In CFRA, a dedicated Preamble ID is allocated to the UE as part of the RRC ReConfiguration message.
My confusion is how/where does the UE acquire info about the root ID, especially in NSA.
As I understand it, for a UE to generate the preamble, it would actually need root ID and Ncs. I did refer to TS 38.331 to understand the Rach-ConfigDedicated structure (?).
I could locate the ZcZ element and Preamble ID message… but not the root ID!
Indeed I may be missing something.
It would be really helpful if someone kindly clear my confusion.