The SNR calculation in the SSB and the SINR calculations in the PDSCH and PUSCH are done:

1. First when the two MIBs are sent (at 80ms and 160ms)
2. Next when the RRC_SI is sent
3. Next when the RRC setup is sent
4. Subsequently at every 120ms (UE Measurement interval) when the UE measurement report is sent
5. Every instance when a UE moves

Useful links

1. Overview of NetSim 5G library: https://tetcos.com/5g.html

2. NetSim 5G documentation (v13.3): https://www.tetcos.com/help/v13.3/Technology-Libraries/5G-NR.html