UE Voice Network Selection via VoIMS Detection and PLMN Storage
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Solution Overview
Problem
User equipment (UE) faces challenges in efficiently selecting and reselecting networks for voice services, particularly when LTE networks do not support voice over internet multimedia subsystem (VoIMS), leading to suboptimal service provision and user experience.
Innovation Solution
The UE determines non-preferred LTE networks for voice services, stores their identification, and uses this information to avoid reselecting them, prioritizing networks that support VoIMS, and fallbacks to 2G/3G networks when necessary, utilizing a connection manager to manage network selection and registration processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If UE attempts to connect to LTE network for voice services, then data service availability is improved, but voice service availability deteriorates when VoIMS is not supported
Solution Approach 1:
The UE performs preliminary actions by determining whether the LTE network supports VoIMS before attempting to establish a voice service connection. This preliminary check prevents wasted connection attempts on networks that cannot provide the required voice service, resolving the contradiction by anticipating service compatibility issues in advance.
Solution Approach 2:
The UE dynamically adjusts its network selection behavior based on real-time determination of VoIMS support. When VoIMS is not supported, the UE switches to alternative networks (2G/3G); when supported, it utilizes LTE. This dynamic adaptation resolves the contradiction by making network selection flexible rather than static.
2Reliability
If UE reselects to 2G/3G networks when LTE does not support VoIMS, then voice service availability is improved, but service speed and data capability deteriorate
Solution Approach 1:
The UE changes the network selection parameter based on the required service type. For voice services, it selects networks with reliable voice support (2G/3G when LTE lacks VoIMS). For data services, it prefers faster networks (LTE). This parameter-based selection resolves the contradiction by optimizing for the appropriate metric depending on service requirements.
3Reliability
If UE continuously scans for preferred voice networks, then voice service availability is improved, but energy consumption increases
Solution Approach 1:
The UE performs preliminary determination of network VoIMS support and stores this information. Instead of continuously scanning, it uses the stored determination to guide network selection, performing scans only when necessary (e.g., when stored information is unavailable or outdated). This preliminary action resolves the contradiction by reducing redundant scanning while maintaining service availability.
Data Source
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AI summary
Methods and apparatus for voice domain operation are described herein. One example method is for use in a UE supporting connections to one or more public land mobile networks (PLMNs), each of which offer a particular network coverage. The method includes storing one or more PLMN identities that respectively identify the PLMNs wherein the PLMNs are not preferred for voice services; and avoiding based on the one or more stored PLMN identities to connect to one of the PLMNs identified by the PLMN identities.