T-Mobile US (NYSE:TMUS), which previously enjoyed the fastest LTE latency speeds according to data from network monitoring firm OpenSignal, was edged out for the top ranking during April and May by AT&T Mobility (NYSE: T). Verizon Wireless (NYSE: VZ) placed third in the rankings for the period, while Sprint (NYSE: S) pulled up in last place. The results were based on OpenSignal's panel of more than 1 million consumer devices, which provide real-world data on the performance and coverage of mobile networks. For more on the network latency results for the nation's top four nationwide wireless carriers, provided through a partnership between OpenSignal and FierceWireless, check out this special report.