This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for a user equipment (UE) to provide listen before talk (LBT) assistance to a transmitting device. The UE may receive a pre-grant (PG) indicating a plurality of beams. The UE may performing a LBT procedure on each beam of the indicated plurality of beams. The UE may transmit an acknowledgment to the pre-grant (APG) as a waveform that indicates that the LBT procedure for one or more of the indicated plurality of beams was successful. The waveform may be a sounding reference signal (SRS) with a sequence that indicates that the LBT procedure was successful.