Scientific Publications
Book chapters
- , “Veins – the open source vehicular network simulation framework,” in Recent Advances in Network Simulation, A. Virdis and M. Kirsche, Eds. Springer, 2019 [BibTeX file, PDF, Details...]
BibTeX
@incollection{sommer2019veins, author = {Sommer, Christoph and Eckhoff, David and Brummer, Alexander and Buse, Dominik S. and Hagenauer, Florian and Joerer, Stefan and Segata, Michele}, doi = {10.1007/978-3-030-12842-5_6}, title = {{Veins -- the open source vehicular network simulation framework}}, booktitle = {Recent Advances in Network Simulation}, editor = {Virdis, Antonio and Kirsche, Michael}, isbn = {978-3-030-12841-8}, publisher = {Springer}, year = {2019} }
Journal articles
- , “Estimating coverage and capacity of high frequency mobile networks in ultradense urban areas,” Elsevier Computer Communications, vol. 223, pp. 81–89, Jul. 2024 [BibTeX file, PDF, Details...]
BibTeX & Abstract
High frequency communications (mmWave and TeraHz) in urban areas require a higher density of base stations compared to pre-5G mobile networks, but open the way to a quantum leap in increased throughput and reduced latency. However, we currently have no indication of how much we need to densify the deployment, and on the trade-off between the density of base stations and the performance improvement. This paper studies the problem of base stations placement to guarantee coverage to vehicles and pedestrians in urban areas when using high frequency communications. Our novel methodology takes advantage of vehicular traffic simulations and precise urban maps to generate a realistic demand model for vehicles and pedestrians in urban areas. We use a bounded error heuristic to find the maximal coverage that can be achieved with a given density of base stations, primarily using line-of-sight communications. We implemented the heuristic using CUDA libraries on Nvidia GPUs and evaluated the coverage in an urban area in the city of Luxembourg, for which vehicular traffic patterns are available. We focus on coverage and capacity analysis for the mmWave frequency, but the results are easily extended to TeraHz communications. Our results are the first to show that a reasonably low density (15 base stations per km) is sufficient to provide coverage for vehicles in urban environments. However, optimizing on vehicles or on pedestrians are competing objectives: the operator needs to choose which one to target based on its business model when designing the network infrastructure. Our algorithms, code and open data can be used to perform this task and reproduce our results in different settings.@article{gemmi2024estimating, author = {Gemmi, Gabriele and Segata, Michele and Maccari, Leonardo}, doi = {10.1016/j.comcom.2024.04.030}, title = {{Estimating coverage and capacity of high frequency mobile networks in ultradense urban areas}}, pages = {81--89}, journal = {Elsevier Computer Communications}, issn = {0140-3664}, publisher = {Elsevier}, month = {7}, volume = {223}, year = {2024} } - , “Optimizing MRAI on large scale BGP networks: An emulation-based approach,” Elsevier Computer Communications, vol. 228, Dec. 2024 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Modifying protocols that pertain to global Internet control is extremely challenging, because experimentation is almost impossible and both analytic and simulation models are not detailed and accurate enough to guarantee that changes will not affect negatively the Internet. Federated testbeds like the ones offered by the Fed4FIRE+ project offer a different solution: off-line Internet-scale experiments with thousands of Autonomous Systems (ASes). This work exploits Fed4FIRE+ for a large-scale experimental analysis of Border Gateway Protocol (BGP) convergence time under different hypotheses of Minimum Route Advertisement Interval (MRAI) setting, including an original proposal to improve its management by dynamically setting MRAI based on the topological position of the ASes in relation to the specific route being advertised with the UPDATE messages. MRAI is a timer that regulates the frequency of successive UPDATE messages sent by a BGP router to a specific peer for a given destination. Its large default value significantly slows down convergence after path changes, but its uncoordinated reduction can trigger storms of UPDATE messages, and set off unstable behaviors known as route flapping. The work is based on standard-compliant modifications of the BIRD BGP daemon and shows the tradeoffs between convergence time and signaling overhead with different management techniques.@article{milani2024optimizing, author = {Milani, Mattia and Segata, Michele and Baldesi, Luca and Nesler, Marco and Lo Cigno, Renato and Maccari, Leonardo}, doi = {10.1016/j.comcom.2024.107940}, title = {{Optimizing MRAI on large scale BGP networks: An emulation-based approach}}, journal = {Elsevier Computer Communications}, issn = {0140-3664}, publisher = {Elsevier}, month = {12}, volume = {228}, year = {2024} } - , “CoopeRIS: A framework for the simulation of reconfigurable intelligent surfaces in cooperative driving environments,” Elsevier Computer Networks, Special Issue on Advances in Wireless Networks Simulation, vol. 248, Jun. 2024 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Future connected vehicles will require high-performance communication technologies for advanced cooperative driving applications such as maneuvering and cooperative perception. mmWave communications can meet the bandwidth requirements of such applications, but the typically harsh propagation conditions of vehicular environments hinder the broad adoption of mmWave devices on cars. Reconfigurable intelligent surfaces (RISs) can help mitigate this problem by enabling the reflection of signals in a configurable direction. In turn, this can result in more stable non-line of sight (NLoS) links whenever a LoS path is not available. RISs have recently gained attention in the vehicular domain but, while providing benefits, they also introduce a lot of research challenges. To measure their effectiveness at scale, it is necessary to develop simulation tools that can reproduce their characteristics with high fidelity and federate them with existing cooperative driving simulation frameworks. In this work we present CoopeRIS, an open-source simulation framework federated within the Plexe/Veins/SUMO ecosystem, capable of modeling and simulating RIS-based mmWave communications in a vehicular environment. We exploit CoopeRIS to perform an initial feasibility study, highlighting the challenges ahead and the performance RISs need to deliver in order to enable this type of communication. In addition we propose a method to combine multiple RIS configurations into a single one to enable multi-user service delivery, showing its performance via CoopeRIS. The insights we presents within this work show the potential of such simulation framework and thus how the community can build further research work on top if it.@article{segata2024cooperis, author = {Segata, Michele and Casari, Paolo and Lestas, Marios and Papadopoulos, Alexandros and Tyrovolas, Dimitrios and Saeed, Taqwa and Karagiannidis, George K. and Liaskos, Christos}, doi = {10.1016/j.comnet.2024.110443}, title = {{CoopeRIS: A framework for the simulation of reconfigurable intelligent surfaces in cooperative driving environments}}, journal = {Elsevier Computer Networks, Special Issue on Advances in Wireless Networks Simulation}, issn = {1389-1286}, publisher = {Elsevier}, month = {6}, volume = {248}, year = {2024} } - , “Multi-Technology Cooperative Driving: An Analysis Based on PLEXE,” IEEE Transactions on Mobile Computing, vol. 22, no. 8, pp. 4792–4806, Aug. 2023 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Cooperative Driving requires ultra-reliable communications, and it is now clear that no single technology will ever be able to satisfy such stringent requirements, if only because active jamming can kill (almost) any wireless technology. Cooperative driving with multiple communication technologies which complement each other opens new spaces for research and development, but also poses several challenges. The work we present tackles the fallback and recovery mechanisms that the longitudinal controlling system of a platoon of vehicles can implement as a distributed system with multiple communication interfaces. We present a protocol and procedure to correctly compute the safe transition between different controlling algorithms, down to autonomous (or manual) driving when no communication is possible. To empower the study, we also develop a new version of PLEXE, which is an integral part of this contribution as the only Open Source, free simulation tool that enables the study of such systems with a modular approach, and that we deem offers the community the possibility of boosting research in this field. The results we present demonstrate the feasibility of safe fallback, but also highlight that such complex systems require careful design choices, as naïve approaches can lead to instabilities or even collisions, and that such design can only be done with appropriate in-silico experiments.@article{segata2023multi-technology, author = {Segata, Michele and Lo Cigno, Renato and Hardes, Tobias and Heinovski, Julian and Schettler, Max and Bloessl, Bastian and Sommer, Christoph and Dressler, Falko}, doi = {10.1109/TMC.2022.3154643}, title = {{Multi-Technology Cooperative Driving: An Analysis Based on PLEXE}}, pages = {4792--4806}, journal = {IEEE Transactions on Mobile Computing}, issn = {1536-1233}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, month = {8}, number = {8}, volume = {22}, year = {2023} } - , “An Overview on Approaches for Coordination of Platoons,” IEEE Transactions on Intelligent Transportation Systems, vol. 23, no. 8, pp. 10049–10065, Aug. 2022 [BibTeX file, PDF, Details...]
BibTeX & Abstract
In the recent past, platooning evolved into an attractive cooperative driving technology, broadly discussed in research and practice. Vehicles in platoons use cooperative adaptive cruise control to drive at close distances to each other. Platooning (i) increases the capacity of the street by a factor of 2; (ii) reduces the fuel consumption and emissions by up to 20%; and (iii) has social implications as it increases driver comfort and safety. As platooning research progresses, platooning coordination becomes a major research focus. The coordination of platoons, including the assignment of vehicles to platoons, the management of inter- and intra-platoon interactions, and the coordination of interactions with other vehicles is an important step towards an effective usage of platooning in practice. Based on a literature review of 1,600 papers, this survey provides an overview of state of the art in platooning coordination research for both cars and trucks. In this paper, we present a novel taxonomy for platooning coordination and classify existing approaches. We use the results of the literature review to discuss challenges and outline avenues for future work such as multi-objectiveness and individualisation.@article{lesch2021overview, author = {Lesch, Veronika and Breitbach, Martin and Segata, Michele and Becker, Christian and Kounev, Samuel and Krupitzer, Christian}, doi = {10.1109/TITS.2021.3115908}, title = {{An Overview on Approaches for Coordination of Platoons}}, pages = {10049--10065}, journal = {IEEE Transactions on Intelligent Transportation Systems}, issn = {1558-0016}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, month = {8}, number = {8}, volume = {23}, year = {2022} } - , “Driving Under Influence: Robust Controller Migration for MEC-Enabled Platooning,” Elsevier Computer Communications, vol. 194, pp. 135–147, Oct. 2022 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Connected cars are becoming more common. With the development of multi-access edge computing (MEC) for low-latency applications, it will be possible to manage the cooperative adaptive cruise control (CACC, also known as platooning) of such vehicles from the edge of cellular networks. In this paper, we present a controller that carries out platooning from the network edge by adapting to varying network conditions. We incorporate a mechanism in the controller that allows vehicles to switch to automated cruise control when delays exceed safety thresholds, and switches back to platooning when the delays are sufficiently low to support it. We also formulate the problem of maintaining a low-latency connection in the presence of high mobility through migration and propose a Q-Learning algorithm to solve this problem. We finally propose an Asynchronous Shared Learning scheme that enables multiple migration agents to cooperate, in order to expedite the convergence of migration policies. Compared to state-of-the-art migration techniques, our scheme exhibits better compliance of vehicle speed and spacing values to preset targets, and ameliorates statistical dispersion.@article{ayimba2022driving, author = {Ayimba, Constantine and Segata, Michele and Casari, Paolo and Mancuso, Vincenzo}, doi = {10.1016/j.comcom.2022.07.014}, title = {{Driving Under Influence: Robust Controller Migration for MEC-Enabled Platooning}}, pages = {135--147}, journal = {Elsevier Computer Communications}, issn = {0140-3664}, publisher = {Elsevier}, month = {10}, volume = {194}, year = {2022} } - , “Cooperative driving: A comprehensive perspective, the role of communications, and its potential development,” Elsevier Computer Communications, vol. 193, pp. 82–93, Sep. 2022 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Inter-vehicle communications may have many reasons to be, but improving road safety and efficiency is arguably the only reason that may differentiate them from other communication infrastructures and justify a special effort in their study and deployment. This work overviews (some of) the past research on the topic to draw some lessons for the future, and tries to dissipate some of the fog that still veils the future of cooperative and autonomous vehicles: Can communications improve mobility or selfish-autonomous vehicles will dominate roads in the future? The paper is not a survey, but rather a critical analysis of what Cooperative Driving (CD) means and how communication is essential for some functions and useful for others, never detrimental. We dedicate a special part to platooning, as iconic application of CD, one of the most studied and also closer to be market ready, at least technologically. A final section discusses the potentialities of CD and what threatens its adoption.@article{locigno2022cooperative, author = {Lo Cigno, Renato and Segata, Michele}, doi = {10.1016/j.comcom.2022.06.034}, title = {{Cooperative driving: A comprehensive perspective, the role of communications, and its potential development}}, pages = {82--93}, journal = {Elsevier Computer Communications}, issn = {0140-3664}, publisher = {Elsevier}, month = {9}, volume = {193}, year = {2022} } - , “A Taxonomy of Optimization Factors for Platooning,” IEEE Transactions on Intelligent Transportation Systems, vol. 22, no. 10, 2021 [BibTeX file, PDF, Details...]
BibTeX & Abstract
The technical maturity of autonomous driving enables the discussion of beneficial use cases to leverage its full potential. In this paper, we target one such use case: Platooning is the efficient convoying of vehicles by making use of self-driving capabilities and inter-vehicle communication. Many advantages arise from grouping vehicles in platoons with a small inter-vehicle distance, such as energy savings, congestion reduction, and safety improvements. However, due to the diversity of involved stakeholders, numerous objectives have to be balanced to leverage the full potential of platooning. Furthermore, these objectives also depend on various factors that influence their optimization. The vast majority of existent literature only targets a subset of related objectives and underlying factors. This paper provides an overview which categorizes objectives and influencing factors. Additionally, metrics for the evaluation of objective attainment are proposed.@article{sturm2020taxonomy, author = {Sturm, Timo and Krupitzer, Christian and Segata, Michele and Becker, Christian}, doi = {10.1109/TITS.2020.2994537}, title = {{A Taxonomy of Optimization Factors for Platooning}}, journal = {IEEE Transactions on Intelligent Transportation Systems}, issn = {1558-0016}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, number = {10}, volume = {22}, year = {2021} } - , “A Comparison of Mechanisms for Compensating Negative Impacts of System Integration,” Elsevier Future Generation Computer Systems, vol. 116, pp. 117–131, Mar. 2021 [BibTeX file, PDF, Details...]
