UE IMS Registration Failure Handling for 5G Voice Service
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Solution Overview
Problem
Existing configurations in 5G wireless communication systems do not effectively address scenarios where voice over IMS becomes unavailable, leading to detrimental user experiences, such as unnecessary connection to low priority RATs.
Innovation Solution
A user equipment (UE) device is configured to send a request for IMS registration to an IMS server, handle IMS rejection messages, and re-attempt registration. The UE determines whether the IMS registration failure is temporary or permanent and adjusts its radio access technology (RAT) disablement accordingly, ensuring optimal RAT selection and minimizing user experience impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE disables N1 mode when voice over IMS becomes unavailable, then the UE can switch to alternative RATs for voice service, but the UE may unnecessarily remain connected to low priority RATs for longer than necessary
Solution Approach 1:
The UE monitors IMS registration status and uses this feedback information to dynamically adjust its RAT selection behavior. When IMS registration succeeds on a high priority RAT, the UE receives feedback that allows it to disable lower priority RATs, thereby reducing unnecessary connections and optimizing service availability.
Solution Approach 2:
The system transitions from static RAT disabling to dynamic RAT management. The UE continuously monitors IMS registration status and adjusts its RAT configuration in real-time, enabling flexible adaptation between high and low priority RATs based on current network conditions and service availability.
2Ease of operation
If the UE switches to low priority RAT when high priority RAT becomes unavailable, then voice service can be maintained, but user experience deteriorates due to unnecessary connection to low priority RAT
Solution Approach 1:
The UE uses feedback from IMS registration status to make intelligent RAT selection decisions. When high priority RAT becomes available again, the UE receives feedback about the successful registration and automatically switches back, eliminating unnecessary connections to low priority RATs and improving user experience.
Solution Approach 2:
The UE autonomously monitors its own registration status and automatically manages RAT selection without requiring manual intervention. The self-service mechanism ensures that the UE independently optimizes its connection based on real-time network conditions and service availability.
Data Source
AI summary
This disclosure describes a user equipment device (UE). The UE includes one or more antennas; one or more radios, where each of the radios is configured to perform cellular communication using a plurality of radio access technologies (RATs) that support voice over an Internet protocol (IP) multimedia subsystem (IMS); one or more processors coupled to the one or more radios, where the one or more processors are configured to cause the UE to perform operations including: sending, via a first RAT, a first request for IMS registration to an IMS server; receiving, from the IMS server, an IMS rejection message indicating failure of the IMS registration; determining, based on the IMS rejection message, that the IMS registration failure is temporary; responsively re-attempting IMS registration with the IMS server; and determining to camp on the first RAT in response to receiving an IMS acceptance message from the IMS server.