Patent ID: 6829358
Filing Date: 2004-12-07
Classification: H04L,H04W

Abstract:
A method for handling a channel reset when performing a ciphering configuration change in a wireless communications system, the wireless communications system comprising a first station in wireless communications with a second station over at least a first channel and a second channel, the first station capable of transmitting protocol data units (PDUs) to the second station, each PDU comprising an associated sequence number that indicates a sequential ordering of the PDU with respect to other PDUs, the first station comprising:a first ciphering configuration; a second ciphering configuration; and a ciphering engine, wherein the ciphering engine uses the first ciphering configuration or the second ciphering configuration when enciphering PDUs; the method comprising: determining a first activation time for the first channel; composing a ciphering reconfiguration message that contains the first activation time; the first station transmitting the ciphering reconfiguration message to the second station along the second channel; prior to the first station receiving acknowledgment of the ciphering reconfiguration message from the second station and prior to the first channel reaching the first activation time, performing a reset operation on the first channel; wherein the reset operation does not affect the first activation time; and the first station awaiting acknowledgement of the ciphering reconfiguration message from the second station; wherein after the reset operation, the ciphering engine uses the first ciphering configuration to encipher all PDUs transmitted along the first channel that have sequence numbers sequentially prior to the first activation time, and uses the second ciphering configuration to encipher all PDUs transmitted along the first channel that have sequence numbers sequentially on or after the first activation time.