Converting E-UTRAN Security Context for CSFB Call Setup
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Solution Overview
Problem
In wireless communication systems, the process of establishing a circuit-switched fallback (CSFB) security context between user equipment and the Mobile Switching Centre/Visitor Location Register (MSC/VLR) is hindered by the need for Authentication and Key Agreement (AKA) procedures, which increase call setup latency.
Innovation Solution
The method involves converting the security context from the Evolved Universal Terrestrial Radio Access Network (E-UTRAN) in the Mobility Management Entity (MME) to a circuit-switched domain security context and transferring it to the MSC/VLR, allowing the creation or update of a shared circuit-switched security context without performing AKA procedures when the user equipment moves from E-UTRAN to GSM EDGE Radio Access Network/Universal Terrestrial Radio Access Network, thereby eliminating the need for AKA during CSFB call setup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If AKA procedures are performed to establish circuit-switched fallback security context, then security authentication is ensured, but call setup latency increases
Solution Approach 1:
The patent performs AKA authentication procedures in advance when the user equipment is in E-UTRAN, establishing a security context before the CSFB call setup. This preliminary authentication eliminates the need to perform AKA again during the actual CSFB call establishment, thus reducing call setup latency while maintaining security authentication.
Solution Approach 2:
The security context including authentication credentials and key material is established and stored in both the user equipment and the network (MME/MSC) before the CSFB operation. This pre-establishment of security parameters allows the CSFB call to proceed without repeating the authentication process.
2Reliability
If AKA procedures are performed during CSFB call setup, then security context is established, but network efficiency decreases
Solution Approach 1:
The patent establishes the security context during the initial E-UTRAN attachment or earlier operations, before the CSFB call setup is triggered. By performing the computationally intensive AKA procedures in advance, the network avoids repeating these operations during time-critical CSFB call establishment, thereby improving overall network efficiency and throughput.
3Loss of time
If security context is transferred from E-UTRAN to circuit-switched domain, then call setup latency is reduced, but security context mapping complexity increases
Solution Approach 1:
The patent introduces a security context mapping mechanism that acts as an intermediary between the E-UTRAN security context and the circuit-switched domain security context. The MME performs the context conversion and transfer to the MSC, handling the complexity of key derivation and context transformation, while the user equipment simply uses the transferred context without needing to understand the mapping process.
Data Source
AI summary
Creation or update of a security context between user equipment and MSC/VLR (Mobile Switching Center/Visitor Location Register) for circuit switched domain services is provided. The creation or update is based on conversion of the security context used in an evolved Universal Terrestrial Radio Access Network (E-UTRAN) in the Mobility Management Entity (MME) to a security context for the circuit switched domain target system and transferring it to a MSC/VLR. When user equipment is moved from E-UTRAN to GSM EDGE Radio Access Network/Universal Terrestrial Radio Access Network (GERAN/UTRAN), a MME does not need to perform authentication and key agreement procedures to establish shared circuit switched security context for the user equipment.