An apparatus for a wireless communication system, wherein the apparatus is configured to be connected to at least one user device, UE, of the wireless communication system via a sidelink for a sidelink communication with the at least one UE, wherein, for a unicast transmission to the UE, the apparatus is configured to transmit a sidelink frame (F n ) having a certain frame duration, a first part of the sidelink frame including control signaling (C 1 ) and a second part of the sidelink frame including a data packet (D 1 ), the sidelink frame indicating to the UE whether a feedback is to be returned to the apparatus, the feedback indicating a successful reception of data at the UE and/or a sidelink channel condition, and wherein, in case the feedback from the UE is desired, the apparatus is configured to - transmit in the second part of the sidelink frame (F n ) an indication (FI) that the feedback is to be provided by the UE, and - receive from the UE, in a subsequent sidelink frame (F n+1 ), the feedback (B) for data transmitted in the sidelink frame, the subsequent sidelink frame (F n+1 ) including a control signaling (C 2 ) and a data packet (D 2 ), the data packet (D 2 )being shortened by a remaining duration (R), and the feedback (B) being transmitted during the remaining duration (R) in the subsequent sidelink frame (F n+1 ). wherein the apparatus is configured to be connected to at least one user device, UE, of the wireless communication system via a sidelink for a sidelink communication with the at least one UE, wherein, for a unicast transmission to the UE, the apparatus is configured to transmit a sidelink frame (F n ) having a certain frame duration, a first part of the sidelink frame including control signaling (C 1 ) and a second part of the sidelink frame including a data packet (D 1 ), the sidelink frame indicating to the UE whether a feedback is to be returned to the apparatus, the feedback indicating a successful reception of data at the UE and/or a sidelink channel condition, and wherein, in case the feedback from the UE is desired, the apparatus is configured to - transmit in the second part of the sidelink frame (F n ) an indication (FI) that the feedback is to be provided by the UE, and - receive from the UE, in a subsequent sidelink frame (F n+1 ), the feedback (B) for data transmitted in the sidelink frame, the subsequent sidelink frame (F n+1 ) including a control signaling (C 2 ) and a data packet (D 2 ), the data packet (D 2 )being shortened by a remaining duration (R), and the feedback (B) being transmitted during the remaining duration (R) in the subsequent sidelink frame (F n+1 ). - transmit in the second part of the sidelink frame (F n ) an indication (FI) that the feedback is to be provided by the UE, and - receive from the UE, in a subsequent sidelink frame (F n+1 ), the feedback (B) for data transmitted in the sidelink frame, the subsequent sidelink frame (F n+1 ) including a control signaling (C 2 ) and a data packet (D 2 ), the data packet (D 2 )being shortened by a remaining duration (R), and the feedback (B) being transmitted during the remaining duration (R) in the subsequent sidelink frame (F n+1 ). <EOS>