AST SpaceMobile chairman and CEO Abel Avellan outlined in a blog the company’s advances in working with Rakuten Group, Vodafone Group and American Tower to address internet coverage gaps, as it ramps efforts to deliver satellite-based mobile service to billions across India, Indonesia and Africa.

In a guest post on Rakuten’s website, the AST SpaceMobile executive noted it now had agreements or understandings with mobile operators covering about 1.5 billion subscribers.

Avellan noted “connectivity is imperfect and people move in and out” of mobile broadband coverage, despite there being little issue from a devices perspective as more than 5 billion compatible models were in use.

The AST SpaceMobile chairman explained about half of humanity lacks mobile broadband service because there is no connectivity or people face a usage gap where affordability and other factors create barriers to getting online.

Avellan asserted coverage issues are not confined to developing nations and emerging markets, pointing to Japan, where it is difficult and costly to provide mobile service to rural and mountainous regions. “This leaves many families without access to amenities that the rest of the nation finds essential.”

In July, the company signed a deal with Philippines-based Smart Communications to extend mobile broadband coverage to rural areas.

Last week, rival Lynk Global revealed its first commercial agreements with operators.