SRS transmission in case of codebook based transmission

5G NR
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1

Hi Experts,

In case of codebook based transmission how SRS transmission happens at UE based on No of SRS ports = 1 or 2 or 4 configured. Also how UE will decide on which antenna ports it has to transmit SRS.

Please help me with this.

2

If SRS is configured with the number of ports set to 1, UE transmits SRS signal on only one port at a time. If SRS is configured with the number of ports set to 2, UE transmits SRS signal corresponding to 2 ports at a time, like in MIMO operation.

Mapping between each SRS resource and the corresponding port set is up to the UE vendor. The network doesn’t need to know this info.

3

Thanks @pradeep.

For example When we have only 1 srs resource configured with No of srs ports = 2 and if UE has four antenna ports then on which 2 antenna ports SRS should be transmitted is up to UE vendor.

Am I correct?

4

Yes… that’s right. But if that one SRS resource is codebook type, UE will use the same ports it is using for pusch transmission.

5

Thanks pradeep