Next seminars:

Past seminars:

PhD defense: Energy Management and Protocol Design for Heterogeneous IoT Networks Leveraging Wake-Up Radio

Friday 26th November 2021 – 10h00 – ENSSAT Lannion room 020G

Nour El Hoda Djidi – IRISA Granit team

Abstract:The Wake-up Radios (WuRs) are a new promising solution allowing asynchronous communications with  ultra low power consumption and low latency. WuR is however a matter of tradeoffs since to reduce as much energy consumption comes at the cost of low sensitivity and thus short range communications.   In this thesis, we propose to enhance the performances of the WuR by using an adequate channel coding. This channel coding is called minimum energy coding and allows to increase the sensitivity. We also propose an improved version of minimum energy coding for additional reduction in both energy consumption and latency. Improving the performance of only the device is not always  sufficient. As several devices are deployed in a network to form a wireless sensor network, it is important to pay attention to the design of the MAC protocol in order to obtain additional gains in range and energy consumption. We propose in this thesis a novel MAC protocol that allows long range communications while being energy efficient by combining WuR and LoRa. Another technique allowing to increase the range has been proposed by integrating the WuRs in a multi-hop network. Finally, devices resilience is limited when the devices are battery powered.  Energy harvesting, that converts energy from environmental sources, is a viable alternative to ensure sustainable operation and improve the quality of service of the network. We propose in this thesis an energy manager adapted to the heterogeneous architecture that combines WuR and LoRa.

PhD defense: Conception d’algorithmes temps-réel pour transpondeurs optiques élastiques à très haut débit.

Monday 21st June 2021 – 09h00 – ENSSAT Lannion room 020G

Marwa Kazdoghli lagha – IRISA Granit team

Abstract: This thesis deals with digital signal processing techniques used in the coherent optical communication systems for high speed and flexible optical transmissions. Three different algorithms have been proposed. The“joint” algorithm performs the polarization demultiplexing and IQ imbalance compensation. Two other carrier phase noise recovery algorithms called “ MDD-CPR ” and “ R-BPS ” were introduced. “joint” approach performs well in the flexible context. Its robustness to other distortions (polarization dependent losses, dynamic multiplexing) has been demonstrated with less complexity compared to classic “CMA + BASS” approach and it was validated experimentally on real data. On the other hand, “MDD-CPR” is a modified version of the classic decision-directed algorithm whose performance in simulation and with real signals has been tested. Advantageous characteristics of its S-curve compared to the conventional approach and its robustness against phase noise underline its interest. “R-BPS” al-lows laser phase noise recovery with a minimum number of test phases. Numerical and experimental parallel processing have demonstrated its ability to operate better than “ BPS ” with lower overall complexity.

Julia: A fresh high performance approach for scientific computing

Tuesday, May 28th 2019 – 10h00 – ENSSAT Lannion room 309N
Raphael Bacher / Robin Gerzaguet – Gipsa-lab / IRISA Equipe Granit

Abstractfrench only

Soutenance d’HDR : Adaptive algorithms and architectures for energy-efficient wireless systems

Friday, May 10th mai 2019 – 10h30 – ENSSAT Lannion room 020G
Matthieu Gautier – IRISA Equipe Granit

Abstractfrench only


PhD defense: Energy Harvesting Wireless Sensor Networks Leveraging Wake-up Receivers: Energy Managers and MAC Protocols

Thursday, September 28th 2017 – 10h30 – ENSSAT Lannion room 020G

Fayçal Ait Aoudia – IRISA Granit team

Abstract: Wireless Sensor Networks (WSNs) are made of multiple sensor devices which measure physical value (e.g. temperature, pressure…) and communicate wirelessly. These networks form a key enabling technology of many Internet of Things (IoT) applications such as smart building and precision farming. The bottleneck of long-term WSN applications is typically the energy. Indeed, traditional WSNs are powered by individual batteries and a significant effort was devoted to maximizing the lifetime of these devices. However, as the batteries can only store a finite amount of energy, the network is still doomed to die, and changing the batteries is not always possible if the network is dense or if the nodes are deployed in a harsh environment.
A promising solution is to enable each node to harvest energy directly in its environment, using individual energy harvesters. As most of the energy sources are dynamic and uncontrolled, avoiding power failures of the nodes is critical to enable reliable networks. Increasing the quality of service typically requires increasing the power consumption, and a simple solution is to set the quality of service of the nodes to a constant value low enough to avoid power failures. However, this solution does not fully exploits the available energy and therefore leads to high energy waste and poor quality of service regarding the available environmental energy.
A more efficient solution is online adaptation of the node power consumption, which is performed by an energy manager on each node. In this thesis, two new approaches for online adaptation of the nodes energy consumption were proposed, relying on fuzzy control theory and reinforcement learning. Moreover, as communications are typically the most energy consuming task of a WSN node, emerging wake-up receivers were leveraged to reduce the energy cost of communications. A generic analytical framework for evaluating Medium Access Control (MAC) protocols was proposed, and it was combined to experiments to evaluate emerging wake-up receivers. A new opportunistic MAC protocol was also introduced for “on-the-fly” relay selection. Finally wake-up receivers and energy harvesting were combined and experimentally evaluated in a practical use case.

