Originally Posted by M60:
“Quick question for those with VoLTE enabled handsets. Does VoLTE calls handoff to 3G and vice versa. Also, will a call originating on 3G handoff to 4G or is it as at present with 3G where a call handing off to 2G stays on 2G for the remainder irrespective of whether 3G is available from the BTS the phone is using.
Not been able to try this on my wife's iPhone 6S and my HTC M9 doesn't yet support it (hopefully not too long) but curious to know. Handing off to VoLTE from WI-Fi calling and back on the iPhone is pretty cool and works well.”
As packages says, 4G to 3G uses something called SRVCC or Single Radio Voice Call Continuity.
Going the other way (Reverse SRVCC) is a thing but is very hard to implement and is not really required on the EE network.
Currently the network layers are set up so 2G is the biggest footprint, 3G in the middle and 4G the smallest footprint. So calls only need to drop down a layer.
Once power levels are raised VoLTE users won't see the 2G/3G layers anymore anyway.