Good question. I'll see if I can look that up in a bit.
Apparently this has been available for Sony Xperia phones since 2014, and only just now released for iPhone. I'm guessing Android is around the corner, but haven't heard anything specific yet.
Btw since I was on wi-fi I couldn't go very far before the connection affected the gameplay.
This does require a fast internet connection indeed. Not sure if this works with 4G. Probably not. Might need 5G for this to work.
5 GB down for VITA
10 GB up for PS4
This is what it is for the VITA, so I imagine phone is no different. I was able to do it off of my wifi hotspot on 4G for my VITA end, but the performance was sketchy. That clocked at about 5 GB down when I did a speed test.
When you say "GB" are you referring to "Mbps"?