Objectives

The huge growth of the request by the market for performing telecommunication in view new and challenging services is pushing the acceleration in the space technology improvement. The demand for high speed, low latency and globally available broadband connectivity has increased dramatically.

Nowadays, terrestrial networks alone may not be able to provide access to a reliable and ubiquitous connectivity service and to reach remote areas due to irregular or insufficient coverage.

These scenarios necessitate the integration of satellite communication infrastructure to seamlessly complement terrestrial ones with low latency and high throughput data exchange, ensuring global coverage. 

VLEO Satellite Communication (SatCom) constellations can ensure high QoS for distinct users bringing several challenges both at system and technological level. 

Challenges

The key challenge of HANDING-OVER project are as in following:

o design the handover, data routing and Radio Resource Management (RRM) techniques for a broadband satellite constellation in VLEO, to improve European knowledge and competitiveness To implement and test all the above techniques in a software system testbed in order to evaluate if their performances meet the expected ones;

To develop a key “enabling system” (SW testbed) for the design and validation of future communication systems based on VLEO/LEO satellite constellation.
 

Companies

Thales Alenia Space Italia

https://www.thalesgroup.com/en/worldwide/space-italy

Italy

Politecnico di Torino

http://www.polito.it/

Italy

Objectives

The key product objectives are to develop and integrate 4 key product features into Druid’s 5G core supporting NTN:

• 5G Multi Operator Core Network

• 5G Public Safety via Cell Broadcast

• 5G Location Management Function

• 5G Integrated Access Backhaul

Challenges

The key challenge of the project is the availability of NTN Ran systems to interoperate and validate the product features. This is slowly changing 

System Architecture

The block diagram below shows those elements that are enhanced and those that are created as part of the proposed 5G Reach project. All aspects of the Druid Raemis EPC are 3GPP compliant and as such all specifications can be found on the 3GPP website, https://www.3gpp.org/specifications/specifications

Plan

The project is divided into two key milestones with Milestone 1 delivering Neutral Host and Cell Broadcast and Milestone delivering Integrated Access Backhaul and Location Management Function.

Current Status

All the features are now complete and ready for market. Druid is currently engaged with a number of NTN Operators in the deployment of these features.

Related Links

• 3GPP Specifications

Companies

Druid Software

http://www.druidsoftware.com/

Ireland

Objectives

The objective of the project is to mature the cathode of the PPS® low power thruster, namely the PPS®X00, for an optimized operation with Krypton as propellant, in view to offer a competitive efficient propulsion solution meeting the small satellite market demand, and of particular interest in the mega-constellation segment where the xenon availability is a key issue.

The following tasks are covered by the project activities: 

• First, the design and manufacture of a highly flexible device functionally and thermally representative of a hollow cathode, so-called BTC. 

• Then functional and thermal characterizations carried out with this hardware by varying the dimensions of the functional parts of the emitter’s housing, the material of the emissive element, and the propellant gases.

• The third step consists in refining the cathode model developed by Safran by adjusting the modelling parameters after the measurements performed on the BTC

• Finally, the design, manufacture and test a BBM “krypton hollow cathode” based on these results and complying with the specification.

• The activities and logic defined at the beginning of the project benefit from synergies with the ARTES C&G PPS®X00 project.

Challenges

The world of space is constantly evolving. Depending on the health, economic and geopolitical context, the space market ecosystem is considerably affected and has to reinvent itself regularly. The compatibility of the propulsion system’s operation with an available propellant gas, krypton, is an asset enabling us to offer an effective, low-cost solution for a low-power Hall-effect thruster, within a very tight time-to-market.

System Architecture

A Hall thruster is composed of an anode assembly and a cathode assembly. To create the thrust a magnetic field is generated in a dielectric chamber to achieve the Hall effect required to ionise the gas, confine the plasma and accelerate the ions under an electrical potential. Electrons are supplied to the anode block by the external cathode to initiate and maintain the discharge. These assemblies consist mainly of an anode/gas distributor, a discharge chamber, a magnetic system, a hollow cathode, gas and power supply lines and mechanical interfaces.

