5G SA Voice Service Acquisition via VoNR Pre-Check and RAT Fallback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In 5G standalone (SA) deployment environments where the LTE radio access technology (RAT) is disabled, existing methods fail to efficiently acquire voice services, leading to prolonged service disruptions and ambiguity in re-enabling LTE RAT for emergency calls.
Innovation Solution
A method and apparatus that enable a terminal to identify the support for voice over new radio (VoNR) before searching for a NR cell, and if VoNR is not supported, select an alternative radio access technology (RAT) to obtain voice services, including emergency calls, by utilizing pre-checks and pre-conditions to determine available RATs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the terminal searches for NR cells without checking VoNR support first, then the terminal can potentially connect to any NR cell, but the terminal experiences prolonged service disruption and wasted time when the NR cell does not support voice services
Solution Approach 1:
The terminal performs preliminary determination of VoNR support capability before initiating NR cell search. This advance check prevents unnecessary cell search operations when VoNR is not supported, thereby reducing service disruption time and avoiding wasted resources on cells that cannot provide voice services.
Solution Approach 2:
The terminal autonomously determines its own VoNR support capability and makes independent decisions about whether to search for NR cells or select alternative RATs. This self-service mechanism eliminates the need for external guidance during the initial connection phase, enabling faster and more reliable voice service acquisition.
2Productivity
If the terminal selects alternative RATs when NR cells do not support VoNR, then the terminal can acquire voice services quickly, but the device complexity increases due to multiple RAT support requirements
Solution Approach 1:
The terminal dynamically changes its operating parameters by selecting different RATs based on the detected VoNR support capability of NR cells. When VoNR is not supported, the terminal switches to alternative RATs such as LTE or 3G, enabling fast voice service acquisition while leveraging existing multi-RAT capabilities without significantly increasing device complexity.
3Adaptability or versatility
If the terminal re-enables LTE RAT for emergency calls when LTE is disabled, then the terminal can make emergency calls, but the ambiguity in re-enabling conditions causes delays and operational complexity
Solution Approach 1:
The terminal performs preliminary determination of VoNR support capability before disabling LTE RAT. This advance knowledge allows the terminal to make informed decisions about whether to re-enable LTE for emergency calls, eliminating ambiguity and enabling clear, automatic operational procedures for maintaining emergency call capability.
Solution Approach 2:
The terminal uses feedback from the VoNR support determination to automatically control the enabling/disabling state of LTE RAT. When VoNR is not supported, the terminal maintains or re-enables LTE for emergency calls; when VoNR is supported, the terminal can safely disable LTE. This feedback mechanism simplifies operation by removing the need for user judgment about when to re-enable LTE.
Data Source
AI summary
A method performed by a terminal in a wireless communication system is provided. The method includes identifying that long term evolution (LTE) radio access technology (RAT) of the terminal is disabled, determining whether each of the terminal and a target network supports voice communication over new radio (VoNR) before searching a NR cell, searching the NR cell in case that the terminal and the target network support the VoNR, determining whether the NR cell supports the VoNR before registration to the NR cell, and selecting a RAT other than the LTE RAT and a NR RAT to obtain a voice service in case that the NR cell does not support the VoNR.