OpenSignal measures mobile data speeds
through an app test used by thousands of consumers and it was able to analyze the fastest mobile networks in the United States. In the last quarter of 2017, T-Mobile was top of the speed league with its customers enjoying download speeds of 19.4 megabytes per second. Verizon came send (17.77 Mbps), AT&T came third (13.27 Mbps) and Spring was fourth (12.02 Mbps).
When AT&T and Verizon moved to reintroduce unlimited data plans, it took a serious toll on their networks, something T-Mobile was able to take advantage of. Amid the data deluge, both carriers scrambled to take steps to improve capacity such as adding connections in new spectrum bands as well as increasing the number of cellular transmitters. Meanwhile, T-Mobile continued to improve its own network and it was able to remain ahead of its rivals in download speeds
If that wasn't bad enough for its competitors, T-Mobile also recorded the highest levels of availablity in OpenSignal's analysis. At the end of 2017. its customers could connect to an LTE network 93.1 percent of the time, just ahead of Verizon's 92.7 percent. AT&T customers could connect 87 percent of the time while Sprint had an availability rate of 85.7 percent.