Routing Strategies and Content Dissemination Techniques for Software-Defined Vehicular Networks

Doctoral thesis (2020)

Over the past years, vehicular networking has enabled a wide range of new applications that improve vehicular safety, efficiency, comfort, and environmental impact. Vehicular networks, however, normally ... [more ▼]

Over the past years, vehicular networking has enabled a wide range of new applications that improve vehicular safety, efficiency, comfort, and environmental impact. Vehicular networks, however, normally operate in communication-hostile environments and are characterized by dynamic topologies and volatile links, making it challenging to guarantee Quality of Service (QoS) and reliability of vehicular applications. To this end, the present work explores how the centralized coordination offered by Software-Defined Networking can improve the Quality of Service in vehicular networks, particularly for Vehicle-to-Vehicle (V2V) unicast routing and content dissemination. With regard to V2V routing, this work motivates the case for centralized network coordination by studying the performance of traditional MANET routing protocols when applied to urban VANETs, showing that they cannot provide satisfactory performance for modern vehicular applications because of their limited global network awareness, slow convergence, and high signaling. Hence, this work proposes and validates a centralized Multi-Flow Congestion-Aware Routing (MFCAR) algorithm to allocate multiple data flows on V2V routes. The first novelty of MFCAR is the SDN-based node-busyness estimation technique. The second novelty is the enhancement of the path-cost formulation as a linear combination of path length and path congestion, allowing the user application to fine-tune its QoS requirements between throughput and delay. Concerning content dissemination, this work proposes a Fairness- and Throughput-Enhanced Scheduling for Content Dissemination in VANETs (ROADNET), a centralized strategy to improve the tradeoff between data throughput and user fairness in deterministic vehicular content dissemination. ROADNET’s main novelties are the design of a graph-based multi-channel transmission scheduler and the enforcement of a transmission-priority policy that prevents user starvation. As additional contributions, the present work proposes a heuristic for the centralized selection of opportunistic content dissemination parameters and discusses the main security issues in Software-Defined Vehicular Networking (SDVN) along with possible countermeasures. The proposed techniques are evaluated in realistic scenarios (LuST), using discrete-event network simulators (OMNeT++) and microscopic vehicular-mobility simulators (SUMO). It is shown that MFCAR can improve PDR, throughput and delay for unicast V2V routing up to a five-fold gain over traditional algorithms. ROADNET can increase content dissemination throughput by 36% and user fairness by 6% compared to state-of-the-art techniques, balancing the load over multiple channels with a variance below 1%. [less ▲]

Rozansky-Witten-type invariants from symplectic Lie pairs

in Communications in Mathematical Physics (2014)

We introduce symplectic structures on “Lie pairs” of (real or complex) Lie algebroids as studied by Chen et al. (From Atiyah classes to homotopy Leibniz algebras. arXiv:1204.1075, 2012), encompassing ... [more ▼]

We introduce symplectic structures on “Lie pairs” of (real or complex) Lie algebroids as studied by Chen et al. (From Atiyah classes to homotopy Leibniz algebras. arXiv:1204.1075, 2012), encompassing homogeneous symplectic spaces, symplectic manifolds with a g-action, and holomorphic symplectic manifolds. We show that to each such symplectic Lie pair are associated Rozansky–Witten-type invariants of three-manifolds and knots, given respectively by weight systems on trivalent and chord diagrams. [less ▲]

RPSL meets lightning: A model-based approach to design space exploration of robot perception systems

in RPSL meets lightning: A model-based approach to design space exploration of robot perception systems (2016)

The design space of a robotic application defines at a meta level what are all of its possible implementations. Those possibilities are called design alternatives and differ on many different aspects, one ... [more ▼]

The design space of a robotic application defines at a meta level what are all of its possible implementations. Those possibilities are called design alternatives and differ on many different aspects, one being preferred to the other depending on how, where, when or what the application should do. Design Space Exploration (DSE) is the process of reviewing those design alternatives, prior to their implementation, with intention to verify that the set of all design alternatives to be implemented covers all the possible scenarios in which the application is to be executed. In this paper we address two challenges related to DSE, namely, (1) the formal definitions of design spaces, a non-trivial task due to the many dimensions to be taken into consideration, and (2) the automatisation of DSE, that is, enabling a domain expert to review design alternatives corresponding to a given design space effortlessly. In this paper, we address those challenges in the context of robot perception software systems by combining two already existing technologies, namely RPSL for the specification of robot perception system's design spaces and Lightning, a language workbench that we use to formalise RPSL and obtain, from RPSL specifications, corresponding design alternatives. [less ▲]

RSA, pilier de la cryptographie symétrique

Presentation (2005, July 06)

RSSI-Based Hybrid Beamforming Design with Deep Learning

in 2020 IEEE International Conference on Communications Proceedings (2020, June 07)

Hybrid beamforming is a promising technology for 5G millimetre-wave communications. However, its implementation is challenging in practical multiple-input multiple-output (MIMO) systems because non-convex ... [more ▼]

Hybrid beamforming is a promising technology for 5G millimetre-wave communications. However, its implementation is challenging in practical multiple-input multiple-output (MIMO) systems because non-convex optimization problems have to be solved, introducing additional latency and energy consumption. In addition, the channel-state information (CSI) must be either estimated from pilot signals or fed back through dedicated channels, introducing a large signaling overhead. In this paper, a hybrid precoder is designed based only on received signal strength indicator (RSSI) feedback from each user. A deep learning method is proposed to perform the associated optimization with reasonable complexity. Results demonstrate that the obtained sum-rates are very close to the ones obtained with full-CSI optimal but complex solutions. Finally, the proposed solution allows to greatly increase the spectral efficiency of the system when compared to existing techniques, as minimal CSI feedback is required. [less ▲]

RTL & Europe n°1 as central actors. The Importance of Mobility for Commercial Radio Stations during the Parisian Events of Mai 68

in Rundfunk & Geschichte (2018), 3(4), 41-51

Ruano, L. (Ed.). (2013). The Europeanization of National Foreign Policies towards Latin America. New York: Routledge. 264 pp.

in Regions & cohesion = Regiones y Cohesión = Regions and Cohesion (2013), 3(2), 107-109

Ein Rückblick auf die Zukunft. 25 Jahre Verkehrswende

in Oekologisches Wirtschaften (2018), 33(2), 16-18

This paper (written in German) provides a reflection on a conceptual framework for transforming mobility policies and practices. It was developed in Germany in the context of the then emerging idea for ... [more ▼]

This paper (written in German) provides a reflection on a conceptual framework for transforming mobility policies and practices. It was developed in Germany in the context of the then emerging idea for transforming energy policies (Energiewende). The aim was to put together related concepts for the sustainable development of the demand for, and supply of, mobility and transport and related contexts (Verkehrswende). It was first presented in book format 25 years ago. On that occasion, and since the term has gained some attention and recognition in political realms recently, the concept is subject to a critical reflection from today's perspective. [less ▲]

Rudolf Seidel, Léon Metz et la Halle des soufflantes

Article for general public (2018)

Ruinous Fathers, Lethal Mothers: A Response to June Sturrock

in Connotations: A Journal for Critical Debate (2012), 22(1), 157-161