PLMN Core Network Detach for MPN Reattachment
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Solution Overview
Problem
User Equipment (UE) often gets stuck on a Public Land Mobile Network (PLMN) when returning to the coverage area of a Mobile Private Network (MPN), due to overlapping coverage and shared frequencies, leading to difficulties in reattachment, even with existing methods like Idle Mode Cell Reselection and power cycling.
Innovation Solution
The core network of the PLMN initiates a detach process for the UE by identifying its association with the MPN, using methods such as Tracking Area Updates, intra/inter-frequency handovers, and location reports, to facilitate reattachment to the MPN, involving entities like the Mobility Management Entity (MME), Packet Data Network Gateway (PGW), and Home Subscriber Server (HSS).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE uses Idle Mode Cell Reselection to reattach to MPN cells, then the UE can reattach to MPN when operating on dedicated frequency bands, but this method does not work when MPN cells operate on the same frequencies as PLMN cells
Solution Approach 1:
Instead of allowing the UE to autonomously select networks based on cell reselection (bottom-up approach), the invention inverts the control by having the network entity (MME) initiate the detach procedure (top-down approach). The MME detects UE presence in overlapping coverage areas and actively triggers detachment to force reattachment to the home network, reversing the traditional autonomous UE selection mechanism.
Solution Approach 2:
The invention introduces a network entity (MME) as an intermediary between the UE and the network selection process. The MME acts as a mediator that monitors UE location, detects overlapping coverage scenarios, and coordinates the detach/reattachment process, replacing the direct UE-autonomous network selection with a mediated network-controlled approach.
2Reliability
If the UE is forced to power cycle to reattach to MPN, then the UE may reconnect to the network, but this approach may still fail if the UE tries stored PLMN network identities or is stuck in connected mode
Solution Approach 1:
The invention performs preliminary actions by having the MME proactively detect UE presence in overlapping coverage areas before the UE attempts problematic reattachment. The MME initiates the detach procedure in advance, preventing the UE from getting stuck trying stored PLMN identities or remaining in connected mode, thereby preemptively resolving potential reattachment failures.
Solution Approach 2:
The invention implements a feedback mechanism where the MME monitors UE location and coverage area information, detects when UE is in overlapping MPN/PLMN coverage, and triggers appropriate detach procedures. This closed-loop feedback system continuously adjusts network control actions based on real-time UE status and coverage conditions.
3Use of energy by moving object
If the PLMN and MPN cells use the same frequencies, then spectrum efficiency is improved, but reattachment of UE to MPN becomes significantly more difficult
Solution Approach 1:
The MME serves as an intermediary that resolves the conflict between spectrum efficiency and reattachment reliability. By monitoring frequency usage and UE location, the MME detects when same-frequency PLMN and MPN cells create reattachment problems and initiates targeted detach procedures, allowing spectrum sharing while maintaining reliable reattachment through network-controlled intervention.
Data Source
AI summary
Reattachment of a User Equipment (UE) from a Public Land Mobile Network (PLMN), on which the UE is roaming, to a Mobile Private Network (MPN) can be instigated by: identifying at the PLMN that the UE is associated with the MPN; and initiating, at a core network of the PLMN or the MPN, a detach of the UE from the PLMN in response to the identification.