The Hybrid Channel Emulator is one of the projects that is currently being developed as a part of ESA’s ongoing ARTES (Advanced Research in Telecommunication Systems) program. The HCE is developed under a strategic goal namely ‘Space for 5G’ and the aim of the project is to design an emulator which can emulate radio propagation conditions of two bi-directional 5G carriers with accurate emulation of satellite-satellite and satellite-terrestrial link characteristics.

The objective of the Hybrid Channel Emulator project is the development and validation of a single solution capable of emulating the radio propagation conditions of two bi-directional 5G carriers (satellite-satellite or satellite-terrestrial). This has the twin challenges of providing an emulator that accurately models the dynamics, and tightly controls the channel impairments, of a wide variety of scenarios, and one that covers frequency bands spanning nearly 30 GHz. 

Processing large bandwidths requires FPGAs with large resource capabilities. Efficient digital processing design is critical to minimize device FPGA costs. Given the large bandwidths and wide range of frequencies being handled, the introduction of unintended signal distortion by the channel emulator is a challenge that requires careful design and built-in compensation techniques.

The benefits of HCE is a new and unique product:

• Highly integrated solution that does not require external applications to model the satellite orbits or generate time-series data for each impairment
• Hardware support for up to 1 GHz of instantaneous bandwidth
• Frequency-agile external RF interface equipment capable of interfacing not only at 3GPP FR1 and FR2 bands but also in Ku- and Ka satellite bands
• Cost-effective multi-channel support for both satellite and terrestrial 5G channels in a single product

Key Features

• Hardware-in-the-loop testing of bi-directional 5G carriers for both satellite-satellite or satellite-terrestrial links
• Realistic and accurate emulation of satellite and terrestrial link characteristics including: atmospheric effects (e.g. rain fade), Doppler, delay, and path loss variations, as well as impairments introduced by transmit and receive RF components, such as nonlinear distortion, phase noise, amplitude ripple, and thermal noise
• Ability to model all forms of satellite constellations, including traditional geostationary satellites as well as MEO, LEO and HEO satellites or combinations thereof
• Frequency-agile external RF interface equipment capable of interfacing not only at 3GPP FR1 and FR2 bands but also in Ku-and Ka satellite bands
• Hardware support for up to 1 GHz of instantaneous bandwidth

System Architecture

The proposed solution for the Hybrid Channel Emulator (HCE) is based on three components:

• An enhanced version of SPCI’s RLS-2100 radio link simulator product.
• An integrated multi-channel FR1 up and down-converter unit (FR1 UC/DC), which supports frequencies up to 7.125 GHz that cannot currently be supported internal to the RLS-2100.
• A multi-channel FR2+ up and down-converter unit (FR2+ UC/DC), which supports frequencies in the mmWave band plus the satellite Ku/Ka-band frequencies.

There are two major development streams. The first stream includes the development of the IF version of the hybrid channel emulator (HCE) together with FR1 up/down converters (UC/DCs). The second stream is the development of FR2+ UC/DCs, where FR2+ is the 3GPP FR2 frequency band (up to 30 GHz) plus the Ku and Ka satellite bands. The outputs of the streams are integrated and tested to provide the final documentation, hardware, and software.

The Project Milestones are as follows:

• Preliminary Design Review – July 2021
• Final Design Review – September 2021
• Critical Design Review – January 2022
• Test Readiness Review – June 2022
• Final Review – August 2022

The Final Design Review Meeting (FDR) was held in September 2021. Progress was made in all areas of the design to address the challenges presented in the preliminary review. Designs are now in place for the extended frequency range (covering FR1 and FR2) and the terrestrial channel models. Design activities are wrapping up and the implementation of critical components has started.

The Prime Contractor for the HCE project is Square Peg Communications and the Subcontractor is WORK Microwave GmbH.

Click here to learn more about the Hybrid Channel Emulator Project.

Click here to get details on RLS-2100 Radio Link Simulator from Square Peg Communications.