Interference cancellation in future full-duplex communication systems

Tuesday, May 9th 2017 – 16h30 – ENSSAT Lannion 309N room

Ahmed Masmoudi – McGill University, Canada

Abstractfrench only

Flexible OFDM transmission for heterogeneous System-on-Chips

Wedneday, April 26th 2017 – 14h – ENSSAT Lannion 309N room

Pascal Cotret – Supelec, IETR Scee team

Abstract: The platform presented in this work emphasizes the use of software/hardware heterogeneous devices for flexible multi-RAT architectures. Hardware improvements are mainly focused on Dynamic Partial Reconfiguration (DPR) and especially reconfiguration speed. Management of the reconfiguration process is based on a Hierarchical and Distributed Cognitive Radio Architecture Management (HDCRAM). Some scenarios based on network centralized orders or power consumption decentralized orders will be explained. The demonstration is a baseband OFDM transceiver with some emulated white Gaussian noise channel. It functionally consists of three parts: a transmitter, a receiver, and an additive white Gaussian noise (AWGN) channel. The transmitter has two blocks: Mapping and Inverse Fast Fourier Transform (IFFT), and the receiver has also two corresponding blocks: Fast Fourier Transform (FFT) and Demapping. On the hardware point of view, the demonstration is implemented on a laptop and a Zynq platform (device including a hardcore processor and a FPGA).

Signal processing methods for RF impairment compensation and  software radio application

Friday, March 23th 2017 – 11h – ENSSAT Lannion 309N room

Robin Gerzaguet – CEA-LETI

Abstractfrench only

Mid-term Evaluation: Power Manager Design and Implementation for Wake-Up Radio WSN Nodes

Friday, September 30th 2016 – 14h – ENSSAT Lannion 309N room

Faycal Ait Aoudia – IRISA Granit

Abstract: french only

Mid-term Evaluation: Architectural exploration of a flexible and low power radio for communications with drones

Monday, June 27th 2016 – 14h – IRISA Rennes, Brehat room & ENSSAT Lannion 309N room (visio)

Baptiste Roux – IRISA Cairn & Granit teams

Abstract: Programming heterogeneous multiprocessor architectures is a real challenge when facing to a huge design space. Computer-aided design and development tools try to circumvent this issue by simplifying instantiation mechanisms. However, energy consumption is not well supported in most of these tools due to the difficulty to obtain fast and accurate power estimation. The goal of my thesis is to address this issue by proposing a new design flow that embeds power modeling tool in a state-of-the-art parallelization tools. During my mid-term evaluation, I will show you my work progress.

Multi-source Energy Harvesting for IoT nodes

Tuesday, June 21th 2016 – 15h30 – ENSSAT Lannion room 309N

Philip-Dylan Gleonec – IRISA Granit team & Wi6labs

Abstract: Power consumption is a primary concern for IoT networks using Lora long range radio. In order to reduce the use of batteries in these devices, the use of energy harvesting technologies has been considered. Yet, most of the existing solutions rely on a single energy source, thus potentially reducing the sensor reliability. In this presentation, we will present a circuit which switches between multiple heterogeneous energy sources, and uses a single power conditioning block.

On the FPGA-based implementation of a flexible waveform from a high-level description: Application to LTE FFT case study

Tuesday, May 24th 2016 – 9h30 – ENSSAT Lannion room 309N

Mai-Thanh Tran – IRISA Cairn & Granit teams

Abstract: The Field Programmable Gate Array (FPGA) technology is expected to play a key role in the development of Software Defined Radio (SDR) platforms. To this aim, leveraging the nascent High-Level Synthesis (HLS) tools, a design ow from high-level specications to Register-Transfer Level (RTL) description can be thought to generate processing blocks that can be recongured at run-time. Based on such a flow, this talk will present the architectural exploration of a Fast Fourier Transform (FFT) for Long Term Evolution (LTE) standard.

