Pal Zarandy, an always interesting analyst, tested Elisa's "world's first" 5G network from inside his office and outside with line of sight. The results were as expected: 5G at 3.5 GHz and Massive MIMO performs about the same as a good 4G network. "Gigabit LTE" - with tested speeds in the low or mid hundreds of megabits - has been shipping since 2016. Adding a minor software tweak, NR, and calling it "5G" did little to improve performance. (The battle to limit the term "5G" to true high-speed millimeter waves has been lost, unfortunately.) This is the dirty secret of "5G." Almost all the claimed new uses can be met with 4G. Anyone who doesn't know that should ask an engineer.
The Elisa results are important because they confirm that Massive MIMO makes 3.5 GHz spectrum practical to use. Pal writes:
"I think this is the key: 'Compared to gigabit LTE, the game changer features of the 3.5 GHz band won’t be single user speeds but instead the aggregate mobile data network capacity. This we couldn’t (and were not planning to) test, but Elisa’s network experts confirmed our views.'
Using 64 transmit antennas, Elisa in 3.5 GHz spectrum is getting throughput in a range similar to 8 antennas in 1.8 GHz. Without far more data, I can't be more specific than that. It may turn out that 100 Mhz in 3.5 GHz delivers about the same capacity as 60 MHz in lower bands. Because higher frequency antennas are smaller, even 128 antennas can be a reasonable size and not prohibitively expensive.
Between 3.5 GHz and 4.2 GHz is enough spectrum to roughly double the capacity of today's networks.