Implementation and Performance Evaluation of Distributed Autonomous Multi-Hop Vehicle-to-Vehicle Communications over TV White Space

This paper presents design and experimental evaluation of a distributed autonomous multi-hop vehicle-to-vehicle (V2V) communication system over TV white space performed in Japan. We propose the two-layer control channel model, which consists of the Zone Aware Control Channel (ZACC) and the Swarm Aware Control Channel (SACC), to establish the multi-hop network. Several vehicles construct a swarm using location information shared through ZACC, and share route and channel information, and available white space information through SACC. To evaluate the system we carried out field experiments with swarm made of three vehicles in a convoy. The vehicles observe channel occupancy via energy detection and agree on the control and the data channels autonomously. For coarse synchronization of quiet periods for sensing we use GPS driven oscillators, and introduce a time margin to accommodate for remaining drift. When a primary user is detected in any of the borrowed channels, the vehicles switch to a vacant channel without disrupting the ongoing multi-hop communication. We present the experimental results in terms of the time to establish control channel, channel switching time, delivery ratio of control message exchange, and throughput. As a result, we showed that our implementation can provide efficient and stable multi-hop V2V communication by using dynamic spectrum access (DSA) techniques

Design and Experimental Evaluation of a Database-Assisted V2V Communications System Over TV White Space

Automakers are increasingly employing wireless communications technologies into vehicles, which are expected to be one of the primary tools to improve traffic flow and traffic safety. Anticipating a significant increase in the accompanying spectrum and capacity requirements, in this paper, we speculate about using dynamic spectrum access in general, and TV white space in particular for vehicular communications. To this end, we describe the concept, design, general architecture and operation principles of a vehicle-to-vehicle communications system over TV white space. This system makes dual use of a geolocation database and spectrum sensing to understand spectrum vacancies. In this architecture, whenever a database query result is available, that information is prioritized over sensing results and when the database access is disrupted, vehicles rely on the spectrum sensing results. After describing the general concepts, we numerically analyze and evaluate the benefits of using proxy vehicles for geolocation database access. Finally, we present the middleware-centric implementation and field test results of a multi-hop vehicle-to-vehicle communications system over the licensed TV-band. We present results regarding multi-hop throughput, delay, jitter, channel switching and database access latencies. This study complements our previous work which described spectrum sensing based vehicle-to-vehicle communications design and testing

Sensor Technologies for Intelligent Transportation Systems

Modern society faces serious problems with transportation systems, including but not limited to traffic congestion, safety, and pollution. Information communication technologies have gained increasing attention and importance in modern transportation systems. Automotive manufacturers are developing in-vehicle sensors and their applications in different areas including safety, traffic management, and infotainment. Government institutions are implementing roadside infrastructures such as cameras and sensors to collect data about environmental and traffic conditions. By seamlessly integrating vehicles and sensing devices, their sensing and communication capabilities can be leveraged to achieve smart and intelligent transportation systems. We discuss how sensor technology can be integrated with the transportation infrastructure to achieve a sustainable Intelligent Transportation System (ITS) and how safety, traffic control and infotainment applications can benefit from multiple sensors deployed in different elements of an ITS. Finally, we discuss some of the challenges that need to be addressed to enable a fully operational and cooperative ITS environment

A survey on vehicular communication for cooperative truck platooning application

Platooning is an application where a group of vehicles move one after each other in close proximity, acting jointly as a single physical system. The scope of platooning is to improve safety, reduce fuel consumption, and increase road use efficiency. Even if conceived several decades ago as a concept, based on the new progress in automation and vehicular networking platooning has attracted particular attention in the latest years and is expected to become of common implementation in the next future, at least for trucks.The platoon system is the result of a combination of multiple disciplines, from transportation, to automation, to electronics, to telecommunications. In this survey, we consider the platooning, and more specifically the platooning of trucks, from the point of view of wireless communications. Wireless communications are indeed a key element, since they allow the information to propagate within the convoy with an almost negligible delay and really making all vehicles acting as one. Scope of this paper is to present a comprehensive survey on connected vehicles for the platooning application, starting with an overview of the projects that are driving the development of this technology, followed by a brief overview of the current and upcoming vehicular networking architecture and standards, by a review of the main open issues related to wireless communications applied to platooning, and a discussion of security threats and privacy concerns. The survey will conclude with a discussion of the main areas that we consider still open and that can drive future research directions.(c) 2022 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

