Satellite Connectivity: A Gradual Rollout to Seamless Global Coverage
The promise of connecting standard smartphones directly to satellites is becoming a reality, but the journey toward full-featured voice and data capabilities is unfolding in phases. While initial services are now live, users anticipating a comprehensive experience akin to terrestrial networks will need patience and compatible devices.
T-Mobile recently launched its T-Satellite service, exiting the beta phase and offering connectivity in most outdoor areas across the United States. This marks a significant step in providing service to subscribers beyond the reach of traditional cell towers, using their existing handsets. This follows New Zealand’s One NZ, which pioneered satellite texting services, reporting millions of messages delivered via satellite.
Supplementary Coverage from Space (SCS)
T-Mobile’s service hinges on a partnership with Starlink, leveraging spectrum allocated to T-Mobile in areas lacking cell tower coverage. This arrangement essentially transforms Starlink into a roaming network, also known as Supplementary Coverage from Space (SCS). Currently, the service is limited to text messaging and location sharing, compatible with approximately 60 smartphone models, primarily from Samsung, Motorola, and Google.
Early testing suggests a seamless user experience. One analyst reported that the T-Mobile satellite service worked flawlessly on a Samsung Galaxy S25 Ultra, transitioning smoothly between cell tower and satellite coverage, even in locations with partially obstructed views.
Apple’s Emergency SOS and 3GPP Standards
Apple introduced satellite messaging with the Emergency SOS feature on the iPhone 14. This system utilizes specialized hardware to connect to a constellation of satellites operated by Globalstar. In contrast, T-Mobile’s service aims for broader compatibility, theoretically working with any smartphone compliant with Release 17 of the 3GPP standards.
Release 17 supports non-terrestrial networks (NTN) for narrowband applications, offering speeds up to 400 Kbps. This bandwidth is sufficient for voice calls and messaging, but future expectations involve a wider range of applications comparable to terrestrial network experiences.
The Future of Broadband NTN Services
Users seeking broadband NTN services exceeding 10 Mbps will likely need to await devices compliant with 3GPP Release 18 and upgrades to satellite operator networks.
“The types of use cases being offered for now are narrowband services, things like texting or emergency SOS,” says Luke Pearce, principal analyst at CCS Insight. While wideband speeds up to 10 Mbps are technically possible, scaling satellite coverage with new Low Earth Orbit (LEO) constellations presents significant challenges.
Release 18, finalized last year, is designed to deliver true broadband via satellites, enabling rich data services and higher throughput. However, this requires upgraded LEO satellite infrastructure and advancements in phased array and antenna miniaturization, making it a medium-term prospect.
Timeline for Wider Adoption
CCS Insight estimates that widespread broadband direct-to-device satellite services are likely to emerge around 2030.
According to Pearce, the industry is currently in the narrowband era, with services launched recently. He anticipates the first wave of wideband satellite connectivity around 2027. This wideband connectivity demands more robust infrastructure, including enhanced LEO constellations, ground-based networking improvements, and widespread adoption of compatible chipsets and devices. By 2030, truly high data rate satellite links are expected to reach smartphones, laptops, and vehicles.
Qualcomm’s X85 modem chipset, introduced in March, represents an early example of Release 18-compliant hardware, expected to appear in devices later this year or next.
Technical Challenges and Solutions
Professor Rob Maunder, founder & CTO of AccelerComm, highlights the technical complexities driving this phased approach to satellite phone support:
- Link Delay and Loss: High satellite altitudes introduce link delays and losses, impacting throughput.
- Capacity Challenges: Large satellite beams cover numerous users, creating capacity constraints.
- Doppler Effect: Rapid satellite movement across the sky generates Doppler shifts.
- Handovers: Frequent satellite transitions require seamless handovers for user devices.
To overcome these challenges, 3GPP has adopted a phased approach, starting with initial NTN support in Release 17, progressing through Release 18, and continuing into Release 19, which is currently under development.
A key focus of Release 19 is moving 5G base station functions from the ground station to the satellite, bringing it closer to user devices and reducing latency for improved quality of service.
Backward Compatibility
A consistent design principle is backward compatibility. Newer satellites and infrastructure will continue to support handsets built around Release 17 specifications.
Other Players in the Satellite Connectivity Space
Other satellite operators are following Starlink’s lead. AST SpaceMobile, for example, has partnered with Vodafone to offer a commercial direct-to-phone satellite service in Europe, slated to launch this year.
Regulatory bodies are also preparing for satellite-to-smartphone services. Britain’s telecoms regulator, Ofcom, has been consulting on authorizing such services in the UK, potentially paving the way for services like Vodafone’s.
Market Considerations
While the UK might not be the ideal initial market due to its dense population and extensive terrestrial network coverage, rural areas could greatly benefit. However, a survey by CCS Insight indicates that only half of UK residents would be willing to pay extra for satellite connectivity. This sentiment may shift as satellite connectivity eliminates coverage gaps and enables ubiquitous access to data-intensive applications.
