Hi all experts,
Flash CSFB based on RIM feature has benefit of reducing CSFB setup time, this is due to RRC-conn-release message that enb sent to UE also contain PSC + SI of UMTS cell.
This feature require enb/CN and UE support R9 and later.
Have anyone ever seen how a R8-UE request CSFB service in a LTE cell enabled flash CSFB?
- CSFB will be failed.
- or enb checked UE capability and just send UMTS-frequency only to UE and UE continue with normal CSFB