User Equipment Voice Call Setup Bypassing LTE Fallback
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Solution Overview
Problem
In mobile communications networks, there is a delay in establishing emergency voice calls when a user equipment (UE) uses multiple wireless access technologies, including LTE and legacy technologies, due to the need to attempt LTE access first, which may result in a CS fallback procedure, leading to prolonged setup times, especially when LTE attach is rejected.
Innovation Solution
A UE method that allows quicker voice call establishment by determining if VoLTE is supported and bypassing initial LTE access procedures to directly attempt a voice call over a legacy wireless access technology that supports voice calls in the CS domain, such as WCDMA or GSM/EDGE, thereby reducing setup time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE attempts to establish a voice call over LTE first, then the UE can utilize modern wireless access technology, but the call setup time increases due to potential CS fallback procedures
Solution Approach 1:
The patent implements dynamic selection of wireless access technology based on real-time conditions. The UE determines whether to attempt voice call establishment over LTE or directly over legacy technology by evaluating whether the UE is in a service area where voice services are supported over LTE. This dynamic adaptation allows the system to optimize call setup time based on network capabilities and current conditions, avoiding unnecessary LTE access procedures when they would result in CS fallback.
2Adaptability or versatility
If the UE always attempts LTE access first for voice calls, then network compatibility is improved, but setup time increases from several seconds to potentially over 20 seconds
Solution Approach 1:
The patent performs preliminary determination of LTE voice service support status before attempting voice call establishment. By checking whether the UE is in a service area where voice services are supported over LTE prior to initiating the call setup process, the system can pre-select the appropriate access technology. This preliminary action prevents unnecessary LTE access attempts that would lead to CS fallback, thereby reducing call setup time while maintaining network compatibility.
3Loss of time
If the UE bypasses LTE access procedures to use legacy technology directly, then call setup time is reduced, but the capability to utilize modern network features is lost
Solution Approach 1:
The patent applies local quality by making the access technology selection specific to the local service area conditions. Instead of using a uniform approach across all areas, the system determines whether to use LTE or legacy technology based on the specific service area where the UE is located and whether voice services are supported over LTE in that area. This localized decision-making optimizes call setup time in areas where LTE voice is not supported while maintaining the ability to use LTE in areas where it is supported.
Data Source
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AI summary
A user equipment (UE), which is able to use a plurality of different wireless access technologies, receives a request to establish a voice call. In response to the request, the UE determines whether voice over a first wireless access technology of the different wireless access technologies is supported, and responsive to determining that voice over the first wireless access technology is not supported, the UE attempts to establish the voice call over a second wireless access technology of the different wireless access technologies.