US Patent 7979767 Automatic repeat request (ARQ) reset method

An Automatic Repeat-reQuest (ARQ) Reset method for an ARQ transmitter disables (120) transmission, starts (130) an ARQ transmitter window at a first unacknowledged block, and discards (140) service data units (SDUs) in the ARQ transmitter window having zero blocks in a ‘not-sent’ state. Thus, for all SDUs having no blocks in a ‘not-sent’ state, the blocks in an ‘outstanding’ or ‘waiting-for-retransmission’ state are changed to a ‘discard’ state. Next, the ARQ transmitter sets (150) the state of all blocks in partially unsent SDUs of the ARQ transmitter window to ‘not-sent.’ So, any remaining blocks in an ‘outstanding,’ ‘waiting-for-transmission’ or ‘discard’ state are changed to ‘not-sent.’ After the ARQ transmitter enables (160) transmission and ends (190) the ARQ Reset procedure, the ARQ transmitter will send blocks in the ‘not-sent’ state. This ARQ Reset method avoids retransmitting blocks that might cause duplicate packets at the ARQ receiver, which some protocols cannot handle.