Publications HAL de villemaud

Journal articles

2022

titre: Experimental Analysis of Spatial Modulation Systems in Mixed LOS/NLOS Scenarios
auteur: Yanni Zhou, Florin Hutu, Guillaume Villemaud
article: IEEE Access, 2022, pp.1-14. ⟨10.1109/ACCESS.2022.3152554⟩
resume: Spatial modulation (SM) as a multiple-input multiple-output (MIMO) technique is a solution suitable which offers, with low system complexity and cost, improved spectral efficiency compared to singleinput-single-output (SISO) systems. Moreover, the transmission chain is simplified which decreases energy consumption. This paper aims to analyze the SM system transmission under different line-of-sight/non-lineof-sight (LOS/NLOS) propagation scenarios. The analysis of the SM system performance is based on both simulations and experimental results and the bit error rate (BER) is tackled. Concerning the experimental results, two strategies are considered in order to configure the propagation channel. One method consists in constructing a controlled propagation environment. More precisely, the multipath channel's Rician K-factor is imposed by configuring the power levels of the LOS and of the NLOS components. The second method consists in performing over-the-air transmissions on a realistic propagation channel. A channel sounding method allows us to measure the channel characteristics. The experimental results are confronted with the system-level simulation results, good agreement between experimental and simulation results are obtained. The results show that the SM system can maintain the performance in multipath propagation in the presence of indirect paths for both two proposed propagation environments.
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titre: Performance Evaluation of Passive Tag to Tag Communications
auteur: Tarik Lassouaoui, Florin Hutu, Yvan Duroc, Guillaume Villemaud
article: IEEE Access, 2022, 10, pp.18832-18842. ⟨10.1109/ACCESS.2022.3149626⟩
resume: In the context of the UHF (Ultra High Frequency) passive RFID (Radio FrequencyIdentification) technology, recent works have proposed a new paradigm demonstrating the possibility toperform short distance tag to tag (T2T) communications. This paper presents a study that focuses on theperformance evaluation of T2T systems. Without loss of generality as to the methodology followed, dipoleantennas are considered here (assumed ideal in the theoretical part, then printed for the rest of the study).The results obtained show that the modulation depth, which can be considered as an evaluation metric forthe T2T systems, is strongly impacted by three main parameters: the switching impedances (here chosen asshort-circuit and open-circuit); the geometrical configuration constituted by the two tag antennas formingthe T2T system; and also, the position of the external source on which the backscatter communicationrelies. As the modulation depth is very sensitive to these three parameters, which are more or less directlyrelated, it is very difficult to predict the communication quality for a given configuration. For example,when the two tags are in parallel and the source is symmetrically positioned, the modulation depth shows adecreasing trend by oscillating when the distance between the tags increases from 0.1 λ to 1 λ (λ being thewavelength): with values going from 70% to less than 5%. As a consequence, from a very complete set ofscenarios considered, the presented study helps to illustrate and explain the interactions of these parametersand their impact on the modulation depth. And at the same time, the paper provides guidelines for definingthe specifications of such a system based on quantified results. The set is completed by introducing the BER(Bit Error Rate) as an evaluation metric by considering then a more complete T2T system (i.e. listener tagincluding a non-coherent envelope detector).
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2021

titre: Towards a Battery-Free Wake-Up Radio
auteur: Achille Fumtchum, Florin Doru Hutu, Pierre Tsafack, Guillaume Villemaud, Emmanuel Tanyi
article: Electronics, 2021, 10 (20), pp.2449. ⟨10.3390/electronics10202449⟩
resume: This paper proposes a contribution to the development of autonomous wake-up radios from the energy supply perspective. More precisely, a rectifier circuit, designed and manufactured in order to provide the energy needed for a quasi passive wake-up radio receiver (WuRx). The WuRx is intended to operate continuously and to ensure a zero energy consumption in standby mode. After the presentation of the said WuRx, the energy requirement for its power supply is defined. Then, the energy harvesting circuit, able to power up the quasi-passive WuRx, is designed, implemented, and then measured. Compared to the state of the art, the energy harvester that we present here is among the few recent designs that replaced the matching network lumped component by butterfly stubs, which brings compactness to the circuit. The rectifier is built on a high efficiency substrate which increases its performance and reduces its form factor.
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titre: A Survey of RF Energy Harvesting Circuits
auteur: Achille Fumtchum, Pierre Tsafack, Florin Doru Hutu, Guillaume Villemaud, Emmanuel Tanyi
article: International Journal of Innovative Technology and Exploring Engineering, 2021, 10 (7), pp.99-106. ⟨10.35940/ijitee.G8944.0510721⟩
resume: The aim of this work is, on one hand, to review the state of the art of the architectures and diodes used in radio-frequency energy harvesting systems, the idea here is to review the most recent works, as well as their characteristics, which include frequency, type of diode used, topology, maximum efficiency and corresponding power, and on the other hand to carry out simulations to determine the most appropriate case for any further work in the field. After having determined the most common topologies, we used the main known radio-frequency diodes to characterize them in a first step, clearly a process of comparing the results of the simulations of the different topologies is done by initially considering an identical frequency. and afterward determine the effect of frequency band on their conversion efficiency.
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2020

titre: Impact of Receiver Non-idealities on a Full Duplex Spatial Modulation System Performance
auteur: Yanni Zhou, Florin Hutu, Guillaume Villemaud
article: IEEE Wireless Communications Letters, 2020, 9 (12), pp.2083-2087. ⟨10.1109/LWC.2020.3013195⟩
resume: In this paper, we analyze, for the first time, the performance of a full-duplex system combined with spatial modulation technique in presence of the receiver non-idealities. IQ imbalance and phase noise are the two radio front-end mismatch factors that have been considered. The impact of the IQ imbalance on the bit error rate (BER) performance of the full-duplex spatial modulation (FDSM) system under different noise levels is investigated. An estimator has also been proposed for the self-interference cancellation (SIC) after the imperfect receiver. The results show that IQ imbalance does not significantly reduce system BER performance at low signal-to-noise ratios. Moreover, it is shown that the proposed estimator is able to maintain the system at an acceptable BER.
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titre: State-Space Model Representation to Characterize an Energy Harvesting Circuit
auteur: Regis Rousseau, Guillaume Villemaud, Florin Hutu
article: Radio Science Letters, In press
resume: This paper presents a method to model an energy harvesting circuit and a propagation channel as parts of a wireless power transfer (WPT) system. Previously , an original solution was proposed by the authors to maximize the collected DC power level, implying to model the different parts of the system by using state space representation and using convex optimization algorithms to calculate multi carrier signal weights. Firstly, a state-space model of the radio channel is obtained by the use of multivariable output-error state space (MOESP) algorithm. Then, by the vector fitting method a state-space representation is obtained in order to model the linear part of the energy harvesting circuit. At last, by the polynomial-nonlinear state-space (PNLSS) method, the non-linear part of the rectifier is also modeled.
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titre: Study of Distributed Beamforming for Wireless Power Transfer in Presence of RF Impairments
auteur: Florin Hutu, Vincent Léchappé, Guillaume Villemaud, Michaël Di Loreto
article: Radio Science Letters, 2020, 2, ⟨10.46620/20-0040⟩
resume: For an equivalent performance (sensitivity, communication range, computational capability, etc.), the energy efficiency of connected devices is continuously increasing. Providing the energy for such objects by the means of electromagnetic waves (wireless power transfer) becomes a feasible option in various scenarios, especially those in which the use of conventional energy resources (e.g. batteries) is unfeasible.This paper tackles a particular method of wireless power transfer, which is the distributed beamforming, i. e. the use of several sources, spatially distributed and which are coordinating together in order to maximize the power of the electromagnetic field in a particular location. Through simulation results, this paper highlights the robustness of this approach to different nonidealities, i.e. frequency and phase synthesis, phase noise and channel characteristics. A first experimental setup is also presented.
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2016

titre: Récepteur de type “wake-up” radio à identification par empreinte fréquentielle
auteur: Regis Rousseau, Florin Doru Hutu, Guillaume Villemaud
article: La Revue de l'électricité et de l'électronique, 2016, Enjeux d’un développement massif des énergies renouvelables dans le système électrique européen du futur, 5, pp.105-111. ⟨10.23723/1301:2016-5/17792⟩
resume: The Internet of Things (IoT) is described as the industrial revolution of the early 21th century. Innumerable communicating objects will be deployed in the coming years and one of the consequences will be the exponential growth of the IoT energy footprint. The use of ultra-low energy radio receivers (wake-up radios) is one of the envisaged solutions to reduce the energy consumption. By using such kind of receivers, the radio transceiver which consumes the most greedy part of energy of communicating objects, will be power supplied only during the active periods. In the scientific literature, the use of on-off keying (OOK) modulation together with envelope detector based radio part and a microcontroller unit is highlighted for the wake-up radios. The authors of this paper proposed an original approach consisting in a quasi-passive wake-up radio where the identification is done by the means of passive filters and the use of orthogonal frequency division multiplexing (OFDM) signal. This approach is validated through measurements on a functional prototype and, in this paper, the receiver sensitivity and the communication range are given.
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titre: Digital I/Q Imbalance Correction for Full-Duplex Dual-Band OFDM Radio Transceivers I Introduction
auteur: Zhaowu Zhan, Guillaume Villemaud, Florin Hutu, Jean-Marie Gorce
article: International Journal of Microwave and Wireless Technologies, 2016, 8 (3), pp.505-519. ⟨10.1017/S1759078715000811⟩
resume: This paper presents a Full-Duplex Dual-Band (FDDB) OFDM radio architecture that enables the radio transceiver to be more flexible and provides a viable radio link capacity gain. A simple but practical I/Q imbalance estimation and compensation method, based on the frequency-flat-fading behavior of the self-interference channel, is proposed. The performance of the proposed I/Q imbalance compensation method is evaluated by system level simulations conducted with ADS and Matlab. The co-simulation results show that the proposed radio transceiver could potentially increase the physical layer transmission rate by four times compared to the conventional radio link at the cost of tolerable loss of BER performance. The I/Q imbalance compensation method can effectively compensate both high and low I/Q imbalance without the problem of algorithm convergence.
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titre: A parallel unbalanced digitization architecture to reduce the dynamic range of multiple signals
auteur: Mathieu Vallerian, Florin Doru Hutu, Guillaume Villemaud, Benoit Miscopein, Tanguy Risset
article: Radio Science, 2016, ⟨10.1002/2015RS005885⟩
resume: Technologies employed in urban sensor networks are permanently evolving, and thus the gateways employed to collect data in such kind of networks have to be very flexible in order to be compliant with the new communication standards. A convenient way to do that is to digitize all the received signals in one shot and then to digitally perform the signal processing, as it is done in software-defined radio (SDR). All signals can be emitted with very different features (bandwidth, modulation type, and power level) in order to respond to the various propagation conditions. Their difference in terms of power levels is a problem when digitizing them together, as no current commercial analog-to-digital converter (ADC) can provide a fine enough resolution to digitize this high dynamic range between the weakest possible signal in the presence of a stronger signal. This paper presents an RF front end receiver architecture capable of handling this problem by using two ADCs of lower resolutions. The architecture is validated through a set of simulations using Keysight’s ADS software. The main validation criterion is the bit error rate comparison with a classical receiver
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2015

titre: Generation of 2D correlated random shadowing based on the deterministic MR-FDPF model
auteur: Meiling Luo, Guillaume Villemaud, Jean-Marie Gorce
article: EURASIP Journal on Wireless Communications and Networking, 2015, 208, ⟨10.1186/s13638-015-0434-y⟩
resume: In modern mobile telecommunications, shadow fading has to be modeled by a two-dimensional (2D) correlated random variable since shadow fading may present both cross-correlation and spatial correlation due to the presence of similar obstacles during the propagation. In this paper, 2D correlated random shadowing is generated based on the multi-resolution frequency domain ParFlow (MR-FDPF) model. The MR-FDPF model is a 2D deterministic radio propagation model, so a 2D deterministic shadowing can be firstly extracted from it. Then, a 2D correlated random shadowing can be generated by considering the extracted 2D deterministic shadowing to be a realization of it. Moreover, based on the generated 2D correlated random shadowing, a complete 2D semi-deterministic path loss model can be proposed. The proposed methodology of this paper can be implemented into system-level simulators where it will be very useful due to its ability to generate realistic shadow fading.
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2014

titre: A new wake-up radio architecture for wireless sensor networks
auteur: Florin Doru Hutu, Aissa Khoumeri, Guillaume Villemaud, Jean-Marie Gorce
article: EURASIP Journal on Wireless Communications and Networking, 2014, 177, ⟨10.1186/1687-1499-2014-177⟩
resume: The last decades have been really hungry in new ways to reduce energy consumption. That is especially true when talking about wireless sensor networks in general and home multimedia networks in particular, since electrical energy consumption is the bottleneck of the network. One of the most energy-consuming functional block of an equipment is the radio front end, and methods to switch it off during the time intervals where it is not active must be implemented. This paper proposes a wakeup radio circuit which is capable of both addressing and waking up not only a more efficient but also more energy-consuming radio front end. By using a frequency footprint to differentiate each sensor, awaking all the sensors except for the one of interest is avoided. The particularity of the proposed wake-up receiver is that the decision is taken in the radio-frequency part and no baseband treatment is needed.
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2013

titre: Packet Error Outage for Coded Systems Experiencing Fast Fading and Shadowing
auteur: Philippe Mary, Mischa Dohler, Jean-Marie Gorce, Guillaume Villemaud
article: IEEE Transactions on Wireless Communications, 2013, 12 (2), pp.574-585. ⟨10.1109/TWC.2012.121812.111785⟩
resume: In this paper, we consider the performance of coded wireless communication systems experiencing non-frequency selective fading channels in shadowed environments. The quality of service (QoS) in a wireless network is dependent on the packet error outage (PEO). We address the problem of finding a tractable expression for the coded PEO over Nakagami-m channels with shadowing, considering multilevel modulations, various block and convolutional channel coding schemes and hard decision decoding. In order to obtain the coded PEO, an inversion of the coded packet error probability (PEP) w.r.t. the signal to noise ratio (SNR) is needed. To this end, we propose an invertible approximation for the coded PEP w.r.t. the uncoded bit error probability (BEP) in Nakagami-m fading channels which is accurate for all BEPs of interest. The BEP itself depends on the average SNR and we hence make use of previous results on the inversion of the uncoded BEP w.r.t. the SNR in Nakagami-m fading channels, holding for M-PSK and M-QAM signals. We were thus able to obtain a reliable closed form expression for the coded PEO in flat fading and shadowing channels. The theoretical findings are verified by means of simulations.
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2012

