T-Mobile said that it has been forced to shut down or power down hundreds of cell sites along the US-Mexico border due to interference from Altán Redes, a private company building a 4G network for the Mexican government.

In a filing with the FCC, T-Mobile said the issue has been "making it more difficult to meet pandemic-fueled increases in need."

The operator added that the FCC "is working with all relevant parties in the US and Mexico to resolve those issues."

T-Mobile officials did not respond to a request for details from Light Reading. Officials from the FCC – the US government agency in charge of managing the nation's spectrum resources – wouldn't comment beyond a 2019 letter on the situation penned by FCC Chairman Ajit Pai.

At issue is a 700MHz LTE network being built by Altán Redes. Called Red Compartida, the network stems from a public-private partnership between the Mexican government and Altán Redes to construct a wholesale wireless network to cover at least 92.2% of the Mexican population by 2024.

If that scenario sounds familiar, it is – the Trump administration has repeatedly floated the idea of a similar effort for 5G, having already witnessed the successful construction of the US government's 700MHz 4G FirstNet network for public safety users by AT&T.

Altán Redes first switched on its network near the US-Mexico border roughly a year ago, and it immediately started creating interference to Verizon's network in the area. Questions from US lawmakers on the topic pushed Pai to compose his 2019 letter on the situation.

"In a phone call with Chairman Gabriel Contreras SaldIvar of the Instituto Federal de Telecomunicaciones (IFT), the Mexican equivalent of the FCC, I made clear that addressing the issue of interference to US communications immediately was and would continue to be a major priority for our government; that even limited operations by Altán to date had caused interference," Pai wrote, adding that "Altán had rejected eminently reasonable proposals for testing."

Pai continued in his 2019 letter: "I can assure you that [FCC] Commission staff have been actively working on this issue with all relevant parties in the United States and Mexico to resolve these issues. We will continue to do so."

FCC officials contacted this week by Light Reading indicated that there have been no new developments on the issue beyond Pai's letter. That's perhaps not a surprise given the strained relationship between the US and Mexico due in part to President Trump's many negative statements and actions toward the country.

T-Mobile revealed its troubles with Altán Redes as part of a request to the FCC to allow it to continue using 600MHz spectrum licenses held by the FCC to add capacity to its network. At the outset of the pandemic, T-Mobile sought FCC permission to temporarily use a range of 600MHz spectrum licenses in order to meet expected COVID-19 traffic spikes. The operator said it hopes to continue doing so through at least November.

— Mike Dano, Editorial Director, 5G & Mobile Strategies, Light Reading | @mikeddano