T-Mobile is moving forward in its mission of being the network with the most expansive 5G coverage. The carrier on Tuesday announced it's building up its 5G network in four cities in 2018 (Los Angeles, New York, Dallas and Las Vegas) and plans to be in 30 major cities by the end of the year.

That detail in particular is one T-Mobile is quite proud of. Most other networks are avoiding major cities in their deployment due to the congested population that may be quite taxing on the network. AT&T, for example, is starting with Dallas, Atlanta, and Waco. But T-Mobile, in its brash style, isn't shying away from a challenge.

Networks have been touting the advancements of 5G, but the full realization of it is still at least another year away. Smartphones nowadays don't even have the proper hardware to take advantage of the new network. Furthermore, customers won't be able to use the 5G network that is being built up in 2018.

T-Mobile has taken drastic gains in LTE coverage, and it wants to ensure that lead remains when 5G rolls out. In the time being, T-Mobile's Gigabit LTE network will serve as the stopgap. The Galaxy S9 is the latest smartphone to take advantage of the faster network thanks to the Snapdragon 845 processor. It can theoretically reach speeds of 1.2Gbps.

If Gigabit LTE devices can reach those speeds, one can only imagine how fast 5G will be. But don't expect those speeds to be the norm; challenges still remain for 5G. Its use of millimeter waves means its connectivity will be spotty at best in the beginning.

Regardless, faster data speeds are on the way for T-Mobile and the other major networks. It's just a matter of waiting.