UE Timer Management for 5G PLMN Change Congestion
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Solution Overview
Problem
The 5G mobile communication system lacks clear processing mechanisms for congestion control, particularly in scenarios where a terminal-initiated session management request is made during congestion control, network slice changes, or when multiple congestion control timers are active, and there is ambiguity in how the network indicates congestion control to the terminal and how the terminal applies it.
Innovation Solution
A User Equipment (UE) is designed to manage timers for congestion control across different Data Network Names (DNNs) and Public Land Mobile Networks (PLMNs, allowing it to transmit PDU session establishment requests without stopping existing timers, ensuring seamless congestion control management across network slices and DNNs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE stops the first timer when changing PLMN, then the congestion control for the old PLMN is properly managed, but the UE cannot transmit PDU session establishment requests in the new PLMN during the congestion control period
Solution Approach 1:
The patent segments congestion control timers by associating each timer with a specific PLMN identifier. When the UE changes PLMN, it determines whether to stop a timer based on whether the timer's associated PLMN matches the new PLMN. This segmentation allows the UE to maintain timers for different PLMNs independently, enabling session establishment in the new PLMN while preserving congestion control for the old PLMN.
Solution Approach 2:
The patent implements dynamic timer management where the UE selectively stops or continues timers based on real-time PLMN change conditions. The timer management is not static but adapts dynamically: if the timer's PLMN matches the new PLMN, the timer continues; if it doesn't match, the timer is stopped. This dynamic approach resolves the contradiction between maintaining congestion control and enabling session establishment.
2Adaptability or versatility
If the UE maintains multiple congestion control timers simultaneously, then congestion control for multiple DNNs and PLMNs is managed, but the processing complexity for identifying and managing timers increases
Solution Approach 1:
The patent employs feedback mechanisms where the UE continuously monitors the state of congestion control timers and their associated PLMNs. When a PLMN change occurs, the UE receives feedback about which timers are active and makes decisions based on this feedback. The network also provides feedback through rejection responses indicating congestion control status, enabling the UE to properly manage multiple timers without excessive complexity.
Solution Approach 2:
The patent segments the timer management system by associating each timer with specific identification information (DNN and PLMN). This segmentation allows the UE to manage multiple timers independently through systematic comparison of timer identifiers with current network parameters, reducing the cognitive load and processing complexity compared to managing undifferentiated timers.
3Measurement precision
If the network provides detailed congestion control indications to the terminal, then the terminal can accurately identify and apply the correct congestion control measures, but the signaling overhead and processing burden increase
Solution Approach 1:
The patent extracts essential congestion control information from detailed network indications and retains only the critical elements needed for timer management. Specifically, the UE extracts the PLMN identifier and DNN information from rejection responses to determine which timers to stop or continue. This extraction approach maintains accurate congestion control identification while minimizing signaling overhead by focusing only on the most important parameters.
Data Source
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AI summary
A User Equipment (UE) includes a transmitter configured to, in a case that, at a time when a Public Land Mobile Network (PLMN) is changed, a first timer is running for a certain Data Network Name (DNN) and an old PLMN but that a second timer is not running for the DNN or a new PLMN and is not deactivated, be capable of transmitting a PDU session establishment request message for the DNN or no DNN in the new PLMN without stopping the first timer for the DNN and the old PLMN. Thus, a communication control method is provided that is used in a case that, in 5G congestion control in which multiple types of congestion control are applied, the PLMN is changed during application of the congestion control.