EFFICIENT AUTOMATIC REPEAT REQUEST METHOD USING VARIABLE LENGTH SEQUENCE NUMBERS

摘要

A variable length sequence number is used to identify data units in acommunication channel. The sequence number associated with the most recentdata thathas been received successfully and the sequence number expected with the nextnew datamessage to be received are examined to determine the minimum size sequencenumbernecessary to unambiguously identify to the transmitter incorrectly receiveddata that mustbe retransmitted in a later message. The receiver provides the transmitterwith thesequence number associated with the last successfully received byte of dataand thesequence number associated with the next expected byte of data. The receivercommunicates this information to the transmitter using a NAK control message.Thetransmitter then uses the sequence number of the next byte of data to betransmitted andthe information received in the control message from the receiver to determinethesmallest number of bits necessary to represent the sequence numbers for bothdatatransmissions and the retransmission of data that was not received properly bythereceiver.