A wireless device receives a sidelink control information (SCI) that may schedule a transport block and may also indicate a first repetition value. The wireless device may also receive a transport block via a physical sidelink shared channel (PSSCH). Based on a comparison of the first repetition value received via the SCI and a repetition threshold, the wireless device may determine to transmit an acknowledgment for the received transport block. The wireless device may then transmit the acknowledgment for the received transport block.