Patent ID: 8175275

Claim:
A method of determining uplink ciphering activation time in a user equipment (UE), the UE configurable for communication with a telecommunications network over a communications channel comprising a radio bearer, the uplink ciphering activation time for determining a time at which a new ciphering configuration is to be implemented between the user equipment and the network, the method comprising the steps of: determining, at the user equipment, the uplink activation time to be greater than a time to receive a response message at the network to a ciphering change request message while minimizing delay in the change to the new ciphering configuration; the method further comprising, at the user equipment, determining a size of the response message to the ciphering change request message and determining a size of queued messages for sending over the communications channel using the radio bearer, the response message configurable to be transmitted from the UE via the communications channel using one or more protocol data units (PDUs); using, at the user equipment, the determined size of the response message and queued messages, and a current sequent number for the radio bearer, in determining the uplink ciphering activation time; inserting, at the user equipment, the uplink ciphering activation time into the response message and queuing the response message for transmission.