Patent ID: 11700290

Abstract:
Techniques and systems for selectively implementing a silent retry procedure after a voice session has moved from a preferred IP-based system (e.g., 5GS) to a legacy IP-based system (e.g., EPS) are disclosed. The silent retry procedure may be implemented by a UE and/or by a TAS using one or more specific error codes and/or timeouts. In this manner, after a voice session has been redirected or handed over from a preferred system (e.g., 5GS) to a legacy system (e.g., EPS), and based on an issue arising that prevents the voice session from being successfully established thereafter, the UE or the TAS may reattempt to establish the voice session directly in the legacy system, instead of allowing the UE to transition back to the preferred system (e.g., 5GS) after a session failure in the legacy system, which increases the overall success rate of establishing voice sessions.