Usage of CSI-RS in 5G NR

I am reading the examples of 5G toolbox about CSI-RS. In the examlpe it seem we just assume the sequence is known by the receiver and we can do measurements using the known sequence and received signal. My question is how the receiver know which CSI-RS is used? Also, how the receiver know when the CSI-RS is transmitted?

Another question is about beam tracking. CSI-RS can be used for beam tracking right? I cannot find detail explaination about how to do it. Do we use different beamforming vector for several CSI-RS, then get the measurements at receiver and evaluate their quality, just like what we do on SSB?

Answer 1

[Graham Freeland]

The CSI-RS in use are signalled to a UE through common and dedicated L3/RRC signalling. Take a look at the RRC ASN in 38.331 for an idea of the message contents that are sent semi-statically. Yes, the CSI-RS are used, in conjunction with various measurements, as part of the beam management procedures.