It’s used for deployment below 6 GHz.
Here 1 SSB beam used per sub sector.
2 sub sectors using 4 trx each (4x4 MIMO supported).
In my LTE RRC reconfig message I see below, ant port count as 8 but in MIMO config I don’t see 8 x 2:
Did you check codebook n1-n2?
This is 4G.
Ok, So how is the mapping for 8 CSI-RS ports done for 4x2 ant port MIMO config?
Sorry, my answer was for 5G. 
Im assuming 8 is csi-rs ports and the above PDSCH info 2x4 as the antenna port.
Is that correct?
In your picture antenna ports is 2
eNodeB is transmitting using 2 antenna ports.
Ok. I think my question was confusing, I’ll rephrase it below:
This is for 4G.
In RRC reconfig I have ant port count as 8 in csi-rs config.
For the same timestamp I have PDSCH MIMO config 2x4 ie 2 antenna ports
I’m trying to understand this:
Should I report 8 x4 or 2x4
Note: it is for a live NW, not a simulator.
Ok. You are trying tm9 if I m not wrong.
Even I observed same 2 antenna port with 8 CSI rs config.
For tm9 I assumed we have virtual antenna port like tm8 we have p7, p8 for user beam.
So what should I interpret from this? (MIMO Config)
Precoding matrix is MxL, where M is antenna ports and L is layers.
It has nothing to do with number of UE RX antenna, that is 4 in your case.
But MIMO mode has to do with number of TX antenna and RX antenna.
Yes, I’m clear on Rx part regarding device antenna count for MIMO.
Tx part 8 vs 2…
Tm9 includes beamforming, right?
Yes, but Tx diversity also works with it.
And any idea why my Rx ant config moves from 4 to 2 as below:
For tm9 it’s like UE can receive 8 layers with 2 ports using port 7 to 14 as mentioned in theory.
For csi-rs port 15 to 22 used.
Because it saves energy when those antenna are not in use.
It is about how each air interface matrix can be divided in 3: precoding, diagonal matrix and equalizer matrix.
Precoding is eNodeB, and equalizer is UE.
And diagonal matrix is air interface after SVD.
If diagonal matrix uses only 2rx antenna for 2 layers why it should keep 4?
Number of layers is always dictated by number of uncorrelated multipaths between enodeb and ue
So it is UE job to calculate rank/layers and report PMI according to those layers
Then in next scheduling enodeb uses what ue reported
For that UE.
Rank is always smaller or equal to min (tx ant, rx ant).
In your case Tx ant is 8.
RI was 2 for this case.
Always smaller or equal to min (8,4).
In your case.
So rank can be 1, 2, 3 or 4.
If you want rank 8 you need to bring a UE with 8 Rx antenna and special RF conditions.
Very likely you will not face those conditions in reality to get rank 8.
How do we conclude this as I have shown csi-rs config with 8 antennas but PDSCH with 2 Tx for TM9?