High performance SDR for sporadic TEMPEST signal detection (2018- )
Information systems are now massively integrated into both industry and administration processes. Thus, their security is matter of importance especially when considering the storing and exchange of sensitive data. Sensitive data is also called "red" data, in opposition with the non-sensitive (or protected by encryption) "black" data. This crucial challenge is present at multiple scales, and leads to the emergence of different security fields linked to data protection (defense protocols) and to data interception (attack protocols)
Since few years, a new threat has emerged with the detection of the red data due to unwanted phenomena. This attack is done trough an over the air interception and thus is difficult to detect. These kind of attacks (called TEMPEST attacks by the NSA) consist in detecting an hidden channel that bear the sensitive information and then decode the "red" information . This unwanted channel may exist due to different physical phenomena such as electro-magnetic coupling, radio frequency leakages, or mechanical mechanisms. Many studies has been conducted in order to detect and decode "red" information when the leaking channel is stationary. Open questions remain when the leaking channel is sporadic.
The purpose of this PhD thesis is to detect a potential security threat when the leaking channel is sporadic (for instance WiFi) in a real time proof of concept. In this case, it is necessary to propose real time high performance methods trough the use of hardware acceleration. A compact approach trough the use of Software Defined Radio (SDR) will be proposed.
This PhD done by Corentin Lavaud has begun in October 2017 and has been funded by the french organisation DGA-MI (Direction Generale de l'Armement, Maitrise de l'Information).
Digital methods for agile optical transceivers (2017- )
Optical network has to cope with various configuration and agile network deployment is envisioned to address the increasing growth in data rate and spectral efficiency. Nowadays, optical receivers are still based on coherent detection supported by advanced digital processing techniques. These algorithms are designed in order to compensate the harsh effects of optical transmissions; non linearity and impairments induced by the analog chain.
The objective of the thesis is to propose and study efficient architectures dedicated to high data rate optical transceivers, in order to enhance the spectral efficiency and the flexibility of the system. A particular glance will be dedicated to the digital baseband algorithms dedicated to multipolarization operations and channel and hardware impairments compensation (phase noise, chromatic dispersion, ...) and a validation on real signal will be assessed.
This PhD thesis done by Marwa Kazdoghli Lagha is a collaboration between Granit team (Pascal Scalart, Robin Gerzaguet and Arnaud Carer) and FOTON institute (Christophe Peucheret and Laurent Bramerie) through the SENDATE CELTIC project.
5G new waveforms and 3.5 GHz field trials (2015 - )
The future generations of wireless networks (a.k.a 5G) will have to cope with a high degree of heterogeneity in terms of services (Broadband, machine type communications (MTC), Internet of Things (IOT), Vehicular to vehicular (V2V) . . . ) and requirements (high data rates, low latency, high reliability, coexistence, . . . )
Even though Cyclic Prefix Orthogonal Frequency Division Multiplexing (CP-OFDM) is the most prominent multi-carrier modulation technique in wireless standards for below 6GHz transmission (used in 4G, DVB-T, Wifi, . . . ), it also exhibits some intrinsic drawbacks. These limitations make CP-OFDM poorly appealing for 5G and have motivated the study and the comparison of alternative waveforms such as Universal-Filtered OFDM (UF-OFDM) or Filter Bank Multicarrier (FBMC).
We have introduced a new quasi-orthogonal waveform called Block-Filtered OFDM (BF-OFDM) that combines most of the advantages of the aforementioned waveforms at the price of slight complexity increase. Spectral localization and performance in multi-user scenario is enhanced w.r.t OFDM and simple equalization as well as all classical MIMO schemes can be straightforwardly considered. The proposed waveform is scalable and can be used in various configurations and services, which paves the way for future heterogeneous systems.
This waveform has been studied in the scope of mmMagic and Fantastic-5G H2020 projects and in the french ANR WONG-5. The initial proposal has won the 2017 International Conference on Communication (ICC-2017) best paper award.
Block Filtered OFDM synoptic (Tx stage)
Multi-service transmissions are expected in the upcoming fifth-generation (5G) of cellular networks. These heterogeneous applications lead to many constraints that need to be addressed in a flexible way. We have investigated the division of the bandwidth into several subbands, each having a different service and numerology.
This work highlights and demonstrates the possible coexistence of Broadband (eMBB), Ultra-Reliable Low-Latency (uRLLC) and new IoT (eIoT) services within the same channel using a flexible waveform. Field test experiments have been done with an implementation of the BF-OFDM physical layer on prototype hardware boards. These field trials have been made in Minatec Campus in Grenoble and use the new 5G 3.5GHz band.
Field trials in Minatec Campus
Riesco Platform (2013 - 2015)
Riesco (for Radio Logicielle pour l'Evaluation des Systèmes complexes) is a platform of the Gipsa-Lab dedicated to digital communication applications. It is composed of software defined radios (SDRs) network and has been developed since 2013 (by Damien Roque) for teaching, proves of concept and real-time digital communication validation .
Channel Estimation versus time and versus OFDM carrier index, with USRP-B200
The platform is composed of 6 software defined radios, 4 USRP N210 and 2 USRP B200 from Ettus Research. The SDRs are mastered by an external Octoclock and controlled by a host PC under Xubuntu with GnuRadio project .
PhD Thesis (2012 - 2015)
Radio frequency transceivers are now massively multi-standards, which means that several communication standards can cohabit in the same environment. As a consequence, analog components have to face critical design constraints to match the different standards requirements and self-interferences that are directly introduced by the architecture itself are more and more present and detrimental.
My work exploits the dirty RF paradigm : we accept the signal to be polluted by self-interferences and we develop digital signal processing algorithms to mitigate those aforementioned pollutions and improve signal quality.
The main purpose is to study different self-interferences and propose baseband models and digital adaptive algorithms for which we derive closed form formulae of both transient and asymptotic performance. This approach is necessary to propose algorithms specifications than can cope with different standards or requirements. We also propose an original adaptive step-size overlay to improve transient performance of our method. The final step is to validate our approach on a system on chip dedicated to cellular communications and on a software defined radio.
Our work on Tx Leakage digital compensation has been granted by Crowncom 2016 Best paper award.