T-Mobile has bought a large amount of the 600 MHz band covering the entire US, it will be assigned band number 71. The low band provides better coverage indoors. They're saying some will be available later this year, will be interesting to see how long the full deployment takes.
Interactive map of new 600MHz spectrum bought by T-Mobile:
http://maps.spectrumgateway.com/t-mobile-600-mhz.html
From T-Mobile press release:
https://newsroom.t-mobile.com/news-and-blogs/tmobile-spectrum-auction-win.htm
"T-Mobile is also announcing they’ll put some of this new spectrum to use for both T-Mobile and MetroPCS customers this year, as a result of work started back in 2016. Already Ericsson and Nokia have announced availability of 600 MHz equipment that T-Mobile will use in its network, and the Un-carrier has 600 MHz licenses covering over one million square miles where T-Mobile expects at least 10 MHz to be clear this year – meaning T-Mobile’s network team can start working to light it up for customers."
Interactive map of new 600MHz spectrum bought by T-Mobile:
http://maps.spectrumgateway.com/t-mobile-600-mhz.html
From T-Mobile press release:
https://newsroom.t-mobile.com/news-and-blogs/tmobile-spectrum-auction-win.htm
"T-Mobile is also announcing they’ll put some of this new spectrum to use for both T-Mobile and MetroPCS customers this year, as a result of work started back in 2016. Already Ericsson and Nokia have announced availability of 600 MHz equipment that T-Mobile will use in its network, and the Un-carrier has 600 MHz licenses covering over one million square miles where T-Mobile expects at least 10 MHz to be clear this year – meaning T-Mobile’s network team can start working to light it up for customers."