BibTeX & Abstract
The demand for passenger and freight transportation has grown sharply over the last decades and will triple by 2050. This also dramatically impacts the environment as traffic is one of the primary sources of CO2 emission. Platooning, which is defined as driving automated vehicles in convoys with minimal inter-vehicle distance enabled by vehicular communication, offers several benefits like energy savings due to slipstream effects, homogenization of traffic flows, increased capacity of streets, as well as improved safety due to communication. However, as the vehicles at inner positions of a platoon experience higher benefits than the first and last vehicle, the compensation of the effects of different positions in a platoon have to be taken into account when integrating vehicles in a platoon. In this paper, we discuss several strategies on how to incentivize vehicles to participate in platooning based on directly or indirectly compensating vehicles for fewer benefits resulting from the integration into a platooning system. Our considerations integrate ideas from research about altruism, social sciences, organ donation, task scheduling on computers, as well as professional cycling sports. Our experiments show that the time spent in a position with negative effects is split equally among all vehicles when using our mechanisms. Additionally, we found that characteristics of the environment – e.g., the number of lanes or traffic density – impact the performance of the compensation mechanisms. We further provide a discussion of the identified challenges and on how to apply our proposed ideas to other systems which require self-integration.@article{lesch2021comparison, author = {Lesch, Veronika and Krupitzer, Christian and Stubenrauch, Kevin and Keil, Nico and Becker, Christian and Kounev, Samuel and Segata, Michele}, doi = {10.1016/j.future.2020.10.029}, title = {{A Comparison of Mechanisms for Compensating Negative Impacts of System Integration}}, pages = {117--131}, journal = {Elsevier Future Generation Computer Systems}, issn = {0167-739X}, publisher = {Elsevier}, month = {3}, volume = {116}, year = {2021} } - , “Platooning Maneuvers in Vehicular Networks: a Distributed and Consensus-Based Approach,” IEEE Transactions on Intelligent Vehicles, vol. 4, no. 1, pp. 59–72, Mar. 2019 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Cooperative driving is an essential component of future intelligent road systems. It promises greater safety, reducing accidents due to drivers distraction, improved infrastructure utilization, and fuel consumption reduction with platooning applications. Proper platoon management requires Inter-Vehicular Communication (IVC), longitudinal control and stability, lateral control for and safety, and protocols, proper application and platoons, algorithms to manage and perform coordinated maneuvers.This work shows how a longitudinal controller based on distributed consensus can, at the same time, guarantee stability and performance in regime platoon operations, and protocols, be at the hearth of maneuvering and algorithms, as it remains stable in face of changes of platoon topology and system, control gains. The adoption of a single control algorithm for two fundamental tasks greatly simplify the overall design of the and stability, improves and mobility, safety as it is not required to switch between different controllers during platoon operation. The theoretical properties are proven in the first part of the paper. The second part of the paper is devoted to its implementation in a state-of- the-art and IVC simulator, which is used for an extensive experimental campaign showing the dynamic properties of the system and its performance in a set of typical platoon maneuvers as join, leave and inclusion of a vehicle in the middle of the platoon. All simulations include realistic details of the vehicle dynamics (mass, dimensions, power train dynamics) as well as extremely detailed modeling of the communication network, from 802.11p protocol details, to collisions, packet errors, path loss and fading on the channel, and delays., source-destination based@article{santini2019platooning, author = {Santini, Stefania and Salvi, Alessandro and Valente, Antonio Saverio and Pescap{\`{e}}, Antonio and Segata, Michele and Lo Cigno, Renato}, doi = {10.1109/TIV.2018.2886677}, title = {{Platooning Maneuvers in Vehicular Networks: a Distributed and Consensus-Based Approach}}, pages = {59--72}, journal = {IEEE Transactions on Intelligent Vehicles}, issn = {2379-8904}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, month = {3}, number = {1}, volume = {4}, year = {2019} } - , “Cooperative Driving and the Tactile Internet,” Proceedings of the IEEE, vol. 107, no. 2, pp. 436–446, Feb. 2019 [BibTeX file, PDF, Details...]
BibTeX & Abstract
The trend towards autonomous driving and the recent advances in vehicular networking led to a number of very successful proposals towards cooperative driving. Maneuvers can be coordinated among participating vehicles and controlled by means of wireless communications. One of the most challenging scenario or application in this context is Cooperative Adaptive Cruise Control (CACC) or platooning. When it comes to realizing safety gaps between the cars of less than 5m, very strong requirements on the communication system need to be satisfied. The underlying distributed control system needs regular updates of sensor information from the other cars in the order of about 10 Hz. This leads to message rates in the order of up to 10 kHz for large networks, which, given the possibly unreliable wireless communication and the critical network congestion, is beyond the capabilities of current vehicular networking concepts. In this article, we summarize the concepts of networked control systems and revisit the capabilities of current vehicular networking approaches. We then present opportunities of Tactile Internet concepts that integrate interdisciplinary approaches from both control theory, mechanical engineering, and communication protocol design. This way, it becomes possible to solve the high reliability and latency issues in this context.@article{dressler2019cooperative, author = {Dressler, Falko and Klingler, Florian and Segata, Michele and Lo Cigno, Renato}, doi = {10.1109/JPROC.2018.2863026}, title = {{Cooperative Driving and the Tactile Internet}}, pages = {436--446}, journal = {Proceedings of the IEEE}, issn = {0018-9219}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, month = {2}, number = {2}, volume = {107}, year = {2019} } - , “The joint network/control design of platooning algorithms can enforce guaranteed safety constraints,” Elsevier Ad Hoc Networks, vol. 94, Nov. 2019 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Vehicular networks supporting cooperative driving are among the most interesting and challenging ad-hoc networks. Platooning, or the act of coordinating a set of vehicles through an ad-hoc network, promises to improve traffic safety, and at the same time reduce congestion and pollution. The design of the control system for this application is challenging, especially because the coordination and cooperation between vehicles is obtained through a wireless network. So far, control and network issues of platooning have been investigated separately, but this is definitely a sub-optimal approach, as constraints of the networked control system impose bounds on the network performance, and network impairments translate into disturbances on the controlled system. In this work we design a cooperative driving system from a joint network and control perspective, determining upper bounds on the error subject to packet losses in the network, so that the actual inter-vehicle gap can be tuned depending on vehicle or network performance. Extensive simulations show that the system is very robust to packet losses and that the derived bounds are never violated. In addition, since the leader control law is part of the proposed control approach, we show that, besides taking into account external events and reacting within the given constraints to ensure the overall road safety, the system can be easily integrated into global traffic optimization tools that mandate the platoon behavior.@article{giordano2019joint, author = {Giordano, Giulia and Segata, Michele and Blanchini, Franco and Lo Cigno, Renato}, doi = {10.1016/j.adhoc.2019.101962}, title = {{The joint network/control design of platooning algorithms can enforce guaranteed safety constraints}}, journal = {Elsevier Ad Hoc Networks}, issn = {1570-8705}, publisher = {Elsevier}, month = {11}, volume = {94}, year = {2019} } - , “Performance Assessment of IEEE 802.11p with an Open Source SDR-based Prototype,” IEEE Transactions on Mobile Computing, vol. 17, no. 5, pp. 1162–1175, May 2018 [BibTeX file, PDF, Details...]
BibTeX & Abstract
We present a complete simulation and experimentation framework for IEEE 802.11p. The core of the framework is an SDR-based OFDM transceiver that we validated extensively by means of simulations, interoperability tests, and, ultimately, by conducting a field test. Being SDR-based, the transceiver offers important benefits: It provides access to all data down to and including the physical layer, allowing for a better understanding of the system. Based on open and programmable hardware and software, the transceiver is completely transparent and all implementation details can be studied and, if needed, modified. Finally, it enables a seamless switch between simulations and experiments and, thus, helps to bridge the gap between theory and practice. Comparing the transceiver’s performance with independent results from simulations and experiments, we underline its potential to be used as a tool for further studies of IEEE 802.11p networks both in field operational tests as well as for simulation-based development of novel physical layer solutions. To make the framework accessible to fellow researchers and to allow reproduction of the results, we released it under an Open Source license.@article{bloessl2018performance, author = {Bloessl, Bastian and Segata, Michele and Sommer, Christoph and Dressler, Falko}, doi = {10.1109/TMC.2017.2751474}, title = {{Performance Assessment of IEEE 802.11p with an Open Source SDR-based Prototype}}, pages = {1162--1175}, journal = {IEEE Transactions on Mobile Computing}, issn = {1536-1233}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, month = {5}, number = {5}, volume = {17}, year = {2018} } - , “A Consensus-based Approach for Platooning with Inter-Vehicular Communications and its Validation in Realistic Scenarios,” IEEE Transactions on Vehicular Technology, vol. 66, no. 3, pp. 1985–1999, Mar. 2017 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Automated and coordinated vehicles’ driving (platooning) is very challenging due to the multi-body control complexity and the presence of unreliable, time-varying wireless Inter-Vehicular Communication (IVC). We propose a novel controller for vehicle platooning based on consensus and analytically demonstrate its stability and dynamic properties. Traditional approaches assume the logical control topology as a constraint fixed a priori, and the control law is designed consequently; our approach makes the control topology a design parameter that can be exploited to reconfigure the controller depending on the needs and scenario characteristics. Furthermore, the controller automatically compensates outdated information caused by network losses and delays. The controller is implemented in PLEXE, a state of the art IVC and mobility simulator that includes basic building blocks for platooning. Analysis and simulations show the controller robustness and performance in several scenarios, including realistic propagation conditions with interference caused by other vehicles. We compare our approach against a controller taken from literature, which is generally considered among the most performing ones. Finally, we test the proposed controller by implementing the real dynamics (engine, transmission, braking systems, etc.) of heterogeneous vehicles in PLEXE and verifying that platoons remain stable and safe regardless of real life impairments that cannot be modeled in the analytic solution. The results show the ability of the proposed approach to maintain a stable string of realistic vehicles with different control-communication topologies even in the presence of strong interference, delays, and fading conditions, providing higher comfort and safety for platoon drivers.@article{santini2017consensusbased, author = {Santini, Stefania and Salvi, Alessandro and Valente, Antonio Saverio and Pescap{\`{e}}, Antonio and Segata, Michele and Lo Cigno, Renato}, doi = {10.1109/TVT.2016.2585018}, title = {{A Consensus-based Approach for Platooning with Inter-Vehicular Communications and its Validation in Realistic Scenarios}}, pages = {1985--1999}, journal = {IEEE Transactions on Vehicular Technology}, issn = {1939-9359}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, month = {3}, number = {3}, volume = {66}, year = {2017} } - , “Let’s Talk in Groups: A Distributed Bursting Scheme for Cluster-based Vehicular Applications,” Elsevier Vehicular Communications, vol. 8, pp. 2–12, Apr. 2017 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Clustering has been an important concept in the scope of vehicular networks. The idea is to reduce channel contention, enable building backbones and might improve spatial reuse. We propose a seemingly simple, yet unexplored idea: extending IEEE 802.11 frame bursting MAC access to multiple stations aggregated into a cluster. We call this approach Distributed EDCA Bursting (DEB). The focus of our work is not on building clusters, but exploring what is the gain that can be achieved by the standard IEEE 802.11p channel access if we introduce the principle of frame bursting (presently not allowed in IEEE 802.11p standard, but the key factor for the efficiency of IEEE 802.11n/ac WiFi channel access). The fundamental idea is to extend the standard frame bursting mechanism so that only the cluster head contends for the channel. Upon winning the contention, the reserved transmission opportunity is shared among the vehicles in the cluster, which transmit a coordinated burst of frames. We describe the idea in detail, particularly analyzing theoretical benefits and limitations of the approach. We implement DEB in the platooning simulation framework Plexe-Veins and analyze its behavior under different loads (i.e., number of vehicles sharing the channel), transmit power policies, and different MAC and physical layer parameters. We present benefits and drawbacks of our approach, showing that it can overcome channel limits in saturation conditions, reduce channel usage at moderate loads, and improve spatial reuse. Moreover, by coordinating and distributing channel access, DEB reduces the number of collisions at the expenses of a slightly increased average beacon inter-arrival time.@article{segata2017lets, author = {Segata, Michele and Dressler, Falko and Lo Cigno, Renato}, doi = {10.1016/j.vehcom.2016.11.006}, title = {{Let's Talk in Groups: A Distributed Bursting Scheme for Cluster-based Vehicular Applications}}, pages = {2--12}, journal = {Elsevier Vehicular Communications}, issn = {2214-2096}, publisher = {Elsevier}, month = {4}, volume = {8}, year = {2017} } - , “Enabling Situation Awareness at Intersections for IVC Congestion Control Mechanisms,” IEEE Transactions on Mobile Computing, vol. 15, no. 7, pp. 1674–1685, Jun. 2016 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Intersection Assistance Systems (IAS) aim to assist road users in avoiding collisions at intersections, either by warning the driver or by triggering automated actions. Such a system can be realized based on passive scanning only (e.g., using LiDAR) or supported by active Inter-Vehicle Communication (IVC). The main reason to use IVC is its ability to provide situation awareness even when a possible crash candidate is not yet in visual range. The IVC research community has identified beaconing, i.e., one-hop broadcast, as the primary communication primitive for vehicular safety applications. Recently, adaptive beaconing approaches have been studied and different congestion control mechanisms have been proposed to cope with the diverse demands of vehicular networks. In this paper, we show that current state-of-the-art congestion control mechanisms are not able to support IAS adequately. Specifically, current approaches fail due to their inherent fairness postulation, i.e., they lack fine grained prioritization. We propose a solution that extends congestion control mechanisms by allowing temporary exceptions for vehicles in dangerous situations, that is, situation-based rate adaptation. We show the applicability for two state-of-the-art congestion control mechanisms, namely Transmit Rate Control (TRC) and Dynamic Beaconing (DynB), in two different vehicular environments, rural and downtown.@article{joerer2016enabling, author = {Joerer, Stefan and Bloessl, Bastian and Segata, Michele and Sommer, Christoph and Lo Cigno, Renato and Jamalipour, Abbas and Dressler, Falko}, doi = {10.1109/TMC.2015.2474370}, title = {{Enabling Situation Awareness at Intersections for IVC Congestion Control Mechanisms}}, pages = {1674--1685}, journal = {IEEE Transactions on Mobile Computing}, issn = {1536-1233}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, month = {6}, number = {7}, volume = {15}, year = {2016} } - , “Towards Communication Strategies for Platooning: Simulative and Experimental Evaluation,” IEEE Transactions on Vehicular Technology, vol. 64, no. 12, pp. 5411–5423, Dec. 2015 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Platooning, the idea of cars autonomously following their leaders to form a road train, has huge potentials to improve traffic flow efficiency and, most importantly, road traffic safety. Wireless communication is a fundamental building block - it is needed to manage and to maintain the platoons. To keep the system stable, strict constraints in terms of update frequency and communication reliability must be met. We investigate different communication strategies by explicitly taking into account the requirements of the controller, exploiting synchronized communication slots as well as transmit power adaptation. As a baseline, we compared the proposed approaches to two state of the art adaptive beaconing protocols that have been designed for cooperative awareness applications, namely ETSI DCC and DynB. Our simulation models have been parameterized and validated by means of real-world experiments. Our results demonstrate that the combination of synchronized communication slots with transmit power adaptation is perfectly suited for cooperative driving applications, even in very crowded freeway scenarios.@article{segata2015communication, author = {Segata, Michele and Bloessl, Bastian and Joerer, Stefan and Sommer, Christoph and Gerla, Mario and Lo Cigno, Renato and Dressler, Falko}, doi = {10.1109/TVT.2015.2489459}, title = {{Towards Communication Strategies for Platooning: Simulative and Experimental Evaluation}}, pages = {5411--5423}, journal = {IEEE Transactions on Vehicular Technology}, issn = {1939-9359}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, month = {12}, number = {12}, volume = {64}, year = {2015} } - , “How Shadowing Hurts Vehicular Communications and How Dynamic Beaconing Can Help,” IEEE Transactions on Mobile Computing, vol. 14, no. 7, pp. 1411–1421, Jul. 2015 [BibTeX file, PDF, Details...]
