A method of user equipment (UE) for random access operation in a wireless communication system is provided. The method comprises receiving, from a base station (BS), random access channel (RACH) configuration information including RACH chunk information corresponding to at least one antenna beam including a beam identifier (ID), determining a RACH chunk based on the RACH configuration information received from the BS, transmitting, to the BS, a RACH preamble on the determined RACH chunk according to the RACH configuration information associated with the beam ID, and receiving, from the BS, a RACH response (RAR) corresponding to the transmitted RACH preamble and a downlink channel for a RAR transmission, wherein a random access-radio network temporary identification (RA-RNTI) is calculated based on an index of a slot and an index of the RACH chunk on which the RACH preamble is transmitted.