Receiver-assisted listen-before-talk procedures with explicit beam indication
Example aspects include a method, apparatus, and computer-readable medium for wireless communication at user equipment of a mobile network, comprising receiving, from a base station via a first beam, a pre-grant message requesting the UE to perform a listen-before-talk (LBT) procedure on a second beam. The aspects further include performing, according to the pre-grant message, the LBT procedure on the second beam. Additionally, the aspects include indicating, to the base station, whether the LBT procedure was successful.
1 . A method of wireless communication at a user equipment (UE) of a mobile network, comprising:
receiving, from a base station via a first beam, a pre-grant message requesting the UE to perform a listen-before-talk (LBT) procedure on a second beam;
performing, according to the pre-grant message, the LBT procedure on the second beam; and
indicating, to the base station, whether the LBT procedure was successful.
2 . An apparatus of wireless communication at a user equipment (UE) of a mobile network, comprising:
a non-transitory memory storing computer-executable instructions; and
a processor communicatively coupled with the non-transitory memory and configured to execute the computer-executable instructions to:
receive, from a base station via a first beam, a pre-grant message requesting the UE to perform a listen-before-talk (LBT) procedure on a second beam;
perform, according to the pre-grant message, the LBT procedure on the second beam; and
indicate, to the base station, whether the LBT procedure was successful.
3 . The apparatus of claim 2 , wherein to receive the pre-grant message comprises further computer-executable instructions to:
receive, from the base station, an indication of a transmission configuration indicator (TCI) state; and
select a corresponding beam of the TCI state as the second beam.
4 . The apparatus of claim 3 ,
wherein to receive the pre-grant message comprises further computer-executable instructions to receive a downlink grant with reserved fields, the downlink grant indicating the TCI state; and
wherein to indicate whether the LBT procedure was successful comprises further computer-executable instructions to send, to the base station via a third beam, a sounding reference signal (SRS) as an indication that the LBT procedure was successful.
5 . The apparatus of claim 3 ,
wherein to receive the pre-grant message further comprises further computer-executable instructions to receive a downlink grant with reserved fields, the downlink grant indicating the TCI state; and
wherein to indicate whether the LBT procedure was successful comprises further computer-executable instructions to refrain from sending, to the base station, a sounding reference signal (SRS) as an indication that the LBT procedure was not successful.
6 . The apparatus of claim 3 ,
wherein to receive the pre-grant message further comprises further computer-executable instructions to receive receiving a downlink grant with reserved fields, the downlink grant indicating the TCI state; and
wherein to indicate whether the LBT procedure was successful comprises further computer-executable instructions to send, to the base station via a physical uplink control channel (PUCCH) on a third beam, a pass indication indicating that the LBT procedure was successful.
7 . The apparatus of claim 2 , wherein to receive the pre-grant message comprises further computer-executable instructions to:
receive, via the first beam, a sounding reference signal (SRS) resource indicator (SRI) requesting a measurement of the second beam; and
perform the measurement of the second beam.
8 . The apparatus of claim 7 ,
wherein to receive the pre-grant message further comprises further computer-executable instructions to receive an uplink grant with reserved fields, the uplink grant comprising the SRI; and
wherein to indicate whether the LBT procedure was successful comprises further computer-executable instructions to send, to the base station via a third beam, a sounding reference signal (SRS) as an indication that the LBT procedure was successful.
9 . The apparatus of claim 7 ,
wherein to receive the pre-grant message further comprises further computer-executable instructions to receive an uplink grant with reserved fields, the uplink grant comprising the SRI and a physical uplink control channel (PUCCH) resource indicator field; and
wherein to indicate whether the LBT procedure was successful comprises further computer-executable instructions to send, to the base station via the PUCCH on a third beam, a pass indication indicating that the LBT procedure was successful.
10 . The apparatus of claim 7 ,
wherein to receive the pre-grant message further comprises further computer-executable instructions to receive an uplink grant comprising the SRI; and
wherein to indicate whether the LBT procedure was successful comprises further computer-executable instructions to send, to the base station via a physical uplink shared channel (PUSCH) on the second beam, a pass indication indicating whether the LBT procedure was successful.
