Apparatus and method of identifying downlink transmission beam in a cellular network

A method performed by a base station in a wireless communication system, the method comprising:

• transmitting, to a terminal, first information on at least one random access (RA) preamble for each system information (SI) request and second information for configuring at least one physical random access channel (PRACH) occasion associated with each synchronization signal (SS) block;
• and
• receiving, from the terminal, a RA preamble in a physical PRACH occasion, the RA preamble indicating an SI message which the terminal needs to request;
• and
• transmitting, to the terminal, the SI message indicated based on the RA preamble.

A terminal in a wireless communication system, the terminal comprising:

• a transceiver;
• and
• a controller coupled with the transceiver and configured to:
• receive, from a base station, first information on at least one random access (RA) preamble for each system information (SI) request and second information for configuring at least one physical random access channel (PRACH) occasion associated with each synchronization signal (SS) block,
• select an SS block,
• select a RA preamble corresponding to the selected SS block, from the at least one RA preamble for an SI message which the terminal needs to request based on the first information,
• identify a PRACH occasion corresponding to the selected SS block based on the second information,
• transmit, to the base station, the RA preamble in the PRACH occasion, the RA preamble indicating the SI message which the terminal needs to request, and
• receive, from the base station, the SI message indicated based on the RA preamble.

A base station in a wireless communication system, the base station comprising:

• a transceiver;
• and
• a controller coupled with the transceiver and configured to:
• transmit, to a terminal, first information on at least one random access (RA) preamble for each system information (SI) request and second information for configuring at least one physical random access channel (PRACH) occasion associated with each synchronization signal (SS) block,
• receive, from the terminal, a RA preamble in a PRACH occasion, the RA preamble indicating an SI message which the terminal needs to request, and
• transmit, to the terminal, the SI message indicated based on the RA preamble.