Method for terminal communicating in mmWave communication system and terminal

A User Equipment (UE) for supporting a millimeter wave (mmWave) communication system, the UE comprising:

• a transmitter;
• a receiver;
• and
• a processor connected to the transmitter and the receiver,
• wherein the processor is configured to:
• control the receiver to receive information on a default uplink/downlink (UL/DL) configuration from a mmWave Base Station (BS);
• generate statistical information on a mmWave DL channel using a reference signal received from the mmWave BS according to the default UL/DL configuration;
• control the transmitter to transmit the statistical information to the mmWave BS via legacy UL;
• control the receiver to receive, from the mmWave BS, information on a UL/DL configuration that is modified based on the statistical information,
• wherein the information on the default UL/DL configuration is received from a mmWave System Information Block (SIB) broadcast by the mmWave BS, and
• align synchronization of mmWave UL, mmWave DL, and the legacy UL using the mmWave SIB.