Methods and apparatuses in a wireless communication system. A method of operating a base station (BS) includes generating an indicator indicating that the BS is capable of supporting a high-capacity radio network temporary identifier (HC-RNTI), wherein a size of the HC-RNTI is based on a configurable granularity; generating a system information block including the indicator and information indicating the size of the HC-RNTI; transmitting, to a user equipment (UE), the system information block; and transmitting, to the UE, the HC-RNTI, wherein the HC-RNTI is allocated to the UE.