According to an example aspect of the present invention, there is provided an apparatus comprising at least one processing core, at least one memory including computer program code, the at least one memory and the computer program code being configured to, with the at least one processing core, cause the apparatus at least to participate in a cooperative wireless transmission of a data block with peer apparatuses, wherein the cooperative transmission comprises an early transmit opportunity and a late transmit opportunity starting after the early transmit opportunity starts, wherein the cooperative transmission may comprise at least one further late transmission opportunity starting after the late transmit opportunity, perform a listen-before-talk test to check, if first radio resources are available, and responsive to the listen-before-talk test indicating the first resources are available, initiate a transmission of a data block on the first radio resources during the early transmit opportunity.