UE RAT Selection Using PLMN Priority and Validity Information
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Solution Overview
Problem
Existing mechanisms for user equipment (UE) network selection in mobile communication systems lead to higher signaling loads and service outages due to unrestricted use of certain radio access technologies (RATs, causing degradation in visited network performance.
Innovation Solution
Implementing a method for UE to perform a registration procedure with a first public land mobile network (PLMN) that includes receiving and storing RAT utilization information, allowing for informed selection or reselection based on priority and validity information, and supporting a RAT utilization feature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing mechanisms reject UE attach/TAU/registration requests to limit RAT utilization, then network performance is protected, but signaling load increases and service outage occurs
Solution Approach 1:
The patent applies preliminary action by providing RAT utilization information to the UE in advance through registration accept messages or configuration update messages. This allows the UE to proactively select appropriate RATs before attempting attachment, preventing rejection scenarios and reducing service outages while still protecting network performance.
Solution Approach 2:
The patent introduces RAT utilization information as an intermediary between the network and UE. This information acts as a mediator that guides UE RAT selection without requiring direct rejection of attachment requests, thus avoiding the signaling overhead and service interruption associated with reject messages.
2Reliability
If existing mechanisms reject UE registration to limit RAT utilization, then visited network performance is protected, but signaling load increases
Solution Approach 1:
The patent extracts the network protection function from the attachment rejection process and implements it through RAT utilization information provision. By taking out the control mechanism from the attachment phase and moving it to the information provision phase, the patent eliminates the need for reject message signaling while still achieving network protection.
Solution Approach 2:
The patent enables self-service by providing UE with RAT utilization information that allows the UE to autonomously make informed RAT selection decisions. This self-guided approach eliminates the need for network-side rejection signaling, reducing signaling load while maintaining network performance protection.
3Adaptability or versatility
If UE performs unrestricted RAT utilization, then connectivity flexibility is improved, but network performance degrades
Solution Approach 1:
The patent applies dynamics by providing RAT utilization information that enables flexible, adaptive RAT selection based on current network conditions and operator policies. The UE can dynamically adjust its RAT preferences according to the provided information, maintaining connectivity flexibility while protecting network performance through informed decision-making.
Data Source
AI summary
A method and apparatus for performing network selection are described. A method may include performing a first registration procedure on a first PLMN, the registration procedure including a capability of a WTRU to support a RAT utilization feature, the RAT utilization feature corresponding to RAT access information. The WTRU may receive a registration accept message or a WTRU configuration update message including RAT utilization information, where the RAT utilization information includes one or more entries, each entry including at least one PLMN Identifier and a corresponding priority and each entry includes validity information for one or more RATs. The WTRU may store the RAT utilization information. The WTRU may perform a PLMN/cell selection procedure according to the stored RAT utilization information, and may determine to perform a second registration procedure with a second PLMN, based on the second PLMN having a PLMN identity corresponding to the highest priority.