Experts agree that mid-band frequencies are critical for 5G usability, since they can provide both improved speeds vs 4G LTE while also providing better coverage than the superfast but extremely limited millimeter wave bands used by Verizon and AT&T. The C-Band, which will be auctioned in December 2021, is a mid-band spectrum between 3.7 and 4GHz, is likely to be highly sought after by US carriers to vastly improve their 5G networks.
Unfortunately, President of Technology Neville Ray confirmed that once the C-Band is in use by any US carriers, any current 5G-capable phones/devices would not be upgrade-able to work on those networks – and the carriers would have to deploy new infrastructure as well.