T-Mobile has been working to build out their network for a little over a year now, and have done it pretty quickly. Right now they cover a ton of people with 4G LTE, over 200 million. Which is pretty crazy considering how late they were to the party. But they aren't just upgrading their network to LTE, but they are also upgrading the antennas the the technology they are using. T-Mobile is working to build out a more consistent network by using 4X2 MIMO - MIMO stands for Multiple Input Multiple Output. Most LTE networks use 2x2 MIMO right now, however T-Mobile is doubling theirs, and those in Dallas and Chicago are already seeing the differences.
In general terms, what this means is that there will be more signals flying into your device that's on T-Mobile's network. Which also means a more consistent network. You're also going to get a better downlink connection as well for better speeds. T-Mobile's VP of Technology, Mark McDiarmid, spoke with Gigaom about the 4x2 MIMO; "We do see the benefits 4—2 MIMO offers and will be deploying this in many cities in 2014 as part of our Wideband LTE rollout." He also stated, "All of T-Mobile's available devices currently support 4—2 MIMO and we'll ensure that new devices will as well. We believe this will be one of the first deployments by a top carrier network in the US."
This boost from 4x2 MIMO has advantages for both T-Mobile and its customers. It'll have faster speeds, as well as larger data capacities, which is a good thing. Especially at the rate that T-Mobile is adding customers. Usually T-Mobile is behind their competitors when it comes to new technology. They were last with 3G and LTE, but once they do get going they usually have newer technology than their competitors. Which is why T-Mobile was named the fastest 3G network in 2011, and they were also able to build out their LTE network so much faster. They were able to watch the mistakes of AT&T and Verizon - and to an extent, Sprint.