(Almost) Fuzzy Power Management for Energy Harvesting Wireless Sensor Nodes

Wednesday, May 18th 2016 – 10h30 – ENSSAT Lannion room 309N

 Faycal Ait-Aoudia and Olivier Berder – IRISA Granit team

Abstract: 2-part seminar about Faycal’s work on Energy Harvesting for Wireless Sensor networks.
First, Olivier will present Fuzzyman, a novel PM based on fuzzy control theory. Because of the unpredictability of the harvested energy, fuzzy control theory constitutes an appropriate framework to tackle the problem of designing power manager for energy harvesting nodes. Performance of Fuzzyman has been evaluated by comparing it to a state of the art approach via extensive trace-driven Castalia/OMNET++ network simulations. 
In the second part of the Seminar, Faycal will explain how Fuzzyman has not been implemented on a real platform but a  power manager inspired from it. This manager has been jointly designed with a new MAC protocol leveraging wake-up radio, both have been evaluated using Powwow platform.

PhD defense: Energy-efficient cooperative techniques for Wireless Body Area Sensor Networks

Tuesday, February 9th 2016 – 10h – ENSSAT Lannion room 020G

Viet Hoa NGuyen – IRISA Granit team

Abstract: Among various cooperative techniques aiming to reduce power consumption for transmissions between Wireless Body Area Networks (WBAN) and base stations, we present a new approach, named distributed max-dmin precoding (DMP), combining MIMO precoding techniques and relay communications. This protocol is based on the deployment of a virtual 2 × 2 max-dmin precoding over one source, one forwarding relay, both equipped with one antenna and a destination involving 2 antennas. In this context, two kinds of relaying, amplify and forward (AF) or decode and forward (DF) protocols, are investigated. The performance evaluation in terms of Bit-Error-Rate (BER) and energy efficiency are compared with non cooperative techniques and the distributed space time block code (STBC) scheme. Our investigations show that the DMP takes the advantage in terms of energy efficiency from medium transmission distances (after 16 meters). In order to maximise the energy efficiency, we propose a power allocation over the source and the relay. Thus, we derive the performance of our system, both for AF and DF, analytically. To further increase the performance of DF cooperative schemes, we also propose to design a new decoder at the destination that takes profit from side information, namely potential errors at the relay. 

Experimental Demonstration of Real Time Receiver for FDMA PON

Monday, October 19th 2015 – 14h – ENSSAT Lannion room 309N

Arnaud Carer– IRISA Cairn & Granit teams

Abstract: Presentation of the first  real  time  implementation  of  a 1Gbps  FDM  receiver  in  FPGA  for  an  ONU  and  OLT receivers without data-aided. This demonstrate, for US and DS, an optical budget up to 34 dB for a BER<10-3.

Green Communication via HARQ Protocols using Message-Passing Decoder over AWGN Channels

Monday, September 28th 2015 – 11h – ENSSAT Lannion room 309N

Haïfa Farès – IRISA Granit team

Abstract: In this work, we study the effect of optimal power allocation on the performance of communication systems using hybrid-automatic repeat request (HARQ) protocols with a limited maximum number of transmission rounds. We formulate the optimization problem aiming to minimize the total average power consumption in order to achieve a target performance constraint, where the total power consumption stands for the sum of the transmission power and the processing power consumed in the decoding. Our analysis relies on the characterization of an information-theoretic bound on the decoding power of any modern code to achieve a specified bit error probability while operating at a certain gap from the capacity. As this bound is built on the sphere-packing analysis, the present study focuses on message-passing decoders. We find that the implementation of power-adaptive HARQ reduces the total average power con- sumption even when taking decoding power into consideration, compared with reference systems.

GRAPMAN: Gradual Power Manager for Consistent Throughput of Energy Harvesting Wireless Sensor Nodes

Monday, September 14th 2015 – 11h – ENSSAT Lannion room 309N

Faycal Ait Aoudia – IRISA Granit team

Abstract: In this work, Wireless Sensor Network (WSN) applications that require long-term sustainability are considered. Energy harvesting forms a promising technology to address this challenge, by allowing each node to be entirely powered by energy harvested from its environment. To be sustainable, each node must dynamically adapt its Quality of Service (QoS), regarding the harvested energy using a power management strategy. This strategy is implemented on each node by the Power Manager (PM). In this paper, GRAPMAN (GRAdual Power MANager) is proposed, a novel PM for Energy-Harvesting WSN (EH-WSN) powered by pseudo-periodic energy sources. Unlike most state of the art PMs, GRAPMAN aims to achieve high average throughput while maintaining consistent QoS, i.e. with low fluctuations with respect to time, by looking for the highest throughput that can be supplied by the node over a finite time horizon while remaining sustainable. We show through extensive trace-driven network simulations that GRAPMAN outperforms state of the art PMs in both average throughput and throughput consistency.

