UTWM - User Terminal Wideband Modem for Very High Throughput Satellites (VHTS)

Funding source: ESA - European Space Agency
Partners: WideNorth (Prime), Space Norway, Norwegian University of Science and Technology (NTNU), IMT Atlantique,
Principal investigator: Dr Symeon Chatzinotas
Researchers: Dr Nicola Maturo, Dr Steven Kisseleff, Dr Houcine Chougrani

The objective of the project is the development and the implementation of an end-to-end hardware demonstrator for a wideband forward link based on the DVB-S2X standard, supporting baud rates up to 1.4 Gbaud. The demonstrator supports user bit rates up to 5.6 Gbps for 16APSK modulations, while the design is prepared for higher order modulation and higher bit rates. The reference scenarios include the realistic use of LEO satellites for Earth observation, as well as next generation point-to-point communications exploiting LEO constellations.

Figure 1: Earth observation satellites. Photo credits: ESA

The key challenges in the project are the high baud rate (resulting in a large bandwidth) and high user data rate. The DVB-S2X modem being developed in this project supports significantly higher baud rates and larger bandwidths than commercial products and demonstrators available per 2018. This allows for a more efficient use of the wideband link, since a single DVB-S2X carrier can replace multiple 250-500 MHz carriers. The key features of this demonstrator are:

adjustable baud rates from 25 Mbaud to 1.4 Gbaud
adaptive coding and modulation (ACM)
powerful, flexible, and module-based hardware platform where FPGA, DAC, and ADC modules can be upgraded separately
1.5 GHz channel emulator
predistortion at the transmitter and equalization at the receiver to compensate for linear and non-linear distortions caused by the wideband transponder
a hardware-friendly design of the synchronization chain
a novel FEC decoder design supporting up to 6 Gbps user bit rate in a single FEC decoder core.