Single Radio Voice Call Continuity (SR-VCC) support for IMS Emergency Calls
SRVCC as specified in TS 23.216 [3], provides handover of voice calls from E-UTRAN/HSPA to UTRAN/GERAN or from E-UTRAN to CDMA2000 1x. SRVCC of IMS emergency calls is not supported in TS 23.216 [3], and thus handover of such calls will have unpredictable effects, in the worst case causing the call to fail. This is a serious concern for operators and their subscribers, and may cause regulatory violations in some parts of the world.
Therefore, the objective of this document is to study both the EPS and IMS aspects of how to best support the handover of ongoing emergency calls for the following scenarios:
- E-UTRAN to UTRAN/GERAN CS.
- HSPA to UTRAN/GERAN CS.
- E-UTRAN to CDMA2000 1x CS.