There is disclosed a method of operating a User equipment, UE, in a cellular communications network. The method comprises receiving a data on a Downlink, DL, time-frequency resource, and transmitting on an Uplink, UL, time-frequency resource, a retransmission feedback to indicate whether a data packet, comprised in the data, was received properly, wherein the UL time-frequency resource is determined based on the DL time-frequency resource. The disclosure also pertains to related methods and devices.