On April 25, AST SpaceMobile, an American satellite communication start-up company, announced that it had opened the world's first space-based cellular voice call.
This is big news for satellite communications and the communications industry as a whole, and one to watch.
In the last year, we have only achieved two-way short message communication between mobile phones and satellites (for certain new mobile phone models). Today, AST's solution has verified the potential service capability of space-based 3GPP technology to provide emergency communications to more than 8 billion stock mobile phones (unmodified smartphones) on the ground.
According to the official information provided by AST, their own BlueWalker 3 (BW3) satellite was used for this test verification.
The satellite will be launched on September 10, 2022, using SpaceX's Falcon 9 launch vehicle.
The BW3 satellite weighs about 1.5 tons, has an unfolded area of 693 square feet (about 65 square meters), and flies at an altitude of 515 kilometers (LEO, low orbit).
This voice call test verifies that the two parties to the call are located in Texas, USA and Rakuten, Japan, respectively, using the Band 5 (850MHz) frequency band of the operator AT&T.
The mobile phone they used was Samsung's commercial smartphone Galaxy S22.
In addition to testing calls, AST's engineers conducted preliminary compatibility tests with various smartphones and devices. The phones' success in exchanging SIM card information and network information directly to the BW3 satellite is critical to providing broadband connectivity to any phone or device from space. Testing of smartphone uplink and downlink signal strength confirmed the ability of the AST solution to support cellular broadband speeds and 4G/5G waveforms.
AST SpaceMobile, founded in 2017 and headquartered in Midland, Texas, is a listed satellite design and manufacturing company with more than 2,600 patents. The founder of the company, Abel Avellan, was born in Venezuela and once worked for Ericsson.
According to AST's plan, they intend to launch the first 5 Block 1 BlueBird satellites in 2024 to build a more powerful constellation.
All in all, the success of this test has verified the feasibility of AST communication commercial array technology, and also shows that low-orbit satellites have the ability to provide voice communication services to mobile phones in stock on the existing network. This has important implications for the 50% of the world's population that is still not connected to cellular broadband.
For satellite communications, 3GPP has been promoting the standardization of NR-NTN (Non-Terrestrial Network, non-terrestrial network) technology. This technology enhances the high delay and frequency offset compensation of satellite-ground communication, which can effectively improve the efficiency and capacity of satellite-ground access.
Currently, 3GPP NTN has been supported by mainstream smart phone chip and terminal manufacturers. It is believed that with the continuous construction of the satellite communication network, there will be more technological breakthroughs.
(Note: The pictures in this article are from Business Wire and the Internet)
