Method and user equipment for transmitting random access signals, and method and base station for receiving random access signals

A user equipment (UE) for transmitting random access signals, the UE comprising:

• a radio frequency (RF) unit, and
• a processor configured to control the RF unit,
• wherein the processor is further configured to:
• control the RF unit to receive, from a base station (BS), configuration information of a first random access channel (RACH) resource for a first RACH preamble format and configuration information of a second RACH resource for a second RACH preamble format;
• and
• control the RF unit to transmit, to the BS, a physical RACH (PRACH) with the first RACH preamble format on the first RACH resource or with the second RACH preamble format on the second RACH resource,
• wherein the processor is configured to control the RF unit to transmit the PRACH with the first RACH preamble format on the first RACH resource if transmission (Tx) and reception (Rx) (Tx/Rx) beam correspondence holds at the UE, and the processor is configured to control the RF unit to transmit the PRACH with second RACH preamble format on the second RACH resource if the Tx/Rx beam correspondence does not hold at the UE,
• wherein if the Tx/Rx beam correspondence does not hold at the UE and holds at the BS, the processor is configured to control the RF unit to transmit the PRACH with the second RACH preamble format by changing Tx beam directions of the UE on the second RACH resource in a form of repetition of a cyclic prefix (CP) and a preamble sequence and a guard time (GT), and
• wherein if the Tx/Rx beam correspondence does not hold at both the UE and the BS, the processor is configured to control the RF unit to transmit the PRACH with the second RACH preamble format by changing Tx beam directions of the UE on the second RACH resource in a form of the CP and repetition of the preamble sequence and the GT.