US Patent 7509554 HARQ protocol with synchronous retransmissions

Mobile stations, base stations, radio network controllers and communication systems perform according to the hybrid automatic repeat request (HARQ) protocol for transmitting data packets from a transmitting entity to a receiving entity via a data channel. A HARQ method sending synchronous retransmissions involves a feedback message received from the receiving entity at the transmitting entity and, in case the feedback message indicates that the data packet has not been received successfully, a retransmission data packet is transmitted to the receiving entity after a predetermined time span upon having received the feedback message. The receiving entity soft combines the retransmission data packet with the previously received data packet.