Georges Kaddoum
Georges Kaddoum
B.Ing. (ENSTA, France), Ph.D. (Université de Toulouse - INSA)
Département de génie électrique

Current Research Projects
5G Communication systems

We are living in an era of virtual products, from virtual shopping stores to virtual reality, the cutting edge technology is changing the world the way we see and feel it. This ever growing and ever changing e-world places new requirements on the way we connect and communicate and sets new constraints  on the next generation of wireless access i.e., 5G systems.  The main goal of 5G system is to transform our society into hyper connected society in which mobile devices will play even more important role in shaping and improving the lives of a common man.

The date rate demands of 5G systems when met with the scarce resources in spectrum of microwave, the result was rather disappointing and therefore it forced research community of both industry and academia to search for new horizons. And it didn’t took them long to come up with the solution in form of huge unused spectrum of millimeter wave (mmW).


Though the idea of using mmW is new in wireless communications but its history goes back to 1890s when J.C. Bose was experimenting with millimeter wave signals and just to have a good perspective about the time, it was the same era when Marconi were inventing radio communications. Therefore when it comes to the basic physics of mmW, we already know almost everything about it.
As of today, 5G communication systems are comprised of a set of goals that must be achieved for future wireless networks. However, despite the lack of standards a few paths are foreseen to achieve those goals, such as,

  • Massive MIMO
  • Downlink and uplink decoupling
  • Spatial and non-orthogonal multiple access
  • Multi-radio access technologies

 In this context, it is of uttermost importance to be able to fully characterize the performance of the proposed technologies to determine how future networks will look like and to guide its deployment.  The classical method to evaluate the system level performance of the coverage and rate of wireless networks always employ a regular deployment of the base stations and a hexagonal coverage area. This model has worked well enough so far but it presented shortcomings in face of the challenges of modern wireless networks. Firstly, this model is not scalable and does not allow for analytical results. Secondly, it does not represent faithfully the deployment patterns of modern networks.

Currently our group is focusing on the following research objectives

  • To use advanced mathematical tools, such as, stochastic geometry, to characterize and derive analytical expressions for the performance of 5G systems
  • To use stochastic geometry to characterize the performance of large wireless networks employing spatial and non-orthogonal multiple access
  • Optimization of downlink and uplink decoupling in multi-radio access technologies
  • Modelling and characterization of massive MIMO channels with beamforming
  • Optimization of hybrid precoding for massive MIMO


Green communications

Over the past few years, green radio communication has drawn much attention from the research community because of its strong impacts on the telecom business, wireless technologies, and the natural environment. Since the overall footprint of information and communication technology (ICT) services, e.g., computer, cell phone, and satellite networks, is predicted to be triple in between 2007 and 2020, re-greening future networks is a global trend. Recently, energy harvesting techniques are gaining much attention, and it has become a potential candidate to deal with the problem of energy inefficiency. The main advantages of energy harvesting techniques are two-fold. First, energy harvesting techniques harness green energy from natural sources, e.g., solar and wind. Thus, they contribute to reducing the overall footprint to protect surrounding environments. Second, they can recharge the devices working in areas where the traditional power supply is infeasible, e.g., hazardous environments. Nevertheless, the natural resources may not always be available. For instance, it is difficult for indoor devices to harvest solar energy. This yields another trend that outdoor base stations harvest-and-store green energy when natural resources are available, and then wirelessly transfer energy to user devices using radio frequency signal. Hence, low-power devices can receive information and energy from RF signals sent by the base stations concurrently. Even through this approach is promising, the performance of energy transfer drastically suffers from path loss. Besides, there exist tight restrictions applied for increasing the transmit power since the intensity of microwave radiation can harm the human health.


Therefore, by taking the aforementioned problems into account, our research objective is to find solutions for the critical question that “how to improve the system performance and the lifetime of future green networks through optimally managing available resources while exploiting green energy sources and avoiding electromagnetic pollution?”

Hence, future wireless communication systems are expected to be a mixture of various novel system concepts, such as full-duplex communications, small-cell densification, millimeter-wave networks, Internet of Things, etc.. However, the existing schemes also need to be renovated and/or redesigned to accommodate the advancement of new transmission technologies as well as network applications.

To reach this objective, in the first step, we aim at developing a clear understanding of the energy consumption of the future wireless networks in a wide range of scenarios. Further, in the second step, new energy harvesting techniques would be investigated to enhance the lifetime of devices. Also, new energy-efficient metrics would be proposed to quantify the greenness of the networks. In the final step, using the mathematical methodology, the performance of proposed scenarios would be analyzed and optimized under the aspects of green communications.


