TM9 - Number of antenna at UE end and eNodeB end

Hi Experts,

It’s known tm9 Introduced as part of 3gpp rel 10 having 8x8 mimo mode, where csi rs reference signal introduced with ports 15 to 22 and pdsch with dm-rs with 7 to 14 ports, i.e. UE specific reference signal.

Need to understand for tm9 how many rx needed at UE end if 8 ports, 4 ports configured at antenna end.

Number of antenna at UE end and at enodeB end are different.
But for 8 layers UE will need 8 RX antenna.
However nobody implemented 8x8 mimo because it does not happen in the field.
For 4x4 MIMO you need 4 RX antenna.

Generally for tm9 we have options for csi rs antenna ports as 1, 2, 4, 8 with virtual ports 15 to 22.
But here UE specific rs ports also 7 to 14.
Like tm8 we have only 2 virtual ports 7, 8 so its clear at UE end 2 RX enough to receive 2 layers from port 7, 8.
In same way I’m thinking for UE specific ports 7 to 14 which are fixed for tm9, how UE will receive beam?

Let me undesrtand, is possible to configure TM9 for 4x4 MIMO or only 8x8?

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