Method for transmitting and receiving uplink signal in wireless communication system supporting unlicensed band, and apparatus supporting same
The present invention discloses a method, in a licensed assisted access (LAA) system, where a base station or user equipment (UE) performs a listen-before-talk (LBT)-based signal transmission, for transmitting and receiving an uplink signal between the UE and the base station, and an apparatus supporting the same. Specifically, the present invention discloses a method for a UE transmitting an uplink signal flexibly and efficiently based on LBT parameters indicated by the base station, and an apparatus supporting the same.
1. A method of transmitting an uplink signal, which is transmitted by a user equipment (UE) to a base station in a wireless communication system supporting an unlicensed band, the method comprising:
receiving a signal for scheduling uplink transmission in an N th (N is a natural number) subframe from the base station;
when there is a currently performed first LBT (listen-before-talk) prior to the N th subframe and a channel access priority class of a first LBT parameter for the first LBT is equal to or greater than a channel access priority class of a second LBT parameter for a second LBT indicated for the N th subframe, continuously performing the currently performed first LBT;
when there is the currently performed first LBT prior to the N th subframe and the channel access priority class of the first LBT parameter for the first LBT is less than the channel access priority class of the second LBT parameter for the second LBT, performing the second LBT; and
performing uplink transmission based on a result of the LBT performed by the UE.
2. The method of claim 1 , further comprising wherein when there is the currently performed first LBT prior to the N th subframe and the channel access priority class of the first LBT parameter for the first LBT is less than the channel access priority class of the second LBT parameter for the second LBT, terminating the first LBT.
3. The method of claim 1 , wherein performing the second LBT comprises initializing operation of the first LBT performed by the UE and performing the second LBT.
4. The method of claim 1 , further comprising when there is uplink transmission in a subframe before the N th subframe, performing uplink transmission in the N th subframe without an LBT operation.
5. A user equipment transmitting an uplink signal to a base station in a wireless communication system supporting an unlicensed band, the user equipment comprising:
a receiver;
a transmitter; and
a processor configured to operate in a manner of being connected with the receiver and the transmitter,
wherein the processor configured to:
receive a signal for scheduling uplink transmission in an N th (N is a natural number) subframe from the base station;
when there is a currently performed first LBT (listen-before-talk) prior to the N th subframe and a channel access priority class of a first LBT parameter for the first LBT is equal to or greater than a channel access priority class of a second LBT parameter for a second LBT indicated for the N th subframe, continuously perform the currently performed first LBT;
when there is the currently performed first LBT prior to the N th subframe and the channel access priority class of the first LBT parameter for the first LBT is less than the channel access priority class of the second LBT parameter for the second LBT, perform the second LBT; and
perform uplink transmission based on a result of the LBT performed by the UE.
6. The user equipment of claim 5 , wherein when there is the currently performed first LBT prior to the N th subframe and the channel access priority class of the first LBT parameter for the first LBT is less than the channel access priority class of the second LBT parameter for the second LBT, the processor is configured to terminate the first LBT.
7. The user equipment of claim 5 , wherein performing the second LBT comprises initializing operation of the first LBT performed by the UE and performing the second LBT.
8. The user equipment of claim 5 , wherein when there is uplink transmission in a subframe before the N th subframe, the processor is configured to perform uplink transmission in the N th subframe without an LBT operation.