Method and device for configuring transmission opportunity period in wireless access system supporting unlicensed band

A method for performing a downlink transmission in a wireless access system supporting an unlicensed band, the method comprising:

• performing a carrier sensing procedure for checking whether a cell of the unlicensed band is idle or not;
• and
• performing the downlink transmission during a downlink transmission duration after the cell of the unlicensed band has been checked as the idle,
• wherein the downlink transmission duration is configured with one or more consecutive time periods, and wherein a last time period of the downlink transmission duration is a small time period which is smaller than a full time period.

An enhanced Node B (eNB) for performing a downlink transmission in a wireless access system supporting an unlicensed band, the eNB comprising:

• a receiver;
• a transmitter;
• and
• a processor supporting the downlink transmission,
• wherein the processor is configured to:
• perform, by controlling the receiver, a carrier sensing procedure for checking whether a cell of the unlicensed band is idle or not;
• and
• perform, by controlling the transmitter, the downlink transmission during a downlink transmission duration after the cell of the unlicensed band has been checked as the idle,
• wherein the downlink transmission duration is configured with one or more consecutive time periods, and wherein a last time period of the downlink transmission duration is a small time period which is smaller than a full time period.