LTE and 5G are so close to Shannon limits you can't get a major performance gain from a traditional connection without breaking the laws of physics. There's only so much you can load on a single signal. The big advances in the last five years have come from using multiple antennas and multiple signals. (MIMO.)
Ronny Haraldsvik claims Cohere's "Spectrum Multiplier software can effectively double network capacity and the capabilities of existing spectrum, supporting twice as many users and devices." That sounds like the kind of bs claim I'd normally ignore. But Cohere has convinced top engineers at major telcos they may have something.
Similarly, Tarana Wireless may have some exciting technology. Neil McRae of BT says
“After just one day of running our pilot on G1, customers are saying ‘please, you’re not going to turn this off for years, right!?!’ It’s a very sticky product.”
MTN in South Africa is in production with Tarana.