Release 8:
Basic SRVCC from LTE PS to UTRAN/GERAN CS with/without PS HO/DTM;
Release 9:
IMS Emergence Call SRVCCfrom LTE PS to UTRAN/GERAN CS;
Release 10:
aSRVCC: support SRVCCPS-CS transfer during alerting phase;
eSRVCC: support mid-callfeature during SRVCC HO procedure, MSC Server assisted mid-call feature enablespacket switched (PS) - circuit switched (CS) Access Transfer for UEs not usingIMS Centralized Service (ICS) capabilities, while preserving the provision ofmid-call services (inactive sessions or sessions using the Conference service).
Release 11:
bSRVCC means SRVCC before ringing;
vSRVCC means video call SRVCC from LTE PS to 3G(UTRAN) CS;
rSRVCC means reverse SRVCC HO from UTRAN/GERAN CS back to LTE PS;
SRVCC during upgrading from VoLTE call to video call.
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