BibTeX & Abstract
We study the effect of radio signal shadowing dynamics, caused by vehicles and by buildings, on the performance of beaconing protocols in Inter-Vehicular Communication (IVC). Recent research indicates that beaconing, i.e., one hop message broadcast, shows excellent characteristics and can outperform other communication approaches for both safety and efficiency applications, which require low latency and wide area information dissemination, respectively. To mitigate the broadcast storm problem, adaptive beaconing solutions have been proposed and designed. We show how shadowing dynamics of moving obstacles hurt IVC, reducing the performance of beaconing protocols. To the best of our knowledge, this is one of the first studies on identifying the problem and the underlying challenges and proposing the opportunities presented by such challenges. Shadowing also limits the risk of overloading the wireless channel. We demonstrate how these challenges and opportunities can be taken into account and outline a novel approach to dynamic beaconing. It provides low-latency communication (i.e., very short beaconing intervals), while ensuring not to overload the wireless channel. The presented simulation results substantiate our theoretical considerations.@article{sommer2015how, author = {Sommer, Christoph and Joerer, Stefan and Segata, Michele and Tonguz, Ozan K. and Lo Cigno, Renato and Dressler, Falko}, doi = {10.1109/TMC.2014.2362752}, title = {{How Shadowing Hurts Vehicular Communications and How Dynamic Beaconing Can Help}}, pages = {1411--1421}, journal = {IEEE Transactions on Mobile Computing}, issn = {1536-1233}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, month = {7}, number = {7}, volume = {14}, year = {2015} } - , “A Vehicular Networking Perspective on Estimating Vehicle Collision Probability at Intersections,” IEEE Transactions on Vehicular Technology, vol. 63, no. 4, pp. 1802–1812, May 2014 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Finding viable metrics to assess the effectiveness of Intelligent Transportation Systems (ITS) in terms of ’safety’ is one of the major challenges in vehicular networking research. We aim to provide a metric, an estimation of the vehicle collision probability at intersections, that can be used for evaluating Inter-Vehicle Communication (IVC) concepts. In the last years, the vehicular networking community reported in several studies that safety enhancing protocols and applications cannot be evaluated based only on networking metrics like delays and packet loss rates. We present an evaluation scheme that addresses this need by quantifying the probability of a future crash, depending on the situation in which a vehicle is receiving a beacon message (e.g., a CAM or a BSM). Thus, our criticality metric also allows for fully distributed situation assessment. We investigate the impact of safety messaging between cars approaching an intersection using a modified road traffic simulator that allows selected vehicles to disregard traffic rules. As direct result we show that simple beaconing is not as effective as anticipated in suburban environments. More profoundly, however, our simulation results reveal more details about the timeliness (regarding the criticality assessment) of beacon messages, and as such, can be used to develop more sophisticated beaconing solutions.@article{joerer2014vehicular, author = {Joerer, Stefan and Segata, Michele and Bloessl, Bastian and Lo Cigno, Renato and Sommer, Christoph and Dressler, Falko}, doi = {10.1109/TVT.2013.2287343}, title = {{A Vehicular Networking Perspective on Estimating Vehicle Collision Probability at Intersections}}, pages = {1802--1812}, journal = {IEEE Transactions on Vehicular Technology}, issn = {1939-9359}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, month = {5}, number = {4}, volume = {63}, year = {2014} } - , “Automatic Emergency Braking - Realistic Analysis of Car Dynamics and Network Performance,” IEEE Transactions on Vehicular Technology, vol. 62, no. 9, pp. 4150–4161, Nov. 2013 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Safety applications are among the key drivers in vehicular ad hoc network (VANET) research, and their true performance can be only assessed if the application and the communication network are jointly considered. This paper presents a simulation study of an emergency braking (EB) application accomplished by embedding mobility, cars’ dynamic, and drivers’ behavior models into a detailed networking simulator (ns-3). The overall system allows capturing the interactions of the communications with the car’s automated braking mechanism (ABM) and the driver’s behavior. At the same time, it yields very detailed information on the communication level. In addition to the integrated tool, this paper presents a novel and simple message aggregation mechanism to empower message repropagation while controlling the network congestion during the peak load due to EB. Then, it discusses the effectiveness of such applications as a function of the market penetration rate (MPR), showing that even cars that are not equipped with communication devices benefit from the smoother and earlier reaction of the cars that can communicate. Fading phenomena and sensitivity to the radio transmitted power are analyzed, whereas the fine-grained dynamics of cars’ collisions, taking into account different masses and different elastic coefficients, are introduced to evaluate the severity of impacts.@article{segata2013automatic, author = {Segata, Michele and Lo Cigno, Renato}, doi = {10.1109/TVT.2013.2277802}, title = {{Automatic Emergency Braking - Realistic Analysis of Car Dynamics and Network Performance}}, pages = {4150--4161}, journal = {IEEE Transactions on Vehicular Technology}, issn = {1939-9359}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, month = {11}, number = {9}, volume = {62}, year = {2013} } - , “A Simulation Tool for Automated Platooning in Mixed Highway Scenarios,” ACM SIGMOBILE Mobile Computing and Communications Review, vol. 16, no. 4, pp. 46–49, Oct. 2012 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Automated platooning is one of the most challenging fields in the domain of Intelligent Transportation Systems (ITS). Conceptually, platooning means creating clusters of vehicles which closely follow each other autonomously without action of the driver, neither for accelerating, nor for braking. This leads to several important benefits from substantially improved road throughput to increased safety. The control of such platoons depends on two components: First, radar is typically to be used to control the distance between the vehicles, and secondly, Inter-Vehicle Communication (IVC) helps managing the entire platoon allowing cars to join or to leave the group whenever necessary. Platooning systems have been mostly investigated in controlled environments such as dedicated highways with centralized management. However, platooning-enabled cars will be deployed gradually and might have to travel on highways together with other non-automated vehicles. We developed a combined traffic and network simulator for studying strategies and protocols needed for managing platoons in such mixed scenarios. We show the models needed and present first results using a simple IVC-based platoon management as a proof of concept.@article{segata2012simulation2, author = {Segata, Michele and Dressler, Falko and Lo Cigno, Renato and Gerla, Mario}, doi = {10.1145/2436196.2436218}, title = {{A Simulation Tool for Automated Platooning in Mixed Highway Scenarios}}, ccs-acm_authorize = {http://dl.acm.org/authorize?6897512}, pages = {46--49}, journal = {ACM SIGMOBILE Mobile Computing and Communications Review}, issn = {1559-1662}, publisher = {Association for Computing Machinery (ACM)}, month = {10}, number = {4}, volume = {16}, year = {2012} }
Conferences and workshops
- , “ColosSUMO: Evaluating Cooperative Driving Applications with Colosseum,” in 15th IEEE Vehicular Networking Conference (VNC 2024), Kobe, Japan, May 2024 [BibTeX file, PDF, Details...]
BibTeX & Abstract
The quest for safer and more efficient transportation through cooperative, connected and automated mobility (CCAM) calls for realistic performance analysis tools, especially with respect to wireless communications. While the simulation of existing and emerging communication technologies is an option, the most realistic results can be obtained by employing real hardware, as done for example in field operational tests (FOTs). For CCAM, however, performing FOTs requires vehicles, which are generally expensive. and performing such tests can be very demanding in terms of manpower, let alone considering safety issues. Mobility simulation with hardware-in-the-loop (HIL) serves as a middle ground, but current solutions lack flexibility and reconfigurability. This work thus proposes ColosSUMO as a way to couple Colosseum, the world’s largest wireless network emulator, with the SUMO mobility simulator, showing its design concept, how it can be exploited to simulate realistic vehicular environments, and its flexibility in terms of communication technologies.@inproceedings{gemmi2024colossumo, author = {Gemmi, Gabriele and Johari, Pedram and Casari, Paolo and Polese, Michele and Melodia, Tommaso and Segata, Michele}, title = {{ColosSUMO: Evaluating Cooperative Driving Applications with Colosseum}}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, issn = {2157-9865}, address = {Kobe, Japan}, booktitle = {15th IEEE Vehicular Networking Conference (VNC 2024)}, month = {5}, year = {2024} } - , “Can Platoons Form on Their Own?,” in 15th IEEE Vehicular Networking Conference (VNC 2024), Kobe, Japan, May 2024, pp. 180–187 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Research on platooning has tackled many different facets of the topic, from lateral and longitudinal control to algorithms for optimization of platoon size and coordination. However, very few works started addressing the following two foundational questions. The first: Given a stretch of road where platooning is enabled and some form of V2X communication is feasible, will vehicles be able to organize locally in platoons without the need of central intervention? The second: Is a coordination protocol for platoon formation possible, or will traffic dynamics prevent the efficient formation of platoons? This paper gives a first, positive answer to these questions: A platoon formation protocol is proposed and tested upon DSRC communications, though it can be implemented on top of any transmission technology. We assess the performance in terms of platoon formation efficiency, on a multi-lane highway, as a function of the penetration rate of platooning-enabled vehicles and traffic characteristics. Realistic simulation results highlight the properties of the protocol as well as the impact of different traffic parameters, foremost the penetration rate and maximum distance between vehicles considered to start a platoon negotiation. These initial results pave the road for more sophisticated analysis, enhancements of the protocol and evaluation of advanced -possibly centralized- approaches to improve platoon management to achieve safer roads with increased capacity.@inproceedings{ghiro2024platoons, author = {Ghiro, Lorenzo and Lo Cigno, Renato and Tonini, Elena and Fontana, Stefano and Segata, Michele}, doi = {10.1109/VNC61989.2024.10575981}, title = {{Can Platoons Form on Their Own?}}, pages = {180--187}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, issn = {2157-9865}, address = {Kobe, Japan}, booktitle = {15th IEEE Vehicular Networking Conference (VNC 2024)}, month = {5}, year = {2024} } - , “On the Feasibility of RIS-enabled Cooperative Driving,” in 14th IEEE Vehicular Networking Conference (VNC 2023), Istanbul, Turkey, Apr. 2023 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Future cooperative autonomous vehicles will require high-performance communication means to support such functions as cooperative maneuvering and cooperative perception. The high-bandwidth requirements of these functions can be met through mmWave communications, whose utilization is often hindered by the harsh propagation conditions of typical vehicular environments. A solution to this problem is the use of reconfigurable intelligent surfaces (RISs), which enable the reflection of signals in a configurable direction, and have recently gained attention in the vehicular domain. In this paper, we provide an initial feasibility study, highlighting the challenges ahead and the performance RISs need to deliver in order to enable this type of communications. Specifically, we utilize CoopeRIS, a simulation framework for RISs integrated into the Plexe/Veins/SUMO ecosystem that we developed and that we plan to release to the public.@inproceedings{segata2023feasibility, author = {Segata, Michele and Casari, Paolo and Lestas, Marios and Tyrovolas, Dimitrios and Saeed, Taqwa and Karagiannidis, George K. and Liaskos, Christos}, doi = {10.1109/VNC57357.2023.10136324}, title = {{On the Feasibility of RIS-enabled Cooperative Driving}}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, issn = {2157-9865}, address = {Istanbul, Turkey}, booktitle = {14th IEEE Vehicular Networking Conference (VNC 2023)}, month = {4}, year = {2023} } - , “Enabling Cooperative Autonomous Driving Through mmWave and Reconfigurable Intelligent Surfaces,” in 18th IEEE/IFIP Conference on Wireless On demand Network Systems and Services (WONS 2023), Madonna di Campiglio, Italy, Jan. 2023 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Future cooperative autonomous vehicles will be able to organize into flexible platoons to improve both the efficiency and the safety of driving. However, platooning requires dependable coordination through the periodic wireless exchange of control messages. Therefore, challenging propagation scenarios as found, e.g., in dense urban areas, may hinder coordination and lead to undesirable vehicle behavior. While reconfigurable intelligent surfaces (RISs) have been advocated as a solution to improper coverage issues, no system-level simulation exists that accounts for realistic road mobility and communication aspects. To this end, we present one such simulator built on top of the OMNeT++-based PLEXE and Veins frameworks. Specifically, our contribution is a simulator that takes into account vehicle mobility, physical layer propagation, RIS coding, and networking protocols. To test our simulator, we implement an RIS-assisted autonomous platoon merging maneuver taking place at an intersection where the absence of any RIS would limit successful communications to an area dangerously close to the intersection itself. Our results validate the simulator as a feasible tool for system-level RIS-assisted cooperative autonomous vehicle maneuvering, and ultimately show the benefit of RIS as roadside infrastructure for wireless coverage extension.@inproceedings{segata2023enabling, author = {Segata, Michele and Lestas, Marios and Casari, Paolo and Saeed, Taqwa and Tyrovolas, Dimitrios and Karagiannidis, George K. and Liaskos, Christos}, doi = {10.23919/WONS57325.2023.10062109}, title = {{Enabling Cooperative Autonomous Driving Through mmWave and Reconfigurable Intelligent Surfaces}}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, address = {Madonna di Campiglio, Italy}, booktitle = {18th IEEE/IFIP Conference on Wireless On demand Network Systems and Services (WONS 2023)}, month = {1}, year = {2023} } - , “Vehicles or Pedestrians: On the gNB Placement in Ultradense Urban Areas,” in 18th IEEE/IFIP Conference on Wireless On demand Network Systems and Services (WONS 2023), Madonna di Campiglio, Italy, Jan. 2023 [BibTeX file, PDF, Details...]
