Communication, Optimization, Radio, and Navigation
The Communications, Optimization, Radio, and Navigation (CORN) group is responsible for teaching and research activities in the Electronics and Physics (EPH) department at Telecom SudParis.
CORN is organized around several research areas:
RF energy recovery (Ghalid Abib)
Connected devices are becoming increasingly common in everyday life. They enable the transmission of different types of data using various wireless standards, while being powered by batteries or cells. The growing demand for energy is prompting us to explore alternative power solutions and contribute to the development of a green IoT. Of the available alternative energy sources, we are particularly interested in radio frequency (RF) energy used in wireless systems (Wi-Fi, 5G, etc.). The main objective of this research is to convert ambient RF energy into direct current (DC) electrical energy that can power low-power connected devices. Due to the low levels of RF power received, the converted DC voltage is also low, requiring voltage supervisors. We are currently investigating voltage supervisors capable of operating at just a few hundred millivolts.
Short-range communications (Muriel Muller)
Digitization in the healthcare sector is one of the key challenges in the years to come. This digital transformation will rely in part on the IoT and AI.
This presents a real opportunity to develop solutions for noninvasive measurements and diagnostic support (during polysomnography) or preliminary diagnoses (using autonomous devices worn or used by patients), thanks to innovative medical devices that can effectively assist healthcare professionals.
Our research in this field focuses on developing innovative sensors based on ultra-wideband (UWB) technology to detect sleep apnea. We will combine these architectures with advanced signal processing, data science, and AI techniques to identify the patient's respiratory phases.
Many applications that require real-time indoor positioning are currently being developed. The limited penetration of GNSS signals indoors makes designing accurate indoor positioning and navigation systems challenging. In collaboration with the Telecom Paris’ Comelec Department, we are developing an indoor ultra-wideband positioning technique that uses both radial distance (the Duplex method) and azimuth angle (the phase correlation (PC) method) measurements [Awarkeh et al., 2020]. The next stage will include determining the elevation angle and developing a demonstration platform. Nour Awarkeh: "2D Indoor Positioning System Using a Multistatic UWB Radar," PhD thesis defended on October 30, 2019.
Antennas and Propagation (Christine Letrou) and Reconfigurable Intelligent Surfaces (RIS) - Integrated Sensing and Communication (ISAC) (Jose Manuel Rubio Hernan)
Recent work has primarily focused on demonstrating the value of the Gaussian beam tracing method based on Gabor frames for computing monostatic radar scattering in large-scale problems, considering both the number of reflections and the electromagnetic dimensions of the problem. The selected test scenarios consist of a reflecting block environment [Letrou et al., 2021b] and a large cavity [Letrou et al., 2022]. The results are compared with benchmark methods as part of a collaboration with Professor A. Boag of Tel Aviv University. Another line of research was recently launched in collaboration with Professors L. Klinkenbusch and G. Manara of the Universities of Kiel and Pisa. This research focuses on investigating the possible hybridization of the Gaussian beam tracing method with exact solutions to diffraction problems using complex sources [Klinkenbusch et al., 2023].
Optimization (Nam Nguyen)
This research focuses on designing, implementing, and validating real-time, embedded optimization algorithms for control systems and signal processing, that are suitable for low-cost hardware platforms, such as microcontrollers.
The most significant constraints are:
- Strict real-time operation: The algorithms must provide a solution in a very short amount of time, for example, in less than 10 milliseconds.
- Low memory footprint: Microcontrollers often have only a few dozen to a few hundred KB of RAM.
- Low energy consumption: This is critical for battery-powered embedded systems.
- Portability and simplicity: The code must be easily portable to architectures such as ARM Cortex-M or RISC-V.
Target applications:
- Autonomous robots: trajectory control and obstacle avoidance.
- Smart vehicles: stability and optimal braking.
- Embedded power systems: optimizing energy consumption.
- Drones: stabilization and guidance.
- GNSS spoofing (Alexandre Vervisch-Picois & Jose Manuel Rubio Hernan)
Spoofing detection and clock analysis
Our work in this field has expanded significantly through an industrial partnership with Thales Six and continues to grow. In recent years, we have been working on GNSS spoofing attacks and methods of detecting them. Spoofing involves transmitting a signal to a target receiver that replaces signals originating from satellites. Signs of GNSS spoofing are particularly apparent in the clock bias (the time offset between the GNSS constellation clock and the receiver clock). We focus on this parameter because attacks can be detected by monitoring variations in the clock bias [Truong et al., 2023]. As part of this work, we established a partnership with the German Aerospace Center (DLR) to test methods of detecting attacks on mobile phones [Munoz Diaz et al., 2023].
Determining the location of a spoofer
We are continuing our work on detecting spoofing attacks, and investigating ways to resist them. We are studying collaborative positioning methods that can both detect and counteract attacks. As part of these efforts, we have developed the ability to locate GNSS spoofers using clock data or pseudorange measurements. We have filed a joint patent with Thales for this approach [Heurguier et al., 2022].
Positioning (Alexandre Vervisch-Picois & Nel Samama)
Two fundamental aspects are addressed here: high-precision GNSS positioning and positioning in environments not covered by GNSS.
Outdoor RTK – PPP Positioning
Precise positioning methods have been around for about twenty years, yet research in this field continues to focus on enhancing performance while minimizing infrastructure requirements. In particular, this involves developing a set of techniques for calculating highly accurate positions, known as Precise Point Positioning (PPP), that do not require an uplink radio connection between the receiver and the network managing the correction data. Our partnership with Exagone Teria, one of France's leading industrial operators in the sector, allows us to develop innovative approaches in this field [Delphine et al., 2022].
Indoor positioning
We are developing approaches based on phase measurements using what is known as an inverse radar configuration. These approaches are unique in that they obtain measurements from phase differences processed on code-bearing signals transmitted by two antennas spaced one wavelength apart, which often appeals to our external partners. This makes it possible to measure the arrival angle without placing the burden of spatial diversity on the receiving module, as is the case with the conventional approach [Rubio-Hernan et al., 2022b].
Another, more pragmatic approach involves incorporating specialized electronics that transmit data into fire evacuation units. These units are distributed throughout public buildings and are subject to regulatory requirements. The current version of the system uses Bluetooth signals. A telecommunication network is established between the units (which are never very far apart) making it possible to collect the measurements. Combining the units' positions with mapping data geolocates all measurements within a limited area while enabling the creation of a positioning system.
