Packet transmission apparatus with retransmission protocol

摘要

Wasteful use of radio resources is minimized in a packet transmission system which performs retransmission control at a higher layer. When transmission of a segment has failed at a lower layer and, for example, when the number of lower-layer retransmit requests from an error detection unit at the lower layer has exceeded a predetermined threshold, any other segment remaining to be transmitted in a packet of which the failed segment forms a part is discarded and, at the same time, a retransmit request is sent to a retransmission control unit at the higher layer.