BibTeX & Abstract
This paper tackles the problem of base stations placement to guarantee line of sight connectivity to vehicles in urban areas, when high frequency communications (mmWave or TeraHertz) are used. Our novel methodology takes advantage of vehicular traffic simulation to generate a realistic demand model for vehicles in urban areas. Then, through a bounded error heuristic, find the maximal coverage that can be achieved with a given density of base stations. The heuristic is implemented on GPU and used to evaluate the coverage in a densely urbanized area in the city of Luxembourg. Our results indicate that a reasonably low density (20 base stations per km²) is sufficient to provide coverage for vehicles in urban environments. However, optimizing solely on vehicles negatively affects the coverage of pedestrians.@inproceedings{gemmi2023vehicles, author = {Gemmi, Gabriele and Segata, Michele and Maccari, Leonardo}, doi = {10.23919/WONS57325.2023.10062000}, title = {{Vehicles or Pedestrians: On the gNB Placement in Ultradense Urban Areas}}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, address = {Madonna di Campiglio, Italy}, booktitle = {18th IEEE/IFIP Conference on Wireless On demand Network Systems and Services (WONS 2023)}, month = {1}, year = {2023} } - , “A Critical Assessment of CV2X Resource Allocation Scheme for Platooning Applications,” in 16th IEEE/IFIP Conference on Wireless On demand Network Systems and Services (WONS 2021), Virtual Conference, Mar. 2021, pp. 39–46 [BibTeX file, PDF, Details...]
BibTeX & Abstract
V2X stands for vehicular to everything communications, but its definition is so vast that it does not even encompass a specific transmission technology. Up to a few years ago the only standardized technology for V2X was 802.11p and the protocol suites built on top of like DSRC and ITS-G5. In recent years, however, Cellular-V2X defined both for LTE and for the upcoming 5G New Radio interfaces is drawing a lot of attention and seems to have a broader support from the automotive and telecom industry compared to 802.11p. C-V2X standardization however, has been slow, but most of all lacks the elegant simplicity of 802.11p, so that performance analysis of automotive applications on top of C-V2X are still very limited. This work presents initial results for platooning applications, highlighting the presence of severe impairments in the resource allocation schemes of C-V2X Out of Coverage modes that, if not corrected in future releases of the standards may hamper the development of this promising technology.@inproceedings{segata2021critical, author = {Segata, Michele and Arvani, Piermaria and Lo Cigno, Renato}, doi = {10.23919/WONS51326.2021.9415551}, title = {{A Critical Assessment of CV2X Resource Allocation Scheme for Platooning Applications}}, pages = {39--46}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, address = {Virtual Conference}, booktitle = {16th IEEE/IFIP Conference on Wireless On demand Network Systems and Services (WONS 2021)}, month = {3}, year = {2021} } - , “On the Progressive Introduction of Heterogeneous CACC Capabilities,” in 13th IEEE Vehicular Networking Conference (VNC 2021), Virtual Conference, Nov. 2021 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Can we introduce Cooperative Adaptive Cruise Control (CACC) technologies on the road without separated road infrastructures? This simple question is often latent in works dealing with cooperative driving, especially in feasibility analysis of cooperative driving. As of today, the question has indeed received no definitive answer in the literature because it is hard to model analytically heterogeneous systems or to experiment with them. This work helps understanding how vehicles interact among each others when they do not run a single, a-priory defined, CACC algorithm, but rather each vehicle adopt its own one. We introduce the concept of mixed platoon, i.e., a string of vehicles where more than one CACC algorithm is used, and we experiment with mixed platoons in silico to study how the mixture of CACC algorithms affects efficiency and safety. For instance we analyze scenarios where we progressively introduce homogeneous and mixed platoons among standard Adaptive Cruise Control (ACC) vehicles, quantifying the positive or negative effects on traffic efficiency and safety induced by the introduction of CACC technologies as a function of their penetration rate. The obtained results encourage additional research on the topic, starting from theoretical analysis of mixed platoons down to performance evaluations of actual implementations.@inproceedings{segata2021progressive, author = {Segata, Michele and Ghiro, Lorenzo and Lo Cigno, Renato}, doi = {10.1109/VNC52810.2021.9644621}, title = {{On the Progressive Introduction of Heterogeneous CACC Capabilities}}, ccs-awards = {Best Paper}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, issn = {2157-9865}, isbn = {978-1-66544-450-7}, address = {Virtual Conference}, booktitle = {13th IEEE Vehicular Networking Conference (VNC 2021)}, month = {11}, year = {2021} } - , “Closer than Close: MEC-Assisted Platooning with Intelligent Controller Migration,” in 24th ACM International Conference on Modeling, Analysis and Simulation of Wireless and Mobile Systems (MSWiM 2021), Virtual Conference, Nov. 2021 [BibTeX file, PDF, Details...]
BibTeX & Abstract
The advent of multi access edge computing (MEC) will enable latency-critical applications such as cooperative adaptive cruise control (also known as platooning) to be hosted at the edge of the network. MEC-based platooning will leverage the coverage of the cellular infrastructure to enable inter-vehicular communications, potentially overcoming crucial problems of vehicular ad-hoc networks (VANETs) such as non-trivial packet loss rates. However, MEC-based platooning will require the controller to be migrated to the most suitable positions at the network edge, in order to maintain low-latency connections as the platoon moves. In this paper, we propose a context-aware Q-learning algorithm that carries out such migrations only as often as is necessary, and thereby reduces the additional delays implicit in application migration across MEC hosts. When compared to the state of the art, our scheme exhibits better compliance of vehicle speed and spacing values to preset targets, as well as a reduced statistical dispersion.@inproceedings{ayimba2021closer, author = {Ayimba, Constantine and Segata, Michele and Casari, Paolo and Mancuso, Vincenzo}, doi = {10.1145/3479239.3485681}, title = {{Closer than Close: MEC-Assisted Platooning with Intelligent Controller Migration}}, address = {Virtual Conference}, booktitle = {24th ACM International Conference on Modeling, Analysis and Simulation of Wireless and Mobile Systems (MSWiM 2021)}, month = {11}, year = {2021} } - , “Modeling Slipstreaming Effects in Vehicle Platoons,” in 12th IEEE Vehicular Networking Conference (VNC 2020), Virtual Conference, Dec. 2020 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Vehicle platooning can produce significant fuel saving due to reduced aerodynamic drag. In the design of future cooperative driving systems, quantifying such benefits will be of utmost importance, because it will need to be considered in designing, forming and managing platoons. This work aims at developing an Open Source framework for modeling aerodynamics effects. We perform a Computational Fluid Dynamics (CFD) study about the aerodynamics of vehicle platoons, describe a model that exploits the resulting measurements, and implement it inside a road traffic simulator to show how savings can be estimated by means of simulations. Furthermore, we publish the necessary tools required to reproduce the results, enabling further research. Strictly speaking, this work does not deal with vehicular networks, but it contributes to tackle the problem of optimizing the management and control of platoons through proper use of communications, from the point of view of fuel consumption and battery usage.@inproceedings{segata2020modeling, author = {Segata, Michele and Stedile, Andrea and Lo Cigno, Renato}, doi = {10.1109/VNC51378.2020.9318331}, title = {{Modeling Slipstreaming Effects in Vehicle Platoons}}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, address = {Virtual Conference}, booktitle = {12th IEEE Vehicular Networking Conference (VNC 2020)}, month = {12}, year = {2020} } - , “Improving BGP Convergence with Fed4FIRE+ Experiments,” in 39th IEEE International Conference on Computer Communications (INFOCOM 2020), IEEE Workshop on Computer and Networking Experimental Research using Testbeds (CNERT 2020), Virtual Conference, Jul. 2020 [BibTeX file, PDF, Details...]
BibTeX & Abstract
The Border Gateway Protocol (BGP) is the single routing protocol that glues the Internet together. Its performance, especially the convergence speed after path changes, is key to global efficiency, also in light of the fact that the number of Autonomous Systems (ASes) and Subnets has reached a level that makes path changes a frequent event. This work presents a testbed-based experimental analysis of BGP convergence time under different hypothesis of Minimum Route Advertisement Interval (MRAI) setting and a proposal to improve it by setting MRAI based on the topological position of the ASes. MRAI is a timer that regulates the frequency of successive UPDATE messages sent by a BGPs router for a given route and destination. The work is based on the modifications of the BIRD BGP daemon and shows that it is possible to execute experiments on testbeds with topologies that have Internet-like characteristics scaling up to thousands of ASes.@inproceedings{milani2020improving, author = {Milani, Mattia and Nesler, Marco and Segata, Michele and Baldesi, Luca and Maccari, Leonardo and Lo Cigno, Renato}, doi = {10.1109/INFOCOMWKSHPS50562.2020.9162970}, title = {{Improving BGP Convergence with Fed4FIRE+ Experiments}}, address = {Virtual Conference}, booktitle = {39th IEEE International Conference on Computer Communications (INFOCOM 2020), IEEE Workshop on Computer and Networking Experimental Research using Testbeds (CNERT 2020)}, month = {7}, year = {2020} } - , “A Modular Simulation Framework for Analyzing Platooning Coordination,” in 20th ACM International Symposium on Mobile Ad Hoc Networking and Computing (MobiHoc 2019), 1st ACM Workshop on Technologies, mOdels, and Protocols for Cooperative Connected Cars (TOP-Cars 2019), Catania, Italy, Jul. 2019, pp. 25–30 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Recent developments by companies as Waymo, Uber, or Tesla show that autonomous driving is no science fiction anymore. Coordinated driving applications such as platooning, i.e., driving in convoys of coordinated vehicles, use the full potential of the automation. In this paper, we present a simulation framework for analyzing platooning coordination strategies which can be used by domain experts without experience in simulation as it abstract from the details of the underlying simulation. We show the applicability of the simulation framework to support the analysis of platooning coordination strategies in a case study with three coordination strategies.@inproceedings{krupitzer2019modular, author = {Krupitzer, Christian and Lesch, Veronika and Pfannem{\"{u}}ller, Martin and Becker, Christian and Segata, Michele}, doi = {10.1145/3331054.3331550}, title = {{A Modular Simulation Framework for Analyzing Platooning Coordination}}, pages = {25--30}, publisher = {Association for Computing Machinery (ACM)}, isbn = {978-1-4503-6807-0}, address = {Catania, Italy}, booktitle = {20th ACM International Symposium on Mobile Ad Hoc Networking and Computing (MobiHoc 2019), 1st ACM Workshop on Technologies, mOdels, and Protocols for Cooperative Connected Cars (TOP-Cars 2019)}, month = {7}, year = {2019} } - , “Towards Adaptive Car-to-Cloud Communication,” in 4th IEEE International Workshop on Pervasive Context-Aware Smart Cities and Intelligent Transport Systems (PerAwareCity’19), Athens, Greece, Mar. 2019 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Recent developments in communication technology have led to cloud resources becoming ubiquitous. These resources enable many new applications by offering computational power for remote embedded devices. In combination with advances in the area of smart driving, this seems to be especially beneficial for applications such as remote maintenance of vehicles or integration with smart city services. As autonomous driving continues to gain traction, Car-to-Cloud communication can support transferring collected data to the cloud, e.g., for dynamic learning of new map information. Additionally, passengers can benefit from novel entertainment services. All these developments require a stable connection between a mobile vehicle and the cloud resources. In this vision paper, we survey Car-to-Cloud communication applications. Based on the analysis of the varying requirements for these applications, we formulate research questions and challenges. Further, we discuss how these challenges can be addressed by means of an adaptive Car-to-Cloud communication middleware. We conclude with an overview on our activities in this area and an outlook on our planned future work on adaptive communication.@inproceedings{herrnleben2019adaptive, author = {Herrnleben, Stefan and Pfannem{\"{u}}ller, Martin and Krupitzer, Christian and Kounev, Samuel and Segata, Michele and Fastnacht, Felix and Nigmann, Magnus}, doi = {10.1109/PERCOMW.2019.8730766}, title = {{Towards Adaptive Car-to-Cloud Communication}}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, address = {Athens, Greece}, booktitle = {4th IEEE International Workshop on Pervasive Context-Aware Smart Cities and Intelligent Transport Systems (PerAwareCity'19)}, month = {3}, year = {2019} } - , “Markov-modulated Models to Estimate the Age of Information in Cooperative Driving,” in 11th IEEE Vehicular Networking Conference (VNC 2019), Los Angeles, CA, Dec. 2019 [BibTeX file, PDF, Details...]
