One problem with current D2D communications is that there is no physical layer feedback (e.g., HARQ feedback) for unicast sidelink communications. That is, the transmitting UE does not know if the receiving UE receives and/or properly decodes the unicast transmission. Instead, current D2D communications require that a transmitting UE send a unicast sidelink communication multiple times to increase the chances that the unicast sidelink communication is received by the receiving UE. By blindly transmitting unicast sidelink communications multiple times, the spectral efficiency and radio resource utilization of the network is decreased. The present disclosure provides a solution to this problem by enabling HARQ feedback for unicast sidelink communications that improves the spectral efficiency and also enables better radio resource utilization for the network.