5G NSA CBRA and CFRA

5G NR
1

Hello experts,

How RACH is decided if CBRA or CFRA is to be used? We seen in the trace that SSB index is present during B1 MR followed by CFRA information. However we also noticed CBRA info.

Is it possible to have CBRA and CFRA in RRC reconfiguration during 5G SG addtion (ENDC) and use CBRA instead of CFRA? What is the use of CFRA if not used in the RRC reconfiguration?

2

When UE needs RA, if there is RA preamble received from eNB/gNB then CFRA, otherwise CBRA. So if CFRA, there must be a procedure that eNB/gNB allocates RA preamble to UE.

3

thanks. So its possible then for CFRA and CBRA info to be present on the trace at the same time.