Having access to blazing-fast data speeds is essential in 2018, and if you've got a phone that supports the 600 MHz band, T-Mobile's Extended Range LTE network is one of the best in terms of speed and reliability.
The Un-Carrier announced that its 600 MHz Extended Range LTE is officially live in 900+ cities/towns across the US in 32 different states. Expanding on that even more, Extended Range LTE will soon make its way to Puerto Rico this coming fall.
Per T-Mobile's CTO, Neville Ray: "After the devastating hurricanes that hit Puerto Rico last year, we saw an opportunity to rebuild the network better than new -- to rebuild with 5G-ready gear. We're laying the foundation for the island to become a technology and innovation hub in the future while adding coverage and capacity with 600 MHz LTE this year."
As a quick refresher, Extended Range LTE can travel twice the distance of mid-band LTE and is four-times stronger/faster while indoors.
Looking beyond 4G LTE, T-Mobile announced in late-February that it plans on launching its 5G network in New York, Los Angeles, Dallas, and Las Vegas during 2019.
Source: https://www.androidcentral.com/t-mobiles-600-mhz-extended-range-lte-now-active-over-900-markets