Device, method, and computer readable storage medium for transmitting and receiving information for communication in licenced band
According to various embodiments, a first user equipment (UE) includes a transceiver to transmit and receive a wireless signal; and a processor connected with the transceiver, wherein the processor is configured to identify a value related to quality of sidelink communication while the first UE performs sidelink communication in licensed band with a second UE, determine to perform a listen before talk (LBT) procedure on a condition that the value related to the quality of the sidelink communication is less than or equal to a reference value, and perform the LBT procedure during performing the sidelink communication in the licensed band.
1 . A first user equipment (UE) comprising:
a transceiver to transmit and receive a wireless signal; and
a processor connected with the transceiver, wherein the processor is configured to:
identify a value related to quality of sidelink communication while the first UE performs sidelink communication on licensed band with a second UE,
determine to perform a listen before talk (LBT) procedure on a condition that the value related to the quality of the sidelink communication is less than or equal to a reference value, and
perform the LBT procedure during performing the sidelink communication on the licensed band.
2 . The first UE according to claim 1 , wherein the processor is configured to:
set, based on the LBT procedure, a backoff counter within a contention window,
decrease the backoff counter within a plurality of slot intervals,
determine, based on a value of the backoff counter being a first value, channel occupancy time, and
transmit data to the second UE on the licensed band within the channel occupancy time.
3 . The first UE according to claim 2 , wherein the processor is further configured to decrease the value of the backoff counter in a state in which a channel state is an idle state within the plurality of slot intervals.
4 . The first UE according to claim 2 , wherein the processor is further configured to maintain the value of the backoff counter in a state in which the channel state is a busy state within the plurality of slot intervals.
5 . The first UE according to claim 2 , wherein the processor is further configured to:
identify that the data is not transmitted to the second UE, and
increase size of the contention window.
6 . The first UE according to claim 5 , wherein the size of the contention window is set less than maximum size of the contention window.
7 . The first UE according to claim 1 , wherein a value related to quality of the sidelink communication is set based on sidelink-reference signal received quality (SL-RSRQ).
8 . The first UE according to claim 1 , wherein the licensed band includes a band adjacent to unlicensed band, and
wherein the value related to the quality of the sidelink communication is determined based on interference caused by communication in the unlicensed band.
9 . The first UE according to claim 1 , wherein the sidelink communication is established based on another LBT procedure, before identifying the value related to the quality of the sidelink communication; and
wherein the processor is configured to:
transmit, based on the another LBT procedure, a first message including a random access preamble through a physical random access channel (PRACH) in order to perform the sidelink communication with the second UE,
receive a second message from the second UE, wherein the second message includes information on resource scheduling,
in response to the second message, transmit a scheduled third message based on the another LBT procedure,
based on the third message, receive a fourth message including contention resolution information from the second UE, and
based on the fourth message, establish a connection of the sidelink communication with the second UE on the licensed band.
10 . The first UE according to claim 1 , wherein the sidelink communication is established based on another LBT procedure, before identifying the value related to the quality of the sidelink communication; and
wherein the processor is configured to:
transmit, based on the another LBT procedure, a message A including a random access preamble and information for performing a collision resolution procedure, to perform the sidelink communication with the second UE,
receive, based on the message A, a message B including information on resource scheduling and collision resolution information from the second UE, and
establish, based on the message B, a connection of sidelink communication with the second UE on the licensed band.
11 . A method for operating a first user equipment (UE), the method comprising:
identifying a value related to quality of sidelink communication while the first UE performs sidelink communication on licensed band with a second UE,
determining to perform a listen before talk (LBT) procedure on a condition that the value related to the quality of the sidelink communication is less than or equal to a reference value, and
performing the LBT procedure during performing the sidelink communication on the licensed band.
12 . The method according to claim 11 , comprising:
identifying priority of the data,
identifying whether the priority of the data is greater than the priority threshold value, and
based on that the priority of the data is greater than the priority threshold value, transmitting the data through the sidelink on the unlicensed band with the second UE.
13 . The method according to claim 12 , further comprising decreasing the value of the backoff counter in a state in which a channel state is an idle state within the plurality of slot intervals.
14 . The method according to claim 12 , further comprising maintaining the value of the backoff counter in a state in which the channel state is a busy state within the plurality of slot intervals.
15 . The method according to claim 12 , further comprising:
identifying that the data is not transmitted to the second UE, and
increasing size of the contention window.
16 . The method according to claim 15 , wherein the size of the contention window is set less than maximum size of the contention window.
17 . The method according to claim 11 , wherein a value related to quality of the sidelink communication is set based on sidelink-reference signal received quality (SL-RSRQ).
18 . The method according to claim 11 , wherein the licensed band includes a band adjacent to unlicensed band, and
wherein the value related to the quality of the sidelink communication is determined based on interference caused by communication in the unlicensed band.
19 . The method according to claim 11 , wherein the sidelink communication is established based on another LBT procedure, before identifying the value related to the quality of the sidelink communication; and
wherein the method further comprises:
transmitting, based on the another LBT procedure, a first message including a random access preamble through a physical random access channel (PRACH) in order to perform the sidelink communication with the second UE,
receiving a second message from the second UE, wherein the second message includes information on resource scheduling,
in response to the second message, transmitting a scheduled third message based on the another LBT procedure,
based on the third message, receiving a fourth message including contention resolution information from the second UE, and
based on the fourth message, establishing a connection of the sidelink communication with the second UE on the licensed band.
20 . A non-transitory computer readable medium storing one or more programs, the one or more programs including instructions, which, when being executed by at least one processor of a first user equipment (UE), cause the first UE to:
identify a value related to quality of sidelink communication while the first UE performs sidelink communication on licensed band with a second UE,
determine to perform a listen before talk (LBT) procedure on a condition that the value related to the quality of the sidelink communication is less than or equal to a reference value, and
perform the LBT procedure during performing the sidelink communication on the licensed band.