New carrier with only 4G and 5G network with no more 3G network support
Rakuten mobile from Japan is a kind of new comer focusing on the next generation of network. What's unique about Rakuten is it owns only 4G and 5G network and does not have legacy 3G network anymore. I found a strange behavior of Zenfone 7 using with Rakuten's SIM card.
At first with all default settings, the phone seems trying to search a proper network and repeats connect and disconnect to 4G network. During this time the connection is unstable and out of normal use. Luckily Z7 has Rakuten's APN in it, but it doesn't help to stabilize. As VoLTE functions is not enabled for Rakuten on the device. No SMS send/receive, no making phone calls are possible at this moment.
One solution I found is set "preferred network" to "LTE only" in the system menu that starts from *#*#. Thereby the connection to 4G is stable and steady. SMS can be received but no phone calls here. Installing "Rakuten Link" helper app makes the device capable about SMS and voice calls. As for 5G, I have no idea so far.
Are the recent android phones designed for such network providers completely with no 3G, 2G support?
As the selectable "preferred network" options like 2G+3G, 2G+3G+4G or 2G+3G+4G+5G, for the next generations, shouldn't it include more options like "only 4G" or "only 4G+5G" ?
Well. Of course as a user in Japan, I really hope my zenfone will support those minor carriers including MVNOs for VoLTE.