PAGE CONTENTS
Objectives
• PD-NOMA Technique Development
Design and assessment of a Power-Domain NOMA (PD-NOMA) scheme for satellite return links, with a focus on heterogeneous terminals and geostationary Earth orbit (GEO) Ku-band scenarios, and benchmarking against classical OMA techniques (FDMA/TDMA).
• End-to-End Demonstration at TRL-5
Implementation of a complete PD-NOMA baseline (terminal and gateway) and validation in both laboratory and live over-the-air conditions, raising the Technology Readiness Level (TRL) from TRL-3 to TRL-5.
• Throughput Improvement
Demonstration of a measurable increase of aggregate return-link throughput with respect to OMA, confirmed through link-level, system-level and end-to-end testing.
• Latency Reduction
Validation that the throughput gain achieved by PD-NOMA translates into a reduction of overall service latency (time needed for multiplexed users to offload their traffic).
• Standard and System Feasibility
Assessment of PD-NOMA applicability within DVB-RCS2-like and 3GPP new radio-non-terrestrial network (NR-NTN) frameworks, including compliance with off-axis emission regulations and identification of potential integration paths into existing standards.
Challenges
• Implementation, tuning and validation of Successive Interference Cancellation (SIC) at the gateway for heterogeneous terminals and higher-order modulations, under realistic GEO channel impairments.
• Characterisation of the different impairments that could impact the effectiveness of NOMA methodologies and identification of corresponding realistic and accurate models.
• Analysis and tuning of several algorithms (e.g. estimation algorithms) in order to deal with the different characteristics of the received signals.
• Accurate modelling and emulation of impairments (phase noise, non-linearities, Doppler, frequency and timing offsets, fading) and verification of their impact on PD-NOMA performance at simulation and testbed level.
• Porting of MATLAB algorithms into an existing Verification Platform originally designed for spread-spectrum random access, requiring significant architectural adaptations (framing, preambles, filtering, frequency estimation).
• Stability and robustness of the live setup, including radio frequency (RF) chain integration, calibration and synchronisation across transmit/receiver chains.
System Architecture
At architecture level, the system involves a number of terminals, a gateway to receive information from the terminals, a feeder link to send information to the terminals, and a HUB to manage communication, as shown in the following figure.
On the terminal side, the transmitter generates DVB or 3GPP waveforms with controlled power levels, predefined MODCODs and burst-based framing compatible with a DVB-RCS2-like or 3GPP-NTN standard.
A logical diagram of the air interface for the DVB-RCS2 like (including RF section) and 3GPP-NTN (only digital section) respectively is shown below.
On the gateway side, the receiver implements a multi-stage SIC chain, including synchronization, channel estimation, demodulation, burst/frame reconstruction and interference cancellation, enabling the separation of multiple users sharing the same time–frequency resource.
In this stage the signal with the highest SNR is first acquired and demodulated, then this is cancelled to allow processing of the following one and so on until the last signal component to be demodulated.
The verification platform integrates RF front-ends, impairment emulators and baseband processing for both PD-NOMA and OMA (FDMA/TDMA) modes according to DVB-RCS2 like mode, allowing direct performance comparison under identical conditions. The architecture supports both single-beam and multi-beam scenarios, and has been exercised in a live GEO satellite link to validate end-to-end PD-NOMA operation.
Plan
The project plan foresees a unique phase which includes the following milestones after the KO meeting (T0):
- System Requirement Review (T0+3M)
- Critical Design Review (T0+8M)
- Test Readiness Review (T0+15M)
- Final Review (T0+18M)
The total duration of the project was 18 months.
Current Status
With reference to the project Gantt diagram, the activities related to all the planned Work Packages have been successfully completed.