titre: Realistic Prediction of BER and AMC for Indoor Wireless Transmissions
auteur: Meiling Luo, Guillaume Villemaud, Jean-Marie Gorce, Jie Zhang
article: IEEE Antennas and Wireless Propagation Letters, 2012, ⟨10.1109/LAWP.2012.2218213⟩
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titre: Computationally Efficient MR-FDPF and MR-FDTLM Methods for Multifrequency Simulations
auteur: Dmitry Umansky, Jean-Marie Gorce, Meiling Luo, Guillaume de La Roche, Guillaume Villemaud
article: IEEE Transactions on Antennas and Propagation, 2012, 61 (3), pp.1309-1320. ⟨10.1109/TAP.2012.2227920⟩
resume: We propose a modification of the multi-resolution frequency domain ParFlow (MR-FDPF) method that allows simulating radio propagation channels in a frequency range. The performance of the proposed MR-FDPF implementation has been analyzed based on different realistic propagation scenarios. We also analyze the possibility of applying the multi-resolution frequency domain approach to the well-known transmission-line matrix method. The proposed multi-resolution frequency domain transmission-line matrix method provides a computationally efficient way of modeling radio wave propagation in threedimensional space at multiple frequencies.
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2011

titre: Symbol Error Outage Analysis of MIMO OSTBC Systems over Rice Fading Channels in Shadowing Environments
auteur: Philippe Mary, Mischa Dohler, Jean-Marie Gorce, Guillaume Villemaud
article: IEEE Transactions on Wireless Communications, 2011, 10 (4), pp.1009 -1014. ⟨10.1109/TWC.2011.021611.091838⟩
resume: We deal with the analytical performance study of orthogonal space-time block codes (OSTBC) applied to multiple-input multiple-output (MIMO) systems experiencing non-frequency selective fast fading and shadowing. We address the problem of finding a tractable closed-form expression for the symbol error outage (SEO) over Rice fading channels in shadowing environments. In order to obtain the SEO, a symbol error probability (SEP) inversion w.r.t. the average signal to noise ratio (ASNR) is needed since no invertible SEP approximations are available in literature. We propose an accurate approximation for the SEP in Rice fading channels. This new approximation is proved to be invertible w.r.t. the ASNR and this expression thus facilitates the derivation of a tight approximation of the SEO in lognormal shadowing environments.
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2010

titre: Low Power Front-End Architecture dedicated to the Multistandard Simultaneous Reception
auteur: Ioan Burciu, Guillaume Villemaud, Jacques Verdier, Matthieu Gautier
article: International Journal of Microwave and Wireless Technologies, 2010
resume: In this paper, we address the architecture of multistandard simultaneous reception receivers and we aim to reduce the complexity and the power consumption of the analog front-end. To this end we propose an architecture using the double orthogonal translation technique in order to multiplex two signals received on different frequency bands. A study case concerning the simultaneous reception of 802.11g and UMTS signals is developed in this article. Theoretical and simulation results show that this type of multiplexing does not significantly influence the evolution of the signal to noise ratio of the signals. In the same time a 30% reduction of the power consumption is expected as well as a significant reduction of the complexity.
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titre: The Multi-antenna Code Multiplexing Front-end : Theory and Performance
auteur: Matthieu Gautier, Guillaume Villemaud, Ioan Burciu
article: International Journal of Microwave and Wireless Technologies, 2010
resume: In this paper, we address the architecture of a multiantenna receiver and we aim at reducing the complexity of the analog front-end. To this end, an innovative architecture is introduced based on code multiplexing. This architecture uses the direct sequence spread spectrum technique in order to multiplex the different antennas contributions through a single IQ demodulator. Simulation and measurement results show that the bit error rate does not increase so much with the multiplexing in both Gaussian and fading environments and with strong RF defaults conditions. The complexity evaluation shows that the proposed architecture significantly reduces the chip area and the power consumption of the front-end.
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titre: Implementation and Validation of a New Combined Model for Outdoor to Indoor Radio Coverage Predictions
auteur: Guillaume de La Roche, Paul Flipo, Zhihua Lai, Guillaume Villemaud, Jie Zhang, Jean-Marie Gorce
article: EURASIP Journal on Wireless Communications and Networking, 2010
resume: In this paper, a new model used to compute the outdoor to indoor signal strength emitted from an outdoor base station is presented. This model is based on the combination of 2 existing models: IRLA (Intelligent Ray Launching), a 3D Ray Optical model especially optimized for outdoor predictions, and MR-FDPF (Multi Resolution Frequency Domain ParFlow), a 2D Finite Difference model initially implemented for indoor propagation. The combination of these models implies the conversion of the ray launching paths on the border of the buildings, into virtual source flows that will be used as an input for the indoor model. The performance of the new combined model is evaluated via measurements at 2 frequencies (WiMAX and WiFi). This solution appears to be efficient for radio network planning, both in term of accuracy and computational cost.
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2009

titre: Coupled Simulation-Measurements Platform for the Evaluation of Frequency-Reuse in the 2.45 GHz ISM band for Multi-mode Nodes with Multiple Antennas
auteur: Guillaume Villemaud, Pierre-François Morlat, Jacques Verdier, Jean-Marie Gorce, Marylin Arndt
article: EURASIP Journal on Wireless Communications and Networking, 2009
resume: In this paper we address the problem of efficiently evaluate performance of concurrent radio links on overlapped channels. In complex network topologies with various standards and frequency channels, simulating a realistic PHY layer communication is a key point. The presented coupled simulation-measurement platform offers a very promising way of rapidly modelling and validating effective performance of multi-mode, multi-channel and multi-antenna radio nodes. An accurate of radio channel is performed and then realistic performance with or without antenna processing is shown, verifying theoretical performance. Finally, available performance of concurrent communications on overlapped channels is exposed, showing that this approach is viable to enhance network capacity.
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titre: M-ary Symbol Error Outage Over Nakagami-m Fading Channels in Shadowing Environments
auteur: Philippe Mary, Mischa Dohler, Jean-Marie Gorce, Guillaume Villemaud, Marylin Arndt
article: IEEE Transactions on Communications, 2009
resume: This letter addresses the problem of finding a tractable expression for the symbol error outage (SEO) in flat Nakagami-m fading and shadowing channels. We deal with M-ary phase shift keying (M-PSK) and quadrature amplitude modulation (M-QAM) which extends our previous results on BPSK signaling. We propose a new tight approximation of the symbol error probability (SEP) holding for M-PSK and M-QAM signals which is accurate over all signal to noise ratios (SNRs) of interest. We derive a new generic expression for the inverse SEP which facilitates the derivation of a tight approximation of the SEO in a lognormal shadowing environment.
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2008

titre: Plateforme de tests et de validation des modèles de simulation
auteur: Jacques Verdier, Guillaume Villemaud, Jean-Marie Gorce
article: Journal sur l'enseignement des sciences et technologies de l'information et des systèmes, 2008
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2007

titre: Etude de systèmes de radiocommunications
auteur: Jacques Verdier, Guillaume Villemaud, Jean-Marie Gorce
article: Journal sur l'enseignement des sciences et technologies de l'information et des systèmes, 2007
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titre: Capnet : réseaux de capteurs et graphes d'interactions
auteur: Guillaume Chelius, Olivier Brevet, Eric Fleury, Antoine Fraboulet, Guillaume Villemaud
article: Techniques de l'Ingénieur - Réseaux sans fil, 2007
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titre: BPSK bit error outage over Nakagami-m fading channels in lognormal shadowing environments
auteur: Philippe Mary, Mischa Dohler, Jean-Marie Gorce, Guillaume Villemaud, Maryline Arndt
article: IEEE Communications Letters, 2007, 11 (7), pp.565-567. ⟨10.1109/LCOMM.2007.070241⟩
resume: In this letter, we address the problem of finding a tractable expression for the bit-error outage (BEO) defined as the probability to observe a given average bit error rate (BER) over a fading channel in a shadowing environment. Our contribution is two-fold: (1) a simple yet tight approximation of the bit error probability (BEP) for binary phase shift keying (BPSK) over a frequency-flat Nakagami-m fading channel is derived, which (2) facilitates the derivation of a tight lower bound of the BEO in presence of lognormal shadowing in closed form. Theoretical results are corroborated by means of simulation results, confirming the tightness of the bounds.
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2004

titre: DUAL-BAND PRINTED DIPOLE ANTENNA ARRAY FOR AN EMERGENCY RESCUE SYSTEM BASED ON CELLULAR-PHONE LOCALIZATION
auteur: Guillaume Villemaud, Cyril Decroze, Christophe Dall'Omo, Thierry Monédière, Bernard Jecko
article: Microwave and Optical Technology Letters, 2004, pp
resume: This paper describes the study of a novel dual-band antenna dedicated to be mounted on a helicopter for emergency localisation of cellular phones within the framework of the RNRT project called LUTECE. A folded dipole placed on a limited ground plane to allow wideband functionality and good radiation characteristics is proposed. Starting from this new topology, a directive array for the emission part and a circular disposition of five radiating elements with separated outputs for the receiving part are studied. All these developments are performed using our simulation code (FDTD method) along with experimental studies.
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Conference papers

2024

titre: Impact of the antenna topology on the combination of full-duplex spatial modulation and RF energy harvesting
auteur: Hery Zo Jean Baptiste Andriamanohisoa, Florin Doru Hutu, Guillaume Villemaud
article: Eucap 2024, Eurapp, Mar 2024, Glasgow, United Kingdom
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2023

titre: Low-input-power Sub-GHz RF Energy Harvester for Powering Ultra-low-power Devices
auteur: Jesus Argote-Aguilar, Muh-Dey Wei, Florin-Doru Hutu, Guillaume Villemaud, Matthieu Gautier, Olivier Berder, Renato Negra
article: International Workshop on Integrated Nonlinear Microwave and Millimetre-wave Circuits, Nov 2023, Aveiro (Portugal), Portugal
resume: Using RF energy to power ultra-low-power devices is an appropriate solution to reduce the dependency on conventional sources (e.g. batteries); however, providing a regulated DC voltage from low RF power is a challenging task. This work presents a low-input-power RF harvester designed with off- the-shelf components and composed of an RF rectifier and a power management integrated circuit (PMIC). In the rectifier, an inductive-matching technique is employed which consists of an inductive branch composed of a lumped inductor together with a short-circuited stub due to sub-GHz frequency. The rectifier is designed to present an optimal DC load in function of the PMIC operation at low powers. Measured RF-to-DC conversion efficiency of 32% and DC output voltage of 186 mV with an input power of −20 dBm at 888.7 MHz are achieved in the rectifier. Measured peak efficiency is 52 % at −4 dBm. At −20 dBm, a relatively high efficiency and output DC voltage are obtained compared to other discrete rectifiers. For this power level, this performance is sufficient to maintain the operation of the PMIC that delivers a power of 324 nW aiming to supply an ultra-low-power wake-up receiver. The required RF power to deliver a regulated DC voltage is so far the lowest reported in the literature for an RF harvester using off-the-shelf components and a continuous wave (CW) signal to date.
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titre: Efficient and uncomplicated RF harvester circuit for Powering an Ultralow-Power Wake-up Radio
auteur: Jesus Argote-Aguilar, Muh-Dey Wei, Florin Hutu, Guillaume Villemaud, Matthieu Gautier, Olivier Berder, Renato Negra
article: 17ème Colloque National du GDR SOC2, Jun 2023, Lyon, France
resume: Using Radio Frequency (RF) energy to power ultralow power devices is an appropriate solution to reduce the dependency on batteries for low power consumption connected devices. However, providing a regulated Direct Current (DC) voltage from RF power is a challenging task. This work presents a simple and efficient rectifier which has an RF/DC conversion efficiency of 29 % and outputs a DC voltage of 227 mV from an input RF power of −20 dBm at 848 MHz. This performance is sufficient to operate a commercial Power Management Integrated Circuit which regulates the DC output voltage of the rectifier and outputs a power of 324 nW aiming to power supply an ultralow power consumption Wake-up Radio Receiver. The required RF power, to output a regulated DC voltage, is so far the lowest reported in the literature for an RF harvester designed with offthe-shelf components and using a continuous wave (CW) signal.
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titre: Considérations sur la conception d'un redresseur destiné à la récupération d'énergie RF dans la bande ISM à 868 MHz
auteur: Jesus Argote-Aguilar, Florin Hutu, Guillaume Villemaud, Olivier Berder, Matthieu Gautier
article: Journées Scientifiques URSI France : L'énergie au coeur des ondes, Mar 2023, Saclay, France
resume: L'étude théorique des redresseurs RF à travers la simulation avec des composants idéaux est une première approche pour comprendre les atouts et les inconvénients d'un tel circuit destiné à la récupération d'énergie RF. Cependant, les composants électroniques réels ont des pertes et des effets parasites qui peuvent changer drastiquement le comportement de ces redresseurs, notamment leur rendement de conversion. Le travail présenté ici met en évidence l'importance de prendre en compte la technologie de fabrication. Les considérations de conception pour le redresseur proposé ici tiennent compte du contexte applicatif qui est l'alimentation avec une tension continue régulée d'une interface de type « wake-up radio » à travers un circuit de gestion d'énergie (PMIC-Power Management Integrated Circuit).
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2022

titre: Efficient Association of Low and High RF Power Rectifiers for Powering Ultra-Low Power Devices
auteur: Jesus Argote-Aguilar, Florin-Doru Hutu, Guillaume Villemaud, Guillaume Villemaud, Matthieu Gautier, Olivier Berder
article: ICECS 2022 - IEEE International Conference on Electronics Circuits and Systems, Oct 2022, Glasgow, United Kingdom. pp.1-4
resume: Nowadays, the efficiency of Radio Frequency (RF) energy harvesting circuits is continuously increasing and, at the same time, the energy consumption of connected devices is drastically decreasing. Despite that, collecting, storing and delivering such kind of harvested energy to the device in an appropriate manner is still a challenge. This paper presents the design of a harvester able to efficiently collect energy from both low and high power levels of the RF field. The objective is to correctly power supply an ultra-low power consumption device requiring a regulated voltage. A RF harvester circuit, specially designed for our application and consisting in the association of a low and a high level power rectifier, is presented. By the means of a circulator and depending on the RF power level received at the input port of the RF harvester circuit, the RF power is absorbed by the low power rectifier or reflected to the high power rectifier. The rectifiers have their outputs associated in series. At a frequency of 868 MHz, the efficiencies of the association of rectifiers are 43 % and 76 % and were obtained for input powers of-20 dBm and 0 dBm respectively.
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titre: Alimentation par énergie RF d'une Wake-Up Radio ultra faible consommation
auteur: Jesus Argote-Aguilar, Florin Hutu, Guillaume Villemaud, Matthieu Gautier, Olivier Berder
article: 16ème Colloque National du GDR SOC2, Jun 2022, Strasbourg, France
resume: Nowadays, the efficiency of the Radio-Frequency (RF) energy harvesting circuits is continuously increasing and, at the same time, the energy consumption of connected devices is drastically decreasing. Despite that, collecting, storing and delivering such kind of harvested energy to the device in an appropriate manner is still a challenge. This paper focuses on a strategy of harvesting energy in an efficient way from both low and high levels of the RF field. The objective is to power an ultralow power consumption wake-up radio requiring a regulated voltage. The starting point is the characterization of a commercial power management integrated circuit which operates with ultralow power levels. Then, some design guidelines of the RF power rectifiers, specifically designed for our envisaged application are given.
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titre: Influence du commutateur RF dans une architecture radio combinant modulation spatiale et full duplex
auteur: Yanni Zhou, Florin Doru Hutu, Guillaume Villemaud
article: JNM 2022 - Journées Nationales Microondes, Jun 2022, Limoges, France. pp.934 - 938
resume: Les approches de type FDSM (Full Duplex et Modulation Spatiale) sont de bonnes candidates pour augmenter les performances des systèmes de communications de type massive MIMO (Multiple Input Multiple Output). L'élément principal dans la mise en place de la partie SM, le commutateur RF, présente des non-idéalités telles que le temps de latence, les pertes d'insertion et l'isolation entre les différentes voies qui peuvent dégrader les performances du système FDSM dans sa globalité. Dans cet article, à travers des simulations système réalistes, l'impact des non-idéalités du commutateur RF sur les performances des récepteurs FDSM est mis en évidence. Le critère d'évaluation choisi est le TEB (taux d'erreur binaire) extrait en fonction du rapport signal à bruit.
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titre: Communications Tag à Tag Passives en RFID UHF
auteur: Tarik Lassouaoui, Florin Hutu, Guillaume Villemaud, Yvan Duroc
article: URSI 2022 - Journées scientifiques, Mar 2022, Paris, France. pp.54-58
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2021

