Rakuten was the pioneer in cloudified RAN or C-RAN.They are selling their expertise in putting together their network. I can see even the RRH's converted into software run on general-purpose hardware and just the antennas being at the site. Of course you need dependable and inexpensive fronthaul for all this to work. Rakuten could find that in Japan but is the US fiber situation similar?
No it’s not required. My 24 month contract was almost up so paid off the two months I had left and had it unlocked just to do some testing on a few other carriers with the esim. Atm my esim has T-Mobile Prepaid. And getting about the same download speeds of between 100-130 mbps on both Sprint and T-Mobile. Uploads are usually around 5mbps on Sprint and about 9-12 on the prepaid T-Mobile line.
Sprint LTE Speed Test
T-Mobile Speed Test