Which of the following statements about VoLTE are correct? (Multiple choice)
A . TTI bundling cannot be used under 1.4MHz bandwidth
B . whether the terminal supports CSFB and SMS over SGs ability, will carry the FGI "FeatureGroupIndicators"
C . In order to ensure speech continuity, SRVCC will hand over from LTE to the PS domain of 2/3G
D . In the silent period, send a SID (Silence Insertion Descriptor) frame every 160ms to enhance user experience.
Answer: ABCD