titre: Modulation Depth Enhancement for Randomly Arranged Tags in Passive RFID Tag to Tag Communications
auteur: Tarik Lassouaoui, Florin Hutu, Guillaume Villemaud, Yvan Duroc
article: RFID-TA 2021 - 11th IEEE International Conference on RFID Technology and Applications, Oct 2021, Delhi, India. pp.1-4, ⟨10.1109/RFID-TA53372.2021.9617243⟩
resume: In this paper, the performance evaluation of the tag to tag (T2T) communications using UHF (Ultra High Frequency) passive RFID (Radio Frequency Identification) tags is tackled. The T2T communication system is performed directly between a reader tag (RT) and a listener tag (LT) in the presence of an external electromagnetic (EM) field. Consequently, this kind of communication system implies the use of low RF signal levels, which makes it very sensitive to the noise, to the arrangement between the tags (i.e. spacing, tilt and shift) but also to the position of the source. The performance evaluation of this communication system is based on the study of the modulation depth, an indicator of the separation between the two modulation states and, indirectly, of the T2T communication quality. Considering scenarios in which the two tags are in the same plane but with the RT tilted and staggered with respect to the LT, our study demonstrates that the modulation depth can be kept higher for different separations between the tags by choosing the proper angle of incidence of the RF source with respect to the tag's plane. The proposed approach is studied through electromagnetic simulations and the obtained results are confronted with measurements. Index Terms-backscattering, passive tags, UHF RFID, tag to tag communications.
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titre: Nonlinear Power Amplifier Effects on a Full Duplex Spatial Modulation System
auteur: Yanni Zhou, Florin Hutu, Guillaume Villemaud, Taneli Riihonen
article: PIMRC 2021 - IEEE 32nd Annual International Symposium on Personal, Indoor and Mobile Radio Communications, Sep 2021, Oulu / Virtual, Finland. pp.1-5, ⟨10.1109/PIMRC50174.2021.9569720⟩
resume: In this paper, we consider a full duplex (FD) system using spatial modulation (SM) technique for simultaneous transmission. Despite the recent studies on the combination of these two techniques, nonlinear effects of devices have been ignored. This paper demonstrates, for the first time, the nonlinear power amplifier (PA) effects on a full duplex spatial modulation (FDSM) system. A digital canceller is adopted to deal with the strong selfinterference (SI) in presence of PA nonlinearities. The results are verifying that the considered canceller can suppress SI close to the thermal noise level and has high reliability to ensure the performance of the system.
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2020

titre: Distributed beamforming for wireless power transfer
auteur: Florin Hutu, Vincent Léchappé, Guillaume Villemaud, Michaël Di Loreto
article: URSI GASS 2020 - 33rd URSI General Assembly and Scientific Symposium, Aug 2020, Rome, Italy. pp.1-4, ⟨10.23919/URSIGASS49373.2020.9232305⟩
resume: With the technology progress, the amount of energy which is necessary to power supply the connected devices will decrease continuously. Providing the energy for such objects by the means of electromagnetic waves (wireless power transfer) becomes a feasible option. This paper tackles a particular method of wireless power transfer, which is the distributed beamforming. By simulation results, the paper highlights the impact on the received power level of the phase coherence and of frequency synthesis mismatch. Then, we present an experimental setup able to test wireless power transfer scenarios through distributed beamforming.
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titre: Full Duplex Spatial Modulation System in presence of IQ imbalance
auteur: Yanni Zhou, Florin Hutu, Guillaume Villemaud
article: URSI GASS 2020, Aug 2020, Rome, Italy. pp.1-3
resume: The combination of the spatial modulation (SM) and of the full duplex (FD) is a challenging research direction because it brings high spectral efficiency and even energy consumption reduction because of the use of a unique radio frequency (RF) receiving chain. This paper presents a full-duplex spatial modulation (FDSM) system over the Rician fading channel. A least-square self-interference (SI) esti-mator is implemented for the self-interference cancellation (SIC). Moreover, the impact of IQ imbalance on the bit error rate (BER) performance is analyzed. The obtained results show that the proposed estimator can reduce SI at a low level. The system is more sensitive to the IQ imbalance under low noise environment.
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titre: Full Duplex Spatial Modulation System Performance Depending on Self-interference Cancellation Accuracy
auteur: Yanni Zhou, Florin Hutu, Guillaume Villemaud
article: EuCAP 2020 - 14th European Conference on Antennas and Propagation, Mar 2020, Copenhagen, Denmark. pp.1-5
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titre: Theoretical BER Evaluation of Passive RFID Tag-To-Tag Communications
auteur: Tarik Lassouaoui, Florin Hutu, Yvan Duroc, Guillaume Villemaud
article: 2020 IEEE Radio and Wireless Symposium, Jan 2020, San Antonio, United States. pp.1-4
resume: — The concept of UHF RFID passive tag-totag communication has been introduced and opens new promising perspectives in the field of Internet-of-Things. This concept enables two powerless tags to exchange information using an external source. Moreover, a simulation framework has been proposed as a tool allowing the performance evaluation of tag-to-tag radio links in terms of Bit Error Rate (BER). The aim of this paper is to provide a theoretical framework for BER estimation. The theoretical framework takes into account various parameters such as modulation rate, receivers topology and the electromagnetic coupling of the tags. Furthermore, in order to validate the obtained results, they are compared with the ones obtained by realistic simulations.
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titre: Analysis of a Spatial Modulation System over Time-varying Rician Fading Channel with a CSI Detector
auteur: Yanni Zhou, Florin Hutu, Guillaume Villemaud
article: RWW 2020 - IEEE Radio & Wireless Week, Jan 2020, San Antonio, United States. pp.1-5
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2019

titre: High Efficiency Rectifier for a Quasi-Passive Wake-up Radio
auteur: Achille Fumtchum, Florin Hutu, Pierre Tsafack, Guillaume Villemaud, Emmanuel Tanyi
article: ISSCS 2019 - 14-th International Symposium on Signals, Circuits and Systems, Jul 2019, Iasi, Romania. pp.1-4, ⟨10.1109/ISSCS.2019.8801754⟩
resume: The ubiquity of wireless sensor networks (WSN), as well as the rapid development of the Internet of Things (IoT), impel new approaches to reduce the energy consumption of the connected devices. The wake-up radio receivers (WuRx) were born in this context to reduce as much as possible the energy consumption of the radio communication part. This article aims at proposing a low-cost, high-efficiency rectifier to improve a quasi-passive WuRx performance in terms of communication range. By optimizing the wideband matching circuit and the proposed rectifier's load impedance, the sensitivity was increased by 5 dB, corresponding to an increase of the communication range (13 meters in free space).
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titre: Efficiency of Wireless Power transfer with a Multi-sine Source Optimized for the Propagation Channel
auteur: Regis Rousseau, Guillaume Villemaud, Florin Hutu
article: WPW 2019 - IEEE MTT's Wireless Power Week, Jun 2019, Londre, United Kingdom. pp.1-4
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2018

titre: Efficiency of Orthogonal Codes for Quasi-passive Wake-Up Radio Receivers using Frequency Footprint IDs
auteur: Mark S Widmaier, Florin Hutu, Guillaume Villemaud
article: ICECS 2018 - 25th IEEE International Conference on Electronics Circuits and Systems, Dec 2018, Bordeaux, France. pp.1-4
resume: This paper introduces robust wake-up IDs for quasi-passive wake-up receivers in an Internet of Things context. These IDs can address single devices and are based on the Hadamard code. Further a novel wake-up threshold is implemented to make the device more sensitive and robust against false wake-ups (FWUs). The wake-up procedure is simulated with a tap delay line (TDL) model for a line of sight (LOS) channel and a non line of sight (NLOS) channel. In both scenarios sufficient wake-up distances are reached with low false wake-up probabilitys (FWUPs). Additionally, the system is tested against the influence of an external bandwidth use. Finally, a recommendation for the global system is given.
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titre: On the Use of Vector Fitting and State-Space Modeling to Maximize the DC Power Collected by a Wireless Power Transfer System
auteur: Regis Rousseau, Florin Hutu, Guillaume Villemaud
article: AT-RASC 2018 - 2nd URSI Atlantic Radio conference, May 2018, Grande Canarie, Spain. pp.1-4
resume: In this paper, the authors are proposing a way to maximize the DC power collected in the case of a wireless power transfer (WPT) scenario. Three main aspects are taken into account: the RF (radio frequency) source, the propagation channel and the rectifier as the main part of the energy collecting circuit. This problem is formulated as a convex optimization one. Then, as a first step towards solving this problem, a rectifier circuit was simulated by using Keysight's ADS software and, by using a classical model identification strategy i. e. Vector Fitting (VF) algorithm, the state-space model of the passive parts of this rectifier were extracted. In order to verify the extracted model, S 11 input reflection coefficients and DC output voltages of the original circuit and the state-space model are compared.
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titre: Wireless Transmission in Ventilation (HVAC) Ducts for the Internet of Things and Smarter Buildings: Proof of Concept and Specific Antenna Design
auteur: Guillaume Villemaud, Florin Hutu, Pierre Belloche, Fatimazhra Kninech
article: EuCAP 2018 - 12th European Conference on Antennas and Propagation, Apr 2018, Londres, United Kingdom. pp.1-4, ⟨10.1049/cp.2018.0471⟩
resume: We present here a preliminary study of wireless transmissions using the ventilation metallic ducts as waveguides. Starting from the waveguide theory, we deeply study in simulation the actual attenuation encountered by radiowaves in such a specific medium. This kind of wireless link appears to be really efficient, and therefore highly promising to implement Internet of Things (IoT) in old buildings to make them smarter. This paper also expresses a very simple empirical model in order to ease dimensioning a wireless network in such conditions and a specific antenna design enabling both good performance and high robustness to the influence of the environment.
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titre: Wireless Transmission in Ventilation (HVAC) Ducts for the Internet of Things and Smarter Buildings: Proof of Concept and Specific AntennaDesign
auteur: Guillaume Villemaud, Florin Hutu, Pierre Belloche, Fatimazhra Kninech
article: IRACON 2018 - 6th MC and 6th Technical Meeting, Jan 2018, Nicosie, Cyprus. pp.1-6
resume: We present here a preliminary study of wireless transmissions using the ventilation metallic ducts as waveguides. Starting from the waveguide theory, we deeply study in simulation the actual attenuation encountered by radiowaves in such a specific medium. This kind of wireless link appears to be really efficient, and therefore highly promising to implement Internet of Things (IoT) in old buildings to make them smarter. This paper also expresses a very simple empirical model in order to ease dimensioning a wireless network in such conditions and a specific antenna design enabling both good performance and high robustness to the influence of the environment.
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titre: On the use of the FBMC modulation to increase the performance of a wake-up radio
auteur: Florin Hutu, Guillaume Villemaud
article: IEEE Radio and Wireless Symposium (RWS 2018), Jan 2018, Anaheim, CA, United States. pp.139-142, ⟨10.1109/RWS.2018.8304968⟩
resume: In this paper, Filter Bank Multi Carrier (FBMC) signals are employed in order to improve the performance of a quasi-passive wake-up radio receiver (WuRx) for which the addressing is performed by the means of a frequency fingerprint. The feasibility of such kind of WuRx was already demonstrated by using orthogonal frequency-division multiplexing (OFDM) signals to form the identifiers. Together with the main advantage of this approach (i.e. no base band processing needed and consequently a reduced energy consumption), one of the drawbacks is their low sensitivity. Through a set of circuit-system co-simulations, it is shown that by their characteristics, especially high Peak to Average Power Ratio (PAPR) and high out of band attenuation, FBMC signals manage to boost the sensitivity and moreover to enhance the robustness of this kind of WuRx.
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2017

titre: Reliable and Reproducible Radio Experiments in FIT/CorteXlab SDR testbed: Initial Findings
auteur: Leonardo Sampaio Cardoso, Othmane Oubejja, Guillaume Villemaud, Tanguy Risset, Jean Marie Gorce
article: Crowncom, Sep 2017, Lisbon, Portugal
resume: The FIT/CorteXlab platform is a wireless testbed situated in Lyon, France, where all radio nodes are confined to an electromagnetically (EM) shielded environment and have flexible radio-frequency (RF) front-end for experimenting on software defined radio (SDR) and cognitive radio (CR). A unique feature of this testbed is that it offers roughly 40 SDR nodes that can be accessed from anywhere in the world in a reproducible manner: the electromagnetic shield prevents from external interference and channel variability. In this paper we show why it is important to have such a reproducible radio experiment testbed and we highlight the reproducibility by the channel characteristics between the nodes of the platform. We back our claims with a large set of measurements done in the testbed, that also refines our knowledge on the propagation characteristics of the testbed.
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titre: Evaluation des performances des communications tag-to-tag : modélisation et outil de simulation
auteur: Lin Zhou, Florin Doru Hutu, Guillaume Villemaud, Yvan Duroc
article: JNM 2017 - 20èmes Journées Nationales Microondes, May 2017, Saint-Malo, France
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titre: Simulation framework for performance evaluation of passive RFID tag-to-tag communication
auteur: Lin Zhou, Florin Doru Hutu, Guillaume Villemaud, Yvan Duroc
article: EUCAP, Mar 2017, Paris, France. ⟨10.23919/EuCAP.2017.7928387⟩
resume: The concept of passive RFID tag-to-tag communications has been recently introduced and opens new promising perspectives, especially in the field of Internet-of-Things. In this paper, a simulation framework is proposed as a new tool allowing the performance evaluation of tag-to-tag radio links. The modeling takes into consideration the external source supplying the communication between tags, radiating characteristics of tag antennas, and reception system aspects. Performance results are expressed in terms of Bit Error Rate (BER) with respect to the distance between the tags and theposition of the energy source relative to the position of the two tags.
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titre: Analysis of an energy harvesting circuit in the presence of complex waveforms
auteur: Regis Rousseau, Florin Doru Hutu, Guillaume Villemaud
article: Journées Scientifiques de l'URSI: "Radiosciences au service de l’humanité", Feb 2017, Sophia-Antipolis, France
resume: This paper shows the incidence of the modulation scheme and of the input power on the RF to DC rectifier conversion efficiency. A commercial energy harvesting (EH) P21XXCSR-EVB evaluation board from Powercast Corporation is used as measurement target and several waveforms are employed to evaluate the rectification efficiency. With a continuous wave as reference, QPSK, QAM and OFDM waveforms usage demonstrates that digital modulated signals can lead to a better efficiency. Thus, by selecting a high peak to average power ratio (PAPR), and under certain conditions, the performances of the energy harvesting circuit are enhanced.
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2016

