AST SpaceMobile has reiterated its plans to enable a satellite phone service covering the entire continental US that will work seamlessly with existing devices, thanks to spectrum sharing agreements with AT&T and Verizon.

The satellite operator inked deals with the two US telecoms giants in May that will eventually allow them to offer subscribers the ability to make calls using its satellite network when they are out of range of a ground-based cell tower.

In an open letter to partners, shareholders, and future users, AST SpaceMobile chief Abel Avellan now claims his company is "uniquely positioned" to achieve 100 percent geographical coverage throughout the continental US, thanks to having both AT&T and Verizon on board.

Avellan was keen to promise that the service would work seamlessly with standard smartphones, and that the frequencies used would reach even inside buildings to provide a connection, minimizing dead zones and dropped calls, even in remote areas.

"You'll have a seamless experience with either carrier," he claimed. "You'll simply connect to AST SpaceMobile's network through your carrier, AT&T or Verizon, for reliable cellular service for a smooth and worry-free experience."

The key to unlocking this coverage lies in the "power of the premium 850 MHz low-band spectrum," which offers "superior signal penetration in the low band cellular range," according to Avellan. "AT&T and Verizon together will share with AST SpaceMobile a portion of their respective bands of 850 MHz low-band spectrum to enable nationwide satellite coverage."

The way this works is that AST "employs a segment of the 850 MHz band in conjunction with our terrestrial operations," Avellan said, and whether users are an AT&T or Verizon subscriber, they don't need to worry about which carrier's 850 MHz spectrum is being used.

"The operators provide radio spectrum, but not across the entire country, just in areas where they don't have coverage," explained Distinguished Gartner VP Analyst Bill Ray.

"The challenge is the footprint size - if you're providing service to someone in the middle of Texas, 50 miles from any AT&T mobile tower, then you don't have a problem, but if you're trying to provide coverage to someone five miles from a tower then your satellite footprint will incorporate that tower, so will need to be on a different frequency. The smaller the footprint, the closer you can provide service without needing more frequency."

AST's satellites are designed to have a huge antenna, which makes it capable of putting down a small spot beam that limits interference, as Ray has previously explained.

The company's mention of indoor coverage could also be a subtle swipe at the rival service planned by Starlink and T-Mobile, according to Ray. This is using frequencies above 1.8GHz, which likely won't work indoors, he said.

Erm, but where are your satellites?

One thing Avellan neglects to mention in his exuberant letter is that AST SpaceMobile has yet to put into orbit any of the commercial satellites it will need to actually provide the service.

The first five BlueBird satellites were supposed to have been lofted into low Earth orbit by the end of last year, but have been repeatedly delayed, and the last update was that these were scheduled to go up on a SpaceX Falcon 9 rocket sometime in Q3 of this year.

We asked AST SpaceMobile if it could confirm when the satellites are expected to launch, and when its service will be operational, but due to the July 4 holiday, we are not expecting an immediate response.

However, the company has agreements with a number of other mobile operators around the world, including Rakuten Mobile in Japan, which plans to start offering satellite connectivity from 2026, and Europe's Vodafone, which said the date would be dependent on AST SpaceMobile successfully deploying its satellites. ®

https://www.theregister.com//2024/07/04/ast_spacemobile_plans/