The basis of the project is to generate an optimal design in terms of cost and performance.

The PPS®X00 cathode architecture and assembly processes simplifications compared to legacy designs enable to reduce drastically the manufacturing cycle.

Plan

The major phases of the project are:

1. Design and manufacture a highly flexible device functionally and thermally representative of a hollow cathode. 

2. Perform functional and thermal characterizations of this device by varying: i/ the dimensions of the functional parts, ii/ the material of the emissive element, iii/ the propellant gases.

3. Refine the cathode model developed by Safran by adjusting the modelling parameters after the measurements performed on the device

4. Design, manufacture and test a BBM “krypton hollow cathode” based on these results and complying with the specification

Current Status

All the elements to pronounce a TRL6 maturity of the PPS®X00 cathode operating with krypton are available: necessary justifications, mitigation of risks associated with critical technologies, compliance with technical and commercial requirements, and industrial conditions such as the whole manufacturing chain consolidation.

The future development phase mainly consists in the assessment of the residual risks to consolidate the flight target definition through lifetime tests with Krypton, additional analyses and tests at component level. These activities are necessary inputs for the qualification phase, and entry into service in 2025.

Companies

Safran

https://www.safran-group.com/companies/safran-spacecraft-propulsion

France

Objectives

The objective of Foresig is to develop a testbed to simulate the performance of a high-throughput SatCom system operating in the Ka-band for the user links and Q/V-band for the feeder links. The SatCom system covers Europe and has by default six gateways located in different parts of Europe. The system includes a Channel Assessment System (CAS) that estimates and predicts tropospheric attenuation, including precipitation, clouds and atmospheric gases. The input data to the CAS are Numerical Weather Product (NWP) data from ECMWF and weather radar data from the Norwegian Meteorological Institute (MET) and OPERA. In addition, user terminal data from THOR 7 and data from several beacon receivers are used to verify the accuracy of the predictions. Based on this information, the link quality can be estimated and predicted for all the links of a SatCom system.

The output from the CAS is used by a Propagation Impairment Mitigation Technique (PIMT) module to optimise the performance of the SatCom system in terms of data throughput, service availability and user terminal energy consumption. The PIMTs included in the testbed are smart gateways (SGWs), ACM and reconfigurable antennas. 

In additions, the reduction of energy consumption user terminals can gain by using forecasts is estimated, provided that transmission of data can be delayed up to 12 hours. Analyses of the results from the simulations give an indication of the gain that can be obtained in a real high-throughput SatCom system using PIMTs and channel predictions.

Challenges

Several challenges are related to the data to be processed:

• Large data files make data transmission, storage and computation challenging.

• Combining heterogeneous data sources different spatial coverage and resolution, and different temporal resolution, to predict attenuation. 

• Lack of ground truth data for estimated tropospheric attenuation, making optimisation of the models and evaluation of their accuracy challenging.

Other challenges are related to the mitigation techniques, e.g.;

• Develop intelligent PIMTs using channel predictions with the temporal resolutions available from the APIs.

• Assessing the actual benefit for SatCom operators implementing the system.

System Architecture

The figure shows the architecture of the testbed.

• DS1: The data set DS1 consists of NWP data from ECMWF, weather radar data from MET and OPERA, user terminal channel quality data from THOR 7 provided by Telenor Satellite, and beacon data from several receiver located in Norway.

• CAS: The Channel Assessment System uses DS1 to estimate and predict the tropospheric attenuation for a fixed grid covering the service area for all frequencies of the system. The results are saved in a new data set DS2.

• DS2: The data set DS2 contains attenuation estimates (nowcast) and predictions for the coverage area. The nowcast data are used in the SatCom system simulator to simulate the communication, and the predictions are used by the Propagation Impairment Mitigation Techniques (PIMTs).

• SatCom system: The operation of the SatCom system is simulated, using the input from DS2. The results are end-to-end SNIR values, together with other scenario specific results.

• DS3: The results of the SatCom system simulator are stored in data set DS3.

