11 research outputs found
Interference modeling of wireless cooperative systems
The main goal of this thesis is to study the impact of interference on cooperative vehicular communications (VCs) with the aid of stochastic geometry tools. This thesis also proposes a framework to model interference in cooperative VCs. First, we study the effects of interference dependence on the received node for several transmission schemes, different channel models, and two mobility models. The performance in terms of outage probability is investigated. Second, we investigate the improvement of using non-orthogonal multiple access (NOMA) in the performance in terms of outage probability and average achievable rate for several transmission schemes. The results show that NOMA improves significantly the performance. We also investigate conditions in which NOMA outperforms OMA. Finally, studies are conducted: 1) an adaptive cooperative NOMA protocol is proposed, 2) an analysis of millimeter waves (mmWave) vehicular networks is carried out, 3) extension scenarios are investigated such as multiple relays, multiple hops, or multiples lanes
Performance Evaluation of Adaptive Cooperative NOMA Protocol at Road Junctions
Vehicular communications (VCs) protocols offer useful contributions in the
context of accident prevention thanks to the transmission of alert messages.
This is even truer at road intersections since these areas exhibit higher
collision risks and accidents rate. On the other hand, non-orthogonal multiple
access (NOMA) has been show to be a suitable candidate for five generation (5G)
of wireless systems. In this paper, we propose and evaluate the performance of
VCs protocol at road intersections, named adaptive cooperative NOMA (ACN)
protocol. The transmission occurs between a source and two destinations. The
transmission is subject to interference originated from vehicles located on the
roads. The positions of the interfering vehicles follow a Poison point process
(PPP). First, we calculate the outage probability related to ACN protocol, and
closed form expressions are obtained. Then we compare it with other existing
protocols in the literature. We show that ACN protocol offers a significant
improvement over the existing protocols in terms of outage probability,
especially at the intersection. We show that the performance of ACN protocol
increases compared to other existing protocols for high data rates. The
theoretical results are verified with Monte-Carlo simulations
Technological Trends and Key Communication Enablers for eVTOLs
The world is looking for a new exciting form of transportation that will cut
our travel times considerably. In 2021, the time has come for flying cars to
become the new transportation system of this century. Electric vertical
take-off and landing (eVTOL) vehicles, which are a type of flying cars, are
predicted to be used for passenger and package transportation in dense cities.
In order to fly safely and reliably, wireless communications for eVTOLs must be
developed with stringent eVTOL communication requirements. Indeed, their
communication needs to be ultra-reliable, secure with ultra-high data rate and
low latency to fulfill various tasks such as autonomous driving, sharing a
massive amount of data in a short amount of time, and high-level communication
security. In this paper, we propose major key communication enablers for eVTOLs
ranging from the architecture, air-interface, networking, frequencies,
security, and computing. To show the relevance and the impact of one of the key
enablers, we carried out comparative simulations to show the superiority
compared to the current technology. We compared the usage of an air-based
communication infrastructure with a tower mast in a realistic scenario
involving eVTOLs, delivery drones, pedestrians, and vehicles.Comment: 8 pages, 10 figure
Harnessing the Potential of Optical Communications for the Metaverse
The Metaverse is a digital world that offers an immersive virtual experience.
However, the Metaverse applications are bandwidth-hungry and delay-sensitive
that require ultrahigh data rates, ultra-low latency, and hyper-intensive
computation. To cater for these requirements, optical communication arises as a
key pillar in bringing this paradigm into reality. We highlight in this paper
the potential of optical communications in the Metaverse. First, we set forth
Metaverse requirements in terms of capacity and latency; then, we introduce
ultra-high data rates requirements for various Metaverse experiences. Then, we
put forward the potential of optical communications to achieve these data rate
requirements in backbone, backhaul, fronthaul, and access segments. Both
optical fiber and optical wireless communication (OWC) technologies, as well as
their current and future expected data rates, are detailed. In addition, we
propose a comprehensive set of configurations, connectivity, and equipment
necessary for an immersive Metaverse experience. Finally, we identify a set of
key enablers and research directions such as analog neuromorphic optical
computing, optical intelligent reflective surfaces (IRS), hollow core fiber
(HCF), and terahertz (THz)
Modélisation des interférences dans un système coopératif sans fil
L’objectif principal de cette thèse est d’étudier l’impact des interférences dans les communications véhiculaires coopératives via des outils de la géométrie stochastique. Cette thèse propose un cadre formel d’étude d’interférences dans les communications véhiculaires coopératives. Dans un premier temps, nous étudions les effets de la dépendance des interférences sur les probabilités de coupure des transmissions, considérant plusieurs type de transmissions, différents modèles de canaux et deux modèles de mobilité. Dans un second temps, nous évaluons comment la probabilité de coupure et le débit moyen des communications véhiculaires peuvent être améliorés via l’utilisation de techniques d’accès non orthogonales (NOMA). Les résultats montrent que NOMA améliore fortement les performances. Nous établissons également les conditions mathématiques nécessaires pour que les techniques NOMA soient meilleures que les techniques orthogonales classiques (OMA) en termes de probabilité de coupure. Enfin, plusieurs autres études sont menées : 1) un protocole adaptatif et coopératif fondé sur la technique NOMA est proposé, 2) une analyse des réseaux véhiculaires à ondes millimétriques est conduite, 3) plusieurs autres extensions sont étudiées telles que plusieurs relais, plusieurs sauts ou plusieurs voies.The main goal of this thesis is to study the impact of interference on cooperative vehicular communications (VCs) with the aid of stochastic geometry tools. This thesis also proposes a framework to model interference in cooperative VCs. First, we study the effects of interference dependence on the received node for several transmission schemes, different channel models, and two mobility models. The performance in terms of outage probability is investigated. Second, we investigate the improvement of using non-orthogonal multiple access (NOMA) in the performance in terms of outage probability and average achievable rate for several transmission schemes. The results show that NOMA improves significantly the performance. We also investigate conditions in which NOMA outperforms OMA. Finally, studies are conducted: 1) an adaptive cooperative NOMA protocol is proposed, 2) an analysis of millimeter waves (mmWave) vehicular networks is carried out, 3) extension scenarios are investigated such as multiple relays, multiple hops, or multiples lanes