Direct 5G Satellite Connectivity

5G Satellite Integration

5G is giving the convergence of terrestrial and satellite-based networks a major boost. For the first time, the concept of non-terrestrial networks (NTN) is systematically taking satellite integration into account in the standardization of a new mobile communications standard. This is good for both sides: not only does it mean terrestrial cellular networks can count on satellite support to overcome any range limitations, it also gives the satellite industry the opportunity to expand its range of services far beyond the provision of satellite TV and Internet.

The traditional method, backhaul, involves using satellites to connect cellular base stations on the ground. Satellite backhaul is what connects base stations in remote areas to the cellular network, if necessary without any further infrastructure. By serving as connection points between cellular base stations on the ground, satellites establish a global communications network that can play a major part in the rapid rollout of 5G connectivity worldwide. This type of connectivity is already well established, but always requires that both the satellites and users’ devices have a stable connection to a cellular base station.

New ways to connect – 5G direct access via satellite

At Fraunhofer IIS, we go one step further and focus on developing technologies for direct communication between satellites and users’ devices as a way to combine terrestrial and satellite-based communication systems.

These newer concepts for integrating satellites into 5G terrestrial infrastructure are based on direct connectivity between satellites and 5G-enabled user equipment (UE). These devices then have satellite-based access to the 5G network at all times – even when there is no base station nearby. In the future, this will mean that smartphones or vehicles can establish a connection either via a cellular base station or directly via satellite, depending on the reception situation. Network architectures are also possible in which the satellite itself, either fully or partially, serves as the base station (gNB).

Why 5G direct satellite access?

For certain applications, a direct connection between satellites and receivers offers particular benefits:


Guarantees reception anywhere for fixed VSAT modems or mobile users and IoT devices – even in the world’s most remote regions.

Seamless reception for mobile applications

Offers reliable transmission of updates and warnings to vehicles or continuous transmission of IoT sensor data.

Efficient broadcast

Relieves terrestrial infrastructure (data offloading) by transmitting media content and software updates via satellite to many mobile devices simultaneously.

Icon LEO satellite constellation
© Fraunhofer IIS


Especially in combination with various satellite operators’ recently launched or planned constellations, comprising a large number of smaller satellites in low earth orbit (LEO), the integration of satellites into the 5G network offers great opportunities for reliable and global cellular coverage without any gaps.

How we are driving 5G satellite integration

Technology development and consulting



We develop and test the latest approaches to integrating terrestrial and satellite-based communication. On this basis, we would be happy to advise you on all questions relating to satellite communications and 5G.

Our offer includes consulting services related to 5G standardization as well as feasibility studies and the development of system-specific integration concepts.

and analysis



Learn how your satellite system can benefit from 5G NR (New Radio): To determine the performance of 5G NR direct access via satellite, we offer link- and system-level simulations for established and new systems.

We have simulation tools available that allow a quick and detailed analysis of all important performance parameters.

and demonstration



To validate the performance of 5G NR via satellite in actual transmission, we use the OpenAirInterface (OAI) prototyping platform.

This enables us to implement new features from the ongoing standardization process at an early stage and to try them out in live tests. Our laboratories also have the necessary equipment to realistically reproduce various channel characteristics in satellite transmission.


From the lab

5G Direct Access:
Real-time implementation on OpenAirInterface (OAI)

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Current research projects

  • 5G-ALLSTAR – 5G AgiLe and fLexible integration of SaTellite And cellulaR

    The 5G-ALLSTAR project aims at demonstrating multiple access comprising terrestrial and satellite links, which are key to ensure the availability of 5G performances and worldwide continuity of services especially to support critical applications. The project receives funding from the European Union Horizon 2020 EU-Korea program and is supported by the Institute for Information & communications Technology Promotion (IITP) grant funded by the Korea government.

    Fraunhofer IIS provides the key components for the 5G transmission over GEO satellites: 5G-enabled prototypes of the base station (gNB) and the static end device (UE), both based on OpenAirInterface.

  • 5G-GOA – 5G enabled ground segment technologies and over the air demonstrator via GEO satellite

    The objective of the 5G-GOA project is the development and implementation of necessary 5G New Radio modifications in parallel to the 3GPP standardization of 5G NTN in order to enable direct radio access of terrestrial communication networks via GEO satellite. The project is funded by the European Space Agency (ESA).

    Fraunhofer IIS provides new software developments for the 5G-enabled prototypes of the base station (gNB) and the mobile end devices (UE), both based on OpenAirInterface.

  • 5G METEORS – ESA MakerSpace for 5G and satellite communication

    5G METEORS, funded by the European Space Agency (ESA), addresses a broad range of challenges in the 5G and satellite convergence and integration domain, specifically for the direct usage of 5G New Radio over satellites. The program funds several smaller activities comprising the implementation and demonstration of 5G direct access over satellites.

    Despite of the technical support for the coordination of the 5G METEORS program, Fraunhofer IIS develops in the 5G-EmuSat subproject the necessary adaptations of 5G New Radio for 5G direct access over LEO satellites in the OpenAirInterface based gNB and UE.

  • ALIX – Support to Standardisation of Satellite 5G Component

    The ALIX project supports the active participation in the 3GPP standardization process to define the 5G satellite component and its interfaces with other networks. The European Space Agency (ESA) funds this project under the ESA ARTES program.

    Fraunhofer IIS contributes actively to the 5G New Radio standardization in the working groups RAN1 (physical layer), RAN2 (radio access protocol stack) and RAN3 (radio access architecture).

Further information


5G – mobile communications and beyond

5G technologies for mobile broadband, Industry 4.0, connected mobility and satellite communication


Consulting for 5G technologies

Benefit from our 5G skill-set