ARQ transmission and reception methods and apparatus

摘要

The invention provides an ARQ scheme where data packets are transmitted from the transmitter to the receiver in first predetermined time intervals, and positive (ACK) and negative (NAK) acknowledgement messages are transmitted from the receiver to the transmitter in second predetermined time intervals. For each data packet that has been transmitted from the transmitter to the receiver, at least two second time intervals can be used for transmitting the acknowledgement message. The invention therefore improves over synchronous feedback transmission schemes by adding flexibility without incorporating the drawback of asynchronous transmission schemes that are known to have a high signalling overhead. The invention is preferably applicable to UMTS and HSDPA systems but can also be applied in any other communications system. The feedback channel may be uplink or downlink.