Beneath Verizon and AT&T’s duopoly lies a pair of scrappy U.S. wireless carriers that have struggled for years to gain ground against the two giants. For a period of time, Sprint looked like it was making headway thanks to its smartphone-friendly service plans that offered unlimited voice calling, messaging and data while Verizon and AT&T were busy implementing data caps. While its service plans were indeed attractive, Sprint’s smartphone initiatives didn’t translate into big subscriber gains. Then, the “Uncarrier” campaign began and T-Mobile became the most important carrier in America. Don’t count Sprint out just yet, however, because CEO Dan Hesse says things are about to turn around.

“What we are going through right now is a massive buildout that is causing some short-term pain for long-term gain,” Hesse said during an investor conference on Tuesday, CNET reports. “This is personally painful for me. We have worked so hard to improve customer satisfaction.”

The executive admitted to the investors and analysts in attendance that it has been painful to watch subscribers flee while it upgraded its network from WiMAX to LTE. “What’s been frustrating is when we come out with something like ‘unlimited data for life,’ and then we have network issues,” he said. “Unfortunately, we have to go through this hard period of time, so we face a headwind that our competitors don’t have.”

But Hesse said that these subscriber loses are predictable and inevitable. While they will likely continue into 2014 according to the executive, things are about to turn around. In the end, Hesse says Sprint will end up with more subscribers than it has ever had before.

“We believe that what we are building is something that is worth waiting for,” he said.