IQ imbalance in digital communications:  theory and experiments

Friday, July 17th 2015 – 14h00 – ENSSAT Lannion room 309N

Part 1: RF imperfection and Blind compensation

Ti-Ti Nguyen – IRISA, Master student

Abstract: Fundamentals of IQ imbalance and introduction to a new blind compensator based on pseudo-rotation
Part 2: Joint simple blind IQ imbalance compensation and adaptive equalization for 16-QAM optical communications

Trung-Hien Nguyen – FOTON, PhD student

Abstract: A novel simple blind adaptive IQ imbalance compensation, based on a Decision-Directed Least-Mean-Square (DD-LMS) algorithm integrated to a butterfly FIR filter, is proposed and experimentally validated with a 40-Gbit/s 16-QAM coherent optical fiber communication system.

CST: Synthèse matérielle d’une radio flexible et reconfigurable depuis un langage de haut niveau dédié aux couches physiques radio

Thursday, June 25th 2015 – 10h30 – ENSSAT Lannion room 309N

Mai Thanh Tran – IRISA Granit-Cairn team

InfiniTIME: A self sustainable multi-sensor device supplied by wearable energy harvesters

Monday, June 8th 2015 – 10h30 – ENSSAT Lannion room 020G

Michele Magno – ETH Zurich

Abstract: Wearable technology is gaining popularity, with people wearing everything “smart” from clothing to glasses and watches. Materializing the vision and the huge business opportunities offered by the Internet-of-Things requires a paradigm shift in sensor data processing, fusing, and understanding. Centralized approaches (sensors at the edges, with centralized intelligence in the cloud) are not scalable, hierarchical, distributed processing is a strong requirement.  Moreover nowadays wearables are battery-powered and a critical issue is the limited lifetime and limited computational resources. So most devices have to be recharged every few days or even hours and thus they miss the expectations for a truly unobtrusive user experience. Although chips makers are responding to the hot wearable-computer trend with new components, microcontrollers and sensors, the most critical challenge is the autonomy of the systems. Even if battery management can help in extending the lifetime, the trade-off between features given by a multi-sensory platforms and autonomy can determine if a platform will win or not in the marketplace. In this talk I present a novel sensor-rich (including camera, microphone) smart bracelet powered by energy harvesters which attempts to maximize the capability of sensors on board, while still keeping the energy consumption low.  Aggressive power management and an accurate selection of the sensors are addressed in this talk to demonstrate the effectiveness of design.

CST: Energy-efficent MAC protocols for cooperative strategies in Wireless Sensor Networks

Thursday, June 4th 2015 – 10h30 – ENSSAT Lannion room 309N

Van Thiep NGuyen – IRISA Granit team

Abstract: In last years, the wireless sensor networks (WSNs) have taken the interest of researchers since they have a number of potential applications in many domains of daily-life such as environment monitoring, healthy monitoring, medicine, surveillance, military, etc. Due to the small size and the difficult access of a sensor node, the power source has limited capacity and cannot be replaced. Therefore, energy consumption is an important constraint in WSNs. Our research focuses on the energy-efficient MAC protocols for WSNs and during this CST defend, the first results will be presented.

Wake Up Radio Receivers for Energy Efficient Communication in Wireless Sensor Network

Thursday, June 4th 2015 – 9h30 – ENSSAT Lannion room 309N

Michele Magno – ETH Zurich

Abstract: Wireless sensor networks (WSNs) have been recognized as a fundamental enabling technology for a wide range of applications in environmental monitoring, healthcare, security, and industrial domains, among others, due to the flexible distribution of WSN devices. Nodes in a WSN traditionally have limited power supply, while networks are often expected to be functional for extended periods. Therefore, the minimization of energy consumption and the maximization of network lifetime are key objectives in WSN. One major research effort focuses on reducing power consumption, especially communication power, as the radio transceiver is one of the highest power consumers in WSNs. Moreover, with the advent of energy-neutral systems, the emphasis has shifted toward research in micro-Watt (or even nano-Watt) communication protocols or systems. In this talk I will present both the design and architecture of nano-power wake up radio and power management at node level can exploit the that technology to extend the life time of the wireless devices

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