Feasibility study on Voice Call Continuity (VCC) support for emergency calls
This document contains the results of the feasibility study into the architectural requirements and alternatives for the support of active voice call continuity between Circuit Switched (CS) domain and the IP Multimedia Subsystem (IMS) for emergency calls. Considerations include overall requirements, architectural requirements, evaluation of potential architectural solutions and alternative architectures.
The Feasibility Study considers different solutions for offering voice call continuity for emergency calls when users move between the GSM/UMTS CS Domain and the IP Connectivity Access Network (e.g., WLAN interworking) with home IMS functionality. The objective is to identify an architectural solution that allows completely automatic connectivity to the correct PSAP (from the end-user point of view) as specified in TS 23.167 [4], and allow for the possibility of a domain transfer as specified in TS 23.206 [3]. The study will also identify configuration impacts upon existing networks in order to realize the desired functionality.
Existing solutions developed by the 3GPP (e.g. 3GPP system to Wireless Local Area Network Interworking (I-WLAN)) should be reused as much as possible.