PDU Session Switching Control in 5G to 4G Network Transitions
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Solution Overview
Problem
In the transition between 5G and 4G networks, the uncontrolled switching of PDU sessions due to insufficient 5G network coverage leads to poor system performance, as multiple PDU sessions with the same DNN can be anchored to different session management devices, causing uncontrolled situations and performance issues.
Innovation Solution
A communication method that determines a target PDU session based on switching indication information, ensuring that only specific PDU sessions are switched to the control plane function network element in the 4G network, thereby controlling the switching process and improving system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple PDU sessions with the same DNN are allowed to be anchored to different session management devices, then the system provides flexibility in session management, but it causes uncontrolled switching situations and deteriorates system performance
Solution Approach 1:
The patent introduces switching indication information as a new parameter to control PDU session switching. By changing the state of this parameter (switching indication enabled/disabled), the system can flexibly control whether PDU sessions should be switched during network transitions, thereby resolving the contradiction between flexibility and reliability.
Solution Approach 2:
The patent implements a feedback mechanism where the network device monitors switching indication information from multiple PDU sessions and uses this feedback to determine which sessions should be switched. This feedback loop ensures controlled switching behavior that maintains system performance while allowing necessary flexibility.
2Reliability
If all PDU sessions with the same DNN are switched to the same control plane function network element, then system performance is improved through controlled switching, but it reduces the flexibility in session management
Solution Approach 1:
The patent applies local quality by treating each PDU session differently based on its specific switching indication information. Instead of uniformly treating all sessions with the same DNN, the system makes differentiated decisions for each session based on its individual switching requirements, thereby maintaining flexibility while ensuring performance.
3Reliability
If the network device determines target PDU sessions based on switching indication information, then controlled switching is achieved, but the complexity of session management increases
Solution Approach 1:
The patent extracts the switching control logic from the complex session management process by introducing a dedicated switching indication information field. This extraction allows the network device to focus on making controlled switching decisions based on clear indication information, thereby achieving controlled switching without proportionally increasing overall system complexity.
Data Source
AI summary
This application provides a communication method and a communications apparatus, to help control switching of a PDU session, thereby improving system performance. The method includes: determining, by a network device based on switching indication information of protocol data unit PDU sessions established by a terminal in a first network, a target PDU session from the established PDU sessions, where all the established PDU sessions have a same data network name DNN; and sending, by the network device, session information of the target PDU session to a mobility management entity device in a second network.