BibTeX & Abstract
This short paper explores for the first time the possibility to model the Age of Information (AoI) in cooperative driving applications. A heuristic analysis shows that it is possible to model the AoI as a system modulated by a Semi-Markov process, where the states depend on the mobility and the radio environment. The dwell time in typical road networks cannot be assumed exponential, so that the model is not a simple Markov Modulated Poisson Process (MMPP), but rather a generic Markov Modulated Process with general dwell time and arbitrary distribution of the AoI. Future work includes the tuning of the model parameters in different scenarios, the characterization of the AoI distribution, validation tests, and obviously its use in the design of cooperative driving applications.@inproceedings{ploeger2019markovmodulated, author = {Pl{\"{o}}ger, Daniel and Segata, Michele and Lo Cigno, Renato and Timm-Giel, Andreas}, doi = {10.1109/VNC48660.2019.9062802}, title = {{Markov-modulated Models to Estimate the Age of Information in Cooperative Driving}}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, issn = {2157-9865}, isbn = {978-1-7281-4571-6}, address = {Los Angeles, CA}, booktitle = {11th IEEE Vehicular Networking Conference (VNC 2019)}, month = {12}, year = {2019} } - , “RoRoute: Tools to Experiment with Routing Protocols in WMNs,” in 14th IEEE/IFIP Conference on Wireless On demand Network Systems and Services (WONS 2018), Isola 2000, France, Feb. 2018 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Routing in wireless mesh networks is a well studied topic, but indeed, a deeper analysis in real world deployments shows that there are still many open issues, the real world is complex enough so that theoretic design, simulations and emulators can hardly encode it. This paper presents a set of tools and best practices we developed thanks to the WiSHFUL experimental platform that enables the analysis of routing protocols robustness and resilience in face of failures and other impairments when the protocols run in real networks with all the complexity and non-linear interactions that characterize wireless meshes. We present results obtained with Optimized Link State Routing (OLSR) and possible extensions to this protocol that clearly document phenomena that are not visible or implementable in either simulation or emulation environments.@inproceedings{segata2018roroute, author = {Segata, Michele and Facchi, Nicol{\`{o}} and Maccari, Leonardo and Lo Cigno, Renato}, doi = {10.23919/WONS.2018.8311668}, title = {{RoRoute: Tools to Experiment with Routing Protocols in WMNs}}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, address = {Isola 2000, France}, booktitle = {14th IEEE/IFIP Conference on Wireless On demand Network Systems and Services (WONS 2018)}, month = {2}, year = {2018} } - , “Towards Infrastructure-Aided Self-Organized Hybrid Platooning,” in IEEE Global Conference on Internet of Things (GCIoT 2018), Alexandria, Egypt, Dec. 2018 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Nowadays, the technical feasibility of autonomous driving is out of the question. This technology opens the door for several research topics (e.g., information exchange, security of information) in the IoT domain. One such application is platooning: coordinated driving of vehicles in convoys. Therefore, such platoons set up Internets-of-Vehicles. Although platooning has been mainly researched on highways, the idea of platooning in smart cities can have several benefits, such as efficient use of roads, time-saving through route optimization, and minimizing traffic in peak times. In this paper, we present a traffic management approach for combining platooning on highways and urban areas. We explain the idea of platooning, how to manage it efficiently, and the differences between platooning on the freeway and in smart cities. Finally, we explore the exchange of information in these systems and highlight on information security.@inproceedings{krupitzer2018towards, author = {Krupitzer, Christian and Segata, Michele and Breitbach, Martin and El-Tawab, Samy S. and Tomforde, Sven and Becker, Christian}, doi = {10.1109/GCIoT.2018.8620134}, title = {{Towards Infrastructure-Aided Self-Organized Hybrid Platooning}}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, address = {Alexandria, Egypt}, booktitle = {IEEE Global Conference on Internet of Things (GCIoT 2018)}, month = {12}, year = {2018} } - , “A LiDAR Error Model for Cooperative Driving Simulations,” in 10th IEEE Vehicular Networking Conference (VNC 2018), Taipei, Taiwan, Dec. 2018 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Cooperative driving and vehicular network simulations have done huge steps toward high realism. They have become essential tools for performance evaluation of any kind of vehicular networking application. Yet, cooperative vehicular applications will not be built on top of wireless networking alone, but rather fusing together different data sources including sensors like radars, LiDARs, or cameras. So far, these sensors have been assumed to be ideal, i.e., without any measurement error. This paper analyzes a set of estimated distance traces obtained with a LiDAR sensor and develops a stochastic error model that can be used in cooperative driving simulations. After implementing the model within the Plexe simulation framework, we show the impact of the model on a set of cooperative driving control algorithms.@inproceedings{segata2018lidar, author = {Segata, Michele and Lo Cigno, Renato and Bhadani, Rahul Kumar and Bunting, Matthew and Sprinkle, Jonathan}, doi = {10.1109/VNC.2018.8628408}, title = {{A LiDAR Error Model for Cooperative Driving Simulations}}, ccs-awards = {Best Paper Award}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, issn = {2157-9865}, isbn = {978-1-5386-9428-2}, address = {Taipei, Taiwan}, booktitle = {10th IEEE Vehicular Networking Conference (VNC 2018)}, month = {12}, year = {2018} } - , “Centrality-based Route Recovery in Wireless Mesh Networks,” in IEEE International Conference on Communications (ICC 2018), Kansas City, MO, May 2018 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Wireless Mesh Networks are subject to frequent node and link failures, and routing protocols currently used, such as Optimized Link State Routing (OLSR) or Babel (Babel), suffer from relatively long recovery times characterized by broken and looped routes due to long timeouts that can not be shortened to keep the overhead at an acceptable level. This paper experiments a novel timer management technique named Pop-Routing on top of OLSR. Pop-Routing exploits the notion of betweenness centrality to tune timers depending on the node position in the network, so that failures that lead to larger traffic losses can be recovered faster. Pop-Routing maintains the overhead constant, but favors the most central nodes, whose failure is devastating from the performance point of view, and penalizes peripheral ones and leaves of the topology, whose failure has a very little impact on the entire network. Pop-Routing has been implemented as a plug-in in the OLSR daemon, coupled with an external process, named Prince, that computes centrality and timer values without interfering with the routing daemon. Experiments are run on the WiSHFUL showing the benefit of Pop-tuning of OLSR Hello and Traffic Control timers.@inproceedings{segata2018centrality, author = {Segata, Michele and Facchi, Nicol{\`{o}} and Maccari, Leonardo and Gemmi, Gabriele and Lo Cigno, Renato}, doi = {10.1109/ICC.2018.8422821}, title = {{Centrality-based Route Recovery in Wireless Mesh Networks}}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, address = {Kansas City, MO}, booktitle = {IEEE International Conference on Communications (ICC 2018)}, month = {5}, year = {2018} } - , “On the Effects of Cooperative Platooning on Traffic Shock Waves,” in 9th IEEE Vehicular Networking Conference (VNC 2017), Poster Session, Turin, Italy, Nov. 2017, pp. 37–38 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Cooperative platooning has been proposed as a promising solution to traffic congestion, safety, and pollution. A platooning application forms road trains of vehicles that autonomously follow a common leader, separated by a small inter-vehicle gap. In terms of traffic efficiency, platooning should improve the vehicular flow and reduce shock waves. The latter are the cause of start-and-stop dynamics which, besides disrupting traffic flow, can lead to accidents. The aim of this poster is to analyze, by means of simulations, the impact of platoons on both the traffic flow and the formation of shock waves.@inproceedings{terruzzi2017effects, author = {Terruzzi, Luca and Colombo, Riccardo and Segata, Michele}, doi = {10.1109/VNC.2017.8275654}, title = {{On the Effects of Cooperative Platooning on Traffic Shock Waves}}, pages = {37--38}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, issn = {2157-9865}, isbn = {978-1-5386-0986-6}, address = {Turin, Italy}, booktitle = {9th IEEE Vehicular Networking Conference (VNC 2017), Poster Session}, month = {11}, year = {2017} } - , “Platooning in SUMO: An Open Source Implementation,” in SUMO User Conference 2017 (SUMO 2017), Berlin, Germany, May 2017, pp. 51–62 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Platooning is an application that enhances autonomous driving by means of cooperation. Vehicles, by using wireless communication, exchange data such as position, speed, and acceleration to reduce their inter-vehicle gap and drive in groups, called indeed platoons. The benefits span from improved infrastructure usage to reduced pollution, and from increased safety to a better travel experience. The analysis of a platooning system is complex as it encompasses several research fields, including communication, control theory, traffic engineering, and vehicle dynamics. In addition, even small field operational tests can be extremely expensive in terms of money and time, let alone large scale scenarios. Research studies in platooning can thus highly benefit from simulative analyses, as they overcome the limitations of real world test beds. To this purpose, we developed PLEXE, an extension to the Veins vehicular networking framework that enables the simulation of platooning systems, both from a network and a vehicle dynamics perspective. In this paper we detail the changes PLEXE makes to SUMO to simulate platooning control systems, including realistic engine models for the simulation of vehicle dynamics. In addition, we provide two sample use cases to show its potential.@inproceedings{segata2017platooning, author = {Segata, Michele}, title = {{Platooning in SUMO: An Open Source Implementation}}, pages = {51--62}, publisher = {German Aerospace Center (DLR)}, address = {Berlin, Germany}, booktitle = {SUMO User Conference 2017 (SUMO 2017)}, month = {5}, year = {2017} } - , “Communication-based Collision Avoidance between Vulnerable Road Users and Cars,” in 36th IEEE Conference on Computer Communications (INFOCOM 2017), International Workshop on Smart Cities and Urban Computing (SmartCity 2017), Atlanta, GA, May 2017 [BibTeX file, PDF, Details...]
BibTeX & Abstract
The advent of wireless communication for vehicles paves the road for a bounty of cooperative applications: The most interesting being cooperative safety awareness. By exchanging information vehicles can become aware of each other and prevent dangerous situations that can lead to crashes either by early warning drivers or by automatic vehicle control, a solution particularly appealing for self-driving cars. While research on vehicular safety mainly focuses on vehicle-to-vehicle safety, we can exploit communication to implement applications aimed at protecting vulnerable road users, such as pedestrians or cyclists. In this paper, we start by exploiting a probability framework for estimating the likelihood of collision between a vehicles approaching an intersection and a cyclist, in light of the feasibility of communication between the two. On top of this framework, we design a simple application that, under certain conditions, informs the car driver (assumed to have to yield precedence) of the possible collision. We model the reaction of the driver to the warning and analyze possible benefits and drawbacks of such an application. The contribution is not the application itself, which is obvious, but the insights in the results in light of communication capabilities and human reaction that provide a specific set of aspects that should be considered in the design of such a safety system.@inproceedings{segata2017communicationbased, author = {Segata, Michele and Vijeikis, Romas and Lo Cigno, Renato}, doi = {10.1109/INFCOMW.2017.8116439}, title = {{Communication-based Collision Avoidance between Vulnerable Road Users and Cars}}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, address = {Atlanta, GA}, booktitle = {36th IEEE Conference on Computer Communications (INFOCOM 2017), International Workshop on Smart Cities and Urban Computing (SmartCity 2017)}, month = {5}, year = {2017} } - , “On the Feasibility of Collision Detection in Full-Duplex 802.11 Radio,” in 13th IEEE/IFIP Conference on Wireless On demand Network Systems and Services (WONS 2017), Jackson Hole, WY, Feb. 2017, pp. 9–16 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Full-duplex radios are becoming a feasible reality thanks to recent advances in self-interference cancellation. Switching from half- to full-duplex requires a major re-design of many network features and characteristics, including the MAC layer. The literature provides several new proposals or improvements that are applicable in different topologies: centralized, distributed, and multi-hop Wireless LANs (WLANs). These proposals, however, mostly focus on directional, unicast communication. While the main goal of unicast-focused approaches is to get as close as possible to doubling the throughput, it is still unclear how to exploit full-duplex radios in broadcast-like environments such as the vehicular one or in general in WiFi-like scenarios where interference is the dominating impairment. In this work we analyze the possible benefits and drawbacks of exploiting self-interference cancellation in full-duplex radios to implement collision detection. We show that, if proved feasible, the required changes to the MAC layer of an 802.11-based transceiver would be minimal, and could largely improve the performance with respect to a standard collision avoidance mechanism. In addition, the paper discusses the tricky aspects and the parameters required to identify a collision in a wireless network and discusses the many differences between managing collisions in a wired and in a wireless environment.@inproceedings{segata2017feasibility, author = {Segata, Michele and Lo Cigno, Renato}, doi = {10.1109/WONS.2017.7888755}, title = {{On the Feasibility of Collision Detection in Full-Duplex 802.11 Radio}}, pages = {9--16}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, address = {Jackson Hole, WY}, booktitle = {13th IEEE/IFIP Conference on Wireless On demand Network Systems and Services (WONS 2017)}, month = {2}, year = {2017} } - , “A Joint Network/Control Design for Cooperative Automatic Driving,” in 9th IEEE Vehicular Networking Conference (VNC 2017), Turin, Italy, Nov. 2017, pp. 167–174 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Cooperative automatic driving, or platooning, is a promising solution to improve traffic safety, while reducing congestion and pollution. The design of a control system for this application is a challenging, multi-disciplinary problem, as cooperation between vehicles is obtained through wireless communication. So far, control and network issues of platooning have been investigated separately. In this work we design a cooperative driving system from a joint network and control perspective, determining worst-case upper bounds on the safety distance subject to network losses, so the actual inter-vehicle gap can be tuned depending on vehicle or network performance. By means of simulation, we show that the system is very robust to packet losses and that the derived bounds are never violated.@inproceedings{giordano2017joint, author = {Giordano, Giulia and Segata, Michele and Blanchini, Franco and Lo Cigno, Renato}, doi = {10.1109/VNC.2017.8275606}, title = {{A Joint Network/Control Design for Cooperative Automatic Driving}}, pages = {167--174}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, issn = {2157-9865}, isbn = {978-1-5386-0986-6}, address = {Turin, Italy}, booktitle = {9th IEEE Vehicular Networking Conference (VNC 2017)}, month = {11}, year = {2017} } - , “RoCoSys: A Framework for Coordination of Mobile IoT Devices,” in 1st International Workshop on Mobile and Pervasive Internet of Things (PerIoT 2017), Big Island, HI, Mar. 2017, pp. 485–490 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Mobile IoT devices enable new classes of systems, such as cyber-physical systems. These systems pose challenges as they should seamlessly interact with users and other systems. In this paper, we address the problem of interaction between mobile pervasive IoT devices. Our contributions are threefold. First, we present a concept for a framework for coordination of mobile IoT devices. Second, we implement a reusable robot platform using the Mindstorms toolkit and a customizable adaptation logic for their coordination based on our framework. Third, we show its usability with two applications: an intelligent vehicle highway system as well as a smart vacuum cleaner.@inproceedings{krupitzer2017rocosys, author = {Krupitzer, Christian and Breitbach, Martin and Saal, Johannes and Becker, Christian and Segata, Michele and Lo Cigno, Renato}, doi = {10.1109/PERCOMW.2017.7917611}, title = {{RoCoSys: A Framework for Coordination of Mobile IoT Devices}}, pages = {485--490}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, isbn = {978-1-5090-4338-5}, address = {Big Island, HI}, booktitle = {1st International Workshop on Mobile and Pervasive Internet of Things (PerIoT 2017)}, month = {3}, year = {2017} } - , “Distributed EDCA Bursting: Improving Cluster-based Communication in IVC,” in 17th ACM International Symposium on Mobile Ad Hoc Networking and Computing (MobiHoc 2016), 1st International Workshop on Internet of Vehicles and Vehicles of Internet (IoV-VoI 2016), Paderborn, Germany, Jul. 2016, pp. 13–18 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Cluster-based communication is a staple topic in vehicular networks. Clustering communication nodes promise to reduce channel contention, enable building backbones and might improve spatial reuse. In this paper we propose a seemingly simple, yet unexplored idea: extending 802.11 frame bursting MAC access to multiple stations aggregated into a cluster. The focus of the paper is thus not building a cluster, but exploring what is the gain that can be achieved by the standard 802.11p channel access if we introduce the principle of frame bursting (presently not allowed in 802.11p standard, but the key factor for the efficiency of 802.11n/ac WiFi channel access). The key scientific question is if we can extend the frame bursting mechanism so that only the cluster leader contends for the channel reserving a Transmission Opportunity that is used by all the vehicles in the cluster transmitting a coordinated burst of frames. We describe in detail the idea, highlight the problems that can be encountered in its implementation (the devil, as usual is in details), and present some preliminary results for a special class of clusters: Cooperative driving platoons of cars.@inproceedings{segata2016distributed, author = {Segata, Michele and Goss, Davide and Lo Cigno, Renato}, doi = {10.1145/2938681.2938686}, title = {{Distributed EDCA Bursting: Improving Cluster-based Communication in IVC}}, pages = {13--18}, publisher = {Association for Computing Machinery (ACM)}, isbn = {978-1-4503-4184-4}, address = {Paderborn, Germany}, booktitle = {17th ACM International Symposium on Mobile Ad Hoc Networking and Computing (MobiHoc 2016), 1st International Workshop on Internet of Vehicles and Vehicles of Internet (IoV-VoI 2016)}, month = {7}, year = {2016} } - , “On Platooning Control using IEEE 802.11p in Conjunction with Visible Light Communications,” in 12th IEEE/IFIP Conference on Wireless On demand Network Systems and Services (WONS 2016), Cortina d’Ampezzo, Italy, Jan. 2016, pp. 124–127 [BibTeX file, PDF, Details...]
