MAC CE - C RNTI
The Cell Radio Network Temporary Identifier (C-RNTI) is a unique identifier used in cellular networks, including 5G. It is a temporary identifier assigned to a UE by the base station (in the case of 5G, this is the gNodeB) when the UE first successfully establishes a connection to the cellular network. Usually it is assigned during the RACH process (msg 4) .
The C-RNTI is specific to the cell the UE is currently connected to. If the UE moves to a different cell, a new C-RNTI will be assigned by the new cell's gNodeB. This identifier is critical for efficient and accurate communication between the UE and the network infrastructure.
The C-RNTI serves the following purposes:
The structure of MAC-CE for C-RNTI is as follows. The C-RNTI MAC CE is identified by MAC subheader with LCID
< 38.321 - Figure 188.8.131.52-1: C-RNTI MAC CE >