MEXICO CITY (Reuters) - Mexico’s landmark wholesale national mobile network launched this week, but without a single major wireless carrier on board, renewing debate about how best to increase competition in the telecom sector dominated by billionaire Carlos Slim.

On Wednesday, President Enrique Pena Nieto and other officials gathered for the official launch of the so-called Red Compartida (shared network), a wholesale-only project written into the country’s 2013-14 telecoms reform.

The government has said the network would cut the costs of developing infrastructure for carriers particularly in rural areas with poor coverage and make it easier for new players to enter the market.

“It’s a model in which everyone wins,” Pena Nieto said.

Mexico’s three major carriers have not signed on yet, raising questions about the network’s business model.

Operated by newly created Altan Redes, the network currently reaches 32 percent of the Mexican population with 4g, and aims to eventually cover over 92 percent.

Analysts thought Telefonica, which has long struggled to gain traction in Mexico, could benefit from the network. But the carrier has not reached an agreement to use it, according to a source with knowledge of the matter.

AT&T, which spent billions to enter Mexico after the reform, suggested it may sign on in the future.

“If the Red Compartida has coverage in an area where we don’t, we would certainly consider using it,” a spokeswoman for AT&T said in a statement.

Slim’s America Movil, which has Mexico’s biggest network by far, has no plans to use it, Chief Executive Daniel Hajj says.

“I don’t think they are going to give me something that I don’t have,” Hajj told an earnings call last month.

Officials at Altan, which counts a fund managed by Morgan Stanley infrastructure and the China-Mexico fund created by the two countries in 2014, as its largest shareholders, gave no details on the network’s clients.

Altan’s President Eugenio Galdon told a news conference on Thursday that the company had been sufficiently cautious in its client projections but voiced optimism that more operators would join.

America Movil’s market share, roughly two-thirds of mobile subscriptions in Mexico, calls for “something unorthodox” like the Red Compartida to spur competition, said Roger Entner, a telecom analyst in Massachusetts.

But the network will initially create business for America Movil, and carriers have little incentive to use it in areas where they already have coverage, said Scott Wallsten, president of the Technology Policy Institute, a U.S.-based think-tank.

The network has a roaming agreement with America Movil and will use some of its towers, Altan said.

Wallsten and other critics of the network argue Mexico would have been better served by auctioning the spectrum it uses.

Altan must make a profit to keep investing in its network, said Jorge Negrete, CEO of think-tank Mediatelecom.

That could be tough without major players on board, though the network could attract more mobile virtual network operators, whose presence has been limited in Mexico.

Though the network aims to reach rural areas, experts say the initial launch skews toward big cities, with coverage in Mexico City, Guadalajara and Monterrey.

Altan said the network will initially cover 5.6 million residents in under-served populations, surpassing its obligation of 4.7 million residents in places with fewer than 10,000 inhabitants.