A user equipment (UE) for random access operation in a wireless communication system. The UE comprises at least one transceiver configured to receive, from a base station (BS), RACH configuration information including an RACH structure corresponding to a first beam identification (ID), beam sweeping operation and mapping between downlink signals and RACH chunks and/or RACH preamble subsets. The UE comprises at least one processor configured to determine an RACH preamble based on the RACH structure configuration received from the BS. The UE comprises the transceiver further configured to transmit, to the BS, the RACH preamble over a first beam associated with the first beam ID and receive, from the BS, an RACH response corresponding to the RACH preamble over a second beam, wherein the first beam is different than the second beam.