TM modes in 5G

Hi 5G Experts,
In 5G we haven’t used concept of TM modes like LTE TM1 to TM10.
Any specific technical reason for the same ?

5G only have transmission scheme 1.
Can be due to beamforming concept TM modes not considered.
Keeping uniform.

But LTE also have BF from TM9, right?

From TM7 infact:

From TM7 correct.
Single stream beamforming.

In 5G we have all included in MIMO transmission schemes Scheme 1 and 2 I guess.

Scheme 2 I don’t have idea.

Scheme 1: Closed-loop transmission where data and DM-RS are transmitted with the same precoding matrix
Demodulation of data at the UE does not require knowledge of the precoding matrix used at the transmitter
Note: spatial multiplexing and rank-1 are included

Scheme 2: Open loop and Semi-open loop transmissions where data and DM-RS may or may not be restricted to be transmitted with the same precoding matrix.
Demodulation of data at the UE may or may not require knowledge of the relation between DM-RS ports and data layers
Note: DM-RS can be pre-coded or not pre-coded"

Scheme1 is only implemented everywhere as per my observation.

Which are the parameters to know from trace?
TS1 or TS2 supported by gNB?
Also UE capability para?

I’m not sure of network setting, but in UE you can get this from below Tree for Qualcomm chipset device:

Qualcomm 5G-NR MAC PDSCH Info PCell MIMO Scheme

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In which 3gpp release TS2 in 5G?

I think scheme 1 is always use in 5G because data and PDSCH DMRS are always coded with same precoding matrix.

Correct @RFSpecialist, but I haven’t seen TS2 in 3gpp.
Open loop/closed loop all MIMO configuration are with TS1 only with different precoder with CSI RS port configuration.
That’s why I asked in which release TS2 is defined?

++ Semi open loop as mentioned.

I think it didn’t make it into the specs but was in TSG WG discussions only.

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