Situational Awareness Enhancement for Connected and Automated Vehicle Systems

Recent developments in the area of Connected and Automated Vehicles (CAVs) have boosted the interest in Intelligent Transportation Systems (ITSs). While ITS is intended to resolve and mitigate serious traffic issues such as passenger and pedestrian fatalities, accidents, and traffic congestion; these goals are only achievable by vehicles that are fully aware of their situation and surroundings in real-time. Therefore, connected and automated vehicle systems heavily rely on communication technologies to create a real-time map of their surrounding environment and extend their range of situational awareness. In this dissertation, we propose novel approaches to enhance situational awareness, its applications, and effective sharing of information among vehicles.;The communication technology for CAVs is known as vehicle-to-everything (V2x) communication, in which vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) have been targeted for the first round of deployment based on dedicated short-range communication (DSRC) devices for vehicles and road-side transportation infrastructures. Wireless communication among these entities creates self-organizing networks, known as Vehicular Ad-hoc Networks (VANETs). Due to the mobile, rapidly changing, and intrinsically error-prone nature of VANETs, traditional network architectures are generally unsatisfactory to address VANETs fundamental performance requirements. Therefore, we first investigate imperfections of the vehicular communication channel and propose a new modeling scheme for large-scale and small-scale components of the communication channel in dense vehicular networks. Subsequently, we introduce an innovative method for a joint modeling of the situational awareness and networking components of CAVs in a single framework. Based on these two models, we propose a novel network-aware broadcast protocol for fast broadcasting of information over multiple hops to extend the range of situational awareness. Afterward, motivated by the most common and injury-prone pedestrian crash scenarios, we extend our work by proposing an end-to-end Vehicle-to-Pedestrian (V2P) framework to provide situational awareness and hazard detection for vulnerable road users. Finally, as humans are the most spontaneous and influential entity for transportation systems, we design a learning-based driver behavior model and integrate it into our situational awareness component. Consequently, higher accuracy of situational awareness and overall system performance are achieved by exchange of more useful information

A RELIABILITY-BASED ROUTING PROTOCOL FOR VEHICULAR AD-HOC NETWORKS

Vehicular Ad hoc NETworks (VANETs), an emerging technology, would allow vehicles to form a self-organized network without the aid of a permanent infrastructure. As a prerequisite to communication in VANETs, an efficient route between communicating nodes in the network must be established, and the routing protocol must adapt to the rapidly changing topology of vehicles in motion. This is one of the goals of VANET routing protocols. In this thesis, we present an efficient routing protocol for VANETs, called the Reliable Inter-VEhicular Routing (RIVER) protocol. RIVER utilizes an undirected graph that represents the surrounding street layout where the vertices of the graph are points at which streets curve or intersect, and the graph edges represent the street segments between those vertices. Unlike existing protocols, RIVER performs real-time, active traffic monitoring and uses this data and other data gathered through passive mechanisms to assign a reliability rating to each street edge. The protocol then uses these reliability ratings to select the most reliable route. Control messages are used to identify a node’s neighbors, determine the reliability of street edges, and to share street edge reliability information with other nodes

