AMF PCF Policy Association Termination in 5G
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Solution Overview
Problem
In 5G mobile communications, when a terminal device changes AMFs due to movement or other reasons, the existing system fails to efficiently manage the termination of access and mobility management policy associations, leading to wastage of system resources as AM policy control information is not properly deleted when the selected PCF differs from the previous one.
Innovation Solution
The method involves a first AMF sending PCF identifier information to a second AMF and requesting the deletion of the AM policy association with the first PCF, ensuring that AM policy control information is deleted when the PCFs selected by the AMFs are different, thereby saving system resources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the second AMF reuses the first PCF when selecting a PCF, then AM policy control information stored in the first PCF does not need to be deleted, but system resources are wasted when the selected PCF is not the first PCF
Solution Approach 1:
The second AMF sends feedback information to the first AMF indicating whether it has selected the first PCF. Based on this feedback, the first AMF determines whether to send a deletion request to the first PCF, enabling dynamic resource management that adapts to actual PCF selection outcomes
Solution Approach 2:
The system prepares for potential resource cleanup by establishing a deletion request mechanism in advance. The first AMF is ready to send deletion requests to the first PCF if needed, ensuring that resource cleanup can occur promptly when PCF reuse is not implemented
2Reliability
If the first AMF sends deletion request information to the first PCF, then AM policy association and control information are properly deleted, but additional signaling overhead is introduced
Solution Approach 1:
The deletion request is sent conditionally based on feedback from the second AMF. Only when the second AMF indicates it has not selected the first PCF does the first AMF proceed with the deletion request, avoiding unnecessary signaling while ensuring reliable cleanup when needed
3Speed
If the system maintains AM policy control information in the first PCF for potential reuse, then future PCF selections can be faster, but system resources are consumed by retained information
Solution Approach 1:
The system uses feedback mechanisms to determine whether retained policy control information should be maintained or deleted. The second AMF's selection decision triggers a feedback loop that determines the fate of the stored information, balancing reuse benefits against resource consumption
Solution Approach 2:
The system dynamically changes the state of stored policy control information based on operational conditions. When PCF reuse is successful, information is retained; when reuse fails, deletion requests are sent to remove the information, adapting resource allocation to actual system needs
Data Source
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AI summary
This application provides an access and mobility management policy association termination method. The method includes: sending, by a first AMF, first PCF identifier information of a first PCF to a second AMF, and sending first deletion request information to the first PCF, where the first deletion request information is used to request the first PCF to delete an AM policy association between the first PCF and the first AMF for a terminal device, and the first PCF is different from a second PCF; and deleting, by both the first AMF and the first PCF, AM policy control information for the terminal device. Therefore, system resources can be saved.