Following the lead of operators like Verizon and T-Mobile, some of the nation’s other wireless network operators—including the likes of Sprint, Bluegrass Cellular, U.S. Cellular, Southern Linc and Eastern Kentucky Network—are launching Voice over LTE services in part to remain viable roaming partners.

However, the finances around VoLTE roaming are much different than roaming in the 3G world. Indeed, the CEO of U.S. Cellular earlier this year admitted that the roaming revenues the company can obtain from VoLTE are lower than the roaming rates the company could command in 3G.

VoLTE, of course, is a much different technology than the circuit-switched voice calls running over 3G networks. VoLTE essentially turns voice calls into data sessions, thus dramatically reducing the overall use of the network. VoLTE also allows operators to use spectrum that was once dedicated to voice calls for LTE instead, thus making their overall spectrum usage more efficient.​

Likely as a result, the nation’s top wireless network operators have been moving to VoLTE with alacrity. Earlier this year, T-Mobile disclosed that more than 80% of all of its voice traffic was carried over VoLTE. Similarly, Verizon said VoLTE was fully deployed over its network, and 100% of its LTE sites have the capability. AT&T’s VoLTE network covered more than 320 million POPs, and all the smartphones it has launched since August 2016 have been VoLTE capable.