정보 중심 네트워킹에서의 콘텐트 탐색 및 데이터 오프로딩

학위논문 (박사)-- 서울대학교 대학원 : 전기·컴퓨터공학부, 2015. 8. 권태경.현재의 인터넷은 자원 공유를 목적으로 호스트간 통신 패러다임에 기반하여 설계되었지만, 오늘날 인터넷 사용 패턴은 콘텐트 획득에 집중되어있다. 이러한 이유로, 대부분의 인터넷 트래픽은 비디오 서비스나 P2P 파일 공유와 같은 콘텐트 획득에 의해 발생하고 있는 상황이다. 하지만, 현재 인터넷의 구조와 실제 사용 패턴의 괴리는 비효율적인 콘텐트 전달 (예, 동일한 인기있는 콘텐트에 대한 중복된 콘텐트 전송)을 야기하고 있고, 이는 트래픽 폭발 문제로 이어지고 있다. 이러한 이슈를 다루기 위해 (i) 인터넷 구조를 새롭게 설계하거나 (ii) 데이터 오프로딩 기법을 통해 네트워크 트래픽을 줄이려는 시도들이 있다. 본 학위 논문에서는 정보 중심 네트워킹과 정보 중심의 차량 네트워크라는 두가지 영역에서의 트래픽 감소 기법에 대해 탐구한다. 첫 번째로, 정보 중심 네트워킹을 위한 트래픽 감소 콘텐트 탐색 기법을 제안한다. 정보 중심 네트워킹은 트래픽 폭발과 같은 현재 인터넷의 문제점을 해결하기 위해, 초기 단계부터 인터넷 구조를 새롭게 설계하자는 방향으로 제안되었다. 정보 중심 네트워킹은 가까이에 존재하는 캐시된 콘텐트를 이용하거나 동일한 콘텐트 전송에 대한 중복된 전송을 줄이는 것을 통해 네트워크 트래픽 감소와 같은 이득을 제공할 수 있다. 하지만, 이전의 연구들은 이러한 캐시된 콘텐트를 이용하기 위해 기회주의적 캐시 일치 방식에 의존을 하고 있다. 이러한 방식은 콘텐트 소스로 가는 경로에 존재하는 캐시된 콘텐트만 이용할 수 있기 때문에 네트워크 곳곳에 있는 네트워크 내재 저장 공간을 충분히 이용하지 못하는 한계가 있다. 제안하는 기법인 SCAN은 네트워크에 산재된 캐시된 콘텐트를 더 잘 이용하기 위해서 가까이에 존재하는 캐시된 콘텐트를 탐색한다. 이를 위해 SCAN은 블룸 필터를 사용하여 주변 라우터들 사이에서 캐시된 콘텐트에 대한 정보를 교환한다. 시뮬레이션을 통해 SCAN은 기회주의적 캐시 일치 방식의 기법에 비해 평균 홉 거리, 트래픽 양, 링크간 로드 분배에서 더 나은 성능을 보임을 알 수 있다. 다음으로, 정보 중심의 차량 네트워크를 위한 트래픽 오프로딩 기법을 제안한다. 무선 환경에서 급증하고 있는 모바일 트래픽은 모바일 네트워크 제공자에게 심각한 우려가 되고 있다. 이러한 트래픽 폭발 문제를 다루기 위해, 트래픽을 셀룰러 네트워크에서 WiFi 핫스팟이나 펨토셀과 같은 다른 네트워크로 오프로딩하려는 연구들이 있었다. 본 연구에서는 기존의 시도에서 더 나아가서 데이터 오프로딩을 위한 차량 네트워크의 잠재적 장점에 집중하여 차량 네트워크를 이용한 데이터 오프로딩 프레임워크인 DOVE를 제안한다. 제안하는 데이터 오프로딩 프레임워크는 차량 내 데이터 서비스를 위해 필요한 셀룰러 트래픽을 비용 효과가 높은 방식으로 감소시킬 수 있다. DOVE에서는 오프로딩을 목적으로 차량 이동 경로를 이용하고, 경제적인 비용 절감을 목적으로 차량에서 요청되는 콘텐트 파일들은 셀룰러 네트워크 대신 차량 네트워크를 통해 전달된다. 이를 위해 오프로딩 위치를 선택하는 문제를 시공간적 집합 덮개 문제로 만들고, 차량 이동 경로를 이용한 시간 예측 기반의 집합 덮개 알고리즘을 제안한다. 시뮬레이션 결과에 따르면, DOVE 프레임워크는 차량 네트워크를 통한 오프로딩을 수행하여 57%의 셀룰러 링크 사용량을 크게 감소시킬 수 있다.While the architecture of current Internet was designed based on the host-to-host communication paradigm for resource sharing, today's Internet usage has been concentrated on content retrievals. As a result, most of Internet traffic is generated by the content retrievals, such as video service and P2P file sharing. However, the discrepancy between the current Internet architecture and the real usage pattern causes inefficient content deliveries (e.g., duplicated content transmission for the same popular content), which leads to traffic explosion problem. To address such issues, there have been a lot of efforts to reduce the network traffic by (i) redesigning the Internet architecture and (ii) proposing data offloading schemes. In this dissertation, we investigate traffic reduction schemes in two different domains, information-centric networking and information-centric vehicular networks. First, we propose a traffic-reduction content-discovery scheme for information-centric networking (ICN). ICN has been proposed to resolve the problem of current Internet such as traffic explosion by redesigning the Internet architecture in a clean-slate manner. ICN can provide substantial benefits such as network traffic reduction by exploiting a nearby (cached) copy of content and reducing duplicated transmissions for the same content request. However, prior studies usually rely on an opportunistic cache-hit (happen-to-meet) to utilize the cached contents. In the happen-to-meet fashion, only the content cached on the path towards the content source can be utilized, which limits the network-wide usage of the in-network storages. To exploit cached contents better, our proposed scheme SCAN discovers nearby content copies. SCAN exchanges the cached content information among the neighbor routers using Bloom filters for the content discovery. With extensive simulations, SCAN shows better performance than a happen-to-meet cache-hit scheme in terms of average hop counts, traffic volume, and load balancing among links. Next, we propose a traffic offloading scheme for information-centric vehicular network. In wireless