• Analysis: DS3 data are used to do statistical analysis of the performance (throughput, availability, energy consumption). The results are stored or visualised.

Plan

The project consists of six outputs:

• SOTA and design of the Channel Assessment System

• Design of the SatCom system testbed

• Implementation of the Channel Assessment System

• Implementation of the SatCom system testbed

• Execution of the SatCom system testbed and analysis of the performance

• Final reporting, roadmap and conclusions

Current Status

The final deliveries containing the software package and final reports were delivered to ESA before the summer 2023. The official end date of the project is planned for late 2023.

Companies

Sintef

http://www.sintef.no/

Norway

UiO

https://www.uio.no/

Norway

FFI

http://www.ffi.no

Norway

Norwegian Meteorological Institute

https://www.met.no/

Norway

Telenor Satellite

http://www.telenorsat.com/

Norway

Objectives

LEO-DIVE objective is to design, develop and verify via a system testbed (STB) multi-satellite (≥2) diversity technique applicable to large LEO constellations to combat the detrimental effects such as shadowing, multipath fading and channel blockage events. Specifically, the Multi-Satellite Diversity Techniques (MDTs) are expected to improve the achievable peak data rate and the link outage probability at the UTs when at least two satellites are in visibility.
The STB is designed and implemented to exploit the multi-satellite diversity techniques and to test them in various system and channel scenarios, including:

• Low frequency band scenarios (e.g., S-band) with omni-directional antennas;

• High frequency band scenarios (e.g., Ka-Band) with high-gain multi-beam ground terminals

The proposed switching diversity techniques are expected to be investigated for both forward (FWD) and return (RTN) links and adapted to the 5G NR NTN specification as proposed by 3GPP (Rel. 17 FR1, and Rel. 18 FR2).

Challenges

The detrimental effects of the satellite propagation channel (e.g. path loss, atmospheric absorption, Doppler, multipath, shadowing) are well-known to be time, location, and frequency dependent. At the same time, system assumptions like constellation geometry, payload capabilities or frequency reuse schemes increase the scenario variability in which the multi-satellite diversity techniques may operate. Additionally, the diversity techniques for LEO constellations have not been investigated yet in 5G NTN specifications, consequently, the switched-diversity techniques (SDTs) of terrestrial networks cannot be directly applied to LEO satellite communications. 
Finally, the signaling of the diversity techniques control and management information in the 5G NTN links with the LEO satellites is also another challenge. Feedback mechanisms (e.g., making use of 5G NTN waveform characteristics) for LEO diversity solutions are investigated by this project’s activities as well as the implementation of proper Channel state information (CSI) mechanisms (either instantaneous or statistical).
 

System Architecture

LEO-DIVE investigates satellite system architectures implementing switched diversity at UT for low frequency band scenarios (e.g., S-band) with omni-directional antennas and/or high frequency band scenarios (e.g., Ka-Band) with high-gain multi-beam ground terminals. The diversity techniques are assessed for either rural or urban scenarios, and an in-depth analysis is conducted for both transparent and regenerative payloads.
The System TestBed (STB) of LEO-DIVE project is one of the activity core developments. The STB integrates various simulators such as Matlab Satellite Communications Toolbox, Matlab 5G NR Toolbox and open-source ns-3 with proper 5G extensions and provides the following capabilities: 

• Standards-based tools for developing, modelling, and validating satellite communications systems and links are available through the commercial MATLAB/Satellite Communication Toolbox.

• Functions and reference examples for the modelling, simulation, and verification of 5G NR and 5G-Advanced communications systems that are standard-compliant with the commercial MATLAB/5G NR Toolbox. 

• Open-source ns-3 based simulator with pluggable 5G modules for simulating traffic and for integrating and testing the multi-diversity techniques in a 5G NTN environment.

The proposed architecture can effectively simulate various systems setups for UTs and LEO constellations under the proposed switched diversity techniques. Next, extensive comparisons considering system scenarios not implementing MDT assess the overall improvement of achievable data rate and outage probability both at FWD and RTN links either in low- or high-frequency bands. 

