Hi Experts.
For NR anyone tried with 4 SSB beams i.e. 8 layer what value of throughput observed?
My understanding is that we can’t use 8 SSB beam for 3 to 6 GHz although it’s mentioned that we can configure 8 SSB beam for 3 to 6 GHz in theory.
8 SSB beams generaly not used.
Rather 7 SSB beams are used.
1 SSB is used as sector beam.
7 SSB beam. Please tell how it possible?
As per 3gpp as of now PDSCH scheme 1 there which allowed max 8 layers.I mean we can use max 8 layers which mean 4 SSB beam. How can 7 SSB beam possible?
Who said that we can’t configure 8 SSB beams for 3:6 GHz, this can be done and I saw some networks using it.
I find we can use max 8 layers by PDSCH transmission scheme 1. (From 5G NR Bullets Book; 4.3 PDSCH Chapter, first bullet).
Excuse me, what do you mean by 1 SSB is used as sector beam?
Actually, I heard this statement for Huawei although I don’t realize how it can be configured at the time domain.
As simply each SSB block has its own limited time that is representing one beam, so for sector beam it should scan all same times where all beams are configured, right?
Or is it configured differently?
Also, what is the benefit for this sector beam if all beams are covering the whole cell?
This sector beam and UE beam concept valid with massive MIMO in LTE.
Never seen sector beam concept with NR.
Sector beam indicates CRS signal read by all UE in cell.
UE beam indicates beam for specific user.
1 Like
Don’t confuse between PDSCH Layers and SSB beams as one SSB beam can support up to 2 layers, so you need only 4 SSB beams to get 8 layers, however UEs are normally supporting 4 layers only.
This is for one UE which is SU-MIMO.
My understanding is that codeword transmit on same layer only i.e.1 SSB beam = 2 layers
In NR upto 4 layers single codeword required.
Point is that with 8 SSB beam we have 16 layers (PDSCH layers)
But as per PDSCH transmission scheme 1 in NR we can have upto 8 layers.
Please correct if understanding not correct.
Max 8 layers per user SU-MIMO, but Huawei has 16 PDSCH layers for MU-MIMO.
Yes, that’s completely right, totally agree with you 
Issue is that there is a chance one in a million to get 8 layers, 8 multipaths, uncorrelated not to interfere each other.
Again, 8 layers are for one user.
For more users there will be reusage of DMRS.
This is what Huawei is doing.
Yes agree understood 8 layers for 1 user or can be between multiple UE as per no of rx capability in UE.
What about 16 layers? It’s required 8 SSB beam.
Does this deployment any where exist?
Huawei does not have PDSCH beams based on SSB beams.
Only Nokia has it this way (or maybe others too).
In Huawei PDSCH beams are either based on PMI or SRS.
I see in Huawei SSB and PDSCH beam separated.
Never find such extract in NR in bullets. Any section I can refer if there please tell.
Yes, that’s true. However, I never saw such an implementation, if UE is lucky, it will get 4 layers.
So 8 layers is basically usefull in mu mimo scenario.
In case of su-mimo 4 there will not be much gain even if system supports 8 layers.
There are few UEs supporting 8 layers.
In LTE only. in 5G never heard of 8 layers.
It would be impossible to happen, it doesn’t worth the effort to develop it anyway.
For SU-MIMO, that’s true.
However for Mu-MIMO, the cell can have up to 16 layers for 8 UEs and each UE can have 2 layers, assuming of course good isolation between all 8 UEs.
Even 4x4 MIMO in real life is less than 5%.