Patent ID: 8493861

Claim:
A method for reducing a risk of transmission stalling between a transmitting unit and a receiving unit in a communication network system, the method comprising: transmitting data blocks to the receiving unit from the transmitting unit, wherein each data block comprises a block sequence number; storing the transmitted data blocks in a transmission buffer; controlling flow of retransmission of the transmitted data blocks by using a transmission buffer window comprising an acknowledge state variable, V(A), that contains the block sequence number value of the oldest data block that has not been positively acknowledged by its peer; responsive to a block sequence number corresponding to V(A) being acknowledged in a piggybacked acknowledgement/negative (PAN) acknowledgement field, setting a status of the block sequence number as tentative acknowledged; and responsive to receiving a packet uplink acknowledgement/negative (PUAN) acknowledgement message or a packet downlink acknowledgement/negative (PDAN) acknowledgement message comprising an acknowledgement for the block sequence number: setting the status of the block sequence number as acknowledged; and advancing the transmission buffer window to the acknowledge state variable, V(A),=[BSN′+1] modulo SNS, wherein BSN′ is the block sequence number and SNS is a sequence number space; wherein the acknowledged status has a different meaning from the tentative acknowledged status.