Verizon is making it easier for its Edge customers to upgrade to new mobile devices. Starting May 31, Edge customer can step up to a newer handset as soon as they've paid off their old devices.

Verizon's Edge program enables customers to subsidize the cost of new mobile devices, paying for the hardware over the course of a two-year contract instead of ponying up the cash up front. So far, the program has been gaining a good deal of momentum, according to Nancy Clark, Verizon's senior vice president of Marketing and Sales Operations.

"The value of Verizon Edge, including lower monthly line access, is quickly making it the option of choice," said Clark. "More than 50 percent of Verizon Wireless customers now choose the simple and flexible Verizon Edge payment program when activating or upgrading smartphones."

The move to offer Edge customers more flexibility further evidences Verizon's drive to stay comfortably ahead in the U.S. wireless market. A few weeks earlier, the wireless carrier celebrated its five-year-old LTE in Rural America (LRA) program.

Since its launch in May 2010, Verizon's LRA campaign for delivering high-speed wireless data has expanded to cover 2.6 million subscribers.

"Verizon believes that customers even in the smallest communities deserve the most modern wireless service and technology," said Philip Junker, Verizon's executive director of Strategic Alliances. "In these first five years, the LRA program has delivered value and high-tech solutions to customers and carriers in rural America. It all comes down to being focused on the customer."

While AT&T and T-Mobile take aim at the top wireless carrier in the U.S. and ignore Sprint, a company with so much excess spectrum that it sat out the last auction, Sprint CEO Marcelo Claure has asserted that his company has recovered, over the course of his eight months with it, and projected that it will rank first or second in network performance in about two years.

Claure was speaking at Re/Code's Code conference when he spoke of Sprint's resurgence. The patient, Sprint, has now stabilized, he said.

"When you look at last quarter, we added more customers than AT&T and Verizon," said Claure. "We've got a long road ahead of us but we have to celebrate every day."