Mobile Station Ringing Tone Continuity During LTE to 3G Transition
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Solution Overview
Problem
Mobile stations connected to LTE face challenges in determining which ringing tone to output after transitioning to 3G via aSRVCC, leading to discomfort due to sudden tone changes or silences, as they cannot differentiate between local and NW-provided ringing tones before the transition.
Innovation Solution
A mobile station equipped with a voice communication control unit and a ringing tone control unit that continues the output of either the NW-provided ringing tone or local ringing tone after transitioning from LTE to 3G, based on the tone being outputted before the transition, ensuring seamless tone continuity during the alert period.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mobile station makes a transition from LTE to 3G via aSRVCC during alerting, then voice communication service continuity is maintained, but the mobile station cannot determine which ringing tone (local or NW-provided) should be outputted after transition, causing sudden tone changes or silences that give user discomfort
Solution Approach 1:
The mobile station performs preliminary identification of which ringing tone (local or NW-provided) is currently outputted before the LTE to 3G transition. This preliminary identification enables the system to maintain the same ringing tone after transition, avoiding sudden tone changes or silences that would cause user discomfort.
Solution Approach 2:
The system implements feedback by having the mobile station identify and track the current ringing tone state (local or NW-provided) and use this information to control the post-transition tone output. This feedback mechanism ensures that the ringing tone continuity is maintained across the radio access system boundary.
2Device complexity
If the mobile station outputs a normal ringing tone (local ringing tone) after transition from LTE to 3G while CAT was received as Early Media, then the system simplifies tone selection, but this switching from CAT to normal ringing tone gives the user a sense of discomfort
Solution Approach 1:
The mobile station uses feedback from the pre-transition state identification to control the post-transition tone output. By identifying that CAT (NW-provided ringing tone) was being outputted before transition, the system maintains CAT output after transition, preventing the uncomfortable switching to normal ringing tone.
3Reliability
If the mobile station checks whether or not to receive CAT after transition to 3G, then the system ensures proper tone reception, but this causes the ringing tone to suddenly fall off into silence giving user discomfort
Solution Approach 1:
The mobile station performs the identification of the current ringing tone state as a preliminary action before the transition occurs. This allows the system to maintain continuous tone output during and after transition, eliminating the sudden silence that would occur if the system waited until after transition to determine which tone to output.
Data Source
AI summary
A mobile station and a mobile communication method are provided, which are, if being able to output a local ringing tone and a NW-provided ringing tone, capable of continuing a ringing tone outputted before a transition from LTE to 3G by aSRVCC even after the transition is made. A UE (100A) executes continuation processing (aSRVCC) of a 3G voice communication service if the mobile station makes a transition of the connection destination from LTE to 3G during an alert period when the other party in the voice communication service is being alerted. Further, the UE (100A) outputs a NW-provided ringing tone without outputting a local ringing tone based on data stored in the mobile station after making a transition to a second radio access system if aSRVCC is executed during a period when the NW-provided ringing tone is being outputted.