titre: On The Duality Between State-Dependent Channels and Wiretap Channels
auteur: David Kibloff, Samir M. Perlaza, Guillaume Villemaud, Leonardo S. Cardoso
article: IEEE Global Conference on Signal and Information Processing (GlobalSIP), Dec 2016, Greater Washington, D.C., United States
resume: In this paper, a duality between wiretap and state-dependent channels with non-causal channel state information at the transmitter is established. First, a common achievable scheme is described for a certain class of state-dependent and wiretap channels. Further, state-dependent and wiretap channels for which this scheme is capacity (resp. secrecy capacity) achieving are identified. These channels are said to be dual. This duality is used to establish the secrecy capacity of certain state-dependent wiretap channels with non-causal channel state information at the transmitter. Interestingly, combatting the eavesdropper or combatting the lack of state information at the receiver turn out to be two non-concurrent tasks.
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titre: Récepteur de type « wake-up » radio à identification par empreinte fréquentielle
auteur: Florin Doru Hutu, Guillaume Villemaud, Jean-Marie Gorce
article: Journées Scientifiques de l'URSI : Energie et Radiosciences, Mar 2016, Rennes, France
resume: Dans le cadre de la réduction de l’énergie consommée par les objets communicants, ce papier présente une architecture de type « wake-up radio » permettant l’adressage et l’allumage d’un récepteur radio principal plus performant et plus énergivore. En utilisant une empreinte fréquentielle pour différencier les équipements, il est évité de réveiller l’ensemble des interfaces radio mais uniquement celle d’intérêt. La technique d’identification par empreinte fréquentielle est validée à travers des mesures effectuées sur un démonstrateur expérimental. La portée de la transmission atteinte dans différents conditions de propagation est également présentée.
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titre: Experimental validation of a wake-up radio architecture
auteur: Florin Doru Hutu, David Kibloff, Guillaume Villemaud, Jean-Marie Gorce
article: 2016 Radio & Wireless Week, Jan 2016, Austin, United States
resume: This paper presents an experimental validation of a wake-up radio receiver (WuRx), allowing to both address and wake-up a main radio front-end, which has best performance but more energy consumption. The main goal is to reduce the total energy consumption of communicating objects by switching off the data transceiver module of each equipment during the periods when it is not used. The wake-up receiver is designed to be able to detect a wake-up signal which has a particular frequency signature and so, avoiding activating all main radio front-ends but only the one of interest. Moreover, the identification is performed in RF domain via passive circuitry and no base-band processing is needed.
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2015

titre: Additive companding implementation to reduce ADC constraints for multiple signals digitization
auteur: Mathieu Vallérian, Florin Hutu, Benoît Miscopein, Guillaume Villemaud, Tanguy Risset
article: IEEE International Conference on New Circuits and Systems Conference (NEWCAS), Jun 2015, Grenoble, France. ⟨10.1109/NEWCAS.2015.7182017⟩
resume: In urban sensor networks, the diversity of propagation conditions can lead to the simultaneous reception of signals having very different power levels. Given the diversity of wireless technologies used in this area, implementing gateways using a Software-Defined Radio (SDR) approach seems to be a very practical solution. Overcoming the large dynamic range may however require a very high resolution Analog-to-Digital Converter (ADC) to digitize the weakest signal with a satisfying precision. One possibility to relax this requirement is to use a companding technique before digitization. This paper describes how to use an additive companding approach to reduce ADC's complexity and proposes two implementations of the compressing law.
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titre: Energy optimization of radio transmission using wake-up radio
auteur: Florin Doru Hutu, Aissa Khoumeri, Guillaume Villemaud, Jean-Marie Gorce
article: Atlantic Radio Science Conference, AT-RASC 2015, Union Radio-Scientifique Internationale, May 2015, Gran Canaria, Spain. ⟨10.1109/URSI-AT-RASC.2015.7302971⟩
resume: Now, more than ever, the time to hasten the efforts made to reduce the energy consumption, especially in the field of radio communications has come. Wireless transmission was often blamed as being energy inefficient. It is well known that, in radio communications, approximatively 80% of the consumed energy is used only to maintain the network connections during standby periods. Moreover, the number of connected devices is continuously growing: as estimated by the International Energy Agency, in 2030 the number of connected devices will be multiplied by eight and, as a consequence, the energy consumption will double.
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titre: A parallel unbalanced digitization architecture to reduce the dynamic range of multiple signals
auteur: Mathieu Vallerian, Guillaume Villemaud, Florin Hutu, Benoit Miscopein, Tanguy Risset
article: 1st URSI Atlantic Radio Science Conference (URSI AT-RASC), 2015 , May 2015, Gran Canaria, Spain. ⟨10.1109/URSI-AT-RASC.2015.7302979⟩
resume: The technologies employed in urban sensor networks are permanently evolving, and thus the gateways of these networks have to be regularly upgraded. The existing method to do so is to stack-up receivers dedicated to one communication protocol. However, this implies to have to replace the gateway every time a new protocol is added to the network. A more practical way to do this is to perform a digitization of the full band and to perform digitally the signal processing, as done in Software-Defined Radio (SDR). The main hard point in doing this is the dynamic range of the signals: indeed the signals are emitted with very different features because of the various propagation conditions. It has been proved that the difference of power between two signals can be so important that no existing Analog-to-Digital Converter (ADC) is able to properly digitize the signals. This paper proposes a solution to reduce the dynamic range of signals before digital conversion. In the paper, the assumption is made that there is one strong signal, and several weak signals. This assumption is made from the existing urban sensor networks topology. A receiver architecture with two branches is proposed with a “Coarse Digitization Path” (CDP) and a “Fine Digitization Path” (FDP). The CDP allows to digitize the strong signal and to get data on it that is used to reconfigure the FDP. The FDP then uses a notch filter to attenuate the strong signal (and then to reduce the dynamic range of the signals) and digitizes the rest of the band.
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titre: Radio link characterization of the CorteXlab testbed with a large number of software defined radio nodes
auteur: Achille Mouaffo, Leonardo Cardoso, Hervé Boeglen, Guillaume Villemaud, Rodolphe Vauzelle
article: Antennas and Propagation (EuCAP), 2015 9th European Conference on , Apr 2015, Lisbon, Portugal
resume: This paper presents the first implementation on software defined radio nodes in the large scale testbed called CorteXlab of a radio link estimation technique based on OFDM transmissions. The purpose of this large scale testbed is to offer to the whole scientific community an open tool to test new techniques for multiuser , cooperative and cognitive radio networks in a controlled environment. As the experimentation room was defined in order to offer reproducible measurements, it is important to be able to characterize each radio link between all transceivers. Therefore, we present here the development of a channel sounder directly implemented on the software radio nodes.
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2014

titre: The Software Defined Radio for Wireless Systems
auteur: Guillaume Villemaud
article: Hot topics in RFID/NFC, Nov 2014, Valence, France
resume: The Software Defined Radio (SDR) paradigm aims at replacing most of analog functions of radio transceivers by digital processing blocks. This approach enables to tend to more flexible and reconfigurable terminals. But up to now, actual SDR systems are mostly applicable for basestations or access points, while it’s still problematic to implement small form factor solutions for mobile terminals.The INRIA Socrate team aims at addressing the challenges of SDR in practical devices, considering technical issues from the viewpoint of flexible radio front-ends, agile resource allocation and efficient programming of such devices.This presentation will focus on the main challenges of designing an SDR system depending on the application scenario and the kind of wireless standards available in the environment. These techniques, currently developed for classical long range wireless systems, could find some new constraints in the field of RFID, from the reader side for example.
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titre: Combination of Digital Self-Interference Cancellation and AARFSIC for Full-Duplex OFDM Wireless
auteur: Zhaowu Zhan, Guillaume Villemaud
article: ICCC 2014, Oct 2014, Shanghai, China
resume: Full-Duplex radio provides many benefits beyond improving spectral efficiency. However, canceling the self-interference completely is a big challenge behind Full-Duplex wireless. Although many intelligent efforts devote to active analog radio frequency self-interference cancellation (AARFSIC), the power of the residual self-interference (SI) after the AARFSIC is still much stronger than that of the receiver thermal noise. In this paper, we first study deeply the AARFSIC and "dig" the core problem that causing the residual SI, and then propose a digital self-interference cancellation in time domain (DSICT) to complement AARFSIC for the Full-Duplex OFDM wireless. The ADS-Matlab co-simulation results demonstrate the actual performance and show that the residual SI after the AARFSIC can be canceled completely by employing the proposed DSICT.
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titre: Digital Estimation and Compensation of I/Q Imbalance for Full-Duplex Dual-Band OFDM Radio
auteur: Zhaowu Zhan, Guillaume Villemaud, Florin Hutu, Jean-Marie Gorce
article: PIMRC 2014, Sep 2014, Washington, United States
resume: With the increasing demand of wireless applications, current radio transceivers are challenged by the requirement of high data rate and high flexibility. Full-Duplex Dual-Band OFDM radio transceiver is a very promising radio technique to approach this goal. However, the mutual undesirable signal leakages due to the I/Q imbalance in the Full-Duplex Dual-Band RF front-end lead to a significant performance degradation in the radio link. In this paper, a practical and suitable digital I/Q imbalance estimation and compensation method for mitigating the I/Q imbalance in this flexible radio transceivers is developed and evaluated. The developed I/Q imbalance estimation method is based on the character of the frequency-flat-fading of the self-interference channel. The ADS-Matlab co-simulation results show that the developed digital compensation method can significantly reduce the impact of the I/Q imbalance on the Full-Duplex Dual-Band OFDM radio receivers.
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titre: Study of a Full-Duplex Dual- Band OFDM Transceiver
auteur: Guillaume Villemaud, Zhaowu Zhan, Florin Hutu, Tanguy Risset, Jean-Marie Gorce
article: DUPLO Workshop on Full - Duplex Radios and Systems, Jun 2014, Oulu, Finland
resume: This presentation discussed system-level simulations (ADS + Matlab) on a dual-band OFDM transceiver: Such a Full Duplex node essentially consists of two OFDM transceivers, one transmitting at f1 and receiving at f2, the other doing the opposite. The system uses training symbols that are stronger compared to the regular TX signal, this allows better self-interference channel estimation and therefore cancellation ofself-interference to below the noise floor.
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titre: CorteXlab: A Facility for Testing Cognitive Radio Networks in a Reproducible Environment
auteur: Leonardo S. Cardoso, Abdelbassat Massouri, Benjamin Guillon, Paul Ferrand, Florin Hutu, Guillaume Villemaud, Tanguy Risset, Jean-Marie Gorce
article: in Proc. 9th International Conference on Cognitive Radio Oriented Wireless Networks and Communications (CROWNCOM), Jun 2014, Oulu, Finland. pp.503 - 507, ⟨10.4108/icst.crowncom.2014.255812⟩
resume: —While many theoretical and simulation works have highlighted the potential gains of cognitive radio, several technical issues still need to be evaluated from an experimental point of view. Deploying complex heterogeneous system scenarios is tedious, time consuming and hardly reproducible. To address this problem, we have developed a new experimental facility, called CorteXlab, that allows complex multi-node cognitive radio scenarios to be easily deployed and tested by anyone in the world. Our objective is not to design new software defined radio (SDR) nodes, but rather to provide a comprehensive access to a large set of high performance SDR nodes. The CorteXlab facility offers a 167 m 2 electromagnetically (EM) shielded room and integrates a set of 24 universal software radio peripherals (USRPs) from National Instruments, 18 PicoSDR nodes from Nutaq and 42 IoT-Lab wireless sensor nodes from Hikob. CorteXlab is built upon the foundations of the SensLAB testbed and is based the free and open-source toolkit GNU Radio. Automation in scenario deployment, experiment start, stop and results collection is performed by an experiment controller, called Minus. CorteXlab is in its final stages of development and is already capable of running test scenarios. In this contribution, we show that CorteXlab is able to easily cope with the usual issues faced by other testbeds providing a reproducible experiment environment for CR experimentation.
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titre: CorteXlab: A Cognitive Radio Testbed for Reproducible Experiments
auteur: Leonardo S. Cardoso, Abdelbassat Massouri, Benjamin Guillon, Florin Hutu, Guillaume Villemaud, Tanguy Risset, Jean-Marie Gorce
article: in Proc. Wireless @ Virginia Tech Symposium, May 2014, Blacksburg, United States
resume: The efficiency and potential gain of cognitive radio and more generally opportunistic cooperative communications have been already demonstrated from a theoretical point of view and supported by various simulation results. Beyond these promising results, several questions remain open from a practical point of view. Addressing these issues is not straightforward because deploying complex heterogeneous systems for cooperative scenarios is tedious, time consuming and hardly reproducible. We propose to make a step in this direction by offering a new ex-perimental facility, called CorteXlab, that allows complex multi-node cognitive radio scenarios deployment from anywhere in the world. Our objective is neither to design new software defined radio (SDR) nodes nor to propose a new software framework, but rather to provide a comprehensive access to a large set of high performance SDR nodes. The CorteXlab facility offers a 167 m 2 electromagnetically (EM) shielded room and integrates a set of 24 universal software radio peripherals (USRPs) from National Instruments, 18 PicoSDR nodes from Nutaq and 42 IoT-Lab wireless sensor nodes from Hikob. CorteXlab is built upon the foundations of the SensLAB testbed and also exploits the free and open-source toolkit GNU Radio. Automation in scenario deployment, experiment start, stop and results collection is performed by an experiment controller, called Minus. CorteXlab is in its final stages of development and is already capable of running specific test scenarios. In this contribution, we show that CorteXlab is able to easily cope with the usual issues faced by other testbeds providing a reproducible experiment environment for CR experimentation.
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titre: CorteXlab: An Open FPGA-based Facility for Testing SDR & Cognitive Radio Networks in a Reproducible Environment
auteur: Albdelbassat Massouri, Leonardo Cardoso, Benjamin Guillon, Florin Hutu, Guillaume Villemaud, Tanguy Risset, Jean-Marie Gorce
article: INFOCOM'2014 Demo/Poster Session, IEEE, Apr 2014, Toronto, Canada
resume: While many theoretical and simulation works have already highlighted the potential gain of cognitive radio, several technical issues still have to be overcome from an experimental viewpoint. This demo describes the process a user should follow to deploy his own experiment on CorteXlab testbed. Two typical scenarios involving several nodes are deployed in live. The first scenario is based on IEEE 802.15.4 communication between two picoSDR nodes. The second scenario is dealing with an avoiding-interference use case where the previous two picoSDRs are communicating while a cognitive MIMO-OFDM transceiver running on one picoSDR must avoid interference with them.
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titre: Realistic prediction of outage probability and confidence interval of BER for indoor radio communications
auteur: Meiling Luo, Guillaume Villemaud, Jean-Marie Gorce, Jie Zhang
article: EUCAP 2014, Apr 2014, The Hague, Netherlands. pp.2105 - 2109, ⟨10.1109/EuCAP.2014.6902223⟩
resume: Outage probability and Bit Error Rate (BER) are both important link quality parameters for wireless communica-tion systems. In this paper, the error in dB between the Multi-Resolution Frequency-Domain ParFlow (MR-FDPF) model and the channel measurement is first modeled to follow the normal distribution which is verified by performing the Lilliefors good-ness of fit test. Then a realistic BER map as well as its confidence interval can be predicted. In addition, the normally distributed error in dB can be regarded as a kind of lognormal shadowing introduced by the MR-FDPF model due to, for instance, the inaccurate scenario modeling. Then a realistic outage probability can be computed by taking into account both the large scale lognormal shadowing and the small scale Nakagami-m fading.
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titre: Study of a Wake Up Radio Architecture for Home Multimedia Networks
auteur: Aissa Khoumeri, Florin Doru Hutu, Guillaume Villemaud, Jean-Marie Gorce
article: ECUMICT 2014, Mar 2014, Gent, Belgium. pp.63-72, ⟨10.1007/978-3-319-05440-7_6⟩
resume: A theoretical study on the impact of using a wake-up radio architecture in terms of energy consumption is proposed. The main objective is to reduce the overall energy consumption of a home multimedia networks. The energy consumed by the proposed wake-up radio architecture is compared to a classical WiFi architecture, for an ad-hoc scenario. The sleep time has an important role to compare the dissipated energy. This study demonstrates that the longer the sleep time the better the energy saved is obtained by the wake-up architecture.
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titre: Enjeux et propositions sur les architectures RF pour l'homme connecté à la société numérique
auteur: Guillaume Villemaud, Florin Hutu, Tanguy Risset, Jean-Marie Gorce
article: Journées Scientifiques URSI 2014, Mar 2014, Paris, France
resume: Cet article présente une vue générale des enjeux du développement croissant de liaisons sans fil visant à permettre une interconnexion de plus en plus constante et transparente entre l'homme et le monde numérique. Ces enjeux se situent au niveau des architectures de terminaux hautes performances pour les applications classiques de l'Internet sans fil, mais également dans le domaine des réseaux de capteurs et des objets connectés. Au-delà, les contraintes de ces diverses applications poussent à développer des architectures à forte composante numérique de type radio logicielle. Dans chacune de ces catégories, des exemples d'approches proposées par l'équipe Inria Socrate sont présentées.
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titre: Analysis and Reduction of the Impact of Thermal Noise on the Full-Duplex OFDM Radio
auteur: Zhaowu Zhan, Guillaume Villemaud, Jean-Marie Gorce
article: IEEE Radio Wireless Symposium, Jan 2014, Newport Beach, United States
resume: Self-Interference has been significantly reduced by current cancelation methods for the practical design of Full- Duplex wireless. However, the residual self-interference is still much stronger than the thermal noise due to many factors, e.g. phase noise in local oscillator, I/Q imbalance, thermal noise and so on, limiting the self-interference cancelation. In this paper, the influence of the thermal noise on the active self-interference cancelation (ASIC) for wideband Full-Duplex OFDM wireless system is analytically studied and demonstrated. We propose a little modification to the structure of data packet of IEEE 802.11g to reduce the impact of the thermal noise on the active selfinterference cancelation (ASIC) for Full-Duplex OFDM wireless. The ADS-Matlab co-simulation results show that we can reduce the residual self-interference to only 1.5dB higher than the receiver thermal noise.
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titre: Full Duplex Prototype of OFDM on GNURadio and USRPs
auteur: Wei Zhou, Guillaume Villemaud, Tanguy Risset
article: IEEE Radio Wireless Symposium, Jan 2014, Newport Beach, United States
resume: Full-duplex is a technology in telecommunication domain that can perform transmitting and receiving at the same time and in the same frequency band. The major obstacle of full-duplex is the self-interference (SI). Some previous works have focused on the SI cancellation in radio frequency (RF), and generally on a narrowband signal model. We have implemented a full-duplex prototype with orthogonal frequency-division multiplexing (OFDM) technology on GNURadio and Universal Software Radio Peripherals (USRP). We focus on the baseband, namely the digital part of the SI cancellation. Our testbed can achieve a digital cancellation of 27dB. After the cancellation, the signal of interest can achieve a bit error rate (BER) in the scale of 105 at 4 meters, which is very close to the performance of half-duplex. This is, to our knowledge, the first full duplex implementation for OFDM technology.
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titre: Wake-up radio architecture for home wireless networks
auteur: Florin Hutu, Aissa Khoumeri, Guillaume Villemaud, Jean-Marie Gorce
article: IEEE Radio Wireless Symposium, Jan 2014, Newport Beach, United States
resume: In this paper it is presented and validated by simulation a wake-up radio receiver (WuRx), allowing to both addressing and wake-up a main radio, with best performance but more energy consuming. The main goal is to reduce the total energy consumption of a home multimedia network by switching off the data module of each equipment during the periods when it is not used. The wake-up receiver is designed to be able to detect a wake-up signal which has a frequency signature and so, it is avoided to activate all data interfaces but only the one of interest
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titre: SDR for SRD: ADC specifications for reconfigurable gateways in urban sensor networks
auteur: Mathieu Vallerian, Guillaume Villemaud, Benoit Miscopein, Tanguy Risset, Florin Hutu
article: IEEE Radio Wireless Symposium, Jan 2014, Newport Beach, United States
resume: Short Range Devices (SRD) are increasingly employed in urban sensor networks using different communication protocols. That becomes a key problem in the gateway design, since its cost and energy consumption increase with the number of implemented technologies. This cost and energy can be reduced by using a reconfigurable gateway to perform the biggest part of signal processing digitally, as it is done in Software-Defined Radio (SDR). As several received signals should be simultaneously digitized, Analog-to-Digital Converter (ADC) must be able to treat the whole frequency band used by SRD, with a high enough resolution to properly demodulate the signals. This paper describes what the ADC's constraints are and how to dimension an ADC in SDR for SRD. An example based on the SmartSantander deployment shows that an ADC resolution of 23 bits is required to properly demodulate the data.
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2013

