Supporting the deployment of highly dynamic satellite constellations through ESA collaboration

Nova models control plane features that can impact 5G NTN performance

We’re designing Nova with the goal to enable the evaluation of 5G control plane procedures with flexible Non-Geostationary Satellite Orbit (NGSO) constellations.

This way, users can discover possible issues and optimization targets for standardization and industrial purposes. NGSO includes satellites in Low Earth and Medium Earth Orbit (LEO, MEO).

Nova can model relevant control plane features that may impact 5G NTN performance in high-speed satellite scenarios. These include, for example, cell access, UE measurements, and mobility management. 

The dynamically steered earth-fixed beams and Inter-Satellite Links (ISL) bring additional challenges to defining and implementing these features. Here, the simulator will be an effective tool. 

We will complement the research with visualization and demonstration of the simulations through Magister SimLab.

Small moving LEO Handover Test Scenario in Magister SimLab Visualization Player

Evaluating control planes of NGSO constellations: Transparent & regenerative satellite systems 

The Nova simulator aims to enable the evaluation of control planes of different NGSO constellations. This supports 3GPP-specified NTN system architectures, and both transparent and regenerative satellite systems.

The simulator focuses on satellite constellations within one type of orbit. This also includes multi-orbit constellations – however, with no cross-orbit communication. The architecture supports simple Inter-Satellite Links (ISLs) and functional splitting of the gNB in regenerative satellite systems.

The system architecture reflects the project’s objectives. This means that greater focus is placed on the control plane rather than the user plane. The architecture focuses on the radio access network, while the core network and backhaul connections are largely simplified.

Nova is designed to accurately simulate subsets of the whole constellation. Subsets of satellites can be selected dynamically, based on the area of interest.

Features

The features of Nova will be introduced in three different software versions. Version 1 includes a selection of NR-NTN Release 17 features and functionality, including RRC signaling and messages, feeder link, conditional handover, and UE measurements. 

Version 2 focuses on 3GPP Release 18 and Release 19 control plane features, especially VSAT UE operability and regenerative satellite payload. This includes, for example, RACH-less handover, satellite switch with re-sync, and Inter-Satellite Links. 

Version 3 doesn’t contain implementation of major new features. Instead, it focuses on improvements and bug fixes of the code base and parameter optimization of the simulators. This version is also used in the analysis of the implemented features in relevant scenarios. 

> See all features here

Strategies for implementing 3GPP 5G compliant control planes in satellite networks

The project aims to fulfill the following objectives:

• Define a reference NTN architecture based on Non-Geostationary Orbits
  
• Review the 5G NR control plane procedures and signaling
• Identify possible strategies for satellite networks to implement a control plane as close as possible to the current 3GPP 5G specifications
• Identify required modifications to the current 3GPP specifications for having an efficient control plane fit to be deployed on non-terrestrial networks
• Demonstrate such architectures and control plane design in a network simulator