BibTeX & Abstract
The control of a platoon using IEEE 802.11p is an active research challenge in the field of vehicular networking and cooperative automated vehicles. IEEE 802.11p is a promising technology for direct vehicle to vehicle communication, but there are concerns about its usage for the control of platoons as it suffers packet losses due to congestion in highly dense scenarios. On the other hand, Visible Light Communication (VLC) recently gained attention as a short range technology for vehicular applications. VLC could be used to support or backup IEEE 802.11p, increasing reliability and scalability, and hence the safety of platooning systems. In this paper, we perform a large-scale simulation campaign using VLC integrated with IEEE 802.11p for platooning. We particularly demonstrate the benefits, but also the limitations, of such heterogeneous networking.@inproceedings{segata2016platooning, author = {Segata, Michele and Lo Cigno, Renato and Tsai, Hsin-Mu and Dressler, Falko}, title = {{On Platooning Control using IEEE 802.11p in Conjunction with Visible Light Communications}}, pages = {124--127}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, address = {Cortina d'Ampezzo, Italy}, booktitle = {12th IEEE/IFIP Conference on Wireless On demand Network Systems and Services (WONS 2016)}, month = {1}, year = {2016} } - , “A Consensus-based Approach for Platooning with Inter-Vehicular Communications,” in 34th IEEE Conference on Computer Communications (INFOCOM 2015), Hong Kong, China, Apr. 2015, pp. 1158–1166 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Automated and coordinated vehicles’ driving (platooning) is gaining more and more attention today and it represents a challenging scenario heavily relying on wireless Inter-Vehicular Communication (IVC). In this paper, we propose a novel controller for vehicle platooning based on consensus. Opposed to current approaches where the logical control topology is fixed a priori and the control law designed consequently, we design a system whose control topology can be reconfigured depending on the actual network status. Moreover, the controller does not require the vehicles to be radar equipped and automatically compensates outdated information caused by network delays. We define the control law and analyze it in both analytical and simulative way, showing its robustness in different network scenarios. We consider three different wireless network settings: uncorrelated Bernoullian losses, correlated losses using a Gilbert-Elliott channel, and a realistic traffic scenario with interferences caused by other vehicles. Finally, we compare our strategy with another state of the art controller. The results show the ability of the proposed approach to maintain a stable string of vehicles even in the presence of strong interference, delays, and fading conditions, providing higher comfort and safety for platoon drivers.@inproceedings{santini2015consensusbased, author = {Santini, Stefania and Salvi, Alessandro and Valente, Antonio Saverio and Pescap{\`{e}}, Antonio and Segata, Michele and Lo Cigno, Renato}, doi = {10.1109/INFOCOM.2015.7218490}, title = {{A Consensus-based Approach for Platooning with Inter-Vehicular Communications}}, pages = {1158--1166}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, address = {Hong Kong, China}, booktitle = {34th IEEE Conference on Computer Communications (INFOCOM 2015)}, month = {4}, year = {2015} } - , “Jerk Beaconing: A Dynamic Approach to Platooning,” in 7th IEEE Vehicular Networking Conference (VNC 2015), Kyoto, Japan, Dec. 2015, pp. 135–142 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Automated car following, or platooning, is a promising Inter-Vehicle Communication (IVC) application which has the potential of reducing traffic jams, improving safety, and decreasing fuel consumption by forming groups of vehicles which autonomously follow a common leader. The application works by sharing vehicles’ data through high frequency periodic beaconing which, due to channel congestion, might not work in highly dense scenarios. To address this issue, in this paper we propose a dynamic approach called Jerk Beaconing which exploits vehicle dynamics to share data only when needed. The results, compared to a commonly assumed 10Hz beaconing, show huge benefits in term of network resource saving. Moreover, our approach outperforms static beaconing in terms of safety as well, as it is able to keep inter-vehicle distance closer to the desired gap even in highly demanding scenarios.@inproceedings{segata2015jerk, author = {Segata, Michele and Dressler, Falko and Lo Cigno, Renato}, doi = {10.1109/VNC.2015.7385560}, title = {{Jerk Beaconing: A Dynamic Approach to Platooning}}, pages = {135--142}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, issn = {2157-9865}, isbn = {978-1-4673-9411-6}, address = {Kyoto, Japan}, booktitle = {7th IEEE Vehicular Networking Conference (VNC 2015)}, month = {12}, year = {2015} } - , “Fairness Kills Safety: A Comparative Study for Intersection Assistance Applications,” in 25th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC 2014), Washington, D.C., Sep. 2014, pp. 1442–1447 [BibTeX file, PDF, Details...]
BibTeX & Abstract
We study the ability of Inter-Vehicle Communication (IVC) solutions to handle real-time requirements in safety scenarios using beaconing as a communication primitive. One of the envisioned safety applications is intersection assistance. The objective of such applications is to either warn the driver or even to act autonomously if other approaching vehicles endanger the vehicle. Fairness, combined with aggressive channel access for low-latency safety messages, has been one of the main research line according to which state of the art congestion control mechanisms have been developed. We show that these solutions are not able to sufficiently support intersection assistance applications. Specifically, we show that current approaches fail exactly due to their fairness postulation. We propose a new situation-aware solution to this fairness dilemma by allowing temporary exceptions for vehicles in dangerous situations. We show the applicability for two state of the art congestion control mechanisms, namely ETSI Transmit Rate Control (TRC) and Dynamic Beaconing (DynB). Our investigation also reveals important research objectives for future IVC protocols, namely how much reactivity and situation-awareness is needed in the highly dynamic environment of vehicular networks.@inproceedings{joerer2014fairness, author = {Joerer, Stefan and Bloessl, Bastian and Segata, Michele and Sommer, Christoph and Lo Cigno, Renato and Dressler, Falko}, doi = {10.1109/PIMRC.2014.7136395}, title = {{Fairness Kills Safety: A Comparative Study for Intersection Assistance Applications}}, pages = {1442--1447}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, address = {Washington, D.C.}, booktitle = {25th IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC 2014)}, month = {9}, year = {2014} } - , “Supporting Platooning Maneuvers through IVC: An Initial Protocol Analysis for the Join Maneuver,” in 11th IEEE/IFIP Conference on Wireless On demand Network Systems and Services (WONS 2014), Obergurgl, Austria, Apr. 2014, pp. 130–137 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Driving vehicles in platoons has the potential to improve trafficefficiency, increase safety, reduce fuel consumption, and make drivingexperience more enjoyable. A lot of effort is being spent in thedevelopment of technologies, like radars, enabling automated cruise controlfollowing and ensuring emergency braking if the driver does not react intime; but these technologies alone do not empower real platooning. Theinitial idea of building dedicated infrastructures for platoons, has beenset aside favoring the philosophy that foresees scenarios, where automatedvehicles share the road with human-driven ones. This arises interesting newquestions regarding the interactions between the two categories ofvehicles. In this paper we focus on the analysis of interferences caused bynon-automated vehicles during a Join maneuver. We define the applicationlayer protocol to support the maneuver, together with situations that canprevent successful termination, and describe how they can be detected. Thevalidity of the approach is proven by means of simulations, showing eitherthat the maneuver can successfully be performed, or safely be aborted.Finally, we analyze the impact of the Packet Error Rate on the failure rateof the maneuver, showing that packet losses mainly affect the maneuver froma coordination point of view, rather than stability of the system, i.e.,even at high loss rates, cars never violated a minimum safety distance.@inproceedings{segata2014supporting, author = {Segata, Michele and Bloessl, Bastian and Joerer, Stefan and Dressler, Falko and Lo Cigno, Renato}, doi = {10.1109/WONS.2014.6814733}, title = {{Supporting Platooning Maneuvers through IVC: An Initial Protocol Analysis for the Join Maneuver}}, pages = {130--137}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, address = {Obergurgl, Austria}, booktitle = {11th IEEE/IFIP Conference on Wireless On demand Network Systems and Services (WONS 2014)}, month = {4}, year = {2014} } - , “Towards Energy Efficient Smart Phone Applications: Energy Models for Offloading Tasks into the Cloud,” in IEEE International Conference on Communications (ICC 2014), Sydney, Australia, Jun. 2014, pp. 2394–2399 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Many people use smart phones on a daily basis, yet, their energy consumption is pretty high and the battery power lasts typically only for a single day. In the scope of the EnAct project, we investigate potential energy savings on smart phones by offloading computationally expensive tasks into the cloud. Obviously, also the wireless communication for uploading tasks requires energy. For that reason, it is crucial to understand the trade-off between energy consumption for wireless communication and local computation in order to assert that the overall power consumption is decreased. In this paper, we investigate the communications part of that trade-off. We conducted an extensive set of measurement experiments using typical smart phones. This is the first step towards the development of accurate energy models allowing to predict the energy required for offloading a given task. Our measurements include WiFi, 2G, and 3G networks as well as a set of two different devices. According to our findings, WiFi consumes by far the least energy per time unit, yet, this advantage seems to be due to its higher throughput and the implied shorter download time and not due to lower power consumption over time.@inproceedings{segata2014towards, author = {Segata, Michele and Bloessl, Bastian and Sommer, Christoph and Dressler, Falko}, doi = {10.1109/ICC.2014.6883681}, title = {{Towards Energy Efficient Smart Phone Applications: Energy Models for Offloading Tasks into the Cloud}}, pages = {2394--2399}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, issn = {1550-3607}, address = {Sydney, Australia}, booktitle = {IEEE International Conference on Communications (ICC 2014)}, month = {6}, year = {2014} } - , “PLEXE: A Platooning Extension for Veins,” in 6th IEEE Vehicular Networking Conference (VNC 2014), Paderborn, Germany, Dec. 2014, pp. 53–60 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Cooperative driving in general and Cooperative Adaptive Cruise Control (CACC) or platooning in particular require blending control theory, communications and networking, as well as mechanics and physics. Given the lack of an integrated modeling framework and theory as well as the prohibitively high costs of using prototypes for what-if studies, simulation remains the fundamental instrument to evaluate entire cooperative driving systems. This work presents PLEXE, an Open Source extension to Veins that offers researchers a simulation environment able to run experiments in realistic scenarios, taking into account physics and mechanics of the vehicles, communications and networking impairments, and Inter-Vehicle Communication (IVC) protocol stacks. PLEXE is easily extensible and already implements protocols to support platooning and cooperative driving applications and several state of the art cruise control models. We describe the structure of the simulator and the control algorithms that PLEXE implements and provide two use cases which show the potential of our framework as a powerful research tool for cooperative driving systems.@inproceedings{segata2014plexe, author = {Segata, Michele and Joerer, Stefan and Bloessl, Bastian and Sommer, Christoph and Dressler, Falko and Lo Cigno, Renato}, doi = {10.1109/VNC.2014.7013309}, title = {{PLEXE: A Platooning Extension for Veins}}, pages = {53--60}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, issn = {2157-9857}, isbn = {978-1-4799-7660-7}, address = {Paderborn, Germany}, booktitle = {6th IEEE Vehicular Networking Conference (VNC 2014)}, month = {12}, year = {2014} } - , “Towards Inter-Vehicle Communication Strategies for Platooning Support,” in 7th IFIP/IEEE International Workshop on Communication Technologies for Vehicles (Nets4Cars 2014-Fall), Saint Petersburg, Russia, Oct. 2014, pp. 1–6 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Platooning, the idea of cars autonomously following their leaders to form a road train, has huge potentials to improve traffic flow efficiency and, most importantly, road traffic safety. Wireless communication is a fundamental building block - it is needed to manage and to maintain the platoons. To keep the system stable, strict constraints in terms of update frequency and reliability must be met. We developed communication strategies by explicitly taking into account the requirements of the controller, exploiting synchronized communication slots as well as transmit power adaptation. The proposed approaches are compared to two state of the art adaptive beaconing protocols that have been designed for generic message dissemination. Our simulation models have been parametrized and validated by means of real-world experiments. We clearly show how taking into account specific requirements can be extremely beneficial even in very crowded freeway scenarios.@inproceedings{segata2014intervehicle, author = {Segata, Michele and Bloessl, Bastian and Joerer, Stefan and Sommer, Christoph and Gerla, Mario and Lo Cigno, Renato and Dressler, Falko}, doi = {10.1109/Nets4CarsFall.2014.7000903}, title = {{Towards Inter-Vehicle Communication Strategies for Platooning Support}}, pages = {1--6}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, address = {Saint Petersburg, Russia}, booktitle = {7th IFIP/IEEE International Workshop on Communication Technologies for Vehicles (Nets4Cars 2014-Fall)}, month = {10}, year = {2014} } - , “Vehicle Shadowing Distribution Depends on Vehicle Type: Results of an Experimental Study,” in 5th IEEE Vehicular Networking Conference (VNC 2013), Boston, MA, Dec. 2013, pp. 242–245 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Simulations play a fundamental role for the evaluation of vehicular network communication strategies and applications’ effectiveness. Therefore, the vehicular networking community is continuously seeking more realistic channel and reception models to provide more reliable results, yet maintaining scalability in terms of computational effort. We investigate the effects of vehicle shadowing on IEEE 802.11p based communication. In particular, we perform a set of real world measurements on a freeway and study the impact of different obstructing vehicles on the received signal power distribution. Different vehicle types not only affect the average received power, but also its distribution, suggesting that the attenuation characteristics of the simulation model need to be tailored to the type of vehicle that obstructs the communication path. Based on these observations, we propose a novel way to compose shadowing and fading models to reproduce the observed effects.@inproceedings{segata2013vehicle, author = {Segata, Michele and Bloessl, Bastian and Joerer, Stefan and Sommer, Christoph and Lo Cigno, Renato and Dressler, Falko}, doi = {10.1109/VNC.2013.6737623}, title = {{Vehicle Shadowing Distribution Depends on Vehicle Type: Results of an Experimental Study}}, pages = {242--245}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, issn = {2157-9865}, isbn = {978-1-4799-2687-9}, address = {Boston, MA}, booktitle = {5th IEEE Vehicular Networking Conference (VNC 2013)}, month = {12}, year = {2013} } - , “An IEEE 802.11a/g/p OFDM Receiver for GNU Radio,” in ACM SIGCOMM 2013, 2nd ACM Software Radio Implementation Forum (SRIF 2013), Hong Kong, China, Aug. 2013, pp. 9–16 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Experimental research on wireless communication protocols frequently requires full access to all protocol layers, down to and including the physical layer. Software Defined Radio (SDR) hardware platforms, together with real-time signal processing frameworks, offer a basis to implement transceivers that can allow such experimentation and sophisticated measurements. We present a complete Orthogonal Frequency Division Multiplexing (OFDM) receiver implemented in GNU Radio and fitted for operation with an Ettus USRP N210. To the best of our knowledge, this is the first prototype of a GNU Radio based OFDM receiver for this technology. Our receiver comprises all layers up to parsing the MAC header and extracting the payload of IEEE802.11a/g/p networks. It supports both WiFi with a bandwidth of 20MHz and IEEE802.11p DSRC with a bandwidth of 10MHz. We validated and verified our implementation by means of interoperability tests, and present representative performance measurements. By making the code available as Open Source we provide an easy-to-access system that can be readily used for experimenting with novel signal processing algorithms.@inproceedings{bloessl2013ofdmreceiver, author = {Bloessl, Bastian and Segata, Michele and Sommer, Christoph and Dressler, Falko}, doi = {10.1145/2491246.2491248}, title = {{An IEEE 802.11a/g/p OFDM Receiver for GNU Radio}}, ccs-acm_authorize = {http://dl.acm.org/authorize?6833243}, pages = {9--16}, publisher = {Association for Computing Machinery (ACM)}, address = {Hong Kong, China}, booktitle = {ACM SIGCOMM 2013, 2nd ACM Software Radio Implementation Forum (SRIF 2013)}, month = {8}, year = {2013} } - , “How Shadowing Hurts Vehicular Communications and How Dynamic Beaconing Can Help,” in 32nd IEEE Conference on Computer Communications (INFOCOM 2013), Mini-Conference, Turin, Italy, Apr. 2013, pp. 110–114 [BibTeX file, PDF, Details...]
