Network Update Procedure Optimizing CSFB Call Setup
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Solution Overview
Problem
Current network update procedures in mobile radio communications networks, particularly during handovers between different systems like 2G/3G and Evolved Packet System, experience significant delays due to unnecessary security procedures like authentication and TMSI re-allocation, which are time-consuming and hinder efficient call setup in Circuit Switched Fall Back (CSFB) scenarios.
Innovation Solution
Implementing a method where network elements like SGSN and MSC determine the reason for Location Area updates and vary connection procedures accordingly, employing 'light security' versions of authentication and TMSI re-allocation only when necessary, and using a CSFB timer to manage security procedures during updates, thereby reducing delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If full security procedures (authentication, TMSI re-allocation) are performed during Location Area update in CSFB, then network security and proper identification are ensured, but call setup delay increases significantly (2-5 seconds)
Solution Approach 1:
The patent applies partial security action by determining whether full security procedures are necessary based on the update reason. When the update reason indicates normal location change (not security concern), the patent performs only light security procedures (skipping authentication and TMSI re-allocation), thereby reducing delay while maintaining adequate security for the specific context.
Solution Approach 2:
The patent changes the security procedure parameter dynamically based on the update reason field. The network element examines the update reason and adjusts the security level accordingly - using full security procedures only when necessary, and light security procedures when the update reason indicates non-security-critical scenarios, thus optimizing the balance between security and speed.
2Reliability
If authentication procedure is performed during Location Area update, then user identity is verified securely, but reading SIM/USM card increases delay
Solution Approach 1:
The patent applies partial action by conditionally performing authentication only when the update reason indicates it is necessary. For updates with reasons indicating normal location changes or CSFB scenarios where identity is already known, the patent skips the authentication procedure entirely, eliminating the SIM/USM card reading delay while maintaining security where needed.
Solution Approach 2:
The patent extracts the authentication step from the mandatory sequence of security procedures and makes it optional based on the update reason. By examining the update reason field, the patent determines whether to include or exclude authentication, thereby removing unnecessary delay-causing steps while preserving security verification when required.
3Reliability
If TMSI re-allocation procedure is performed during Location Area update, then temporary identity is updated securely, but reading SIM/USM card increases delay
Solution Approach 1:
The patent applies partial action by conditionally performing TMSI re-allocation only when the update reason indicates it is necessary. For updates where the mobile station is already in the network or the update reason indicates non-security-critical scenarios, the patent skips TMSI re-allocation, eliminating the SIM/USM card reading delay while maintaining proper identity management where needed.
Solution Approach 2:
The patent extracts the TMSI re-allocation step from the mandatory security procedure sequence and makes it conditional based on the update reason. By evaluating the update reason field, the patent determines whether to include or exclude TMSI re-allocation, thereby removing unnecessary delay-causing steps while preserving identity management security when required.
4Productivity
If combined RA/LA update procedure is performed in NMO I system, then routing area and location area are updated together, but procedure complexity increases
Solution Approach 1:
The patent merges the Routing Area update and Location Area update procedures into a single combined operation when the update reason indicates it is appropriate. By examining the update reason field, the patent determines whether to perform a combined RA/LA update (reducing overall procedure steps and improving efficiency) or separate updates, thereby optimizing the balance between procedural efficiency and complexity management.
Data Source
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AI summary
The invention provides a method of controlling LA-based update procedure in a mobile radio communications network, and including the step of determining the reason for the LA-based update request, and varying connection procedures upon receipt of such request and responsive to the determination, and so can also provide a mobile radio communications network device arranged for operation in the network including plural terminal devices, the network device being arranged to forward to a target network device an indication of reasoning for a LA-based update procedure (during CSFB to the legacy system for example). Further the invention can also be embodied in a mobile radio communications network target device arranged for operation in the network including plural terminal devices and further arranged to monitor for an indication from a network device for reasoning for a LA-based update procedure, and further arranged to vary a connection procedure responsive to the said monitoring.