Regular data packets are scheduled for transmission from a sender to multiple receivers in a multicast ARQ system. In a joint scheduling and encoding procedure, a composite data packet is formed as a weighted linear combination of regular data packets. The corresponding coding weights are adapted based on feedback information from the receivers about received data packets such the composite packet represents a new linearly independent coding of regular data packets different from any multicast data packet previously received in a selected set of the receivers during the multicast session. A weight vector with at least two different non-zero coding weights adds a further degree of freedom and guarantees the ability to form a composite data packet that represents a new linearly independent coding for transmission.