Physical layer security in wireless networks


Due to the exponential growth of personal data flow over wireless networks, information security is increasingly becoming a big concern when designing new communication systems. As shown in the figure, the private messages from the transmitters are exposed to the legitimate destinations, as well as to the malicious users (eavesdroppers), because of the shared nature of wireless medium. Henceforth, how to protect the private information from eavesdropping is our challenge.

Such security issues are usually addressed by deploying encryption algorithms, key management schemes, fingerprints, attack detection and prevention at the upper layers. Unfortunately, such configuration are becoming more unreliable and hard to implement in the future networks with the rapid progress of computational devices. Inspired by such reality, an alternative or complement approach, termed as Physical layer security, takes advantages of the randomness and fading property of wireless channels to minimize the possibility of information leakage. Observed from the figure, one possible solution is to diminish the quality of the received signal at eavesdropper whilst increasing that of the intended receiver from the information theoretical perspective. Apart from that, plenty of researchers from the academia and industrial community are focusing on investigating how to enhance physical layer security from other perspectives, such as game theory, graph theory, etc.

To this end, the core of this project is on the exploration of how to jam the eavesdroppers at reasonable prices. Specifically, we will deploy the existing promising techniques, such as beamforming, energy harvesting, and channel coding etc., for the purposing of designing the novel reliable and secure communication systems.

On top of that, Shifting from physical layer security to medium access control and other upper layers, corresponding secrecy-enhancement behaviors should be well understood and designed to accommodate the use of secrecy-based physical layer transmission schemes. All in all, the security issues of many networks are awaiting for further analysis from the viewpoint of cross-layer designing.  


 Internet of things for smart living

Today, all objects are becoming connected to the internet. Internet of Things (IoT) is a generic term to denote objects connected to each other for several uses in a wide range of fields to measure and exchange data from real world.  As example, the use of IoT communication has been increasing and developing to cover more applications, such as in the medical field including patient monitoring and remote healthcare. With the introduction of commercial off-the-shelf technologies (COST) in the Body Area Network (BAN) sensing devices, the demands on IoT applications in the medical field are expected to continue increasing incredibly in order to reduce obtrusiveness, costs, and time consumption of health care by making remote operations possible. On the other hand, the industrial field occupies a tremendous part in the revolution of IoT applications leading to transforming countries and companies in a new generation of economic progress and competition. Nowadays, connected factories are designed to communicate internally, i.e., within the plant network, and with the outside world to ensure a reliable processing of industrial operations. The ultimate goal is to provide a global platform through which an optimized interaction of people, smart machines, and data will lead to far-reaching effects on the production, operation rates, and efficiency capabilities of industries worldwide.


Because of the multiple aspects involved, such as knowing that confidentiality and security e.g., data/ID anonymization are tremendous in health research and applications ethics, the safety of IoTs will be an essential concern that must be addressed in order to guarantee the reliability of medical data communication between these components.

Taking into account the heterogeneity and enormous scale of their application fields, IoT systems are more vulnerable to threats such as interference and jamming attacks. Moreover, technical requirements are constraining the effective and secure communication in IoT applications in many of its stages including accessing, processing, collecting, controlling and distributing data. Among the challenges, malicious radio jamming, side channel attack (SCA), replay attack, Sybil attack, node capture and wormhole attack which result in a Denial of Service (DoS).

Therefore, our goal is to develop reliable solutions to the aforementioned problems by taking into consideration the involved physical aspects and modeling the real world constraints to ensure the realistic behavior of the system and its robust integration into its environment by answering the questions:

  • How to conceive resilient MAC protocol in order to build a network communication immune against sophisticated jamming attacks?
  • How could we optimize the integration of BAN devices into IoT communication schemes to improve healthcare monitoring and treatment operations in terms of robustness, efficiency and care cost?
To reach our goal, the research directions we seek to follow can be divided into four main categories: network architectures and platforms, interoperability, new services and applications, and security.

The objective is to connect objects to each other locally and through the internet consistently. We mean by consistently, optimizing the layers parameterization step to provide a reliable communication system, and IoT layers, namely, application layer in which the data processing and service providing to the end user are performed, as well as in the transmission layer where long distance communications are aimed, and the perception layer where the acquisition, processing and local communication through Wireless Sensor Networks (WSNs) of the physical data are involved.