Dynamic adaptation of delayed time of diffusion of emergency messages in cognitive vehicular networks

[ES] En este artículo se presenta un protocolo de difusión de mensajes de seguridad para emergencia que utiliza una adaptación dinámica del tiempo de retraso en el entorno de una red vehicular cognitiva. El escenario que se estudia considera la compartición del espectro entre la banda para comunicaciones vehiculares y la banda de la televisión digital con el objetivo de mitigar los efectos de la tormenta de difusión en una red vehicular. Dos de las técnicas de mitigación de la tormenta de difusión más utilizadas en la literatura son comparadas contra el protocolo propuesto en términos de las probabilidades de accesibilidad de los mensajes de emergencia y de la ocupación del canal. Los resultados numéricos muestran que el protocolo con la adaptación dinámica del tiempo presenta un mejor desempeño en condiciones de alta densidad de vehículos, lo cual es característico de un escenario de tormenta de difusión.[EN] This article presents a protocol for the dissemination of emergency safety messages that uses a dynamic adaptation of the delay time in the environment of a cognitive vehicular network. The scenario studied considers the spectrum sharing between the band for vehicular communications and the digital television band with the objective of mitigating the effects of the diffusion storm on a vehicular network. Two of the most commonly used diffusion mitigation techniques in the literature are compared against the proposed protocol in terms of the probabilities of reachability of emergency messages and channel occupancy. The numerical results show that the protocol with the dynamic adaptation of the time presents a better performance in conditions of high density of vehicles, which is characteristic of a diffusion storm scenario.El presente trabajo de investigación ha sido parcialmente financiado por el Consejo Nacional de Ciencia y Tecnología ( CONACYT) de México a través de la Beca Nacional para Estudios de Posgrado no. 445821.Avalos Gómez, JU.; Stevens-Navarro, E.; Pineda-Rico, U.; Cárdenas-Juárez, M.; Arce, A.; González, S. (2020). Adaptación dinámica del tiempo de retraso de difusión de mensajes de emergencia en redes vehiculares cognitivas. Revista Iberoamericana de Automática e Informática industrial. 17(3). https://doi.org/10.4995/riai.2019.12067OJS284173Avalos Gómez, J. U., Pineda-Rico, U., Cardenas-Juarez, M., Garcia- Barrientos, A., Arce, A., Stevens-Navarro, E., nov 2018. Broadcast storm mitigation of esms using spectrum sharing in cognitive radio vanets. In: 2018 International Conference on Mechatronics, Electronics and Automotive Engineering (ICMEAE). pp. 102-107. https://doi.org/10.1109/ICMEAE.2018.00026Bechler, M., Horozovic, A., Kastner, R., 2015. Evaluation of car-2-x scenarios for automated driving. In: FAST-zero'15: 3rd International Symposium on Future Active Safety Technology Toward zero traffic accidents. pp. 397-402.Bi, Y., Shan, H., Shen, X. S., Wang, N., Zhao, H., mar 2016. A multi-hop broadcast protocol for emergency message dissemination in urban vehicular ad hoc networks. IEEE Transactions on Intelligent Transportation Systems 17 (3), 736-750. https://doi.org/10.1109/TITS.2015.2481486Feukeu, E. A., Zuva, T., dec 2017. Overcoming broadcast storm problem in a vehicular network. In: 2017 13th International Conference on Signal-Image Technology Internet-Based Systems (SITIS). pp. 402-407. https://doi.org/10.1109/SITIS.2017.72IEEE802.11p, jul 2010. Ieee standard for information technology- local and metropolitan area networks- specific requirements- part 11: Wireless lan medium access control (mac) and physical layer (phy) specifications amendment 6: Wireless access in