titre: Design and Evaluation of a Wideband Full-Duplex OFDM System Based on AASIC
auteur: Zhaowu Zhan, Guillaume Villemaud, Jean-Marie Gorce
article: IEEE Personal Indoor and Mobile Radio Communications (PIMRC), 2013, Sep 2013, London, United Kingdom. pp.68 - 72, ⟨10.1109/PIMRC.2013.6666106⟩
resume: Existing methods of self-interference cancellation have greatly reduced the strong self-interference signal for the practical design of Full-Duplex (FuDu) wireless systems. However, current FuDu wireless is hard to be put into practice due to the reason that residual self-interference after interference cancellation is still much stronger than the thermal noise. In this paper, a wideband FuDu OFDM system with a single path self-interference channel is developed based on active analog self-interference cancellation (AASIC) at the RF component. Furthermore, a mathematical model of the wideband FuDu OFDM wireless system and the AASIC at the RF component are presented and elaborated. The performance of this FuDu system is evaluated by ADS-Matlab co-simulation based on the IEEE 802.11g system parameters. The comparison of the spectrum power of signals before and after the AASIC and the bite error rate (BER) performance of the FuDu OFDM wireless system show that the strong self-interference can be significantly reduced to almost noise level.
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titre: Proposition d'une architecture de réveil radio utilisée dans le contexte des réseaux multimédia domestiques
auteur: Aissa Khoumeri, Florin Hutu, Guillaume Villemaud, Jean-Marie Gorce
article: Journées Nationales Microondes, May 2013, Paris, France
resume: Ce papier propose une architecture de type " wake-up radio " permettant l'adressage et l'allumage d'un récepteur radio principal plus performant et plus énergivore. L'objectif est de réduire la consommation énergétique des équipements formant les réseaux multimédia domestiques par l'extinction de la partie radio durant les périodes où celle-ci n'est pas utilisée. En utilisant une empreinte fréquentielle pour différencier les équipements, il est évité de réveiller l'ensemble des interfaces radio mais uniquement celle d'intérêt.
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titre: Realistic Prediction of BER for Adaptive OFDM Systems
auteur: Meiling Luo, Guillaume Villemaud, Jean-Marie Gorce, Jie Zhang
article: Antennas and Propagation (EuCAP), 2013 7th European Conference on, Apr 2013, Gothenburg, Sweden
resume: Adaptive OFDM systems improve the spectral efficiency. In this paper, block adaptive modulation is implemented based on the realistic prediction of BER and fading parameters from the MR-FDPF model. The aggregate data rate from block adaptive modulation is compared to that from non-adaptive modulation, and at the end, the data rate gain is obtained.
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titre: Realistic Prediction of BER and AMC with MRC Diversity for Indoor Wireless Transmissions
auteur: Meiling Luo, Guillaume Villemaud, Jialai Weng, Jean-Marie Gorce, Jie Zhang
article: Wireless Communications and Networking Conference (WCNC), 2013 IEEE, Apr 2013, Shanghai, China. ⟨10.1109/WCNC.2013.6555227⟩
resume: Bit Error Rate (BER) is a key parameter used to evaluate the performance of radio communication systems. In this paper, a realistic BER of radio MRC diversity systems is predicted based on the Multi-Resolution Frequency Domain ParFlow (MRFDPF) model. The prediction takes into account the correlations among diversity branches and makes no assumptions of the correlation model. The predicted realistic BER for MRC diversity systems can be very useful to many wireless applications, such as, adaptive modulation and coding (AMC) scheme, or optimal power allocation.
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2012

titre: Realistic Prediction of Available Throughput of OFDM Small Cells
auteur: Guillaume Villemaud
article: 6th Small Cell and HetNetWorshop, Jun 2012, Londres, United Kingdom
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titre: CorteXlab: A Large Scale Testbed for Physical Layer in Cognitive Radio Networks
auteur: Leonardo S. Cardoso, Guillaume Villemaud, Tanguy Risset, Jean-Marie Gorce
article: IC1004 Scientific Meeting, May 2012, Lyon, France
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titre: Wake-up radio architectures used in wireless sensor networks
auteur: Aissa Khoumeri, Florin Hutu, Guillaume Villemaud, Jean-Marie Gorce
article: COST IC1004, May 2012, Lyon, France
resume: This paper treats the problem of the energy consumption in wireless sensor networks. In order to minimize the consumed power at the analog and RF part, an energy recovering system combined with a wake-up radio is proposed for discussion. The proposed architecture has thee activity levels : zero consumption, low and high energy consumption. In order to quantify the gain in terms of power consumption, a power consumption model state of the art is proposed.
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titre: Performance Evaluation of Multi-antenna and Multi-mode Relays Using a Network Simulator
auteur: Guillaume Villemaud, Cédric Lévy-Bencheton, Tanguy Risset
article: EUCAP 2012, Mar 2012, Prague, Czech Republic
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titre: On Predicting Large Scale Fading Characteristics with the MR-FDPF Method
auteur: Meiling Luo, Nikolai Lebedev, Guillaume Villemaud, Guillaume de La Roche, Jie Zhang, Jean-Marie Gorce
article: 6th European Conference on Antennas and Propagation (EECAP) 2012, Mar 2012, Prague, Czech Republic. 5 p
resume: The MR-FDPF (Multi-Resolution Frequency Domain Partial Flow) method is proven to be a fast and efficient method to simulate radio wave propagation. It is a deterministic model which can provide an accurate radio coverage prediction. In reality, radio channels have the nature of randomness due to e.g. moving people or air flow. Thus they can not be rigorously simulated by a pure deterministic model. However, it is believed that some statistics can be extracted from deterministic models and these statistics can be very useful to describe radio channels in reality. In this paper, large scale fading statistical characteristics are extracted based on the MR-FDPF method. They are validated by comparison to both the theoretical result and measurement. The match also demonstrates that MR-FDPF is capable of simulating large scale fading.
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titre: On Predicting Large Scale Fading Characteristics with a Finite Difference Method
auteur: Meiling Luo, Nikolai Lebedev, Guillaume Villemaud, Guillaume de La Roche, Jie Zhang, Jean-Marie Gorce
article: IC1004 Scientific Meeting, Feb 2012, Barcelona, Spain
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titre: Coverage Prediction for Heterogeneous Networks: From Macrocells to Femtocells
auteur: Guillaume Villemaud
article: Femtocell Winter School, Feb 2012, Barcelone, Spain
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2011

titre: Toward an energy reduction in mobile relays: combining MIMO and multi-mode
auteur: Cédric Lévy-Bencheton, Guillaume Villemaud, Tanguy Risset
article: IFIP Wireless Days 2011, Oct 2011, Niagara Falls, Canada
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titre: Simulation of Wide Band Multipath Fast Fading Based on Finite Difference Method
auteur: Meiling Luo, Guillaume de La Roche, Guillaume Villemaud, Jean-Marie Gorce, Dmitry Umansky, Jie Zhang
article: IEEE Vehicular Technology Conference 2001, Sep 2011, San Francisco, United States
resume: In this paper we propose to use finite difference propagation methods to evaluate the wide band properties of the fast fading. For this purpose we adapted the MR-FDPF propagation model to simulate large bandwidth by combining numerous narrow band simulations. The results are compared with a channel sounder measurement campaign covering a bandwidth of up to 70 MHz. It is verified that fading characteristics in wireless channels varies with frequency and the MR-FDPF method is capable for simulating this variation of fadings for wide band systems.
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titre: Comparison between Two Implementations of ParFlow for Simulating Femtocell Networks
auteur: Guillaume de La Roche, Jean-Frederic Wagen, Guillaume Villemaud, Jean-Marie Gorce, Jie Zhang
article: International Conference on Computer Communications and Networks 2011, Jul 2011, Maui, United States
resume: In the context of heterogeneous networks, femtocells are very promising. In order to properly simulate their behavior and their impact on the macrocell layer, it is necessary to be able to simulate the radio coverage of femtocells. Hence ParFlow is a possible deterministic model that can be used for such simulation. In this paper two implementations of ParFlow are presented: time domain and frequency domain. The performance are compared and the advantages/drawbacks of each model are investigated.
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titre: Estimating channel fading statistics based on radio wave propagation predicted with deterministic MRFDPF method
auteur: Meiling Luo, Dmitry Umansky, Guillaume Villemaud, Marc Lafort, Jean-Marie Gorce
article: European Conference on Antennas and Propagation 2011, Apr 2011, Roma, Italy
resume: The MR-FDPF (Multi-Resolution Frequency-Domain Partial Flow) method has proved to be an efficient tool for the indoor radio coverage prediction. In this paper, a new approach is proposed allowing extracting the fading statistics for indoor radio channels based on the electric field strength predicted with the MR-FDPF method. The performance of the proposed approach is verified both by simulations and measurements.
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titre: A new deterministic hybrid model for indoor-to-outdoor radio coverage prediction
auteur: Dmitry Umansky, Guillaume de La Roche, Zhihua Lai, Guillaume Villemaud, Jean-Marie Gorce, Jie Zhang
article: European Conference on Antennas and Propagation 2011, Apr 2011, Roma, Italy
resume: In this article, we propose a new hybrid modeling method for indoor-to-outdoor radio coverage prediction. The proposed method is a combination of a ray-optical channel modeling approach and the frequency domain ParFlow method. While the former is widely used for modeling outdoor propagation environments, the latter is computationally efficient and accurate for modeling indoor environments.
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titre: Antenna Height Compensation for an Indoor to Outdoor Channel model based on a 2D Finite Difference Model
auteur: Guillaume de La Roche, Dmitry Umansky, Zhihua Lai, Guillaume Villemaud, Jean-Marie Gorce, Jie Zhang
article: PIERS 2011, Mar 2011, Marrakesh, Morocco
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titre: Candidate architecture for MIMO LTE-Advanced receivers with multiple channels capabilities and reduced complexity and cost
auteur: Ioan Burciu, Mathieu Gautier, Guillaume Villemaud, Jacques Verdier
article: IEEE Radio and Wireless Symposium 2011, Jan 2011, Phoenix, United States
resume: In this paper, a candidate architecture for LTE-Advanced receiver is proposed. Based on the combination of MIMO techniques and flexible spectrum access, LTE-Advanced terminals will require the increasing of the analog front-end complexity. To reduce the complexity of the analog front-end, an innovative architecture based on the merge between the double IQ and the code multiplexing structures is proposed. Simulation and measurement results show that, in a Gaussian case, the bit error rate is similar when using the proposed architecture and the state of the art front-end stack-up structure. A complexity evaluation study reveals significantly reduced power consumption of the proposed single front-end architecture.
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titre: Multi-mode relay simulations: an energy evaluation on WSNet
auteur: Cédric Lévy-Bencheton, Doreid Ammar, Guillaume Villemaud, Tanguy Risset
article: IEEE Radio and Wireless Symposium (RWS), Jan 2011, Phoenix, United States
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2010

