UMTS RB0 Integrity Protection Activation Time
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Solution Overview
Problem
In UMTS systems, the setting of the uplink message sequence number for radio bearer RB0 during the UTRAN MOBILITY INFORMATION procedure is undefined, leading to a delay in applying a new integrity protection configuration, which compromises the security of the system.
Innovation Solution
A method and apparatus that allow user equipment (UE) to receive a UTRAN MOBILITY INFORMATION message, transmit a UTRAN MOBILITY INFORMATION CONFIRM message with a selected activation time for applying a new integrity protection configuration for RB0, and set the uplink application time to ensure the next RRC message uses the new configuration, by using a Sequence Number Setting (SNS) RRC module.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the uplink message sequence number is not set for UTRAN MOBILITY INFORMATION procedure, then the procedure can be implemented with existing standards, but the integrity protection configuration is delayed and security is compromised
Solution Approach 1:
The UE sets the uplink application time in advance based on the downlink activation time received in the UTRAN MOBILITY INFORMATION message. This preliminary action ensures that the new integrity protection configuration is applied immediately when the next RRC message is transmitted, eliminating the security delay without requiring changes to the core protocol flow.
2Reliability
If the uplink application time is set to ensure immediate security, then integrity protection is enhanced, but the complexity of setting the sequence number increases
Solution Approach 1:
The UE uses the downlink activation time information provided in the UTRAN MOBILITY INFORMATION message as feedback to determine the appropriate uplink application time. This feedback mechanism simplifies the sequence number setting by basing it on existing protocol parameters rather than requiring complex independent calculation.
Data Source
AI summary
The details of an apparatus and method are disclosed for setting the Uplink RRC message sequence number for a new integrity protection configuration to be applied for signalling radio bearer RB0, on completion of a UTRAN MOBILITY INFORMATION procedure. The sequence number is set to a value such that the next RRC message to be sent on uplink RB0 will use the new integrity protection configuration.