You should listen to Shahriar Shahramian on The Amp Hour Podcast: https://theamphour.com/430-shahriar-discusses-5g/

There's a ton of interesting things, like 5G is for a lot more than cellphones. I've always heard that 5G will have phased array and I wondered how that would work -- he talks about possibility that the array is on the roof of a car and your devices will connect back to that. Lots of issues, like size of antenna and power consumption, to get those blazing fast speeds.