Patent ID: 7801142

Claim:
A method for a Service Data Unit, called SDU hereafter, discard function, wherein the SDU discard function is triggered by a first maximum allowed number of transmissions of an acknowledged mode data protocol data unit, called AMD PDU hereafter, by a sender, wherein the transmission from the sender to a receiver in the wireless communications system is operated in acknowledged mode and the AMD PDU contains segments or length indicators, called LI hereafter, and wherein LI is used to indicate an end position of a SDU, the method comprising the steps of: discarding a first set of SDUs by the sender if a number of times of a first AMD PDU scheduled for transmission reaches a second maximum allowed number; and executing a SDU discard with an explicit signaling procedure to inform the receiver of discarding the first set of SDUs, wherein the first set of SDUs contain a particular SDU and a particular LI carried by the first AMD PDU indicates that the particular SDU ends within a second AMD PDU, which is sequentially earlier and next to the first AMD PDU.