Some Thoughts on 3 GHz Bands n78 and n77 – Europe and the U.S.

It’s been a while since I’ve been in North America, actually it must be close to 4 years. How time flies. Anyway, I might have the opportunity to go there again soon, so I started thinking a bit about the current spectrum situation there, particularly the 3 GHz range for 5G. Back in 2019, quite a number of countries in Europe had auctioned spectrum for 5G in 3GPP band n78 (3300 – 3800 MHz). Most network operators got additional spectrum between 80 and 100 MHz, with some network operators being even luckier and grabbing up to 150 MHz. This was massive compared to previous spectrum auctions for LTE, where channels of typically 10 or 20 MHz in lower frequency bands went on sale. In Europe, band n78 significantly pushed available capacity and network speeds, particularly in cities to previously unknown levels. So lets have a look what happened in the U.S. back then and in the meantime.

From a European point of view, the US was a bit late to the game, or went a different way that didn’t really work so far. Particularly, until 2021, there were no spectrum auctions for a meaningful amount of spectrum in the 3 GHz range. Instead, carriers were eager to try new bands in the 20+ GHz range. Unfortunately, that did not work very well. This was mostly due to the range of this spectrum being very limited. Up to this day, there are no meaningful deployments that would make a difference on the national level. One carrier in the US, however, was lucky, because they had significant amount of spectrum in the 2.5 GHz range and could use this to launch 5G on a sub 6-GHz band.

But better late than never, the US auctioned spectrum in the 3 GHz range as part of their C-Band auction. The C-band ranges from 3.7 to 4 GHz, i.e. 400 MHz. In 3GPP parlance, that’s a part of band n77, and at least a part of those 400 MHz was dedicated to cellular service. One network operator claims to have received 160 MHz on average across the country, while another network operator claims to have received 80 MHz on average. In other words, that is very similar to the amount of 3 GHz spectrum that is used in Europe, it was just assigned a few years later.

So I had a look at the mobile devices that I will probably take to the U.S., and most of them do support band n77. So I am very much looking forward to see how it is used there.