|Personal data||Research themes||Ongoing teaching||Publications|
Person in charge of the Unit : Oui
The Wireless Communications Group was founded in 2007. Its strategic vision focus on the development of a team of researchers working in synergy to address new challenges of emerging wireless communications systems, from propagation physics to network architectures through modems. The Group owns expertise in three complementary fields : (i) propagation channel modeling (Prof. Ph. De Doncker); (ii) digital signal processing (Prof. Fr. Horlin); (iii) cybersecurity and network architecture and protocols (Prof. J-M Dricot). The mission of the channel team is the theoretical and experimental characterization and modeling of propagation for emerging communications systems. Expertise range from propagation in indoor environments, urban, and in the near-body region, from HF to mm-wave frequencies. The mission of the DSP team is to develop solutions for emerging digital communications systems taking into account hardware implementation and integration constraints. The team studies modulation, access techniques, channel equalization and synchronization. The network team has a special focus on software-defined architectures and security protocols for wireless communications. More specifically, our research domain covers wireless networks, Internet of Things (IoT), and cyber-physical systems. The network team is a founding member of the ULB cybersecurity research center.
Capitalizing on the paradigms of wireless network virtualization and slicing, and of densification promoted all across the wireless ecosystem, this project intends to investigate multi-service wireless networks (MUSE-WINETs) based on a common and shared infrastructure made of Cloud/Fog servers and radio heads equipped with large antenna arrays. The targeted wireless services significantly extend the concept of data transfer slicing, towards power transfer, positioning and wireless access to shared computational resources for cooperative sensing and IoT applications. To enable the optimization of the performance jointly achievable for all radio and computational services, the project will investigate a cross (X)-service design paradigm. X- service design combines initial slicing of the resources for the different services, a cooperative management of the resources across services in view of their coupling, and inter-service message passing to exploit possible synergies between services. The project intends to understand the performance trade-offs achievable with MUSE-WINETs and the synergies and inter-service fertilization originating from the X-service design, and to design optimized algorithms for the transceivers, the resource management, and the computational load distribution. This requires the setting up of proper stochastic analytical frameworks. The research questions will be instantiated to use cases and the answers illustrated and corroborated by prototype elements. In MUSE-WINET, ULB-WCG will focus on the interplay existing between communication and positioning services supported by the network. While communications signals can serve as a reference to improve positioning of a terminal, the information on the location itself is interesting to enhance communications with the terminal.
The AMPERE project aims to develop an advanced approach of spatio-temporal EMF exposure mapping by means of advanced statistical tools. The spatial and temporal EMF distribution assessment can request long computation times, extensive measurements and data that are not always publicly available. The combination of EMF exposure, usage of ICT, population density and environment characteristics involved in the data fusion is therefore facing strong limitations. To overcome these latters, AMPERE will develop advanced methods based on statistics and surrogate models
SWS general objective is to increase safety in the use of weapons, by introducing new technologies.
An intelligent crowd monitoring system for large public events will be developed. The system will be based on a multi-fidelity approach: cellular networks will be used as large-scale coarse estimates of the crowd density, while Wifi access points deployed through the event area will provide small-scale estimations. By combining the two estimates, the system will be able (i) to provide crowd density and directional fluxes maps in real-time; (ii) to anticipate abnormal crowd movements, especially for safety issues, by learning crowd dynamics.
The emergence of connected electronic devices has paved the way for the concept of "smart city". In the paradigm of smart cities, each electronic device becomes a miniature computing platform, equipped with multiple sensors and interacting with the infrastructure through wireless connectivity. In the context of smart cities, streetlights are a particularly coveted resource, for two reasons: (i) access to the power grid makes it possible to equip the lamp post with multiple sensors, without having to worry about consumption problems; (ii) the regular deployment of lampposts makes it possible to have a regular and repetitive mesh of the sensors. This project will mainly study RF systems to locate, track and classify road users. Each streetlight is equipped with wireless signal sensors (for detecting transmitters) as well as a radar system, providing each an independent estimate of the location of a user. The high density of streetlights provides access to numerous user location estimates, which can be combined using data fusion algorithms to achieve accurate positioning. In this project, we propose to: (i) design algorithms to locate, track and classify users, making full use of the high density and multi-technology nature of smart street lights; (ii) characterize the performances of these algorithms by simulations; (iii) validate the algorithms experimentally.
