Mobile Device PLMN Code Retention for Roaming Continuity
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Solution Overview
Problem
Mobile devices lose stored PLMN codes when transitioning between home and roaming networks, leading to disrupted cellular coverage and increased processing resources usage.
Innovation Solution
Implementing techniques for mobile devices to maintain stored PLMN codes from past registration procedures, allowing them to recall and utilize home network coverage even when roaming, by refraining from deleting these codes during registration with roaming networks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the mobile device replaces the ePLMN list on each registration (following 3GPP specifications), then the device complies with network protocols and maintains proper network registration, but the device loses access to home network coverage when moving between roaming and home networks, requiring repeated registrations
Solution Approach 1:
The mobile device performs preliminary actions by storing PLMN codes from the ePLMN list in a persistent registry before leaving the home network coverage area. This advance storage ensures that when the device later moves to a roaming network and returns to home network coverage, it can immediately utilize the stored PLMN codes to access home network services without requiring re-registration, thus maintaining network access continuity while complying with protocol requirements.
2Productivity
If the mobile device stores multiple ePLMN lists from different registration procedures, then the device can maintain access to home network coverage while roaming, but the device increases memory usage and complexity in managing multiple PLMN lists
Solution Approach 1:
The mobile device extracts only the essential PLMN codes from the ePLMN list received during home network registration and stores them in a persistent registry. By taking out only the necessary PLMN identification information rather than storing complete ePLMN lists, the device maintains the ability to access home network coverage while minimizing memory usage and simplifying the management complexity of PLMN information.
3Reliability
If the mobile device repeatedly registers with the home network upon returning from roaming, then the device ensures proper network authentication and service provisioning, but the device increases processing resource consumption and registration overhead
Solution Approach 1:
The mobile device performs preliminary authentication by storing PLMN codes and network identification information during the initial home network registration. When the device later returns to home network coverage from a roaming network, it can use the stored PLMN codes to quickly re-establish network access without performing a complete re-registration procedure. This preliminary action reduces processing resource consumption and energy usage while maintaining proper network authentication through the use of stored credentials.
Data Source
AI summary
Disclosed herein are techniques, devices, and systems for a mobile device to keep track of public land mobile networks (PLMNs) codes from a list(s) of equivalent PLMNs that the mobile device received at a time of performing a past registration procedure(s). For example, memory of the mobile device may store a PLMN code(s) from a list of equivalent PLMNs that the mobile device received from a mobility management entity (MME) or an access and mobility function (AMF) node. During a subsequent registration, the mobile device may send a message to another MME or another AMF node, and may receive a message, such as an ATTACH ACCEPT message or a REGISTRATION ACCEPT message, from the other MME or the other AMF node. In response to receiving the message, the mobile device can maintain the stored PLMN code(s) in the memory.