SRVCC Interworking Function for Seamless Voice Handover
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Solution Overview
Problem
In next-generation wireless communication systems, single radio voice call continuity (SRVCC) handovers from next-generation radio access network (NG-RAN) to universal terrestrial radio access network (UTRAN) are not supported, leading to potential voice call disruptions when there is no overlapping coverage between LTE and NG-RAN, or when VoLTE is not supported.
Innovation Solution
Introducing updates to registration and handover procedures, including the use of a SRVCC-interworking function (SRVCC-IWKF) that reuses existing interfaces to facilitate SRVCC handovers between NG-RAN and UTRAN, with the SRVCC-IWKF being a standalone function or collocated with the MME or AMF, and including SRVCC indications in key messages to ensure seamless handovers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SRVCC handover from NG-RAN to UTRAN is not supported, then the system maintains simplicity in network architecture, but voice call continuity is disrupted when there is no overlapping coverage between LTE and NG-RAN
Solution Approach 1:
The patent introduces an SRVCC-interworking function (SRVCC-IWKF) as an intermediary component that enables handover between NG-RAN and UTRAN. This intermediary reuses existing interfaces (Sv interface between MSC server and AMF, N2 interface between AMF and NG-RAN) to facilitate the handover process without requiring completely new architecture, thus improving voice call continuity while limiting the increase in system complexity.
2Reliability
If SRVCC handover procedures are updated to include SRVCC-IWKF, then seamless handovers are enabled between NG-RAN and UTRAN, but the registration and handover procedures become more complex
Solution Approach 1:
The SRVCC-IWKF is designed to perform multiple functions: it handles SRVCC handover signaling, reuses existing Sv and N2 interfaces, and can be deployed as a standalone function or collocated with existing MME or AMF components. This multi-functionality approach enables seamless handovers while reusing existing infrastructure, thereby limiting the increase in procedure complexity.
3Adaptability or versatility
If SRVCC-IWKF is deployed as a standalone function, then flexibility in deployment is improved, but the number of network components increases
Solution Approach 1:
The patent provides two deployment options for SRVCC-IWKF: as a standalone function or collocated with existing MME or AMF components. The merging option allows the SRVCC-IWKF to be combined with existing network elements, thereby providing deployment flexibility while avoiding the increase in the number of separate network components that would result from a purely standalone deployment.
Data Source
AI summary
Embodiments of the present disclosure describe methods, apparatuses, storage media, and systems for single radio voice call continuity handover from next-generation radio access network to universal terrestrial radio access network, and return to the next-generation radio access network after single radio voice call continuity service. Other embodiments may be described and claimed.