Radio frequency (RF) energy harvesting is founded on the ability of converting the energy carried by an electromagnetic wave through the air into electrical energy at the point of use. Though the physics behind RF energy harvesting is extremely simple and clear, transposing these principles into marketable technological solutions poses challenging issues. COPINE-IoT proposes the development of an original WPT technology in which the traditional wireless information gateways (IGs) are complemented with additional distributed and coordinated radiating elements, also referred to as remote power heads (RPHs). The RPHs shall be able of intercepting the flow of information from the wireless sensors to the IGs in order to enable the beamforming of the electromagnetic waves and sensors localization. The integration with the data communications system will permit the development of context-aware algorithms for energy management at the whole network scale. ULB-WCG is responsible for the design of the indoor localization of the ultra-low power sensors based on the estimation of the communication signals angle-of-arrivals at the RPHs equipped with multiple antennas.
L’objectif scientifique du projet GEMS est de développer un système distribué de monitoring et analyse des réseaux de télécommunications sans fil, 3G/4G et WiFi. Les méthodes actuelles de monitoring basées sur des drive-tests ou walk-tests sont très couteuses en temps et en matériel, et ne permettent d’obtenir une analyse qu’en un instant donné et en certains points de mesure. Le système GEMS permettra une analyse détaillée de la couverture et des performances établie sur une longue période de temps (plusieurs jours) et sur l’ensemble de la zone considérée. Pour atteindre cet objectif, deux challenges scientifiques devront être abordés : - Développer de nouvelles méthodes de mapping des paramètres réseaux (en terme de puissance, d’interférence, de diversité,..) sur bases des techniques de la géostatistique. -Développer des réseaux de capteurs de monitoring des réseaux. L’objectif n’est pas de réaliser les capteurs, mais bien d’intégrer des solutions existantes en un réseau facile à déployer sur site.
Localization has recently become a key functionality in cellular networks to support position-based services. Current techniques used in 4G provide an estimate of the location using a two-step process. The signal time of arrival (ToA) from multiple base stations is first estimated using a dedicated positioning reference signal (PRS). The position is then determined based on the observed time difference of arrival (OTDoA) using a multilateration technique. However, rich multipath channels typical in urban or indoor environments highly degrade the ToA estimation resulting in significant location errors (20m to 50m). This problem is only partially addressed in the literature. This project aims at developing a localization system for 5G networks delivering a high position accuracy in urban and indoor environments (error target of the order of the meter). The first phase of the project targets the development of ToA estimation schemes adapted to the new modulation formats foreseen for 5G. New reference signals will be designed to optimize the ToA estimation. The project will secondly investigate how the TDoA positioning multilateration algorithms can be improved for urban/indoor environments by exploiting the knowledge of the channel response acquired based on the reference signals. The last phase of the project investigates the possibility to iterate between the two successive steps generally applied when localizing a mobile terminal (ToA estimation/multilateration) to better take benefit from all the information present in the observed signals.
Associating wireless information to certain physical locations is an interesting feature that many applications can benefit from. This capability is known as geocasting. Just like pictures are tagged with the location where they have been clicked, geocasting enables to tag a real physical location by wirelessly transmitting data that are only decodable within desired delimited areas. Thus, users can receive information related to the place where they are. Consequently, GEOHYPE’s focus is to investigate physical solutions that enable the broadcasting of information to specific spatial locations, using limited infrastructures. From a scientific point of view, the problem is to find a way for a base station to wirelessly transmit data that are decodable only within desired areas. To do so at the physical layer, base stations have to exhibit spatial focusing capabilities. Multiple-Input Single-Output (MISO) architectures can be used for that purpose. The goal is to focus the transmitted data rather than focusing the transmitted power as is usually done with beamforming technology. The idea is to process the precode the signalm in order to be decodable only at a predetermined spot.
The project general objective is to develop a localization system that will complement the 5G functionalities by delivering localization with one-meter accuracy together with an uncertainty indicator. This system will use anchor devices foreseen already for 5G networks: simple and cheap devices of known location that can be deployed to help the network infrastructure to localize efficiently.