It is a problem still with computational power. You see this already with DSPs in highspeed ethernet. Doing that stuff at 25 Mbaud is nice and all, but doing it at 25 Gbaud is a whole other kettle of fish. Your tranciever for 112 Gbit/s consumes 250 mW. The DSP to deal with all of the non-ideal crap uses 5 W.
I guess you are right though, let the MIMO algorithms figure a bunch of this stuff out. I'm working at the limits of what is possible, so everything has to be optimized to the nth degree, and you can't leave a few dB's hanging somewhere because you can be sure your competitor wont.
Yeah, will need a few generations of DSP optimization to make that combination feasible.
I wonder, at what point do you just throw everything into neural networks -- can they be made to run fast enough? (Are memristors at all useful up here (or at least at whatever IF might be)?)
Stupid I'm sure, to throw the "we don't know how it works" box at an otherwise well-understood problem we just need a certain well-defined amount of computation to handle -- but eh, if there's a way to do it fast, and cheap enough (in terms of power), eh... who cares if it spits out a few more bits in error if the radiation pattern saves 10s of dB and watts of P?
How not-impressed would the FCC be if you marry a "we don't know"-box to an antenna, anyway?......
...Also, sustained rates likely don't matter, at least for a lot of applications? You'll max out an SSD (maybe not NVMe) pretty easily at these rates, and, there's not too much you'd use on a phone that needs more than streaming video? If the thing can shut down quickly between bursts (and, Idunno, maybe it's TDMA, probably it's something much cleverer), and you've got well over 5W of peak capacity from your next-generation battery, well... that might turn out fine anyway.
Atmospheric attenuation is actually not that big (except some dips in the spectrum due to molecular resonances, such as around 60 GHz). Sure, link loss is higher due to the smaller wavelength, but once you throw some arrays at it (which you can easily do if your antenna is wwaaay smaller) and you get the same range.
I think it is a chicken and egg problem - the expertise required makes it hard to penetrate a general market. It's not that there are limited applications, it's just a pain in the ass to design for them.
"Build it and they will come". Just a little trouble with that tiny word "build"...
Tim