Question: In MR-DC, how does the UE acquire radio frame timing and SFN of SCG?
Option 1: Through broadcasted system information by the SN.
Option 2: From the PSS/SSS and MIB (if the SN is an eNB) / NR-PSS/SSS and PBCH (if the SN is a gNB) of the PSCell via dedicated RRC signalling.
Option 3: Through OAM configuration by the network.
Option 4: From the MN during initial configuration.
Explanation: In MR-DC, the UE acquires radio frame timing and SFN of SCG from the PSS/SSS and MIB (if the SN is an eNB) / NR-PSS/SSS and PBCH (if the SN is a gNB) of the PSCell via dedicated RRC signalling. This is because the SN is not required to broadcast system information other than for radio frame timing and SFN, and instead provides system information for initial configuration through dedicated RRC signalling via the MN.