Asa Mathat for Recode

Talk about bold. Sprint Chief Executive Marcelo Claure said he believes he will have a top-tier wireless network in less than two years.

"You can invite me back here in two years -- our network will be ranked No. 1 or No. 2," Claure said Wednesday at Recode's Code Conference in Rancho Palos Verde, Calif. He later clarified that he meant No. 1 or 2 in the major markets.

It's a tough claim to accept, given that Sprint is ranked in many network surveys as dead last -- particularly in data speeds. Though recent studies have shown improvement in phone calls and text messages, Sprint still lags behind the competitors in coverage -- especially in many major markets. Verizon typically takes the top spot for wireless coverage, with AT&T close behind. T-Mobile lays claim to the fastest network.

Claure, who took over Sprint last summer with the mission to revitalize the struggling carrier, gave his prognosis of the company. "The patient is doing well now, and I think the patient is in stable condition," he said.

While the company continues to improve its network, Claure has moved quickly to slash prices and introduce new family plans, as well as offer a new leasing program for smartphones, as he works to get customers to give Sprint a second chance.

Sprint held on to its position as the nation's third-largest wireless carrier by subscribers by adding 1.2 million net new customers in the first calendar quarter. Rival T-Mobile added 1.8 million customers in the same period but trails Sprint by less than 500,000 customers. The growth is a sign of progress for Sprint, the second consecutive quarter of growth for a company that had been losing customers for years.

Much of Claure's hope for his network lies in the smart use of the company's wireless assets, namely its multiple bands of spectrum, which carry all of our data between the smartphone and its cellular towers. Sprint boasts that because it has three bands of different spectrum, it will be able to deliver a superior experience over time.

Claure said he has a plan for the network build-out, but wouldn't specify the cost, noting only that he has the financial means. Japanese carrier Softbank is a majority shareholder in Sprint, and Claure said CEO Masayoshi Son has made a "pretty strong commitment to build a strong network."

Still, the other carriers are also pouring billions of dollars into their networks, and it was Verizon and AT&T that came away as the big winners from the last spectrum auction -- one in which Sprint didn't participate. Likewise, T-Mobile has also been working on improving its network at a torrid pace.

AT&T and Verizon declined to comment. The usual vocal John Legere, CEO of T-Mobile, had a short response when asked about Sprint's comments on Twitter: "Swing bata bata!"

Regarding Sprint's unlimited-data offer, Claure said it "works very well" but warned that it couldn't last forever, especially as the company builds a faster network. For now, it makes financial sense, but that may not always be the case.

Updated at 9:37 p.m. PT: To include a response from T-Mobile's CEO.