UE capability. However, most of the infravendors currently support both approaches.
In the case of DL Tx (gNB) Beam refinement (used to be called by P2 procedure), the eNB must configure TCI States (QCL Type, ReferenceSignal, TCI state ID, etc) through RRC signaling, on top of that, the UE must be configured with L1-RSRP reports. Only after receiving the L1 measurements reports the gNB might change the Beam through DCI or MAC-CE.
On the other hand, if the device is configured with DL UE Rx beam refinement (used to be called by P3 procedure), there is no need to report L1-RSRP and the decision is done autonomously by the UE.
Hello Experts.
Any network having refined beam deployment?
If yes please share how refined beam work with coarse beams.
1 coarse or ssb beam = 4 refined beams for FR1
How user will select beam in that case for cell access if both coexist
Right, one of the OEM have this implementation.
4 refined beams per SSB, CSI-RS is used for beam management which is broadcasted as Frequency multiplexed with SS PBCH.
UE may report best / 2 best CSI-RS based on that gNB decides the refined beam to be used.
Thanks!
So csi-rs beams used for beam management only.
Is it possible to have user data schedule on it?
It is not possible to schedule user data in CSI-RS as it is meant to be used for the measurement and is a Reference signal (something which is standard and known to N/W and UE both).
PDSCH can be allocated in SSB slots as well in the remaining REs where UE data can be scheduled.
CSI-RS transmission can be beamformed or without beamformed.
In our network, Ericsson is transmitting 1 CSI-RS beam only using 32 port antenna ( N:N2=8:2) whereas Nokia is transmitting 4 beams using 8 port antenna (N:N2=2:2).
Any reference link / doc for csi-rs beam vs ssb beam clear major difference? Please share…
As per idea csi-rs beams deployed in rare network.
SSB beam is for initial access. CQI, PMI, and Ri reporting is based on CSI-RS. Codebook based PDSCH beamforming is based on CSI-RS configuration ( N1, N2, O1, O2).
Ericsson is radiating with 1 SSB beam to cover the entire cell whereas Nokia is using 6 SSB beams.
Yes, it’s clear UE will use csi-rs reference signal for cqi, ri etc. reporting in NR.
Here concern is for csi-rs beams, how is it used in network?
Do you mean codebook based PMI base beamforming?
Nokia uses 4 CSI RS beam to transmit the CSI reference signal, each beam having 2:2 N1N2 configuration.
So the UE will computes 64 beams ( N1O1N2O2 =2424) and reports the best beam using i11 i12, i13 and i2 when RI is 2, 3 or 4.
So, there is 4 CSI-RS beams, total no of beams available in the entire cell will be 64*4=256 beams.