BibTeX & Abstract
We study the effect of radio signal shadowing dynamics, caused by vehicles and by buildings, on the performance of beaconing protocols in Inter-Vehicular Communication (IVC). Recent research indicates that beaconing, i.e., one hop message broadcast, shows excellent characteristics and can outperform other communication approaches for both safety and efficiency applications, which require low latency and wide area information dissemination, respectively. We show how shadowing dynamics of moving obstacles hurt IVC, reducing the performance of beaconing protocols. At the same time, shadowing also limits the risk of overloading the wireless channel. To the best of our knowledge, this is the first study identifying the problems and resulting possibilities of such dynamic radio shadowing. We demonstrate how these challenges and opportunities can be taken into account and outline a novel approach to dynamic beaconing. It provides low-latency communication (i.e., very short beaconing intervals), while ensuring not to overload the wireless channel. The presented simulation results substantiate our theoretical considerations.@inproceedings{sommer2013how, author = {Sommer, Christoph and Joerer, Stefan and Segata, Michele and Tonguz, Ozan K. and Lo Cigno, Renato and Dressler, Falko}, doi = {10.1109/INFCOM.2013.6566745}, title = {{How Shadowing Hurts Vehicular Communications and How Dynamic Beaconing Can Help}}, pages = {110--114}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, address = {Turin, Italy}, booktitle = {32nd IEEE Conference on Computer Communications (INFOCOM 2013), Mini-Conference}, month = {4}, year = {2013} } - , “Towards an Open Source IEEE 802.11p Stack: A Full SDR-based Transceiver in GNURadio,” in 5th IEEE Vehicular Networking Conference (VNC 2013), Boston, MA, Dec. 2013, pp. 143–149 [BibTeX file, PDF, Details...]
BibTeX & Abstract
We present the first steps towards an Open Source simulation and experimentation framework for IEEE 802.11p networks. The framework is implemented based on GNURadio, a real-time signal processing framework for use in Software Defined Radio (SDR) systems. The core of the framework is a modular Orthogonal Frequency Division Multiplexing (OFDM) transceiver, which has been thoroughly evaluated: First, we show that its computational demands are so low that it can be run on low-end desktop PCs or laptops and thus, the transceiver is also feasible to use in field operational tests. Secondly, we present simulation results to highlight the transceiver’s capability to study and debug PHY and MAC variants in a reproducible manner. We show that the simulations match very well to a widely accepted error model for IEEE 802.11p networks. Finally, we discuss results from an extensive set of measurements that compare our SDR-based transceiver with commercial grade IEEE 802.11p cards. We made the framework available as Open Source to make the system accessible for other researchers and to allow reproduction of the results. This might also pave the way for future proofing cars by means of fully reconfigurable radios.@inproceedings{bloessl2013towards, author = {Bloessl, Bastian and Segata, Michele and Sommer, Christoph and Dressler, Falko}, doi = {10.1109/VNC.2013.6737601}, title = {{Towards an Open Source IEEE 802.11p Stack: A Full SDR-based Transceiver in GNURadio}}, ccs-awards = {Best Paper Award}, pages = {143--149}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, issn = {2157-9865}, isbn = {978-1-4799-2687-9}, address = {Boston, MA}, booktitle = {5th IEEE Vehicular Networking Conference (VNC 2013)}, month = {12}, year = {2013} } - , “A GNURadio Based Receiver Toolkit for IEEE 802.11a/g/p,” in 19th ACM International Conference on Mobile Computing and Networking (MobiCom 2013), 5th Wireless of the Students, by the Students, for the Students Workshop (S3 2013), Demo Session, Miami, FL, Oct. 2013 [BibTeX file, PDF, Details...]
BibTeX & Abstract
We present an open source Software Defined Radio (SDR) receiver toolkit that is able to decode OFDM frames of IEEE 802.11a/g/p WiFi in real time. It is the first for GNURadio that supports channel bandwidths of up to 20MHz. The toolkit comprises the physical layer, decoding of MAC frames, and extracting the payload of IEEE 802.11a/g/p frames. It is further possible to access and visualize the data in every step of the decoding process in numerous ways. As an example demonstration, the impact of moving antennas and changing settings can be displayed live in time and frequency domain. Lastly, the decoded frames can be fed to Wireshark and/or received on a Linux network interface. Our receiver toolkit has been well received by the community and is already serving as the basis of further research.@inproceedings{bloessl2013gnuradio, author = {Bloessl, Bastian and Segata, Michele and Sommer, Christoph and Dressler, Falko}, title = {{A GNURadio Based Receiver Toolkit for IEEE 802.11a/g/p}}, ccs-awards = {Best Demo/Poster Award}, publisher = {Association for Computing Machinery (ACM)}, address = {Miami, FL}, booktitle = {19th ACM International Conference on Mobile Computing and Networking (MobiCom 2013), 5th Wireless of the Students, by the Students, for the Students Workshop (S3 2013), Demo Session}, month = {10}, year = {2013} } - , “Decoding IEEE 802.11a/g/p OFDM in Software using GNU Radio,” in 19th ACM International Conference on Mobile Computing and Networking (MobiCom 2013), Demo Session, Miami, FL, Oct. 2013, pp. 159–161 [BibTeX file, PDF, Details...]
BibTeX & Abstract
We just released an Open Source receiver that is able to decode IEEE 802.11a/g/p OFDM frames in software. This is the first Software Defined Radio (SDR) based OFDM receiver supporting channel bandwidths up to 20 MHz that is not relying on additional FPGA code. Our receiver comprises all layers up to parsing the MAC header and extracting the payload of IEEE 802.11a/g/p networks. In our demo, visitors can interact live with the receiver while it is decoding over the air frames. The impact of moving the antennas and changing the settings are displayed live in time and frequency domain. Furthermore, the decoded frames are piped to Wireshark where the WiFi traffic can be further investigated. It is possible to access and visualize the data in every decoding step from the raw samples, frame detection, channel estimation, up to the decoded MAC packets. The receiver is completely Open Source and represents one step towards experimental research with SDRs.@inproceedings{bloessl2013decoding, author = {Bloessl, Bastian and Segata, Michele and Sommer, Christoph and Dressler, Falko}, doi = {10.1145/2500423.2505300}, title = {{Decoding IEEE 802.11a/g/p OFDM in Software using GNU Radio}}, ccs-acm_authorize = {http://dl.acm.org/authorize?N70220}, pages = {159--161}, publisher = {Association for Computing Machinery (ACM)}, address = {Miami, FL}, booktitle = {19th ACM International Conference on Mobile Computing and Networking (MobiCom 2013), Demo Session}, month = {10}, year = {2013} } - , “To Crash or Not to Crash: Estimating its Likelihood and Potentials of Beacon-based IVC Systems,” in 4th IEEE Vehicular Networking Conference (VNC 2012), Seoul, South Korea, Nov. 2012, pp. 25–32 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Is it possible to estimate some ’safety’ metric to assess the effectiveness of Intelligent Transportation Systems? In particular, we are interested in using Inter-Vehicle Communication (IVC) beaconing for increasing drivers’ safety at intersections. In the last couple of years, the vehicular networking community reported in several studies that simple network metrics are not sufficient to evaluate safety enhancing protocols and applications. We present a classification scheme that allows the quantification of such improvements by determining how many potential crashes happen or can be avoided by a specific IVC approach. Using a modified road traffic simulator that allowed selected vehicles to disregard traffic rules, we investigated the impact of safety messaging between cars approaching an intersection. We show that in suburban environments simple beaconing is not as effective as anticipated. Yet, simple one-hop relaying, e.g., by vehicles parked close to an intersection, can improve drivers’ safety substantially. Since the key purpose of IVC is safety, the paper closes the loop in the evaluation of the effectiveness of vehicular networks as defined today.@inproceedings{joerer2012tocrash, author = {Joerer, Stefan and Segata, Michele and Bloessl, Bastian and Lo Cigno, Renato and Sommer, Christoph and Dressler, Falko}, doi = {10.1109/VNC.2012.6407441}, title = {{To Crash or Not to Crash: Estimating its Likelihood and Potentials of Beacon-based IVC Systems}}, pages = {25--32}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, issn = {2157-9865}, isbn = {978-1-4673-4996-3}, address = {Seoul, South Korea}, booktitle = {4th IEEE Vehicular Networking Conference (VNC 2012)}, month = {11}, year = {2012} } - , “A Simulation Tool for Automated Platooning in Mixed Highway Scenarios,” in 18th ACM International Conference on Mobile Computing and Networking (MobiCom 2012), Poster Session, Istanbul, Turkey, Aug. 2012, pp. 389–391 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Automated platooning is one of the most challenging fields in the domain of Intelligent Transportation Systems (ITS). Conceptually, platooning means creating clusters of vehicles which closely follow each other autonomously without action of the driver, neither for accelerating, nor for braking. This leads to several important benefits from substantially improved road throughput to increased safety. The control of such platoons depends on two components: First, radar is typically to be used to control the distance between the vehicles, and secondly, Inter-Vehicle Communication (IVC) helps managing the entire platoon allowing cars to join or to leave the group whenever necessary. Platooning systems have been mostly investigated in controlled environments such as dedicated highways with centralized management. However, platooning-enabled cars will be deployed gradually and might have to travel on highways together with other non-automated vehicles. We developed a combined traffic and network simulator for studying strategies and protocols needed for managing platoons in such mixed scenarios. We show the models needed and present first results using a simple IVC-based platoon management as a proof of concept.@inproceedings{segata2012simulation-tool, author = {Segata, Michele and Dressler, Falko and Lo Cigno, Renato and Gerla, Mario}, doi = {10.1145/2348543.2348591}, title = {{A Simulation Tool for Automated Platooning in Mixed Highway Scenarios}}, ccs-acm_authorize = {http://dl.acm.org/authorize?6729857}, pages = {389--391}, publisher = {Association for Computing Machinery (ACM)}, isbn = {978-1-4503-1159-5}, address = {Istanbul, Turkey}, booktitle = {18th ACM International Conference on Mobile Computing and Networking (MobiCom 2012), Poster Session}, month = {8}, year = {2012} } - , “Simulation of 802.11 PHY/MAC: The Quest for Accuracy and Efficiency,” in 9th IEEE/IFIP Conference on Wireless On demand Network Systems and Services (WONS 2012), Courmayeur, Italy, Jan. 2012, pp. 99–106 [BibTeX file, PDF, Details...]