11 . The apparatus of claim 10 ,
wherein to receive the pre-grant message further comprises further computer-executable instructions to receive a transmission configuration of the PUSCH, the transmission configuration indicating at least one of a modulation and coding scheme (MCS) and a transmission resource; and
wherein to send, to the base station via the PUSCH on the second beam, the pass indication comprises further computer-executable instructions to send the pass indication according to the transmission configuration.
12 . An apparatus of wireless communication at a base station of a mobile network, comprising:
a non-transitory memory storing computer-executable instructions; and
a processor communicatively coupled with the non-transitory memory and configured to execute the computer-executable instructions to:
send, to a user equipment (UE) via a first beam, a pre-grant message requesting the UE to perform a listen-before-talk (LBT) procedure on a second beam;
obtain, from the UE, an indication of whether the LBT procedure was successful; and
send, to the UE in response to the indication indicating that the LBT procedure being successful, downlink data via the second beam.
13 . The apparatus of claim 12 , wherein to send the pre-grant message comprises further computer-executable instructions to:
send, to the UE, an indication of a transmission configuration indicator (TCI) state, causing the UE to select a corresponding beam of the TCI state as the second beam.
14 . The apparatus of claim 13 ,
wherein to send the pre-grant message further comprises further computer-executable instructions to send a downlink grant with reserved fields, the downlink grant indicating the TCI state; and
wherein to obtain the indication of whether the LBT procedure was successful comprises further computer-executable instructions to receive, from the UE via a third beam, a sounding reference signal (SRS) as an indication that the LBT procedure was successful.
15 . The apparatus of claim 13 ,
wherein to send the pre-grant message further comprises further computer-executable instructions to send a downlink grant with reserved fields, the downlink grant indicating the TCI state; and
wherein to obtain the indication of whether the LBT procedure was successful comprises further computer-executable instructions to receive, from the UE via a physical uplink control channel (PUCCH) on a third beam, a pass indication indicating that the LBT procedure was successful.
16 . The apparatus of claim 12 , wherein to send the pre-grant message comprises further computer-executable instructions to:
send, via the first beam, a sounding reference signal (SRS) resource indicator (SRI) requesting a measurement of the second beam, causing the UE to perform the measurement of the second beam.
17 . The apparatus of claim 16 ,
wherein to send the pre-grant message comprises further computer-executable instructions to send an uplink grant with reserved fields, the uplink grant comprising the SRI; and
wherein to obtain the indication of whether the LBT procedure was successful comprises further computer-executable instructions to receive, from the UE via a third beam, a sounding reference signal (SRS) as an indication that the LBT procedure was successful.
18 . The apparatus of claim 16 ,
wherein to send the pre-grant message further comprises further computer-executable instructions to send an uplink grant with reserved fields, the uplink grant comprising the SRI and a physical uplink control channel (PUCCH) resource indicator field; and
wherein to obtain the indication of whether the LBT procedure was successful comprises further computer-executable instructions to receive, from the UE via the PUCCH on a third beam, a pass indication indicating that the LBT procedure was successful.
19 . The apparatus of claim 16 ,
wherein to send the pre-grant message further comprises further computer-executable instructions to send an uplink grant comprising the SRI; and
wherein to obtain the indication of whether the LBT procedure was successful comprises further computer-executable instructions to receive, from the UE via a physical uplink shared channel (PUSCH) on the second beam, a pass indication indicating whether the LBT procedure was successful.
20 . The apparatus of claim 19 ,
wherein to send the pre-grant message further comprises further computer-executable instructions to send a transmission configuration of the PUSCH, the transmission configuration indicating at least one of a modulation and coding scheme (MCS) and a transmission resource; and
wherein to receive, from the UE via the PUSCH on the second beam, the pass indication comprises further computer-executable instructions to receive the pass indication according to the transmission configuration.