Wireless communications systems and methods related to autonomous sidelink communication in a radio frequency band (e.g., in a shared spectrum or an unlicensed spectrum) shared by multiple network operating entities are provided. A first user equipment (UE) performs a listen-before-talk (LBT) in a shared radio frequency band based on a first starting point of a plurality of starting points within an LBT gap duration. The first UE transmits, to a second UE, a first sidelink communication in the shared radio frequency band based on the LBT, the first sidelink communication including first sidelink control information (SCI) and first sidelink data.