5G from space: toward the integration of satellites into mobile networks

The evolution of digital usage and the pursuit of global coverage are now leading operators to bring these two infrastructures closer together, notably through so-called “Direct-to-Device (D2D)” services, which establish a direct link between a satellite and a device (phone, sensor, car, etc.) without going through an intermediate relay antenna on the ground. A smartphone can thus communicate with a satellite just as it would with a terrestrial base station. In the case of the mobile phone, this is more precisely called a “Direct to Cell” (D2C) link.

While the first commercial D2C services rely mainly on messaging and emergency communications, space-based 5G, more accurately called “5G Non-Terrestrial Network” (5G NTN), is meant to integrate satellite communications into the standards and architecture of 5G mobile networks in the future. According to some estimates, direct connectivity services between satellites and devices are expected to generate nearly $1.7 billion in 2029, compared with around $30 million expected in 2025.

Direct-to-Cell: the first satellite services accessible from a smartphone

The first commercial services offering direct connectivity between a satellite and a consumer mobile phone appeared in the early 2020s. Users no longer need a dedicated satellite antenna or a specialized terminal, as is the case with satellite telephony, which has existed since the 1990s.

Apple, for instance, has offered an SOS via satellite feature since 2022, allowing the iPhone to communicate directly with a Globalstar satellite when no cellular or Wi-Fi coverage is available. The satellite then relays the message to a ground station before it is forwarded to emergency services.

SpaceX, for its part, offers a D2C service that allows a standard 4G/LTE phone to connect directly to low Earth orbit satellites, with no hardware modification or special app. The first satellites capable of communicating with 4G phones were launched in early 2024, and the messaging service was commercialized in the United States and New Zealand in 2025, with T-Mobile and One NZ.

Limits and physical constraints of Direct-to-Cell services

While the solutions mentioned above are innovative, they are mostly limited to messaging and remain far from the performance of a terrestrial 4G or 5G network. A voice call or a continuous data connection requires much higher capacity.

Several physical constraints explain this situation. A low Earth orbit satellite moves at several kilometers per second. This movement produces a Doppler effect: the apparent frequency of a signal varies when the transmitter and the receiver move relative to each other. The phenomenon is comparable to the change in pitch of a siren as it approaches and then moves away. In a satellite link, the frequency shift changes constantly and must be compensated for by the radio system. The distance between the smartphone and the satellite is another constraint. The device has to transmit to a satellite located several hundred kilometers away, with transmission power limited by the size of its antenna and its battery. The network must also handle the movement of the satellites, beam switching and handovers from one satellite to another. These constraints explain why the first D2D/D2C services appeared for low-bandwidth uses.

5G NTN: integrating satellites into the architecture of mobile networks

To address these limitations, manufacturers are now working on a deeper evolution of network architecture. The goal is no longer just to enable occasional communication between a smartphone and a satellite, but to integrate satellites as a full component of 5G networks.

This evolution is based on the work of the 3rd Generation Partnership Project (3GPP). This international consortium brings together the main telecommunications standards organizations, as well as mobile operators, equipment manufacturers and semiconductor makers. For more than twenty years, it has defined the technical specifications of mobile networks, from 3G to 5G, in order to guarantee the interoperability of equipment worldwide. 3GPP specifications are published in successive versions, called Releases. Each Release introduces new features that are compatible with the previous ones. Release 17, published in 2022, is an important milestone, as it integrates Non-Terrestrial Networks (NTN) into the 5G standard for the first time. Releases 18 and 19 continue this work in order to improve radio performance, mobility management between satellites and terrestrial networks, and quality of service.

The mechanisms introduced in the 3GPP notably make it possible to compensate for the Doppler effect, to take into account the propagation delays specific to space communications, and to automatically adapt the operation of radio protocols to satellites in constant motion. Over time, these developments should allow an operator to manage a satellite as an additional base station within its 5G core network (5G Core), without changing the authentication, subscriber management or communications routing mechanisms.

First 5G NTN experiments

In Europe, one of the most significant tests was carried out in July 2025 by Eutelsat-OneWeb with MediaTek, Airbus Defence and Space and Sharp. The partners demonstrated a connection compliant with Release 17 specifications between a 5G terminal and a satellite of the OneWeb constellation. The aim was to verify that equipment using exclusively 3GPP standards could operate on a low Earth orbit constellation. This experiment is an important step toward the integration of satellites into mobile operators’ networks and paves the way for commercialization in the coming years.

Other manufacturers are pursuing complementary approaches. AST SpaceMobile is developing satellites equipped with deployable antennas of more than 60 m², capable of establishing a direct link with conventional smartphones. Its BlueWalker 3 demonstrator made the first 4G voice call between a standard smartphone and a satellite in 2023, before demonstrating 5G-compatible communications in 2024. Ericsson, Nokia and Samsung are taking part in the standardization work, while Qualcomm and MediaTek are developing the future NTN-compatible modems intended for smartphones.

5G NTN: ultra-fast, low-latency mobile Internet anywhere on Earth?

The long-term goal of 5G NTN is to extend mobile connectivity to territories where terrestrial networks cannot ensure continuous coverage. For users, the prospect is one of continuous connectivity with an ordinary smartphone, including in deserts, mountainous areas, isolated rural areas or at sea.

Finally, 5G NTN is also of interest in terms of network resilience. Integrating terrestrial and satellite access would provide multiple communication paths and maintain connectivity when part of the ground infrastructure becomes unavailable. This capability is of particular interest for government applications. It also raises a question of sovereignty. Eutelsat’s OneWeb constellation is, in this respect, a European capability available to develop satellite services compatible with the international 3GPP standards, even though its operation relies on a global industrial and regulatory ecosystem.

Toward a truly global mobile network

The integration of satellites into 3GPP standards marks an important development for the telecommunications industry. Satellite networks may no longer be developed as independent infrastructures, but as an extension of existing mobile networks. The first Direct-to-Cell services show that this convergence is technically possible, while the demonstrators from Eutelsat-OneWeb and AST SpaceMobile are preparing the next stage: the full integration of satellites into 5G architectures.

This evolution will remain gradual. Terrestrial networks will retain a lasting advantage in capacity and throughput in urban areas. Satellites will mainly serve to ensure continuity of service, extend coverage and strengthen the resilience of infrastructure. As future 3GPP Releases are deployed and constellations gain capacity, could the distinction between terrestrial and space networks begin to fade? For operators and manufacturers alike, the challenge is no longer to substitute one infrastructure for another, but to build a single network in which the choice between a terrestrial antenna and a satellite becomes transparent to the user.

Victor-Charlie