titre: Parflow: Comparison Between Two Implementation
auteur: Guillaume Villemaud, Jean-Frederic Wagen, Jean-Marie Gorce, Guillaume de La Roche
article: Second International Workshop on Femtocells, Jun 2010, Luoton, United Kingdom
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titre: On Simulating Propagation for OFDM/MIMO Systems with the MR-FDPF Model
auteur: Jean-Marie Gorce, Guillaume Villemaud, Paul Flipo
article: The 4th european conference on antennas and propagation (Eucap), Apr 2010, Barcelona, Spain
resume: Radio propagation tools are needed for wireless network optimization. The MR-FDPF approach earlier proposed uses a multi-resolution pre-processing in the frequency domain. However, the current challenge for radio propagation tools not relies on providing signal power levels but beyond on providing a realistic prediction of the system performance. A system level simulator should comply with OFDM and MIMO features. This paper investigates the appropriateness of the MR-FDPF approach for such task.
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titre: Combination of Geometric and Finite Difference Models for Radio Wave Propagation in Outdoor to Indoor Scenarios
auteur: Guillaume de La Roche, Paul Flipo, Zhihua Lai, Guillaume Villemaud, Jie Zhang, Jean-Marie Gorce
article: The 4th european conference on antennas and propagation (Eucap), Apr 2010, Barcelona, Spain
resume: In this paper, a new model used to compute the outdoor to indoor signal strength emitted by a base station is presented. This model is based on the combination of 2 existing models: IRLA (Intelligent Ray Launching), a 3D geometric-like model especially optimized for outdoor predictions, and MRFDPF (Multi Resolution Frequency Domain ParFlow), a 2D FDTD-like model initially implemented for indoor propagation. The combination of these models implies the conversion of the ray launching signals on the border of the buildings, into virtual source flows that will be used as an input for the indoor model. The performance of the new combined model is evaluated via measurements, and it appears to be an efficient solution for radio network planning, both in term of accuracy and computational cost.
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titre: Combined Model for Outdoor to Indoor Radio Propagation
auteur: Guillaume de La Roche, Paul Flipo, Zhihua Lai, Guillaume Villemaud, Jie Zhang, Jean-Marie Gorce
article: COST2100 Management Meeting, Feb 2010, Athens, Greece
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2009

titre: Analyse du PAPR pour un récepteur multi-antennes à multiplexage par code
auteur: Matthieu Gautier, Ioan Burciu, Guillaume Villemaud
article: GRETSI, Oct 2009, Dijon, France
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titre: Power Consumption Optimization in Multi-mode Mobile Relay
auteur: Cédric Lévy-Bencheton, Guillaume Villemaud
article: European Wireless Technology Conference 2009, Sep 2009, Rome, Italy
resume: Multi-mode is a common feature in current generation terminals, enabling the user to stay connected at any time. By selecting an appropriate standard, multi-mode can reduce terminal power consumption. Software Defined Radio is an enabler towards multi-mode for the next generation of terminals. In such a radio, communication modes are implemented by a general processor through digital functions, instead of dedicated chips. Providing access to users in bad conditions through relays, is another solution to reduce power consumption. We look at multi-mode relaying, where a mobile terminal, connected to an UMTS base station, acts as an 802.11g-relay for those users. In this paper, we evaluate the algorithmic complexity of 802.11g and UMTS to estimate the power consumption of a Software Defined Radio. We propose a multi-mode relay scheme using such terminals, with the purpose of minimizing the global power consumption. Finally, we enounce different rules to maximize the local and global power gain by implementing multi-mode relays.
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titre: Low Power Multistandard Simultaneous Reception Architecture
auteur: Ioan Burciu, Jacques Verdier, Guillaume Villemaud
article: European Wireless Technology Conference 2009, Sep 2009, Rome, Italy
resume: In this paper, we address the architecture of multistandard simultaneous reception receivers and we aim at improving both the complexity and the power consumption of the analog front-end. To this end we propose an architecture using the double orthogonal translation technique in order to multiplex two received signals. A study case concerning the simultaneous reception of 802.11g and UMTS signals is developed in this article.
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titre: Multiband Simultaneous Reception Front-End with Adaptive Mismatches Correction Algorithm
auteur: Ioan Burciu, Guillaume Villemaud, Jacques Verdier
article: IEEE Personal, Indoor and Mobile Radio Communications Symposium, Sep 2009, Tokyo, Japan
resume: This paper addresses the architecture of multistandard simultaneous reception receivers and aims at improving the performance-power-complexity trade-off of the front-end. To this end we propose a single front-end architecture offering lower complexity and therefore lower power consumption. In order to obtain the same performance as the state of the art receivers, a light weight adaptive method is designed and implemented. It uses a mix of two digital implemented algorithms dedicated to the correction of the frontend IQ mismatches. A study case concerning the simultaneous reception of 802.11g and UMTS signals is developed in this article.
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titre: Opportunistic relaying protocols for human monitoring in BANs
auteur: Jean-Marie Gorce, Claire Goursaud, Guillaume Villemaud, Raffaele d'Errico, Laurent Ouvry
article: IEEE PIRMC, Sep 2009, Tokyo, Japan
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titre: Global system approach to validate a wireless system even with a multi-antennas receiver structure
auteur: Jose-Cruz Nunez-Perez, Jacques Verdier, Guillaume Villemaud, Jean-Marie Gorce
article: Circuits and Systems, 2009. MWSCAS '09. 52nd IEEE International Midwest Symposium on, Aug 2009, Cancun, Mexico
resume: This article discusses key points to easily develop, simulate and validate a large scale platform to evaluate different possible combinations of promising techniques in the field of converged wireless systems. The idea is there to propose to merge a maximum of degrees of freedom to offer an agile enough receiver, by the addition of multi-antenna, multi-standard and multichannel principles. A general architecture is presented and major relevant points are described.
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titre: Symbol Error Outage for Spatial Multiplexing Systems in Rayleigh Fading Channel and Lognormal Shadowing
auteur: Philippe Mary, Mischa Dohler, Jean-Marie Gorce, Guillaume Villemaud
article: 10th IEEE International Workshop on on Signal Processing Advances in Wireless Communications, IEEE, Jun 2009, Perugia, Italy
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titre: Frontal d'un récepteur à diversité d'antenne
auteur: Matthieu Gautier, Ioan Burciu, Guillaume Villemaud
article: JNM, May 2009, Grenoble, France
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titre: Architecture de front-end multistandard à réception simultanée
auteur: Ioan Burciu, Guillaume Villemaud, Jacques Verdier
article: JNM, May 2009, Grenoble, France
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titre: Cooperation mechanisms in BANs
auteur: Jean-Marie Gorce, Claire Goursaud, Christophe Savigny, Guillaume Villemaud, Raffaele d'Errico, Francois Dehmas, Mickael Maman, Laurent Ouvry, Benoit Miscopein, Jean Schwoerer
article: COST 2100, 9th management meeting, COST 2100, May 2009, Valencia, Spain
resume: It is expected that Body Area Networks will be deployed in various applications to instrument and support humans in many aspects of their life. Different standards actually compete to fulfil the constraints associated with possible applications. Among all possible applications, we focus in this work on multi-nodes monitoring applications. The body is thus equipped with a set of sensors transmitting in real-time their measures to a common sink. The underlying network topology is thus classical in the field of wireless sensor networks (WSN) and referred to as the star topology. The classical super-frame structure as proposed in 802.15.3 seems to comply with the needs of such an application. However, the specificities of the BAN channel can reduce the performance of such protocol. Indeed, the channel time variations make the star structure unstable and subject to a high level of packet loss. We propose to investigate some cooperative mechanisms to address this problem and we evaluate their implementation in the superframe structure. The paper is organized as follows. The scenario, application constraints and super-frame structure are described in section I. Section II depicts the most important radio channel properties which impact this kind of scenario (time varying radio channel). Section III reviews some cooperative mechanisms and in section IV, these mechanisms are integrated in the super-frame structure. Section V, simulation results are provided.
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titre: Candidate Architecture for MIMO LTE-Advanced Receivers with Multiple Channels Capabilities and Reduced Complexity and Cost
auteur: Ioan Burciu, Guillaume Villemaud, Jacques Verdier
article: COST2100 Pervasive Mobile & Ambient Wireless Communications, May 2009, Valence, Spain
resume: In this paper, a candidate architecture for LTEAdvanced receiver is proposed. Based on the combination of MIMO techniques and flexible spectrum access, LTE-Advanced terminals will require an increasing complexity of the front-end part. To reduce the complexity of the analog front-end, an innovative architecture is introduced based on the merging between the double IQ and code multiplexing structure. Simulation results show that, in a Gaussian case, the bit error rate does not increase significantly when using this architecture. A complexity evaluation study reveals significantly reduced power consumption when implementing the proposed single front-end architecture.
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titre: A 802.11g and UMTS Simultaneous Reception Front-End Architecture using a double IQ structure
auteur: Ioan Burciu, Guillaume Villemaud, Jacques Verdier, Matthieu Gautier
article: IEEE VTC Spring 2009, Apr 2009, Barcelona, Spain
resume: In this paper, we address the architecture of multistandard simultaneous reception receivers and we aim to reduce the complexity of the analog front-end. To this end, we propose an architecture using the double orthogonal translation technique in order to multiplex two signals received on different frequency bands. A study case concerning the simultaneous reception of 802.11g and UMTS signals is developed in this paper. Theoretical and simulation results show that this type of multiplexing does not significantly influence the evolution of the signal to noise ratio of the signals.
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titre: IQ imbalance reduction in a SMI multi-antenna receiver by using a code multiplexing front-end
auteur: Matthieu Gautier, Pierre-Francois Morlat, Guillaume Villemaud
article: IEEE VTC Spring 2009, Apr 2009, Barcelona, Spain
resume: In this paper, we address the IQ imbalance sensibility of the code multiplexing front-end architecture. This innovative architecture has been recently proposed in order to reduce the analog complexity of an antenna diversity receiver front-end. An interesting characteristic of this structure is that the resulting IQ imbalance is equal for each received baseband signal. Associated with Single Matrix Inversion algorithm, this property ensures a high IQ imbalance robustness. A global antenna diversity system including analog front-end and digital processing has been implemented in order to perform simulation validation. Results show that the bit error rate does not increase significantly with the multiplexing and this increase is compensated for a high IQ imbalance.
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titre: Low complexity antenna diversity front-end: Use of code multiplexing
auteur: Matthieu Gautier, Guillaume Villemaud
article: IEEE Wireless Communications and Networking Conference, Apr 2009, Budapest, Hungary
resume: In this paper, we address the architecture of an antenna diversity receiver and we aim to reduce the complexity of the analog front-end. To this end, an innovative architecture is introduced based on code multiplexing. This architecture uses the direct sequence spread spectrum technique in order to multiplex the different antennas contributions through a single demodulator. Simulation and measurement results show that, in a Gaussian case, the bit error rate does not increase so much with the multiplexing. The complexity evaluation shows that the proposed architecture significantly reduces the power consumption of the front-end.
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titre: New antenna diversity front-end using code multiplexing
auteur: Matthieu Gautier, Ioan Burciu, Guillaume Villemaud
article: European Conference on Antennas and Propagation, Mar 2009, Berlin, Germany
resume: In this paper, we address the architecture of an antenna diversity receiver. An innovative architecture has been introduced based on code multiplexing, it significantly reduces the power consumption of the front-end. This architecture uses the direct sequence spread spectrum technique in order to multiplex the different antennas contributions through a single IQ demodulator. This paper address the performances of this kind of architecture. Simulation and measurement results show that, in a Gaussian case, the bit error rate does not increase significantly with the multiplexing. IQ imbalance study shows that the new architecture has the same sensitivity to IQ mismatches than the classical stack-up architecture.
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titre: Optimisation de la Consommation dans les Relais Mobiles Multi-modes
auteur: Cédric Lévy-Bencheton, Guillaume Villemaud
article: JDIR, Feb 2009, Belfort, France
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2008

titre: A Multistandard Simultaneous Reception Front-End Architecture
auteur: Ioan Burciu, Guillaume Villemaud, Jacques Verdier, Matthieu Gautier
article: COST2100 Pervasive Mobile & Ambient Wireless Communications, Oct 2008, Lille, France
resume: In this paper, we address the architecture of multistandard simultaneous reception receivers and we aim to reduce the complexity of the analog front-end. To this end we propose an architecture using the double orthogonal translation technique in order to multiplex two signals received on different frequency bands. A study case concerning the simultaneous reception of 802.11g and UMTS signals is developed in this article. Theoretical and simulation results show that this type of multiplexing does not significantly influence the evolution of the signal to noise ratio of the signals.
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titre: On relaxing constraints on multi-branch RF front-end for a SIMO OFDM receiver – A global system evaluation scheme
auteur: Pierre-Francois Morlat, Guillaume Villemaud, Jacques Verdier, Jean-Marie Gorce
article: COST2100 Pervasive Mobile & Ambient Wireless Communications, Oct 2008, Lille, France
resume: In this article, main of the presented results are obtained by taking into account most as possible realistic working condition by the use of a global system evaluation scheme based on Agilent Technologies equipments. As presented in previous works, realistic consideration of the characteristics of transmission channel, the antenna coupling and also the channel correlation would indeed allow a fast and effective design of multiantenna wireless systems in order to obtain an important design cycle reducing. The first part presents the used global system level approach and the associated tools with some theoretical, simulated and measured results in order to validate the developed testbed radio plateform. In the second part, the three presented RF impairments are considered one by one in a Zero-IF down conversion structure and their effect on OFDM transmission performances are detailed. In the last part, after a short description of the SIMO processing that is used, the natural compensation of each RF impairment it is possible to obtained taking advantage of space diversity is presented. Results given in this part are obtained by taking into account different measured propagation channels (AWGN or fading channels) and a complete 802.11g structure.
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titre: Structure and Implementation of a SIMO Multi-Standard Multichannel SDR Receiver
auteur: Pierre-Francois Morlat, Antonio Luna, Xavier Gallon, Guillaume Villemaud, Jean-Marie Gorce
article: IEEE Radio and Wireless Symposium, Jan 2008, Orlando, United States
resume: This article presents the structure of a multiantenna multi-channel and multi-standard receiver based on Software Defined Radio (SDR) concept. At this time our work is focused on 802.11g and 802.11b signals cohabiting in a 40 MHz frequency bandwidth around the 2.4 GHz RF carrier frequency. Using classical Single Input Multiple Output (SIMO) processing, these incoming signals are combined to increase transmission performances and to mitigate fading effect. Simulated and measured results of our structure are given and a description of the real proposed architecture is detailed.
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2007

