The invention relates to feedback transmission for data packets in a mobile communication system. In particular the invention provides a communication system wherein feedback information of a retransmission protocol for transmitted data packets is transmitted. Further, the invention relates to a method for determining radio resources for the transmission of feedback information of a retransmission protocol for transmitted data packets as well as to a base station and a mobile station performing the method. In order to prevent potential collisions of feedback information while omitting a destination identifier for identifying the receiver of the feedback, the feedback resources for sending the feedback are determined at least based on a current transmission counter for a packet.