Multi-USIM UE Network Leaving for Graceful PLMN Switching
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Solution Overview
Problem
Existing multiple USIM devices face issues with abrupt connection releases, leading to network errors and inefficient use of resources due to unnecessary paging, impacting key performance indices (KPIs) when switching between USIMs.
Innovation Solution
A method for multiple USIM devices to gracefully leave the network at the NAS or RRC level, allowing the UE to enter CM-IDLE or RRC inactive states, providing information for the network to handle mobile terminating signaling and data, thereby improving KPIs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a multi USIM UE uses common radio and baseband components shared among multiple USIMs, then cost efficiency is improved, but network errors and resource inefficiency worsen due to abrupt connection releases when switching between USIMs
Solution Approach 1:
The UE sends a service request with an indication of impending connection release to the AMF before actually releasing the connection. This preliminary notification allows the network to prepare for the release, redirect resources, and avoid errors that would occur with abrupt disconnection. The AMF can then gracefully handle the transition when the UE switches to another USIM.
2Adaptability or versatility
If a multi USIM UE performs monitoring and measurements on other systems while actively communicating, then network switching capability is improved, but interruption of active communication worsens due to shared radio components
Solution Approach 1:
The UE notifies the AMF in advance about the need to switch networks or about impending connection release. This allows the network to prepare the target system for the incoming connection, ensuring that when the UE does switch, the transition is smooth and communication can resume quickly without significant interruption.
3Adaptability or versatility
If the network sends paging requests to a UE that has switched to another USIM, then mobile terminating signaling is improved, but resource waste worsens due to unnecessary paging to unavailable UEs
Solution Approach 1:
The UE sends a service request with an indication of impending connection release or network switch to the AMF before actually leaving the current network. This preliminary notification allows the AMF to update its records and stop sending paging requests to the UE in the old network, preventing waste of network resources on paging a UE that is no longer available.
Solution Approach 2:
The UE provides feedback to the network about its connection status and intended actions through the service request mechanism. This feedback loop enables the network to adapt its paging behavior accordingly, stopping paging when the UE indicates it will release the connection or switch networks, thus avoiding resource waste.
Data Source
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AI summary
A method, UE, and computer programs are provided where the UE has multiple universal subscriber identity modules. Information is received from a first PLMN indicating there is one of mobile terminating (MT) signaling or data in the first PLMN while the UE is in a second PLMN. Responsive to receiving the information, a service request is sent to an AMF node of the second PLMN. A radio resource control (RRC) connection release is received from a RAN node in response to sending the service request. Responsive to receiving the RRC connection release, the second PLMN is left to be in the first PLMN.