There is disclosed a user equipment, UE, for a Radio Access Network, the UE being adapted for sidelink communication on a sidelink, the UE further being adapted for transmitting acknowledgement signaling pertaining to sidelink data. The sidelink data includes one or more data elements and the acknowledgement signaling has a signaling format comprising one or more acknowledgement substructures. Each of the substructures carries acknowledgement information pertaining to one of the data elements. Further, each of the acknowledgment substructures is mapped to a different one of the data elements based on at least one acknowledgement position indication provided in control signaling received by the UE. The disclosure also pertains to related devices and methods.