Method for transmitting uplink signal and apparatus supporting method in wireless communication system supporting non-licensed band
Discloses are a method for a terminal for transmitting an uplink signal to a base station and an apparatus supporting the method in a licensed assisted access (LAA) system in which a base station or a terminal transmits listen-before-talk (LBT)-based signals. Specifically, disclosed are a method for a terminal transmitting an uplink signal by executing a particular LBT action and an apparatus supporting the method if the uplink signal is transmitted by the terminal by sharing a maximum channel occupancy time (MCOT) with a base station.
1. A method for performing a Listen-Before-Talk (LBT)-based channel access procedure by a user equipment (UE), the method comprising:
detecting, by the UE, each physical downlink control channel (PDCCH) signal from a base station (BS); and
performing by the UE, a LBT-based channel access procedure for an uplink transmission based on each PDCCH signal,
wherein, based on i) the UE detecting a first PDCCH signal, ii) the first PDCCH signal indicating a set of time resources as being within a remaining duration of a BS-initiated channel occupancy time (COT), and iii) after the first PDCCH signal, a subsequent PDCCH signal indicating that the set of the time resources indicated as being within the remaining duration of the BS-initiated COT is not within a subsequent remaining duration of the BS-initiated COT, the method further comprises operations by the UE based on an assumption that:
the subsequent PDCCH signal indicating the set of the time resources is not within the subsequent remaining duration of the BS-initiated COT, is not detected.
2. The method according to claim 1 , wherein the UE considers that the remaining duration of the BS-initiated COT which has been indicated by the first PDCCH signal, is not to be shortened.
3. The method according to claim 1 , wherein the each PDCCH signal indicates its remaining duration of the BS-initiated COT based on a time where a corresponding PDCCH signal is detected.
4. The method according to claim 1 , wherein the LBT-based channel access procedure is related to a random-backoff-less LBT in which the UE is allowed to perform the uplink transmission after determining that a channel is idle for a predetermined time duration.
5. The method according to claim 4 , wherein the predetermined time duration is 25 us.
6. The method according to claim 4 , wherein the UE performs a random-backoff-based LBT for an uplink transmission not within any remaining duration of the BS-initiated COT.
7. The method according to claim 1 , wherein the UE obtains information regarding at least one of a start and a length of a corresponding remaining duration of the B S-initiated COT from the each PDCCH signal.
8. The method according to claim 1 , wherein the BS-initiated COT is based on a result of a LBT-based channel access procedure performed by the BS being determined as idle.
9. The method according to claim 1 , wherein the each PDCCH signal is related to multi-UE common signaling.
10. The method according to claim 1 , wherein the LBT-based channel access procedure is for performing the uplink transmission on an unlicensed band.
11. The method according to claim 1 , wherein each remaining duration of the BS-initiated COT is a time duration of the BS-initiated COT not used by the BS for a downlink transmission.
12. The method according to claim 11 , wherein each remaining duration of the B S-initiated COT is related to an early completion of the downlink transmission before an end of the BS-initiated COT.
13. A non-transitory medium readable by a processor and recorded thereon instructions cause the processor to perform the method according to claim 1 .
14. A device for processing a signal for wireless communication, the device configured as a user equipment (UE) and comprising:
a memory configured to store instructions; and
a processor configured to perform operations by executing the instructions, the operations comprising:
detecting by the UE, each physical downlink control channel (PDCCH) signal from a base station (BS); and
performing by the UE, a Listen-Before-Talk (LBT)-based channel access procedure for an uplink transmission based on each PDCCH signal, wherein, based on i) the UE detecting a first PDCCH signal, ii) the first PDCCH signal indicating a set of time resources as being within a remaining duration of a BS-initiated channel occupancy time (COT), and iii) after the first PDCCH signal, a subsequent PDCCH signal indicating that the set of the time resources indicated as being within the remaining duration of the BS-initiated COT is not within a subsequent remaining duration of the BS-initiated COT, the method further comprises operations by the UE based on an assumption that:
the subsequent PDCCH signal indicating the set of the time resources is not within the subsequent remaining duration of the BS-initiated COT, is not detected.
15. The device according to claim 14 , further comprising:
a transceiver, and wherein the device is a user equipment (UE) configured to perform 3rd generation partnership project (3GPP)-based wireless communication.
16. The device according to claim 15 , wherein the device is an application specific integrated circuit (ASIC) or a digital signal processing device.
17. A method for performing a Listen-Before-Talk (LBT)-based channel access procedure by a base station (BS), the method comprising:
performing, in a BS-initiated channel occupancy time (COT), a downlink transmission based on a LBT-based channel access procedure; and
transmitting each physical downlink control channel (PDCCH) signal,
wherein, based on i) the BS transmitting a first PDCCH signal, ii) the first PDCCH signal indicating a set of time resources as being within a remaining duration of a BS-initiated channel occupancy time (COT), and iii) the BS being configured to transmit a subsequent PDCCH signal indicating a subsequent remaining duration of the BS-initiated COT after the first PDCCH signal, the BS determines that:
the subsequent PDCCH signal is not going to indicate that the set of the tim e resources indicated as being within the remaining duration of the BS-initiated COT is not within the subsequent remaining duration of the BS-initiated COT.
18. A base station (BS) comprising:
a transceiver; and
a memory configured to store instructions; and
a processor configured to perform operations by executing the instructions, the operations comprising:
performing, in a BS-initiated channel occupancy time (COT), a downlink transmission based on a Listen-Before-Talk (LBT)-based channel access procedure; and
transmitting each physical downlink control channel (PDCCH) signal,
wherein, based on i) the BS transmitting a first PDCCH signal, ii) the first PDCCH signal indicating a set of time resource as being within a remaining duration of a BS-initiated channel occupancy time (COT), and iii) the BS being configured to transmit a subsequent PDCCH signal indicating a subsequent remaining duration of the BS-initiated COT after the first PDCCH signal, the BS determines that:
the subsequent PDCCH signal is not going to indicate that the set of the time resources indicated as being within the remaining duration of the BS-initiated COT is not within the subsequent remaining duration of the BS-initiated COT.
19. A method for performing a Listen-Before-Talk (LBT)-based channel access procedure by a user equipment (UE), the method comprising:
detecting, by the UE, each physical downlink control channel (PDCCH) signal from a base station (BS); and
performing, by the UE, a LBT-based channel access procedure for an uplink transmission based on the each PDCCH signal,
wherein, based on i) the UE detecting a first PDCCH signal ii) the first PDCCH signal indicating a set of time resources as being within a remaining duration of a BS-initiated channel occupancy time (COT), and iii) the UE being configured to detect a subsequent PDCCH signal indicating a subsequent remaining duration of the BS-initiated COT after the first PDCCH signal, the UE determines that:
the subsequent PDCCH signal is not going to indicate that the set of the time resources indicated as being within the remaining duration of the BS-initiated is not within the subsequent remaining duration of the BS-initiated COT.