AT&T satellite picks up phone signals from space

A historic telephone conversation has taken place between Texas and Japan, which has the potential to pave the way for a space-based cellular network that can be accessed worldwide.

AST SpaceMobile, a satellite manufacturer based in Texas, recently announced a groundbreaking achievement in the field of satellite communication. The company successfully routed an audio call between two standard smartphones through its BlueWalker 3 (BW3) satellite in low Earth orbit, a feat never before accomplished. This breakthrough has the potential to revolutionize global cellular connectivity, particularly in remote areas that lack access to cell towers.

To achieve this remarkable feat, AST SpaceMobile had to overcome several technical challenges. Ordinarily, standard smartphones cannot communicate directly with satellites in space, as they operate using different spectrums. To work around this limitation, AST SpaceMobile designed its network architecture to mirror the 3GPP (3rd Generation Partnership Project) standard used by terrestrial cellular networks.

Additionally, the BW3 satellite, which is the largest commercial communications array ever deployed in low Earth orbit, measures 693 square feet (just over 64 square meters) and has 100,000 individual antenna elements, making it capable of picking up cellphone signals from over 1,000 miles away.

During the test, an unmodified Samsung Galaxy S22 located in Midland, Texas, made a phone call using mobile spectrum from AT&T and connected to an iPhone belonging to Japanese tech giant Rakuten. Engineers from AT&T, Rakuten, and UK-based telecommunications company Vodafone assisted with the test. The phones connected to BW3 did not require any hardware or software changes, and the call was made using just the standard Samsung dialer. While the companies involved did not disclose details regarding the performance of the test call, an AT&T spokesperson confirmed that the initial call was made over 2G and that further testing phases will include LTE, 4G, and 5G.

The ability to connect directly with satellites from standard smartphones has the potential to significantly improve global cellular access in remote regions that lack infrastructure such as cell towers. This includes rural areas around the US that struggle to achieve even a 3G wireless connection, let alone 5G. AST SpaceMobile has agreements in place with several mobile carriers, including AT&T, Rakuten, and Vodafone, as well as Bell Canada, Telefónica, and Orange. Combined, these carriers have approximately 2 billion subscribers. While it is currently unclear how these carriers might integrate direct satellite connectivity into their existing services or when this utility will become available to general consumers, the potential for increased global connectivity is significant.

Other carriers have also made similar partnerships to expand rural broadband access using satellites. In 2021, Verizon announced that it was working with Amazon to add "cellular backhaul solutions" to the e-commerce giant's Project Kuiper system, which is expected to begin deployment in 2024. Additionally, some smartphone services have developed message-based satellite routing solutions, such as Apple's Emergency SOS feature for the iPhone 14.

Overall, AST SpaceMobile's achievement represents a major step forward in the field of satellite communication and has the potential to significantly improve global cellular access in remote regions.