The proposed STB is also expected to model the orbital configuration and its effects (e.g. velocity of the satellite and Doppler shifts) together with the selected channel models.   

Plan

LEO-DIVE involves the following phases:
P1: System Scenarios Definition (reference scenarios, KPI definitions, value proposition, etc.)
P2: Finalised Technical Specification (SOTA, benchmark solution, gap analysis, etc.)
P3: Selected technical Baseline (comparison and trade-off, and selected technical baseline)
P4: Verified Detailed Design (preliminary design baseline, verified detailed design)
P5: Implementation and Verification (demonstrator technical specification, implementation, test, and verification plans)
P6: Technology and Development Plan (technology evaluation and roadmap)
and the following milestones (MS):
MS1: Finalised Technical Specifications & Selected technical Baseline
MS2: Implementation and Verification Plan
MS3: Verified Deliverable Items and Compliance Statement
MS4: Technology Assessment and Development Plan  

The flow chart of the study plan presenting the logic of the envisaged work to be undertaken is as follows:
 

Current Status

LEO-DIVE started on March 1, 2024. The Work Packages (WPs) expected to be completed during the first six months are as follows:

• WP1: System Scenarios Definition 

• WP1.1: Reference Operational Scenarios

• WP1.2 KPI Definition 

• WP1.3: Value Proposition 

• WP1.4 Preliminary Requirements Definition 

• WP2: Technical Specification

• WP2.1: State-of-the-Art Survey 

• WP2.2: Benchmark Solution and Gap Analysis

• WP2.3: Finalized Technical Specification 

• WP2.4: Outline Verification Plan 

Companies

University of Thessaly

https://www.uth.gr/en

Greece

OHB Hellas Single Member L.L.C

https://www.ohb-hellas.gr/

Greece

Objectives

Preliminary analyses have shown that the NB-IoT standard can be used by satellite systems in non-geostationary orbits under certain constraints. However, to enable the integration of user sensors employing this technology, it is necessary to develop an on-board evolved node B (eNB) capable of using a standard not originally conceived for satellite communications with adaptation and additional features dictated by the scenarios. Moreover, the eNB is preferably compatible with small satellites platforms in terms of mass, power and volume since these platforms are usually the ones selected to provide M2M/IoT services. Finally, it is also important to develop and propose UU (radio interface between UE and eNB) adaptations that would allow maximizing the efficiency of a satellite system. 
The goal of the project is the development of a demonstrator in which communication between an NB-IoT User Equipment and an eNB adapted for satellite communications is functionally verified. 
The state-of-the-art technology for NB-IoT is critically revised, referring to integration with satellite systems and associated technical requirements expected by the demonstrator.

Challenges

The project aims at developing a demonstrator where the communication between a NB-IoT UE and the adapted eNB is functionally verified. The main challenges are:

• identification of the scenarios suitable for NB-IoT via NTN and what are their impacts in terms of key architectural strategies;

• identification of adaptations needed to enable the operation of satellite links for NB-IoT for both Access Stratum (AS) and Non-Access Stratum (NAS);

• development of a satellite RAN, including a User Equipment (UE), an RF and baseband processing unit and an eNB;

• Functional and performance verification of NB-IoT over satellite.

System Architecture

The System Architecture is shown in the following picture:

The main sub-systems are:

• NB-IoT Traffic Emulator:  to emulate the traffic generated by several UEs.     

• NB-IoT Adapted UE: is an NB-IoT terminal emulator based on an SDR with UU interface adaptations.

• Channel Emulator: to emulate all the impairments caused by LEO satellites. In particular, is able to introduce variable delay, variable Doppler Shift, Phase Noise, Fading. 

Plan

The project foresees the following relevant milestones:

• MS1: Preliminary Operation Scenario Requirements and acceptance of all related deliverables. 

• MS2: Technical Requirements (traffic emulator, NB-IoT UE, Channel Emulator, On-board eNodeB Prototype) and acceptance of all related deliverables. 

• MS3: Testbed Implementation and acceptance of all related deliverables. 

MS4: Results, Roadmap and acceptance of all related deliverables.