vehicular environments. IEEE Std 802.11p-2010 (Amendment to IEEE Std 802.11-2007 as amended by IEEE Std 802.11k-2008, IEEE Std 802.11r-2008, IEEE Std 802.11y-2008, IEEE Std 802.11n-2009, and IEEE Std 802.11w-2009), 1-51. https://doi.org/10.1109/IEEESTD.2010.5514475Khattab, A., Bayoumi, M. A., may 2015a. An overview of ieee standardization efforts for cognitive radio networks. In: 2015 IEEE International Symposium on Circuits and Systems (ISCAS). pp.982-985. https://doi.org/10.1109/ISCAS.2015.7168800Khattab, A., Bayoumi, M. A., dec 2015b. Standardization of cognitive radio networking: a comprehensive survey. annals of telecommunications - annales des télécommunications 70 (11), 465-477. https://doi.org/10.1007/s12243-015-0468-5Korkmaz, G., Ekici, E., Özgüner, F., jun 2006. An efficient fully ad-hoc multi-hop broadcast protocol for inter-vehicular communication systems. In: 2006 IEEE International Conference on Communications. Vol. 1. pp. 423-428. https://doi.org/10.1109/ICC.2006.254764Korkmaz, G., Ekici, E., Özgüner, F., Özgüner, U., 2004. Urban Multihop broadcast protocol for inter-vehicle communication systems. In: Proceedings of the 1st ACM International Workshop on Vehicular Ad Hoc Networks. VANET '04. ACM, New York, NY, USA, pp. 76-85. https://doi.org/10.1145/1023875.1023887Lim, J., Kim, W., Naito, K., Yun, J., Cabric, D., Gerla, M., nov 2014. Interplay between tvws and dsrc: Optimal strategy for safety message dissemination in vanet. IEEE Journal on Selected Areas in Communications 32 (11), 2117-2133. https://doi.org/10.1109/JSAC.2014.1411RP02Pagadarai, S., Lessard, B. A., Wyglinski, A. M., Vuyyuru, R., Altintas, O., 2013. Vehicular communications, enhanced networking through dynamic spectrum access. IEEE Vehicular Technology Magazine 8, 93-103. https://doi.org/10.1109/MVT.2013.2268659Sahoo, J., Wu, E. H., Sahu, P. K., Gerla, M., sep 2011. Binarypartition-assisted mac-layer broadcast for emergency message dissemination in vanets. IEEE Transactions on Intelligent Transportation Systems 12 (3), 757-770. https://doi.org/10.1109/TITS.2011.2159003Singh, K. D., Rawat, P., Bonnin, J. M., 2014. Cognitive radio for vehicular ad hoc networks (cr-vanets): Approaches and challenges. EURASIP Journal on Wireless Communications and Networking 2014, 49. https://doi.org/10.1186/1687-1499-2014-49Sum, C., Villardi, G. P., Rahman, M. A., Baykas, T., Tran, H. N., Lan, Z., Sun, C., Alemseged, Y., Wang, J., Song, C., Pyo, C., Filin, S., Harada, H., jul 2013. Cognitive communication in tv white spaces: An overview of regulations, standards, and technology [accepted from open call]. IEEE Communications Magazine 51 (7), 138-145. https://doi.org/10.1109/MCOM.2013.6553690Suthaputchakun, C., Dianati, M., Sun, Z., jul 2014. Trinary partitioned black-burst-based broadcast protocol for time-critical emergency message dissemination in vanets. IEEE Transactions on Vehicular Technology 63 (6), 2926-2940. https://doi.org/10.1109/TVT.2013.2293020Tsukamoto, K., Oie, Y., Kremo, H., Altintas, O., Tanaka, H., Fujii, T., apr 2015. Implementation and performance evaluation of distributed autonomous multi-hop vehicle-to-vehicle communications over tv white space. Mobile Networks and Applications 20 (2), 203-219. DOI: https://doi.org/10.1007/s11036-015-0576-5Wisitpongphan, N., Tonguz, O. K., Parikh, J. S., Mudalige, P., Bai, F., Sadekar, V., dec 2007. Broadcast storm mitigation techniques in vehicular ad hoc networks. IEEE Wireless Communications 14 (6), 84-94. https://doi.org/10.1109/MWC.2007.4407231Wu, L., Nie, L., Fan, J., He, Y., Liu, Q., Wu, D., 2017. An efficient multi-hop broadcast protocol for emergency messages dissemination in vanets. Chinese Journal of Electronics 26 (3), 614-623. https://doi.org/10.1049/cje.2017.03.00

