Method for uplink channel access to unlicensed band in wireless communication system, and device therefor

A user equipment of a wireless communication system, the user equipment comprising:

• a wireless communication module;
• and
• a processor configured to:
• receive, from a base station, an uplink grant that schedules an uplink transmission to the base station in at least one subframe through an unlicensed cell,
• determine a channel access type for performing the uplink transmission among a first type channel access and a second type channel access according to a predetermined interval determined based on a downlink transmission through the unlicensed cell from the base station, and
• perform, through the wireless communication module, the uplink transmission using the determined channel access type,
• wherein the first type channel access is based on a channel sensing with a random backoff before data transmission, wherein the second type channel access is based on a channel sensing with a single interval before data transmission,
• wherein the processor is configured to perform the uplink transmission using the second type channel access when all of the uplink transmission is included in a predetermined interval determined based on a downlink transmission through the unlicensed cell from the base station.

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

• a wireless communication module;
• and
• a processor configured to:
• transmit, through the wireless communication module, an uplink grant scheduling transmission of an uplink transmission through an unlicensed cell in at least one subframe and indicating a channel access type to be used when the user equipment transmits the uplink transmission among the first type channel access or the second type channel access to a user equipment, wherein the first type channel access is based on a channel sensing with a random backoff before data transmission, wherein the second type channel access is based on a channel sensing with a single interval before data transmission,
• receive, through the wireless communication module, the uplink transmission from the user equipment in the at least one subframe, and
• determine a channel access type to be used by the user equipment among the first type channel access and the second type channel access based on a predetermined interval determined based on downlink transmission from the base station to the user equipment through the unlicensed cell,
• wherein when all of the uplink transmission in the at least one subframe is included in the predetermined interval, the processor is configured to transmit common downlink control information indicating to perform the second type channel access in the uplink transmission.

A wireless communication network comprising:

• a user equipment,
• a base station
• wherein the user equipment configured to:
• receive, from the base station, an uplink grant that schedules an uplink transmission to the base station in at least one subframe through an unlicensed cell,
• determine a channel access type for performing the uplink transmission among a first type channel access and a second type channel access according to a predetermined interval determined based on a downlink transmission through the unlicensed cell from the base station, and
• perform the uplink transmission using the determined channel access type, wherein the first type channel access is based on a channel sensing with a random backoff before data transmission, wherein the second type channel access is based on a channel sensing with a single interval before data transmission,
• wherein the processor is configured to perform the uplink transmission using the second type channel access when all of the uplink transmission is included in a predetermined interval determined based on a downlink transmission through the unlicensed cell from the base station.