Access Control for Emergency Call Continuity in CSG Networks
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Solution Overview
Problem
Current access control mechanisms in communication networks, particularly in the context of Closed Subscriber Group (CSG) mechanisms, fail to ensure continuous Emergency Call (EMC) services during handovers, leading to service interruptions when a UE is handed over to a target access network without prior access control, and lack a mechanism to handle EMC services effectively.
Innovation Solution
An access control method and apparatus that obtain CSG area information and EMC service status to control UE access to a target area, ensuring continuity of EMC services by allowing access if the CSG ID exists in the Allowed CSG List or if an EMC service is active, and initiating handover or detach procedures accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If access control is exercised only after handover to target access NE or target cell, then the CSG mechanism can be implemented, but the ongoing service on the UE is terminated and user experience is impaired
Solution Approach 1:
The patent applies preliminary action by performing access control checks before handover is completed. The target access NE or target cell verifies whether the UE is allowed to access before the handover is finalized, preventing service termination while maintaining security. This is achieved by checking the UE's authorization status against the target area's access control list prior to completing the handover procedure.
2Reliability
If the CSG ID corresponding to the target home WAP does not exist in the Allowed CSG List of the UE, then access control is maintained, but the EMC service is interrupted
Solution Approach 1:
The patent applies local quality by differentiating the access control treatment for EMC services versus regular services. For EMC services, the system temporarily suspends the CSG ID verification requirement, allowing UEs to access target home WAPs even when the CSG ID is not in the Allowed CSG List. This localized exception ensures EMC service continuity while maintaining access control for other services.
3Reliability
If access control is exercised before handover, then service continuity can be maintained, but the access control mechanism becomes more complex
Solution Approach 1:
The patent introduces an intermediary mechanism where the target access NE or target cell acts as a mediator between the UE and the access control database. Instead of requiring complex real-time verification during handover, the target access NE performs a simplified check by comparing the UE's identity against pre-stored authorization information, reducing the complexity of the access control mechanism while maintaining service continuity.
Data Source
AI summary
An access control method, an access control apparatus and a communication system are disclosed, and a mechanism for processing Emergency Call (EMC) services is disclosed, and such mechanism ensures continuity of the EMC service while implementing the access control under a Closed Subscriber Group (CSG) mechanism. The access control method includes: obtaining CSG area information of a target area; and controlling the access of a User Equipment (UE) to the target area according to the CSG area information of the target area and/or whether an EMC service exists on the UE. The present invention is applicable to the scenario in which the UE accesses a network.