Sprint is the only US carrier who has been pretty quiet in regards to 5G. Verizon, the US' largest wireless carrier, has already begun running trials of 5G at their headquarters in New Jersey. AT&T is also expected to be running field trials pretty soon for 5G. T-Mobile has opted to wait a bit and see what the standards for 5G will be, before they start making plans. Which is smart, in the long run. Sprint, however, is looking to "wait and see" what happens first. Now this is also smart on Sprint's behalf. If anyone remembers the whole WiMax fiasco, you'll agree. Sprint was first with "4G" but it was the wrong 4G technology. Sprint went with WiMax, while the rest of the world opted for 4G LTE. After building out WiMax in a good part of the country, the carrier opted to switch to LTE. This is something Sprint is still paying the price for today.
With 5G, Sprint is looking and evaluating it, before making any decisions. This is coming from Sprint's VP of Network Planning, Jay Bluhm. He also noted that there is still plenty in "4G and LTE Advanced still to be had". This is especially true in the US. Which is actually one of the slower countries to adopt LTE Advanced. However, Sprint has tons of spectrum and network capacity for LTE Advanced, which is why they'll likely stick with LTE for a good bit. Bluhm also noted that Sprint's traffic has increased 85% year over year. Which means it's going to triple in four years, by 2020.
Verizon and AT&T are in the forefront of standardizing 5G. Which we'll likely hear a whole lot about in 2016. 5G is the next evolution in wireless networks and will work really well for the Internet of Things as well as many of the other products we see on carrier networks now like cars. 5G will also provide around 10Gbps data speeds, and a whole lot more capacity. A big reason why the carriers are excited to jump on the 5G bandwagon right now. It means they'll have more room to expand their services.