ASCENT - Demonstrator of license assisted spectrum access satellite networks


The applicability of the licensed shared access (LSA) concept is studied and validated with system level demonstrations. Specifically,

  • A proof-of-concept testbed is designed and implemented. The testbed exploits efficiently frequency sharing scenarios between 5G satellite and terrestrial networks taking into account realistic network traffic dynamics.
  • The combined use of LSA and other interference mitigation techniques to guarantee interference protection and QoS for satcom services are examined.
  • Reference implementations of LSA vs. non-spectrum sharing approaches and centralised vs. distributed database-enabled LSA architectures are compared.
  • Robust procedures and protocols between involved incumbent and challenger operators to guarantee coordinated frequency sharing taking into account the terrestrial and satellite network’s traffic dynamics are validated.
  • Cost efficient and technically effective spectrum sharing between 5G satellite and terrestrial networks for different verticals are proposed.


Finding and understanding the protocol bottlenecks in a sharing scenario when a high latency satellite connection is involved is one of the challenges in the activity. The maximum tolerances allowed for the protocols, key protocol parameters that can be adjusted, and the development of robust protocols and procedures between incumbent and challenger operators are of main concern. In addition, the operation and management systems in the telecom domain are vendor specific and typically somewhat inflexible. Therefore, understanding which functionalities a satellite link introduces and how it should be integrated to the overall infrastructure is an important issue.


The results of the project show how to enable satellite networks to operate with shared spectrum resources and exploit future expansion opportunities. Especially, the results can be used to guide ground and space segment developments when implementing the proposed sharing techniques as well as large scale experiments to validate them further.


Broad state-of-the art review on spectrum sharing techniques is made and selection of the most suitable ones done in the beginning. The work focuses then on defining the LSA architecture and testbed for 5G pioneer bands, assessing also the criticalities. The developed testbed will allow comparative evaluation of the proposed techniques, using LSA to control satellite and terrestrial system in the defined sharing scenarios. The testbed can be used in the development of co-existing, cooperating or integrated satellite-terrestrial communication systems.

System Architecture

The spectrum manager is in the central part of the system. It includes LSA repository and LSA controller. User interface (UI) is used to provide the incumbent data to the repository. The testbed can use data from the regulator delivered in the form of an excel table, for example.


In the first option, the spectrum manager sends commands to terrestrial cellular base stations (BS) through the BS controller, which converts them to a BS and vendor specific commands. The BS can be either real or emulated. In case of a real BS, measurement devices can be used to determine the interference level at the satellite receiver. The overall target is to keep the interference levels acceptable. The measurement results are fed back to the spectrum manager for adapting the transmission if needed.


In the second option, the spectrum manager controls the satellite system through the satellite control and management system, which relays the control commands to the satellite gateway. The satellite system is simulated or emulated. The interference calculations are made using ITU-R channel models and 5G receiver characteristics defined for the particular band under study.

Testbed architecture with satellite system as incumbent

Testbed architecture with terrestrial system as incumbent


The progress is monitored with four milestones. At first, the use cases, network traffic models, interference environments and the architecture of the LSA system are defined. The critical elements and development risks are analysed. The roles, relationships and interfaces of involved operators are defined. These results are evaluated in the preliminary system design review (PSDR). Secondly, the LSA testbed is developed and validated for the LSA testbed review (LTR). Successful review is followed by system level testing and proof-of-concept demonstrations (PD). Finally, a technology roadmap is prepared and recommendations for future work are presented for the final review (FR). Duration of the project is 24 months.

Current status

The project work focuses currently on defining system use cases and application scenarios. We also define KPIs for further work.


ESA Contacts

Status date

Monday, July 9, 2018 - 10:14