titre: Measured Performances of a SIMO Multi-Standard Receiver
auteur: Pierre-Francois Morlat, Xavier Gallon, Guillaume Villemaud, Jean-Marie Gorce
article: European Conference on Antennas and Propagation, Nov 2007, Edinburgh, United Kingdom
resume: SIMO algorithms ensure important increasing of radio communications robustness, but their performances strongly depend on channel propagations conditions and antenna characteristics. This article presents performances of different SIMO treatments applied on WLAN (802.11b and 802.11g) transmissions in a multi-standard and multi-channel context. These performances are obtained by measure, under different propagation channels and for realistic working conditions.
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titre: Efficient Finite Difference Method for Simulating Radio Propagation in Dense Urban Environments
auteur: Guillaume de La Roche, Guillaume Villemaud, Jean-Marie Gorce
article: European Conference on Antennas and Propagation, Nov 2007, Edinburgh, United Kingdom
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titre: Wlan Preamble Detection Methods in a Multi-Antenna, Multi-Standards Software Defined Radio Architecture
auteur: Laurent Alaus, Guillaume Villemaud, Pierre-Francois Morlat, Jean-Marie Gorce
article: European Conference on Antennas and Propagation, Nov 2007, Edinburgh, United Kingdom
resume: This paper presents a comparison of different detection methods which could be used to sense a frequency band in order to select a particular channel and a particular communication standard in a wideband melted signal. Here we focus on a generic WLAN receiver based on SDR principles, capable of sampling several overlapping channels to demodulate simultaneously concurrent users possibly using different waveforms.
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titre: Estimation du taux de coupure d'une liaison radio MIMO dans un canal de Nakagami avec effet de masque
auteur: Philippe Mary, Mischa Dohler, Jean-Marie Gorce, Guillaume Villemaud, Marylin Arndt
article: 21ieme colloque GRETSI, Sep 2007, Troyes, France
resume: Dans cet article, nous nous intéressons au problème de la probabilité de coupure symbole (PCS) définie comme la probabilité d'observer une certaine probabilité d'erreur symbole (PES) dans un canal à évanouissement plat et en présence d'effet de masquage long terme (shadowing). Nous considérons un système multi-antennaire à l'émission et à la réception (MIMO) dans un environnement présentant simultanément des évanouissements rapides (canal de Nakagami), et un effet de masque long terme de type log-normal. Notre contribution consiste dans l'obtention d'une nouvelle approximation simple et très précise de la probabilité d'erreur d'un signal à modulation de phase à M états (MDP-M), qui facilite la dérivation de la PCS en présence d'effet de masquage log-normal.
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titre: On predicting fast fading strength from Indoor 802.11 simulations
auteur: Guillaume de La Roche, Xavier Gallon, Jean-Marie Gorce, Guillaume Villemaud
article: International Conference on Electromagnetics in Advanced Applications (ICEAA), Sep 2007, Torino, Italy. pp.407-410, ⟨10.1109/ICEAA.2007.4387324⟩
resume: In this article fast fading in indoor environments is predicted, using the MR-FDPF algorithm. MR-FDPF (frequency domain par flow) is a FDTD like method that can compute indoor radio coverage at a very precise resolution (a few centimeters). Using the simulated points in particular regions, it is possible to plot the distribution of the power signal, and to fit this distribution with Rice laws. In order to confirm our results, real radio measurements have also been done. In the considered environment, MR-FDPF has been proved to be efficient for the prediction of statistics of fading channels in indoor environment.
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titre: Caractérisation expérimentale du canal de propagation indoor à 2.45 GHz
auteur: Guillaume Villemaud, Gallon Xavier, Jean-Marie Gorce
article: JNM, May 2007, Toulouse, France
resume: Cet article présente une méthode pour caractériser le canal de propagation radio indoor à la fréquence de 2.45 GHz basée sur une approche temporelle ne nécessitant pas de synchronisation des parties émettrices et réceptrices. Outre le fait d'avoir une véritable approche temporelle moins répandue que les techniques de transformées classiques, l'originalité est aussi de fonder la chaîne de caractérisation sur le même matériel de test qui doit servir par la suite pour l'optimisation globale de chaînes de transmissions à forte composante radio logicielle. Après avoir introduit la méthode temporelle et son contexte, nous détaillons la structure du banc de test puis présentons quelques exemples de caractéristiques extraites à partir de cette méthode, sous forme de réponses impulsionnelles, de leur évolution temporelle et de l'étalement moyen. L'extension de cette plateforme à la caractérisation de systèmes MIMO 2x2 est également présentée.
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titre: Influence des limitations RF sur les performances d'un récepteur SIMO-OFDM pour systèmes WIFI 802.11g. Application à la conception globale de systèmes de radiocommunications multi-antennes et multi-normes
auteur: Jose-Cruz Nunez-Perez, Pierre-François Morlat, Jacques Verdier, Guillaume Villemaud, Christian Gontrand
article: JNM, May 2007, Toulouse, France
resume: Cet article traite de l'impact des imperfections radiofréquences (RF) sur les performances d'un récepteur SIMO-OFDM dans le cas de standard WIFI 802.11g. En particulier notre travail a porté sur l'influence du déséquilibre des voies I et Q en gain et en phase, le bruit de phase de l'oscillateur local ainsi que les non-linéarités de l'amplificateur de puissance utilisé au niveau de l'émetteur.
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titre: Validation par la mesure des performances d'algorithmes SIMO appliqués aux récepteurs multi-standards
auteur: Pierre-François Morlat, Xavier Gallon, Guillaume Villemaud, Jean-Marie Gorce
article: JNM, May 2007, Toulouse, France
resume: Les traitements d'antennes SIMO consistant à utiliser plusieurs antennes réceptrices au lieu d'une seule et d'utiliser différents algorithmes pour recombiner de manière optimale les différentes versions du signal émis sont utilisés depuis de nombreuses années dans le domaine des communications radio. Mais un même algorithme SIMO n'est pas forcement aussi optimal pour deux standards de communications ou pour deux environnements de fonctionnement distincts en termes de complexité et de performances. Dans l'optique de développement de terminaux à SDR (Software Defined Radio), nous présentons ici une comparaison des performances de traitements SIMO classiques appliqués aux transmissions 802.11g et 802.11b dans différents environnements de propagation en simulation et en mesure.
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titre: Reduced Complexity MUD-MLSE Receiver for Partially-Overlapping WLAN-Like Interference
auteur: Philippe Mary, Jean-Marie Gorce, Guillaume Villemaud, Mischa Dohler, Marylin Arndt
article: IEEE VTC Spring 2007, Apr 2007, Dublin, Ireland
resume: The roll-out density of wireless local area networks (WLANs) has recently witnessed a dramatic increase and is currently reaching saturation levels. The frequency bands designated to WLANs do thus not suffice anymore to provide nonoverlapping, and hence interference-free, communication bands. A large body of research has been dedicated to a wide variety of optimum maximum likelihood sequence estimation (MLSE) and sub-optimum in-band interference mitigation techniques. Our contribution lies in a reduction of the state-space of a MLSE detector in the case of a desired WLAN receiver experiencing delayed interference from some other transmitters operating in partially overlapping spectral bands and over independent frequency-selecting block-fading channels. Based on the formulation of the optimum receiver, we derive a sub-optimum receiver of reduced complexity and demonstrate its satisfactory performance in the context of strong interference.
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titre: Performance Analysis of Mitigated Asynchronous Spectrally-Overlapping WLAN Interference
auteur: Philippe Mary, Jean-Marie Gorce, Guillaume Villemaud, Mischa Dohler, Marylin Arndt
article: IEEE Wireless Communications and Networking Conference (WCNC), IEEE, Mar 2007, Kowloon, South Korea. pp.2097-2102, ⟨10.1109/WCNC.2007.393⟩
resume: The deployment of wireless local area networks (WLANs) has recently gained in popularity with roll-out densities often reaching saturation levels. The frequency bands designated to WLANs do thus not suffice anymore to provide non-overlapping, and hence interference-free, communication. Prior research has therefore been dedicated to a wide variety of mainly cochannel interference mitigation techniques. Our contribution lies in the performance analysis of the more realistic case of spatially close WLAN systems interfering asynchronously in DSSS mode and on adjacent channels. The authors expose the performance of optimum and sub-optimum multiuser detection maximum likelihood sequence estimators (MUD-MLSEs) under varying conditions, e.g. level of interference, degree of spectral overlap, etc. This facilitates a better understanding and design of future interference-limited WLAN systems. The performance results are also important to spectrum policy makers, allowing to knowledgeably estimate the degree of tolerated interference in license exempt bands.
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2006

titre: Impact of RF Front-end non-idealities on performances of SIMO-OFDM receiver
auteur: Xin Xu, Abhimanyu Sahai, Pierre-Francois Morlat, Jacques Verdier, Guillaume Villemaud, Jean-Marie Gorce
article: European Conference on Antennas and Propagation, Nov 2006, Nice, France
resume: This article presents a performance comparison of a single antenna OFDM receiver and a SIMO structure using zero-IF front end topology. The performances evaluation was made in most as possible realistic working conditions. That is why numerical processing is applied on recorded signals, ensuring to take into account antenna coupling, channel correlation and also realistic propagation channel characteristics. Simulated results are also detailed. I/Q imbalance, oscillator phase noise and power amplifier non-linearity are the studied RF impairments.
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titre: Performance validation of a multi-standard and multi-antenna receiver
auteur: Pierre-François Morlat, Philippe Mary, Guillaume Villemaud, Jean-Marie Gorce, Marylin Arndt
article: First European Conference on Antennas and Propagation (EuCAP), Nov 2006, Nice, France. ⟨10.1109/EUCAP.2006.4584970⟩
resume: This paper assesses the efficiency of a multi standard and multi antenna receiver using simulation and test measurements in a real propagation environment. A multi-standard and multi-antenna receiver is firstly designed with the ADSÂ© software. Secondly, the performance of this system is evaluated with several multi-antenna algorithms, under real radio propagation conditions depending on the standard we choose to deal with. At this time the receiver can run with 802.11b and 802.11g standards in a 36 MHz bandwidth. Some first results are presented using multi antenna algorithm in a receiver dealing with two 802.11g or 802.11b transmission on overlapped communication channels.
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titre: Modern approach to drive RF design and verify system performance
auteur: Jacques Verdier, Jose-Cruz Nunez-Perez, Abhimanyu Sahai, Pierre-Francois Morlat, Guillaume Villemaud
article: SAME 2006, Oct 2006, Nice, France
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titre: On the Compensation of RF Impairments with Multiple Antennas in SIMO OFDM systems
auteur: Pierre-François Morlat, Jose-Cruz Nunez-Perez, Guillaume Villemaud, Jacques Verdier, Jean-Marie Gorce
article: VTC Fall, IEEE, Sep 2006, Montréal, Canada. ⟨10.1109/VTCF.2006.109⟩
resume: This paper provides an analysis of the impact of radio frequency (RF) front end impairments (I/Q gain and phase imbalance, phase noise, non-linear distortion and direct current offset) on the performance of a single input multiple output orthogonal frequency division multiplexing (SIMO OFDM) receiver. We developed a new estimation/compensation scheme to jointly compensate for the effect of multipath and RF nonidealities on baseband signals in the special case of Zero-IF receivers. Some first results illustrating this approach are presented for a 4 antenna 802.11g receiver with the SMI algorithm and with or without IQ imbalance, as well as BER curves for different phase noise models.
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titre: Global System Evaluation Scheme for Multiple Antennas Adaptive Receivers
auteur: Pierre-Francois Morlat, Herve Parvery, Guillaume Villemaud, Jacques Verdier, Jean-Marie Gorce, X. Xin
article: The 9th European Conference on Wireless Technology (EWCT), IEEE, Sep 2006, Manchester, United Kingdom. pp.197-200, ⟨10.1109/ECWT.2006.280469⟩
resume: This paper describes a global system approach to easily develop, simulate and validate a multi-antennas receiver structure. Our aim is to offer a rapid evaluation for future wireless systems, including promising techniques such as SIMO or MIMO, Software Defined Radio (SDR), OFDM and Interference Cancellation. A particular focus is on the impact of RF front-ends characteristics on the effective performances of a receiver in a realistic environment. A complete connected solution based on Agilent Technologies tools is presented, combining simulations and measurements with realistic conditions. This testbed allows a direct evaluation of all parts of a wireless link with multiple antennas. For instance IQ imbalance and phase noise influence on a four antennas 802.11g receiver is herein exposed.
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titre: 2.5D Extensions of the Frequency Domain ParFlow Algorithm for Simulating 802.11b/g Radio Coverage in Multifloored Buildings
auteur: Guillaume de La Roche, Xavier Gallon, Jean-Marie Gorce, Guillaume Villemaud
article: IEEE 64th Vehicular Technology Conference (VTC), IEEE, Sep 2006, Montreal, Canada. ⟨10.1109/VTCF.2006.25⟩
resume: We have recently proposed an original 2D multi-resolution algorithm for solving a TLM-like formulation of the Indoor propagation problem. This approach is referred to as MR-FDPF (multi-resolution frequency domain parflow). In this paper, a fast and simple extension for predicting radio coverage in multifloored building is proposed. Because a full 3D is time consuming, three 2.5D schemes are investigated and compared. The accuracy of MR-FDPF is firstly assessed in a single floor configuration. Results exhibit a RMSE of about 3.5 dB, after an automatic calibration. Then 2.5D extensions are evaluated on a multifloored building. The more sophisticated one yields a RMSE of about 4.4 dB for the inter-level prediction. The potential of this approach and the obvious limitations when compared to a true 3D approach are discussed.
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titre: Accuracy Enhancement of a Multi-Resolution Indoor Propagation Simulation Tool by Radiation Pattern Synthesis
auteur: Guillaume Villemaud, Guillaume de La Roche, Jean-Marie Gorce
article: IEEE Antennas and Propagation Society International Symposium, IEEE, Jul 2006, Albuquerque, United States. ⟨10.1109/APS.2006.1711012⟩
resume: This paper presents an innovative approach that offers both a precise modeling of the propagation environment and a reduced computational load taking advantage of a multi-resolution algorithm. In this approach, radiating sources are simulated as point sources and are thus obviously omnidirectional leading to an important limit of the method. This paper tackles this problem by introducing multi-point sources. A regularized radiation pattern synthesis is then proposed for modeling particular radiation patterns. This approach enhances the accuracy of the predictions while preserving fast calculation times
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2005

titre: Antennes pour les réseaux de capteurs : contraintes d'intégration et potentiels des techniques multi-antennes
auteur: Guillaume Villemaud
article: Workshop RECAP, Nov 2005, Nice, France
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Book sections

