Method and apparatus for providing immediate ciphering after an inter-system UTRAN-GSM handover
First Claim
1. A mobile station executed method for handing over from a current system to a target system, comprising:
- triggering the handover of the mobile station from the current system to the target system by receiving a current system-specific handover command from the current system, where the target system is one that requires the mobile station to initiate the use of ciphering only in response to receiving a specific command from the target system to initiate the use of ciphering; and
starting the use of ciphering after handing over to the target system in response to receiving a target system-specific handover command that is sent transparently with the current system-specific handover command, where the target system-specific handover command has an information element set for indicating that ciphering is to be started.
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Accused Products
Abstract
Disclosed is a method for performing an inter-system handover. The method triggers the handover of a mobile station (100) from a UTRAN system to a GSM system by sending a HANDOVER FROM UTRAN COMMAND message from the UTRAN system. For the case where a HANDOVER COMMAND is sent transparently with the HANDOVER FROM UTRAN COMMAND, where the HANDOVER COMMAND has an information element set for indicating that ciphering is to be started, the method begins data ciphering immediately after handing over to the GSM system such that the first data frame transmitted by the mobile station in the GSM system is a ciphered data frame. For the case where there is a pre-existing UTRAN system ciphered data connection when the HANDOVER FROM UTRAN COMMAND message is received, the method continues without interruption the use of data ciphering with the data connection after handing over to the GSM system.
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Citations
12 Claims
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1. A mobile station executed method for handing over from a current system to a target system, comprising:
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triggering the handover of the mobile station from the current system to the target system by receiving a current system-specific handover command from the current system, where the target system is one that requires the mobile station to initiate the use of ciphering only in response to receiving a specific command from the target system to initiate the use of ciphering; and
starting the use of ciphering after handing over to the target system in response to receiving a target system-specific handover command that is sent transparently with the current system-specific handover command, where the target system-specific handover command has an information element set for indicating that ciphering is to be started. - View Dependent Claims (2, 3, 4)
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- 5. A mobile station operable for being handed over from a current system to a target system, comprising an RF transceiver coupled to a data processor, said data processor being responsive to a receipt through said RF transceiver of a current system-specific handover command from the current system for triggering the handover of the mobile station from the current system to the target system, where the target system is one that requires the mobile station to initiate the use of ciphering only in response to receiving a specific command from the target system to initiate the use of ciphering, said data processor operating to immediately start the use of ciphering after handing over to the target system in response to receiving a target system-specific handover command that is sent transparently with the current system-specific handover command, where the target system-specific handover command has an information element set for indicating that ciphering is to be started.
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9. A method for performing an inter-system handover, comprising:
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triggering the handover of the mobile station from a UTRAN system to a GSM system by sending a HANDOVER FROM UTRAN COMMAND message from the UTRAN system; and
for the case where a HANDOVER COMMAND is sent transparently with the HANDOVER FROM UTRAN COMMAND, where the HANDOVER COMMAND has an information element set for indicating that ciphering is to be started, beginning ciphering immediately after handing over to the GSM system such that a first data frame transmitted by the mobile station in the GSM system is a ciphered data frame. - View Dependent Claims (10)
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11. A wireless mobile communications system operable for performing an inter-system handover, comprising:
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wireless network means for triggering the handover of a mobile station from a UTRAN system to a GSM system by sending a predetermined command message from the UTRAN system, the predetermined command comprising a HANDOVER FROM UTRAN COMMAND message with a HANDOVER COMMAND that is sent transparently with the HANDOVER FROM UTRAN COMMAND, the HANDOVER COMMAND comprising an information element set for indicating that ciphering is to begin; and
mobile station means, responsive to a receipt of the predetermined command, for beginning ciphering immediately after handing over to the GSM system. - View Dependent Claims (12)
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Specification