UE Disaster Roaming PLMN Selection and Registration
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Solution Overview
Problem
In mobile communications, existing technologies face challenges in minimizing service interruption and managing user equipment (UE) and network behavior during and after a network disaster, such as natural disasters, where neighboring networks may be overwhelmed by users seeking access, leading to potential signaling overload and limitations in UE selection options.
Innovation Solution
The proposed solution involves user equipment (UE) determining disaster conditions in a first public land mobile network (PLMN) and selecting a second PLMN from a list of allowed networks for registration, using information on pre-configured or provisioned disaster roaming PLMNs, and managing registration attempts to minimize impact on both the affected network and the UE's home network.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If neighboring networks accept all users from disaster-affected networks, then service continuity is improved, but signaling overload occurs on the neighboring networks
Solution Approach 1:
The patent applies partial action by implementing rate limiting mechanisms that allow only a controlled portion of users from disaster-affected networks to access neighboring networks. The network node prioritizes and limits the number of registration requests accepted, preventing complete overload while still providing service continuity to critical users. This is achieved through configurable thresholds and priority-based admission control.
Solution Approach 2:
The patent changes the parameter of user admission control by dynamically adjusting acceptance criteria based on network conditions. When disaster conditions are detected, the system modifies registration parameters to allow emergency access while simultaneously implementing rate limiting. The network node can switch between different admission modes (permissive during disaster, restrictive during normal conditions) to balance service continuity and network load.
2Reliability
If UEs are restricted from selecting other networks before disaster, then network security is improved, but service interruption increases when disaster occurs
Solution Approach 1:
The patent applies preliminary action by pre-configuring UEs with a list of allowed PLMNs for disaster scenarios before the disaster occurs. The network provides this whitelist of acceptable networks in advance through system information broadcasting or dedicated signaling. When a disaster strikes, the UE can immediately select from this pre-approved list without needing to perform security checks against the entire network database, thus reducing service interruption while maintaining security constraints.
Solution Approach 2:
The patent implements dynamic behavior by allowing the UE's network selection restrictions to change based on disaster condition detection. During normal operation, the UE follows standard security restrictions. When a disaster is detected (through network signaling or UE determination), the UE dynamically switches to a more permissive mode that allows selection from the pre-configured disaster PLMN list, thereby adapting the security-policy balance to current conditions.
3Reliability
If UEs immediately switch to alternative networks during disaster, then service continuity is improved, but network stability deteriorates due to sudden load increase
Solution Approach 1:
The patent applies periodic action through rate limiting mechanisms that spread user migration over time rather than allowing simultaneous switches. The network node processes registration requests at a controlled rate, introducing time-based throttling that prevents sudden load spikes. This periodic admission control allows users to switch networks gradually, maintaining service continuity while preserving network stability through controlled load distribution.
4Object-generated harmful factors
If neighboring networks impose restrictions on UE selection, then signaling overload is prevented, but service accessibility worsens for affected users
Solution Approach 1:
The patent applies local quality by implementing different restriction levels for different users and different networks. Not all UEs from disaster-affected networks are treated uniformly - priority users (e.g., emergency services, critical infrastructure) receive preferential treatment with fewer restrictions. Similarly, different neighboring networks can have different acceptance policies based on their capacity and conditions. This differentiated approach prevents signaling overload while maintaining accessibility for critical users.
Data Source
AI summary
Solutions pertaining to user equipment (UE) and network behavior at and after a network disaster in mobile communications are proposed. An apparatus, implemented in or as a UE, determines whether a disaster condition is met with respect to a first public land mobile network (PLMN). The apparatus then selects a second PLMN according to information listing one or more PLMNs which are allowed to be selected by the UE when the disaster condition is met. The apparatus also attempts a registration in the second PLMN.