2013

titre: Radio Propagation Modeling
auteur: Zhihua Lai, Guillaume Villemaud, Meiling Luo, Jie Zhang
article: Chu, Xiaoli and Lopez Perez, David and Yang, Yang and Gunnarsson, Fredrik. Heterogeneous Cellular Networks: Theory, Simulation and Deployment, Cambridge, 2013
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2012

titre: MIMO and Next Generation Systems
auteur: Alister Burr, Ioan Burciu, P. Chambers, T. Javornik, K. Kansanen, J. Olmos, C. Pietsch, J. Sykora, W. Teich, Guillaume Villemaud
article: Springer. Signals and Communication Technology, Springer, pp.301-339, 2012, Pervasive Mobile and Ambient Wireless Communications, ⟨10.1007/978-1-4471-2315-6_7⟩
resume: For the past decade or more MIMO systems have been the subject of very intensive research. For example, it was one of the most important topics in the previous COST Wireless Action, COST 231. However in the past few years, in the time-frame of COST 2100 these techniques have begun to be implemented in practice. In particular they have appeared in the standards for next generation systems such as LTE, 3GPP-LTE Advanced (LTE-Adv) and WiMAX, as well as the latest versions of WiFi. This chapter brings together the MIMO systems used in next generation systems with other work on the implementation and simulation of these systems. It also describes advances in MIMO techniques in a number of areas. The first section is divided into two sub-sections dealing first with simulators and testbeds which are used in system-level simulators to evaluate overall system capacity, as discussed in later chapters of this book. Secondly the development of terminals for next generation MIMO systems is considered, especially considering the additional RF hardware required for MIMO. Section 7.2 then discusses especially precoding techniques used in many of the recent standards to implement MIMO. In particular precoding allows the implementation of closed loop or adaptive MIMO. In next generation systems there is also much increased attention on MU-MIMO and on multi-terminal MIMO in general, including so-called “network MIMO” approaches, which appear in LTE as Coordinated Multiple Point (CoMP): this is covered in Sect. 7.3. Various advanced MIMO transmission and detection approaches are covered in Sects. 7.4 to 7.6, including some interesting work on MIMO techniques involving Continuous Phase Modulation (CPM), giving advantages in terms of Peak-to-Average Power Ratio (PAPR).
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2011

titre: Front-end Architectures and Impairment corrections in multimode and multi-antenna systems
auteur: Guillaume Villemaud, Jacques Verdier, Matthieu Gautier, Ioan Burciu, Pierre-Francois Morlat
article: Fa-Long Luo. Digital Front-End in Wireless Communications and Broadcasting: Circuits and Signal Processing, Cambridge University Press, 2011
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titre: Cross-layer design and digital front-end for cognitive wireless link
auteur: Matthieu Gautier, Guillaume Villemaud, Cédric Lévy-Bencheton, Dominique Noguet, Tanguy Risset
article: Fa-Luong. Digital Front-End in Wireless Communication and Broadcasting, Cambridge university press, 2011
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titre: Miniature Antennas
auteur: Guillaume Villemaud
article: Jean-Marc Laheurte. Compact Antennas for Wireless Communications and Terminals, Wiley, 2011
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titre: Antennes Miniatures
auteur: Guillaume Villemaud
article: Jean-Marc Laheurte. Petites Antennes - Communications sans fil et terminaux, Hermès, 2011
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2009

titre: Couche physique et antennes
auteur: Jean-Marie Gorce, Guillaume Villemaud, Philippe Mary
article: Hermès - Lavoisier. Réseaux de capteurs, héorie et modélisation, Eyrolles, 2009, Architecture, applications
resume: Modélisation du canal radio * Interface radio * Interférences et partage des ressources
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Habilitation à diriger des recherches

2013

titre: Les communications multi-* : contribution au développement d'architectures radio flexibles pour les réseaux sans fil hétérogènes
auteur: Guillaume Villemaud
article: Electronique. INSA de Lyon, 2013
resume: Il est devenu depuis des années évident, même pour le simple amateur de nouvelles technologies, que le nombre des systèmes utilisant une connexion sans fil ne fait qu'augmenter. Les usages liés au nomadisme ou même simplement à la disparition de câbles jugés encombrants ou inesthétiques poussent à développer encore et toujours de nouvelles interfaces radio adaptées aux contraintes amenées par lesdits usages. Dès lors, à partir du moment où l'on souhaite développer des équipements compatibles avec plusieurs de ces usages (deux exemples faciles étant les téléphones portables et les tablettes tactiles), cela sous-entend qu'il faut être capable d'intégrer dans ces mêmes dispositifs un nombre d'interfaces radio de plus en plus important. Dès lors, le fil-rouge qui sous-tend cet ouvrage est le concept général de systèmes multi-*. Ce paradigme couvre l'étendue des systèmes radios qui offrent de multiples degrés de liberté : multi-standard, multi-fréquence, multi-canal, multi-antenne, etc... Partir d'emblée du postulat qu'une architecture va dès sa conception intégrer plusieurs interfaces permet alors d'avoir une optimisation différente de l'ensemble du système.
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Books

2014

titre: Les communications multi-*
auteur: Guillaume Villemaud
article: Presses académiques francophones, 2014, 978-3-8381-7436-5
resume: Il est devenu depuis des années évident, même pour le simple amateur de nouvelles technologies, que le nombre des systèmes utilisant une connexion sans fil ne fait qu’augmenter. Les usages liés au nomadisme ou même simplement à la disparition de câbles jugés encombrants ou inesthétiques poussent à développer encore et toujours de nouvelles interfaces radio adaptées aux contraintes amenées par lesdits usages. Dès lors, à partir du moment où l’on souhaite développer des équipements compatibles avec plusieurs de ces usages (deux exemples faciles étant les téléphones portables et les tablettes tactiles), cela sous-entend qu’il faut être capable d’intégrer dans ces mêmes dispositifs un nombre d’interfaces radio de plus en plus important. Dès lors, le fil-rouge qui sous-tend cet ouvrage est le concept général de systèmes multi-*. Ce paradigme couvre l’étendue des systèmes radios qui offrent de multiples degrés de liberté : multi-standard, multi-fréquence, multi-canal, multi-antenne, etc… Partir d’emblée du postulat qu’une architecture va dès sa conception intégrer plusieurs interfaces permet alors d’avoir une optimisation différente de l’ensemble du système.
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Patents

2019

titre: Installation de ventilation et procédé comprenant la transmission d'informations par propagation des ondes dans le réseau de conduites de ventilation
auteur: Guillaume Villemaud, Florin Doru Hutu, Laurent Demia, Hector Bravo
article: France, N° de brevet: F1758247. 2019
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2009

titre: METHOD FOR PROCESSING TWO SIGNALS RECEIVED BY A SINGLE TERMINAL
auteur: Ioan Burciu, Matthieu Gautier, Guillaume Villemaud, Jacques Verdier
article: France, N° de brevet: WO/2010/031944. 2009
resume: L'invention concerne un procédé de traitement de deux signaux initiaux reçus par un même terminal comportant : une première translation en fréquence de chacun des signaux initiaux pour l'obtention de quatre signaux intermédiaires, deux signaux en phase et deux signaux en quadrature, centrés autour d'une même fréquence intermédiaire, une sommation respectivement des deux signaux en phase et des deux signaux en quadrature obtenus à l'issue de la première translation en fréquence, les spectres de fréquences des deux signaux issus de la sommation étant superposés, une deuxième translation en fréquence des deux signaux issus de la sommation pour l'obtention de quatre signaux en bande de base.
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2008

titre: Semi space/space omnidirectional resonant antenna having single electrical radiating conductor having three strips three different orientations formed producing omnidirectional radiation
auteur: Bernard Jecko, François Torres, Guillaume Villemaud
article: Japan, Patent n° : JP2008029037 (A). 2008
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Reports

2020

titre: Smart Anything - Comment alimenter des milliards d'objets connectés ?
auteur: Guillaume Villemaud, Bogdan Stefanescu
article: [Rapport Technique] INSA LYON; SPIE ICS. 2020
resume: Il est devenu évident depuis des années, même pour le simple amateur de nouvelles technologies, que le nombre des systèmes utilisant une connexion sans fil ne fait qu’augmenter. Les usages liés au nomadisme ou même simplement à la disparition de câbles jugés encombrants ou inesthétiques poussent à développer encore et toujours de nouvelles interfaces radio adaptées aux contraintes amenées par lesdits usages. Mais au-delà même des usages classiques de la connexion de l’humain au monde numérique, l’explosion de l’internet des objets (plus souvent dénommé IoT, de l’anglais Internet of Things) voit une explosion du nombre d’équipements connectés, équipements ayant des caractéristiques de taille, coût, débit, cycle et autonomie extrêmement variées. Cette tendance se trouve d’ailleurs parfaitement illustrée au travers de l’initiative européenne Smart Everything Anywhere qui démontre cette volonté d’offrir une connectivité dans tous les domaines. La multitude et la diversité des objets connectés remettent en cause les méthodes classiques d’échange d’informations entre les nœuds. Le réseau devra composer avec un environnement changeant qui n’est pas maîtrisé en profondeur. L’interconnexion des objets connectés entraine des changements technologiques radicaux qui métamorphosent le cadre existant. Que ce soit dans le domaine grand public, dans le domaine médical, pour l’industrie 4.0, les bâtiments intelligents ou même les villes intelligentes, tous ces équipements ont au moins en commun une chose essentielle : pour communiquer, ils ont besoin d’énergie. Un enjeu majeur du Smart Anything sera donc de garantir l’alimentation énergétique de ces milliards d’objets connectés, tout en en minimisant l’impact économique et écologique. Il est dès lors indispensable de dimensionner au mieux le système global en fonction des besoins essentiels de l’application. Les métriques classiques de performance (débit, latence, portée, QoS...) doivent être pondérées par de nouveaux critères : coût énergétique de l’information, autonomie, type d’alimentation ou même possibilité de maintenance du système et analyse du cycle de vie.
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2018

titre: COST Action CA15104 Experimental Facilities Report
auteur: Sławomir J Ambroziak, K Bregar, K Cwalina, M Deruyck, Céline Fortuna, G Gardašević, U Gregorc, A Hrovat, T. Javornik, F. Kaltenberger, M Mohorčič, I Ozimek, P Rajchowski, M T Sandikkaya, M Smolnikar, T Šolc, Erik Ström, Guillaume Villemaud, M Vučnik, Chiara Buratti
article: [Research Report] COST IRACON. 2018
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2015

titre: A study of companding approaches to alleviate the ADC constraints when demodulating multiple signals
auteur: Mathieu Vallérian, Florin Hutu, Guillaume Villemaud, Benoît Miscopein, Tanguy Risset
article: [Research Report] RR-8683, Inria - Research Centre Grenoble – Rhône-Alpes; INRIA. 2015, pp.21
resume: In urban sensor networks, the diversity of propagation conditions can lead to the simultaneous reception of signals having very different power levels. Given the diversity of wireless technologies used in this area, implementing gateways using a Software-Defined Radio (SDR) approach seems to be a very practical solution. Overcoming the high dynamic range may however require an Analog-to-Digital Converter (ADC) with a resolution fine enough to digitize the weakest signal with a satisfying precision. In order to relax these specifications, an analog processing, such as companding, should be performed before digitization. The companding technique is usually employed on one signal (and not on multiple signals that are only separated on the frequency domain). This report studies three companding laws to test their efficiency in relaxing the digitization constraints with multiple signals. A µ-law, a Piecewise-Linear (PL) law and a Piecewise-Linear, Constant Gain with Offsets (PLCGO) law are tested. It is described how to use a PLCGO approach to reduce ADC's complexity, and two implementations of the compressing law are proposed.
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2014

titre: Full-Duplex Dual-Band Radio Dedicated to Flexible Radio Communications
auteur: Zhaowu Zhan, Guillaume Villemaud, Florin Hutu, Jean-Marie Gorce
article: [Research Report] RR-8558, INRIA. 2014
resume: This report presents the design of Full-Duplex Dual-Band radio which allows simultaneous transmission and reception in two separate spectrum fragments by combining the Full-Duplex radios and Dual-Band RF front-end. Our design employs two antennas, each one being used for simultaneous transmitting and receiving. To overcome the self-interference (SI) induced by the Full-Duplex radios, simple band pass lters (BPF) are utilized to suppress the inner SI and active analog self-interference cancellation (AASIC) method is used to cancel the inter SI. The two radio frequency (RF) signals corrupted individually by the residual SI are down-converted by the double I/Q structure. Then, the two output baseband signals are processed by the corresponding base-band receivers. We theoretically analyze and evaluate by simulation this Full-Duplex Dual-Band radio operating on the standard WiFi OFDM PHY in two separate spectrum fragments.
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2012

titre: Récepteur multi-antennes multi-modes à radio logicielle
auteur: Pierre-François Morlat, Guillaume Villemaud, Philippe Mary
article: 2012
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2011

titre: Computationally Efficient MR-FDPF Method for Multifrequency Simulations
auteur: Dmitry Umansky, Jean-Marie Gorce, Meiling Luo, Guillaume de La Roche, Guillaume Villemaud
article: [Research Report] RR-7726, INRIA. 2011
resume: In this report, we propose a modification of the multi-resolution frequency domain ParFlow (MR-FDPF) method that allows simulating radio propagation channels in a frequency range. The performance of the proposed MR-FDPF implementation has been analyzed based on different realistic propagation scenarios.
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2010

titre: Multi-mode relaying for energy consumption reduction
auteur: Cédric Lévy-Bencheton, Doreid Ammar, Guillaume Villemaud, Tanguy Risset, Clément Reboul
article: [Research Report] RR-7245, INRIA. 2010, pp.31
resume: Today mobile terminals offer today the possibility of switching between different physical layers of radio protocols. With a generalization of Software Defined Radio, this multi-mode property improves the connectivity but has an important cost in terms of energy consumption. In this paper, we study the possibility of reducing energy consumption by using a relay on possibly different communication modes. We show that a multi-mode relay, compared to simple (mono-mode) relay, has an impact on energy consumption. We propose an analytical study of energy consumption in multi-mode terminals. Then, we will compare the network energy consumption following two scenarios: in the first one, a mobile terminal relays other users, in the second one terminals connect directly to an Access Point. We evaluate the consumption of the terminals in an 802.11g-to-UMTS and an 802.15.4-to-802.11g relay scheme. We isolate rules to minimize the network global energy consumption through multi-mode relaying. We show that the most intuitive solution is not always the best one and that a very precise simulation is necessary to make good choices at run time.
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