To end with, an important problematic that could be faced in this field is how we can design robust networks based on Wireless Sensor Networks for effective, safe and easy deployment of sensing nodes to collect physical data. Infinite are the applications and outcomes of such work, particularly in our research, we will be focusing on two main applications:

  • Industrial applications, in what relates to smart cities and convergence of intelligent data and machine learning to create a new of its kind robust platform for public services, which increases the progress of operations and the overall productivity. A new standard 802.15.4e TSCH has been proposed to allow 802.15.4 devices to support the wide range of applications. In the same vein, we are focusing to bring improvements to this protocol by proposing and implementing some modifications at the MAC layer in order to provide an adaptive channel hopping mechanism and node access to channel scheduling.
  • Biomedical applications, particularly the design of intelligent medical care systems and that includes the conventional medical operations that require time, resources, and obtrusive protocols namely monitoring, feedback and treatment operations. In this vein, an important direction would be the design of a remote medical monitoring system that will shortcut distances making the whole world a client target of a one geographically limited medical center.



Smart grid communications


Smart grid, the next generation power grid empowered by Information and Communication Technology (ICT) has become one of the most burning topics in scientific researcher community. For a reliable smart grid, monitoring of power system parameters in the transmission and distribution segments as well as monitoring and control of substation devices from outside the station is crucial. In order to allow such advanced functionalities and avoid possible disruptions in electric systems due to any unexpected failure, a highly reliable, scalable, secure, cost-effective, and robust communication network must be operational within the power grid. In this regard, the most promising method of smart grid monitoring explored in the literature is based on Wireless Sensor Network (WSN) due to its inherent characteristics of being low-cost, flexible, wider coverage, self-organization and rapidly deployed.
The research objectives of this axis are to lay down the fundamental basis for the development of a robust and secure collaborative WSN for substation monitoring to realize real-world smart grid applications.
With this goal in mind, the research goals include the characterization of substation RF environments, design and performance analysis of robust WSN transceiver architecture for harsh smart grid environments, design and development of algorithms for prevention and detection of security flaws in transmission in smart grid, etc.

In addition to cyber security issues that have been widely investigated in the literature since the beginning of smart grid projects, we will also analyze the  physical layer security aspects that has been hardly investigated in the smart grid scenario. How the performance of the later scheme can be improved by designing new advanced algorithms to satisfy smart grid scenarios needs further investigation.

Our research group at ETS in collaboration with Hydro Quebec research center (IREQ) has already demonstrated the characteristics of noise behavior in substation environments. Future work will incorporate the design and performance analysis of distributed collaborative secure WSN by considering realistic scenarios as the observed noise characteristics in the designing process to meet smart grid requirements.




Vehicular cooperative wireless networks

Vehicular cooperative wireless networks have become an interesting research area recently due to the need to improve the quality of service and the performance of V2V wireless communication systems. The cooperation between vehicles and infrastructures can provide reliable and strong communication links between users. Also, it can extend the coverage and the connectivity of V2V and V2I. Vehicular applications such as ITSs can improve safety and help in traffic management. ITSs could also be used to exchange general information between vehicles to avoid accidents. On the other hand, the utilization of MMW in 5G systems to provide a huge amount of spectrum is another motivation in vehicular communications.

In our Lab, we are currently studying different scenarios of vehicular cooperative wireless communications with/without MMW under several constraints such as   power, mobility, and channel modeling.

Our goals are to design several models and protocols of vehicular cooperative wireless communications that provide high throughput, low latency, high data rate, etc.


Design and implementation of random number generators for secure wireless communications


Random Number Generators (RNGs) are required in many applications such as wireless networking, gaming, military communications, online payment, etc…. RNGs are used to generate keys, initialize vectors and other random numbers used in many security standards and applications. As an example, the Internet of Things (IoT) is a fast-growing market where data can easily be intercepted and devices can be hacked, especially if weak RNGs are selected.

Our main objective  is to design robust low-cost low RNGs for secure wireless communication applications.  We are investigating several aspects in this area:

  • Exploring different ways to generate RNG i.e. chaos, non-linear maps, laser, quantum, ambient noise

  • Analyzing different performance metrics of the designed generators

  • Exploring the automatic and manual reseeding techniques

  • Optimizing the designed random number generation to secure wireless communications

  • Integrating designed RNGs on digital platform


Free space optical communications

A rapid advancement in the area of broadband wireless communication has been experienced over the last few decades. The demand for high capacity links up to last mile is increasing day by day. Currently, the existing radio frequency (RF) or microwave technologies are capable of providing data rates up to several 100 Mbps. Therefore, researchers are now aiming for alternate technologies that can provide larger bandwidth and higher data rates.