Content Caching and Delivery in Heterogeneous Vehicular Networks

Connected and automated vehicles (CAVs), which enable information exchange and content delivery in real time, are expected to revolutionize current transportation systems for better driving safety, traffic efficiency, and environmental sustainability. However, the emerging CAV applications such as content delivery pose stringent requirements on latency, throughput, reliability, and global connectivity. The current wireless networks face significant challenges to satisfy the requirements due to scarce radio spectrum resources, inflexibility to dynamic traffic demands, and geographic-constrained fixed infrastructure deployment. To empower multifarious CAV content delivery, heterogeneous vehicular networks (HetVNets), which integrate the terrestrial networks with aerial networks formed by unmanned aerial vehicles (UAVs) and space networks constituting of low Earth orbit (LEO) satellites, can guarantee reliable, flexible, cost-effective, and globally seamless service provisioning. In addition, edge caching is a promising solution to facilitate content delivery by caching popular files in the HetVNet access points (APs) to relieve the backhaul traffic with a lower delivery delay. The main technical issues are: 1) to fully reveal the potential of HetVNets for content delivery performance enhancement, content caching scheme design in HetVNets should jointly consider network characteristics, vehicle mobility patterns, content popularity, and APs’ caching capacities; 2) to fully exploit the controllable mobility and agility of UAVs to support dynamic vehicular content demands, the caching scheme and trajectory design for UAVs should be jointly optimized, which has not been well addressed due to their intricate inter-coupling relationships; and 3) for caching-based content delivery in HetVNets, a cooperative content delivery scheme should be designed to enable the cooperation among different network segments with ingenious utilization of heterogeneous network resources. In this thesis, we design the content caching and delivery schemes in the caching-enabled HetVNet to address the three technical issues. First, we study the content caching in HetVNets with fixed terrestrial APs including cellular base stations (CBSs), Wi-Fi roadside units (RSUs), and TV white space (TVWS) stations. To characterize the intermittent network connection caused by limited network coverage and high vehicle mobility, we establish an on-off model with service interruptions to describe the vehicular content delivery process. Content coding then is leveraged to resist the impact of unstable network connections and enhance caching efficiency. By jointly considering file characteristics and network conditions, the content placement is formulated as an integer linear programming (ILP) problem. Adopting the idea of the student admission model, the ILP problem is then transformed into a many-to-one matching problem between content files and HetVNet APs and solved by our proposed stable-matching-based caching scheme. Simulation results demonstrate that the proposed scheme can achieve near-optimal performances in terms of delivery delay and offloading ratio with a low complexity. Second, UAV-aided caching is considered to assist vehicular content delivery in aerial-ground vehicular networks (AGVN) and a joint caching and trajectory optimization (JCTO) problem is investigated to jointly optimize content caching, content delivery, and UAV trajectory. To enable real-time decision-making in highly dynamic vehicular networks, we propose a deep supervised learning scheme to solve the JCTO problem. Specifically, we first devise a clustering-based two-layered (CBTL) algorithm to solve the JCTO problem offline. With a given content caching policy, we design a time-based graph decomposition method to jointly optimize content delivery and UAV trajectory, with which we then leverage the particle swarm optimization algorithm to optimize the content caching. We then design a deep supervised learning architecture of the convolutional neural network (CNN) to make online decisions. With the CNN-based model, a function mapping the input network information to output decisions can be intelligently learnt to make timely inferences. Extensive trace-driven experiments are conducted to demonstrate the efficiency of CBTL in solving the JCTO problem and the superior learning performance with the CNN-based model. Third, we investigate caching-assisted cooperative content delivery in space-air-ground integrated vehicular networks (SAGVNs), where vehicular content requests can be cooperatively served by multiple APs in space, aerial, and terrestrial networks. In specific, a joint optimization problem of vehicle-to-AP association, bandwidth allocation, and content delivery ratio, referred to as the ABC problem, is formulated to minimize the overall content delivery delay while satisfying vehicular quality-of-service (QoS) requirements. To address the tightly-coupled optimization variables, we propose a load- and mobility-aware ABC (LMA-ABC) scheme to solve the joint optimization problem as follows. We first decompose the ABC problem to optimize the content delivery ratio. Then the impact of bandwidth allocation on the achievable delay performance is analyzed, and an effect of diminishing delay performance gain is revealed. Based on the analysis results, the LMA-ABC scheme is designed with the consideration of user fairness, load balancing, and vehicle mobility. Simulation results demonstrate that the proposed LMA-ABC scheme can significantly reduce the cooperative content delivery delay compared to the benchmark schemes. In summary, we have investigated the content caching in terrestrial networks with fixed APs, joint caching and trajectory optimization in the AGVN, and caching-assisted cooperative content delivery in the SAGVN. The proposed schemes and theoretical results should provide useful guidelines for future research in the caching scheme design and efficient utilization of network resources in caching-enabled heterogeneous wireless networks