Current Status

The activities started on 1st April 2020.
The milestone MS1 has been achieved with the completion of WP1 relating to scenarios definition and challenge identification.
The milestone MS2 has been achieved with the completion of work packages WP2 and WP3, concerning UU Interface and Testbed Requirements.
The milestone MS3 has been achieved with the completion of the activities concerning the Testbed Design, Development and Verification and the Test Plan definition. 
The Final Review has been achieved at the end of the overall activities.

Companies

RINA Consulting

https://www.rina.org

Italy

CNIT

http://www.cnit.it/

Italy

Nitel

http://www.nitel.it/

Italy

RAME S.r.l.

https://www.ramesrl.it

Italy

Thales Alenia Space Italia

https://www.thalesgroup.com/en/worldwide/space-italy

Italy

Objectives

The main objectives of the project are as follows:

• Design novel Congestion Control (CC) mechanisms for the QUIC transport protocol, which deliver acceptable performance over both satellite and terrestrial networks.

• Prove the effectiveness of the new mechanisms in relevant GEO/NGSO scenarios.

Both verification and validation campaigns are performed to show that the designed solution satisfies the technical requirements and to evaluate the effectiveness compared to existing options. A goal is to attain similar or higher performance than can be achieved using a PEP with TCP.  A set of demonstration campaigns use commercial satellite links for both GEO (e.g., Eutelsat Konnect, SES ASTRA) and NGSO (Starlink),  and consider migration scenarios (satellite to terrestrial network switching).

The key results of the project are contributing to the Internet Engineering Task Force (IETF), the principal Internet standards development organisation.

Challenges

The recently defined QUIC protocol (RFC9000) has been widely deployed across the Internet. This uses TLS 1.3 to encrypt the end-to-end communication. This prevents using techniques to mitigate the differences introduced in satellite systems (e.g., PEPs) and therefore introduces performance limitations (RFC9065). Instead, the project proposes to change the QUIC sender to optimise transfers over satellite using the QUIC transport protocol.

System Architecture

The project has implemented the congestion control mechanism in two QUIC stacks: A fork of the CloudFlare Quiche, and a fork of Picoquic. These implementations have been validated and then evaluated using a range of applications operating over commercial satellite links for both GEO (e.g., Hylas, Eutelsat Konnect, SES ASTRA) and NGSO (Starlink). A range of non-satellite paths have also been evaluated and many also experience benefit, as well as considering migration scenarios where the path changes between satellite to terrestrial networks. Configuration and KPI recording is implemented through a web-interface (GUI).

Plan

The project has three phases:

• Phase 1: Definition of a technical baseline and preliminary validation of the mechanisms using simulation campaigns in ns-3. This was used to derive the initial design. 

• Phase 2: Development of a consolidated technical baseline in a real-world QUIC implementation followed by in-depth analysis over emulation testbeds. 

• Phase 3: Demonstration over real-satellite services using real applications. 

Current Status

Phases 1 and 2 have been completed: The project has finalised a technical specification (Careful Resume), supported by simulation analysis and evaluation. This has been shown to significantly improve the performance and reliability of the Internet, especially for users of high-bandwidth-delay-product paths – such as those provided by some cellular services and by broadband satellite providers.
The project has successfully contributed an Internet-Draft (draft-ietf-tsvwg-careful-resume) specifying Careful Resume to the IETF TSVWG working group. This has been adopted as a work item and is currently progressing towards publication as an IETF Standards Track RFC.

The final stage of the project evaluates satellite performance of the implemented QUIC protocol stack.

Related Links

• https://www.rfc-editor.org/rfc/rfc9000
• https://datatracker.ietf.org/doc/draft-ietf-tsvwg-careful-resume
• https://erg.abdn.ac.uk/video/IETF-121-hackathon-CR.m4v
• https://datatracker.ietf.org/doc/draft-ietf-tsvwg-careful-resume

Companies

DLR

http://www.dlr.de/

Germany

University of Aberdeen

https://www.abdn.ac.uk/

United Kingdom

Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)

https:// www.cs7.tf.fau.de