One of the alternatives is free space optical (FSO) communication system that provides point-to-point optical link through atmospheric channel using optical signal as the carrier wave. It is a line-of-sight technology that enables highly secured optical link between two transceivers separated by a certain distance. This technology has drawn lot of attention these days over owing to it large gain, higher bandwidth, quick deployment, less power, mass requirement, and license free spectrum. As the frequency of optical carrier lies between of 1012 – 1016 Hz, data rates in the range of Tbps can be achieve with FSO communication system. Also, due to its extremely narrow beam width (in mrad), FSO communication provides less or no interference with enhanced data security. FSO communication involves terrestrial links, underwater optical links, ground-to-satellite/satellite-to-ground links, inter-satellite links, deep space probes, high altitude platform (HAP) links and unmanned aerial vehicles (UAVs) links. It also provides backhaul solutions where it carries the traffic of cellular phones from antenna towers back to the PSTN with high speed and large data rate. Major applications of FSO system are:

  • Last mile access

  • Enterprise connectivity

  • Metro-network extensions

  • Service acceleration

  • Fiber backup

  • Telecom  network extensions

  • Bridging WAN Access

  • Military access

Although FSO system has several advantages over conventional RF systems, this technology has to face several challenges due to random nature of the atmospheric channel. The signal in FSO link suffers due to various adverse effects (viz., absorption, scattering and turbulence) of the atmospheric channel. Although FSO link is relatively unaffected by rain and snow, but it is seriously affected due to fog and atmospheric turbulence. Both these factors lead to serious degradation in the link performance and make the communication link infeasible. The degrading effect of atmospheric channel can be improved by use of various mitigation techniques like aperture averaging, diversity, adaptive optics and coding.

Ongoing research in this area is focusing on following topics:

  • Adaptive optics

  • Channel correlation and diversity

  • Coded optical wireless links for space and underwater communication

  • Adaptive transmission in FSO systems

  • Relay assisted transmission in space and underwater optical communication

  • Hybrid RF/FSO system

  • Pointing and tracking requirements

  • Coherent and Non-coherent FSO systems

Advanced modulation techniques 


The Internet of Things is intended to offer wireless connections with multiple devices and sensors. Therefore, low latency, low complexity, low energy consumption, low data rate are important metrics that need to be fully or partially satisfied in several IoT applications.

The concept of internet of things (IoT) is developed in parallel to the continuous progress in 5G networks by virtue of wireless sensor networks (WSN) that have emerged as the most promising technology for the future. And it is expected to touch various aspects of our life like fitness, automation, security, localization, consumer electronics, smart grid devices, and many more.

In fact, WSNs have been among one of the most researched areas in the last decade. The emergence of this technology has only been possible via advances in and availability of small and inexpensive smart sensors that are cost effective and easily deployable. Various modulation schemes so far have been used in wireless sensor nodes, among these schemes are M-ary quadrature amplitude modulation (MQAM), offset quadrature phase-shift keying (OQPSK) and multiple frequency-shift keying (MFSK), which is also known as the green modulation scheme providing the advantage of low complexity and low cost of implementation.

Our main goal in this research project is to design an alternative low-complexity, energy efficient, low latency, and/or low data rate secure modulation schemes which fit the requirements of both current and emerging wireless sensor networks.

To achieve the aforementioned research goals, many research directions will be investigated.  For example, we will exploit degrees of freedom that already exist in the wireless modem to carry extra bits without increasing the receiver’s complexity.

Moreover, we will propose new non-coherent modulator schemes that exploit new waveforms to increase the robustness of the transmission, to enhance the spectral efficiency while keeping the implementation complexity of the system within its pragmatic limits.  Therefore, a careful design of the transmitted signals in non-coherent communication techniques will be exploited in order to approach the channel capacity of coherent systems.


Development of localization algorithms dedicated for aircraft using ADS-B technology

This research project aims to develop new techniques and algorithms to improve the precision of location by using multilateration technique. This technology is gaining popularity in radio navigation industry due to its high localization accuracy, flexibility, and low cost of deployment.


Memberships in groups and research laboratories

Laboratoire de communications et d'intégration de la microélectronique - LaCIME





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