ARQ system with status and packet acknowledgement

摘要

A communication system includes a downlink indicator channel for the transmission of an indicator signal indicating that a data packet is scheduled to be transmitted on a downlink data channel from a primary station to a secondary station. In response to detection of the indicator signal, the secondary station transmits a status signal, for example a negative acknowledgement signal, on an uplink channel to the primary station immediately before transmission of a positive or negative acknowledgement signal to indicate the status of the received data packet. By providing the primary station with two chances to detect the case where the secondary station fails to detect the indicator signal, peak power requirements of the uplink channel can be reduced, thereby reducing system interference levels.