Context Handling for Mobility Control Nodes in 3GPP Networks
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Solution Overview
Problem
The existing context handling procedures in 3GPP specifications result in increased signalling load when user equipment moves between access networks, leading to capacity issues and security pitfalls due to the need for double context requests and transfer of security information across multiple nodes.
Innovation Solution
A method and nodes for context handling that involve a user equipment detecting a mobility area and initiating a Mobility Area Update procedure, where a first mobility control node derives and sends a context request to a second mobility control node, reducing the need for double requests and transferring only relevant information, thereby simplifying the procedure and avoiding security issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If the MME requests context from two other core network nodes (old SGSN and old MME) in the same procedure, then the context information is retrieved, but the signalling load increases
Solution Approach 1:
The patent extracts only the necessary context information from the old MME (specifically security information and authentication vectors) rather than retrieving all context from both old SGSN and old MME. The new MME derives the old MME identity from the UE Temporary ID and selectively requests only the required security context, reducing the overall signalling load while still obtaining all necessary information.
Solution Approach 2:
The patent performs preliminary derivation of the old MME identity from the UE Temporary ID before initiating the context request. This allows the new MME to directly target the specific node holding the required security information, avoiding the need to request context from both old SGSN and old MME, thus reducing signalling load while ensuring complete context retrieval.
2Loss of information
If the SGSN requests context from two other core network nodes (old SGSN and old MME) in the same procedure, then the context information is retrieved, but the signalling load increases
Solution Approach 1:
The patent extracts only the necessary context information from the old MME (specifically security information and authentication vectors) rather than retrieving all context from both old SGSN and old MME. The new MME derives the old MME identity from the UE Temporary ID and selectively requests only the required security context, reducing the overall signalling load while still obtaining all necessary information.
Solution Approach 2:
The patent performs preliminary derivation of the old MME identity from the UE Temporary ID before initiating the context request. This allows the new MME to directly target the specific node holding the required security information, avoiding the need to request context from both old SGSN and old MME, thus reducing signalling load while ensuring complete context retrieval.
3Reliability
If authentication vectors are transferred between different access networks, then security information is available, but security restrictions are violated
Solution Approach 1:
The patent applies local quality by storing and using authentication vectors in their designated network domains: E-UTRAN authentication vectors are kept in the MME for E-UTRAN access, while GERAN/UTRAN authentication vectors are kept in the SGSN for GERAN/UTRAN access. The new MME derives the old MME identity from the UE Temporary ID and requests only E-UTRAN security context, ensuring that authentication vectors are used only within their authorized access network domains and preventing security violations.
4Ease of operation
If the UE transfers address information to the MME, then the context request can be performed, but the procedure complexity increases
Solution Approach 1:
The patent implements self-service by enabling the new MME to autonomously derive the old MME identity from the UE Temporary ID without requiring the UE to explicitly transfer address information. The UE simply provides its temporary identity, and the new MME uses this to automatically identify and contact the old MME for security context retrieval, simplifying the procedure while maintaining the necessary context request capability.
Data Source
AI summary
The invention therefore relates to a method, a first Mobility Control Node and a second Mobility Control Node for context handling when a user equipment, UE, moves from a previous Access Network, AN, to a present AN. The ANs are adapted to communicate with a Core Network, CN, and the UE is adapted to communicate wirelessly with the AN's. The method comprises the steps of: the UE detecting that it has entered a Mobility Area, MA, belonging to the present AN, said MA not being registered with the CN, the UE initiating a Mobility Area Update, MAU, procedure in response to the detection by sending a MAU Request message comprising an UE Temporary ID to a Radio Access Node, RAN, the RAN adding a Mobility Area Identity, MAI, to the Request message and forwarding the message to a first Mobility Control Node, MCN, responsible for the present AN, the first MCN deriving one second MCN from the UE Temporary ID and sending a context request message to said second MCN.