Ciphering Parameter Handling for Seamless Wireless Handover
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Solution Overview
Problem
Multimode wireless telecommunications devices face issues with ciphering when handover occurs between radio access networks, as the ciphering parameter settings may prohibit encryption in the new network, leading to failed authentication procedures.
Innovation Solution
The device examines ciphering parameters for the new network and sets them to default or substitute values to enable encryption, ensuring seamless handover and authentication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the device maintains ciphering parameters from the first radio access network during handover to the second radio access network, then the device can maintain encryption continuity, but the ciphering parameters may be inappropriate for the second network causing failed authentication procedures
Solution Approach 1:
The device performs preliminary examination of ciphering parameters before handover to the second radio access network. By checking whether the current ciphering parameters are appropriate for the target network in advance, the device can prevent authentication failures and determine whether parameter adjustment is needed prior to completing the handover procedure.
Solution Approach 2:
The ciphering parameters are made dynamic rather than static during handover. The device adjusts the ciphering parameters based on the target network's requirements, transitioning from using parameters from the first network to using appropriate parameters for the second network, thereby ensuring both reliability and adaptability.
2Reliability
If the device adjusts ciphering parameters to default values before handover, then authentication success improves, but the complexity of the handover procedure increases
Solution Approach 1:
The device performs preliminary examination of ciphering parameters before handover to determine if adjustment is actually needed. By checking parameter appropriateness in advance, the device avoids unnecessary adjustments and only modifies parameters when required, thereby improving authentication success while minimizing the increase in procedure complexity.
Solution Approach 2:
The device changes ciphering parameters from their current values to default or network-appropriate values only when necessary. This selective parameter adjustment approach ensures authentication success while avoiding unnecessary complexity in the handover procedure by not always resetting parameters.
Data Source
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AI summary
A method in a wireless telecommunications device operative with a plurality of radio access networks, the method comprising: when operating with a first radio access network reading at least one ciphering variable applicable in the second radio access network (e.g. in UMTS reading the value of a variable START from the USIM of the device). When at least one ciphering variable applicable in the second radio access network renders ciphering in the second radio access network infeasible without further authentication (e.g. in UMTS when the value of START in USIM is equal to a value THRESHOLD), using a substitute value for the ciphering parameter (e.g. START) when establishing a connection with the second radio access network.