Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may transmit an uplink communication, associated with a reference duration, in an uplink burst. The UE may receive hybrid automatic repeat request (HARQ) feedback after transmitting the uplink communication. The UE may adjust a size of a listen before talk (LBT) contention window based at least in part on whether the HARQ feedback is associated with the reference duration. Numerous other aspects are provided.