BibTeX & Abstract
The goal of this work is to highlight and explain the limitations of traditional physical channel models used in network simulators for wireless LANs, with particular reference to VANETs, where these limitations may jeopardize the validity of results, specially for safety applications. The fundamental tradeoff is between simulation time and realism. Indeed, a simulator should provide realistic results as fast as possible, even if several nodes (i.e., hundreds) are considered. Our final goal, beyond this initial contribution, is the development of a stochastic channel model which improves reliability of simulations while increasing computational complexity only marginally. The design of our model is based on the representation of the packet decoding procedure as a Markov Decision (Stochastic) Process (MDP), thus avoiding the computational complexity of the simulation of the entire transmission - propagation - decoding chain bit-by-bit, which can surely provide enough accuracy, but at the price of unacceptable computational (and model) complexity. The paper identifies the key phenomena such as preamble detection, central-frequency misalignment, channel captures, vehicles relative speed, that represent the "state" of the MDP modeling the transmission chain, and propose an MDP structure to exploit it. The focus is on 802.11p and OFDM-based PHY layers, but the model is extensible to other transmission techniques easily. The design is tailored for implementation in ns-3, albeit the modeling principle is general and suitable for every event-driven simulator.@inproceedings{segata2012simulation, author = {Segata, Michele and Lo Cigno, Renato}, doi = {10.1109/WONS.2012.6152246}, title = {{Simulation of 802.11 PHY/MAC: The Quest for Accuracy and Efficiency}}, pages = {99--106}, publisher = {Institute of Electrical and Electronics Engineers (IEEE)}, address = {Courmayeur, Italy}, booktitle = {9th IEEE/IFIP Conference on Wireless On demand Network Systems and Services (WONS 2012)}, month = {1}, year = {2012} } - , “Emergency Braking: a Study of Network and Application Performance,” in 8th ACM International Workshop on Vehicular Internetworking (VANET 2011), Las Vegas, NV, Sep. 2011, pp. 1–10 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Safety applications are among the key drivers in VANET research. Their study is complex as it encompasses different disciplines, from wireless networking to car dynamics, to drivers’ behavior, not to mention the economic and legal aspects. This work presents a simulative study of emergency braking applications tackled by embedding a mobility, cars’ dynamic, and driver’s behavior model into a detailed networking simulator (ns-3). The results, derived both at the network and at the application level, capture correctly the interactions of the communications and protocols with the car’s adaptive cruise control system and the driver’s behavior for cars that are not equipped with communication devices. The paper presents in detail the improvements we contribute in simulation techniques and model completeness. It introduces a novel and easy message aggregation technique to empower message re-propagation while controlling the network load during the peak due to the emergency braking. Finally it discusses the effectiveness of such applications as a function of the market penetration rate, showing that even cars that are not equipped with communication devices benefit from the smoother and earlier reaction of those cars that can communicate and whose adaptive cruise control implements a correct deceleration strategy.@inproceedings{segata2011emergency, author = {Segata, Michele and Lo Cigno, Renato}, doi = {10.1145/2030698.2030700}, title = {{Emergency Braking: a Study of Network and Application Performance}}, pages = {1--10}, publisher = {Association for Computing Machinery (ACM)}, isbn = {978-1-4503-0869-4}, address = {Las Vegas, NV}, booktitle = {8th ACM International Workshop on Vehicular Internetworking (VANET 2011)}, month = {9}, year = {2011} }
Theses
- , “Safe and Efficient Communication Protocols for Platooning Control,” PhD Thesis, Institute of Computer Science, Feb. 2016 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Modern vehicles are becoming smarter and smarter thanks to the continuous development of new Advanced Driving Assistance Systems (ADAS). For example, some new commercial vehicles can detect pedestrians on the road and automatically come to a stop avoiding a collision. Some others can obtain information about traffic congestion through the cellular network and suggest the driver another route to save time. Nevertheless, drivers (and our society as well) are always striving for a safer, cleaner, and more efficient way of traveling and standard, non-cooperative ADAS might not be sufficient. For this reason the research community started to design a vehicular application called "platooning". Platooning simultaneously tackles safety and traffic congestion problems by cooperatively coordinating vehicles in an autonomous way. Traffic flow is optimized by using an advanced Adaptive Cruise Control (ACC), called Cooperative Adaptive Cruise Control (CACC), which drastically reduces inter-vehicle gaps. By being autonomously coordinated, platooning vehicles implicitly implement automated emergency braking, a fundamental application for freeway safety. The idea is to form optimized road trains of vehicles where the first drives the train, while the others autonomously follow at a close distance, without requiring the driver to steer, accelerate, or brake. Platooning can have an enormous impact on future transportation systems by increasing traffic flow (and thus reducing congestion), increasing safety, reducing CO2 emissions, and reducing the stress of driving. This application is extremely challenging due to its inter-disciplinary nature. Indeed, it involves control theory, vehicle dynamics, communication, and traffic engineering. In this thesis we are mostly concerned with the communication aspects of this application, which is fundamental for making the vehicles cooperate, improving the efficiency of the application with respect to a pure sensor-based solution. Application requirements are very tight and, given that the envisioned communication technology will be IEEE 802.11-based, there are concerns on whether these requirements can really be met. The focus of the thesis is in this direction. The first contribution is the design of PLEXE, an extension for the widely used vehicular simulation framework Veins that enables research studies on various platooning aspects, including design and evaluation of control algorithms, communication protocols, and applications. The tool is open source and free to download and use, and it realistically simulates both communication and vehicle dynamics. This makes PLEXE a valid testing platform before real world deployment. The second contribution is a set of undirected information broadcasting (beaconing) protocols that specifically take into account the requirements of the application. We initially develop four static (i.e., periodic) approaches and compare them against two state of the art dynamic protocols, showing that our approaches are capable of supporting the application even in heavily dense scenarios. Then, we propose a dynamic protocol that further improves the application (increasing safety) and the network layer (reducing resource usage) performance. The final contribution is a platooning control algorithm that, compared to state of the art approaches, is re-configurable at run-time and that can be adapted to network conditions. We thoroughly test the algorithm in highly challenging scenarios. These scenarios include a realistic network setup where the road is shared by human- and automated-driven vehicles. Human-driven vehicles interfere with automated-driven ones by sending data packets on the same channel. Moreover, we also consider a scenario with realistic vehicle dynamics, which takes into account vehicles’ engine and braking characteristics. The algorithm is shown to be robust to network and external disturbances, to have a fast convergence, and to be very stable. The results in this work thus represent a big step towards the real world implementation of platooning systems.@phdthesis{segata2016safe, author = {Segata, Michele}, title = {{Safe and Efficient Communication Protocols for Platooning Control}}, advisor = {Dressler, Falko and Lo Cigno, Renato}, institution = {Institute of Computer Science}, location = {Innsbruck, Austria}, month = {2}, referee = {Dressler, Falko and Lo Cigno, Renato and Casetti, Claudio Ettore}, school = {University of Innsbruck}, type = {PhD Thesis}, year = {2016} }
Technical reports and local workshops
- , “A Joint Network/Control Design for Cooperative Automatic Driving: Extended Version,” DISI, University of Trento, Italy, Technical Report DISI-17-012, Aug. 2017 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Cooperative automatic driving, or platooning, is a promising solution to improve traffic safety, while reducing congestion and pollution. The design of a control system for this application is a challenging, multi-disciplinary problem, as cooperation between vehicles is obtained through wireless communication. So far, control and network issues of platooning have been investigated separately. In this work we design a cooperative driving system from a joint network and control perspective, determining worst-case upper bounds on the safety distance subject to network losses, so the actual inter-vehicle gap can be tuned depending on vehicle or network performance. By means of simulation, we show that the system is very robust to packet losses and that the derived bounds are never violated.@techreport{giordano2017joint-tr, author = {Giordano, Giulia and Segata, Michele and Blanchini, Franco and Lo Cigno, Renato}, title = {{A Joint Network/Control Design for Cooperative Automatic Driving: Extended Version}}, institution = {DISI, University of Trento, Italy}, month = {8}, number = {DISI-17-012}, type = {Technical Report}, year = {2017} } - , “A Modular Approach to Platooning Maneuvers,” in 2nd GI/ITG KuVS Fachgespräch Inter-Vehicle Communication (FG-IVC 2014), Luxembourg, Luxembourg, Feb. 2014 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Driving vehicles in platoons has the potential to improve traffic efficiency, increase safety, reduce fuel consumption, and make driving experience more enjoyable. A lot of effort is being spent in the development of technologies, like radars, enabling automated cruise control following and ensuring emergency braking if the driver does not react in time; but these technologies alone do not empower real platooning. As platoons will initially share the road with human-driven vehicles, interesting new questions regarding the interactions between the two categories of vehicles arise. In this paper we briefly describe the focus of our research, i.e., the analysis of interferences caused by non-automated vehicles during a maneuver. As an example, we consider the JOIN maneuver. We define the application layer protocol to support the maneuver, together with situations that can prevent successful termination, and describe how they can be detected. We then show the validity of the idea by simulating some sample scenarios, showing either that the maneuver can successfully be performed, or safely be aborted. As final contribution, we describe our idea toward a modular approach, i.e., the development of complex maneuvers by combining smaller sub-maneuvers, aiming to ease development and safety analysis.@inproceedings{segata2014modular, author = {Segata, Michele and Dressler, Falko and Lo Cigno, Renato}, title = {{A Modular Approach to Platooning Maneuvers}}, ccs-peer_reviewed = {no}, address = {Luxembourg, Luxembourg}, booktitle = {2nd GI/ITG KuVS Fachgespr{\"{a}}ch Inter-Vehicle Communication (FG-IVC 2014)}, month = {2}, year = {2014} } - , “Shadowing or Multi-Path Fading: Which Dominates in Inter-Vehicle Communication?,” Institute of Computer Science, University of Innsbruck, Technical Report CCS-2013-03, Jun. 2013 [BibTeX file, PDF, Details...]
BibTeX & Abstract
We aim to resolve a long standing dispute in the vehicular networking community when it comes to modeling the physical layer most accurately. Essentially, two major groups have formed: one believes that shadowing is the most important source of signal attenuation (and fading can essentially be ignored); the other argues that the exact opposite is true. So, depending on the simulation study, either accurate shadowing models have been used - or the focus was on multi-path fading. Thus, we conducted specific measurements in the field, collecting extensive experimental data, to explore the dominance of one or the other aspect and resolve this dispute. Our aim was to define a set of models to be used in simulation that most realistically represents the signal attenuation in Inter-Vehicular Communication (IVC), while also preventing unnecessary complexity (and, thus, unnecessarily long simulation times). In brief, we can show that neither of the two effects is dominant over the other, and that both affect the received signal power considerably. As the most interesting result, we show that the distribution of the received signal power due to multi-path fading even depends on the amount of shadowing.@techreport{segata2013shadowing, author = {Segata, Michele and Bloessl, Bastian and Joerer, Stefan and Erlacher, Felix and Mutschlechner, Margit and Klingler, Florian and Sommer, Christoph and Lo Cigno, Renato and Dressler, Falko}, title = {{Shadowing or Multi-Path Fading: Which Dominates in Inter-Vehicle Communication?}}, institution = {Institute of Computer Science, University of Innsbruck}, location = {Innsbruck, Austria}, month = {6}, number = {CCS-2013-03}, type = {Technical Report}, year = {2013} } - , “Novel Communication Strategies for Platooning and their Simulative Performance Analysis,” in 1st GI/ITG KuVS Fachgespräch Inter-Vehicle Communication (FG-IVC 2013), Innsbruck, Austria, Feb. 2013 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Platooning, the act of a car autonomously following its leaders to form a road train, is a hot topic in research. It has the potential to improve traffic flow on freeways, improve safety, and enhance the driving experience. A lot of effort has been put in several projects in order to implement and test systems capable of performing close car following. While the problems related to control theory seems to be solved, some questions regarding communication are still open. Wireless networking is fundamental for this application, as it is needed to manage and maintain the platoons and, clearly, has strict requirements in terms of frequency update and delay constraints. This paper surveys the literature about platooning systems and related research, identifies some open challenges, presents a simulation framework which can be used to tackle them, and outlines promising approaches.@inproceedings{segata2013novel, author = {Segata, Michele}, title = {{Novel Communication Strategies for Platooning and their Simulative Performance Analysis}}, ccs-peer_reviewed = {no}, address = {Innsbruck, Austria}, booktitle = {1st GI/ITG KuVS Fachgespr{\"{a}}ch Inter-Vehicle Communication (FG-IVC 2013)}, month = {2}, year = {2013} } - , “An IEEE 802.11a/g/p OFDM Receiver for GNU Radio,” Institute of Computer Science, University of Innsbruck, Technical Report CCS-2013-02, Mar. 2013 [BibTeX file, PDF, Details...]
BibTeX & Abstract
Experimental research on wireless communication protocols frequently requires full access to all protocol layers, down to and including the physical layer. Software Defined Radio (SDR) hardware platforms, together with real-time signal processing frameworks, offer a basis to implement transceivers that can allow such experimentation and sophisticated measurements. We present a complete Orthogonal Frequency Division Multiplexing (OFDM) receiver implemented in GNU Radio and fitted for operation with an Ettus USRP N210. To the best of our knowledge, this is the first prototype of a GNU Radio based OFDM receiver for this technology. Our receiver comprises all layers up to parsing the MAC header and extracting the payload of IEEE 802.11a/g/p networks. It supports both WiFi with a bandwidth of 20MHz and IEEE 802.11p DSRC with a bandwidth of 10 MHz. We validated and verified our implementation by means of interoperability tests, and present representative performance measurements. By making the code available as Open Source we provide an easy-to-access system that can be readily used for experimenting with novel signal processing algorithms.@techreport{bloessl2013ofdm-tr, author = {Bloessl, Bastian and Segata, Michele and Sommer, Christoph and Dressler, Falko}, title = {{An IEEE 802.11a/g/p OFDM Receiver for GNU Radio}}, institution = {Institute of Computer Science, University of Innsbruck}, location = {Innsbruck, Austria}, month = {3}, number = {CCS-2013-02}, type = {Technical Report}, year = {2013} }
Copyright notice
Links to final or draft versions of papers are presented here to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author’s copyright. In most cases, these works may not be reposted or distributed for commercial purposes without the explicit permission of the copyright holder.
The following applies to all papers listed above that have IEEE copyrights: Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.
The following applies to all papers listed above that are in submission to IEEE conference/workshop proceeedings or journals: This work has been submitted to the IEEE for possible publication. Copyright may be transferred without notice, after which this version may no longer be accessible.
The following applies to all papers listed above that have ACM copyrights: ACM COPYRIGHT NOTICE. Permission to make digital or hard copies of part or all of this work for personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the first page. Copyrights for components of this work owned by others than ACM must be honored. Abstracting with credit is permitted. To copy otherwise, to republish, to post on servers, or to redistribute to lists, requires prior specific permission and/or a fee. Request permissions from Publications Dept., ACM, Inc., fax +1 (212) 869-0481, or permissions@acm.org.
The following applies to all SpringerLink papers listed above that have Springer Science+Business Media copyrights: The original publication is available at www.springerlink.com.