Method for transmitting signal in wireless communication system, and apparatus therefor

1. A method of transmitting a signal in an unlicensed band, which is transmitted by a transmission node in a wireless communication system, the method comprising:

receiving information on additional channel sensing from a center node, information on a period of restricted signal transmission and information on a length of a minimum signal transmission period;

performing channel sensing for transmitting the signal within a first time period;

performing the additional channel sensing within a second time period immediately after the first time period according to the information on the additional channel sensing when a channel is in an unoccupied state as a result of the channel sensing;

transmitting the signal when a channel is in an unoccupied state as a result of the additional channel sensing and when the length of the minimum signal transmission period finishes before the period of restricted signal transmission according to the information on the period of restricted signal transmission; and

reserving the signal when the channel is in the occupied state as a result of the additional channel sensing or when the length of the minimum signal transmission period finishes after the period of restricted signal transmission according to the information on the period of restricted signal transmission,

wherein a length of the second time period and the period of restricted signal transmission are determined according to a transmission priority level of the transmission node,

wherein the period of restricted signal transmission has a length and an interval, and

wherein the period of restricted signal transmission is not for channel sensing of the transmission node.

2. The method of claim 1 , wherein the first time period is configured to be after a prescribed time from a transmission allowed time period of another transmission node having a transmission priority level higher than the transmission priority level of the transmission node.

3. The method of claim 1 , wherein the length of the second time period is configured in proportion to or in reverse proportion to a value of the transmission priority level of the transmission node.

4. The method of claim 1 , further comprising:

sequentially performing channel sensing in each of a plurality of slots when the second time period consists of a plurality of slots; and

transmitting the signal when a back-off counter value becomes 0.

5. The method of claim 4 , wherein the back-off counter value is configured in proportion to or in reverse proportion to a value of the transmission priority level of the transmission node.

6. The method of claim 1 , further comprising:

receiving information on a period of restricted channel sensing from the center node.

7. The method of claim 6 , wherein the period of restricted signal transmission or the period of restricted channel sensing has a length and an interval configured in proportion to or in reverse proportion to a value of the transmission priority level of the transmission node.

8. The method of claim 1 , wherein when the signal to be transmitted by the transmission node corresponds to an uplink signal, if priority of the uplink signal is higher than priority of a downlink signal, a transmission timing of the uplink signal is advanced as much as a predetermined time offset; and if the priority of the uplink signal is lower than the priority of the downlink signal, the transmission timing of the uplink signal is delayed as much as the predetermined time offset.

9. A transmission node for transmitting a signal in an unlicensed band in a wireless communication system, the transmission node comprising:

a transceiver; and a processor configured to:

control the transceiver to receive information on additional channel sensing from a center node, information on a period of restricted signal transmission and information on a length of minimum signal transmission period,

perform channel sensing for transmitting the signal within a first time period,

perform the additional channel sensing within a second time period immediately after the first time period according to the information on the additional channel sensing when a channel is in an unoccupied state as a result of the channel sensing,

control the transceiver to transmit the signal when a channel is in an unoccupied state as a result of the additional channel sensing and when the length of the minimum signal transmission period finishes before the period of restricted signal transmission according to the information on the period of restricted signal transmission, and

reserve the signal when the channel is in the occupied state as a result of the additional channel sensing or when the length of the minimum signal transmission period finishes after the period of restricted signal transmission according to the information on the period of restricted signal transmission,

wherein a length of the second time period and the period of restricted signal transmission are determined according to a transmission priority level of the transmission node, and

wherein the period of restricted signal transmission has a length and an interval, and

wherein the period of restricted signal transmission is not for channel sensing of the transmission node.

10. The transmission node of claim 9 , wherein the first time period is configured to be after a prescribed time from a transmission allowed time period of a transmission node having a transmission priority level higher than the transmission priority level of the transmission node.

11. The transmission node of claim 9 , wherein the length of the second time period is configured in proportion to or in reverse proportion to a value of the transmission priority level of the transmission node.

12. The transmission node of claim 9 , wherein the processor is further configured to:

sequentially perform channel sensing in each of a plurality of slots when the second time period consists of a plurality of slots, and

transmit the signal when a back-off counter value becomes 0.

13. The transmission node of claim 12 , wherein the back-off counter value is configured in proportion to or in reverse proportion to a value of the transmission priority level of the transmission node.

14. The transmission node of claim 9 , wherein the processor is further configured to:

receive information on a period of restricted channel sensing from the center node.

15. The transmission node of claim 14 , wherein the period of restricted signal transmission or the period of restricted channel sensing has a length and an interval configured in proportion to or in reverse proportion to a value of the transmission priority level of the transmission node.

16. The transmission node of claim 9 , wherein when the signal to be transmitted by the transmission node corresponds to an uplink signal, if priority of the uplink signal is higher than priority of a downlink signal, a transmission timing of the uplink signal is advanced as much as a predetermined time offset; and if the priority of the uplink signal is lower than the priority of the downlink signal, the transmission timing of the uplink signal is delayed as much as the predetermined time offset.