environments, the increasing mobile traffic is becoming a serious concern for mobile network providers. To address the traffic explosion problem, there have been a lot of efforts to offload the traffic from cellular networks to other networks, such as WiFi hotspots and femtocells. Our work moves forward from prior studies by focusing on the potential benefits of vehicular networks for data offloading. In particular, we propose a Data Offloading framework using Vehicular nEtworks (DOVE), which reduces the cellular traffic for in-vehicle data services in a cost effective way. DOVE exploits vehicle trajectories for offloading purposes so that content files requested by vehicles can be delivered via vehicular networks rather than cellular networks for economical purposes. We formulate the problem of selecting offloading positions as a spatio-temporal set-covering problem, and propose a time-prediction based set-covering algorithm using vehicle trajectories. Simulation results show that our DOVE framework can significantly reduce 57% of cellular link usage by performing data offloading through vehicular networks.I. Introduction 1 II. Content Discovery for Information-Centric Networking 4 2.1 Introduction 4 2.2 Related Work 7 2.2.1 Named Data Networking (NDN) 7 2.2.2 ICN-based Schemes 8 2.2.3 Approaches using BFs 10 2.3 SCAN Architecture 11 2.3.1 SCAN Description 11 2.3.2 SCAN Operation 16 2.3.3 Discussion 19 2.4 CIB Maintenance in SCAN 21 2.4.1 Information Unit 21 2.4.2 Information Exchange 22 2.4.3 Information Decay 23 2.5 Performance Evaluation 25 2.5.1 Content Discovery Performance 27 2.5.2 Network-wide Performance 28 2.5.3 Effect of Cache Size 30 2.5.4 Effect of Scanning Depth 32 2.5.5 Effect of Information Decay Probability 34 2.5.6 Effect of BF Size 36 2.5.7 Effect of BF Exchange Interval 39 2.5.8 Comparison with ICN-enhancements 39 III. Data Offloading for Information-Centric Vehicular Networks 42 3.1 Introduction 42 3.2 Related Work 44 3.3 Problem Formulation 46 3.3.1 Target Scenario and Goal 46 3.3.2 DOVE Components and Assumptions 46 3.3.3 Design Principles using RNs 49 3.3.4 The Concept of Offloading in DOVE 50 3.4 Design and Operations of DOVE 51 3.4.1 Travel Time Prediction 51 3.4.2 The Operation of TCC 53 3.4.3 The Selection Algorithm for Offloading Positions 54 3.4.4 The Selection of Providers 59 3.4.5 The Operation of Vehicles using Offloading Positions 59 3.5 Performance Evaluation 60 3.5.1 Overall Performance of Data Offloading 61 3.5.2 The Impact of Vehicle Number 67 3.5.3 The Impact of Vehicle Speed 68 3.5.4 The Impact of Waiting Time 70 3.5.5 The Impact of Deployment Ratio and Tolerance Time 71 IV. Conclusion 74 Bibliography 76 Korean Abstract 82Docto

SymbioCity: Smart Cities for Smarter Networks

The "Smart City" (SC) concept revolves around the idea of embodying cutting-edge ICT solutions in the very fabric of future cities, in order to offer new and better services to citizens while lowering the city management costs, both in monetary, social, and environmental terms. In this framework, communication technologies are perceived as subservient to the SC services, providing the means to collect and process the data needed to make the services function. In this paper, we propose a new vision in which technology and SC services are designed to take advantage of each other in a symbiotic manner. According to this new paradigm, which we call "SymbioCity", SC services can indeed be exploited to improve the performance of the same communication systems that provide them with data. Suggestive examples of this symbiotic ecosystem are discussed in the paper. The dissertation is then substantiated in a proof-of-concept case study, where we show how the traffic monitoring service provided by the London Smart City initiative can be used to predict the density of users in a certain zone and optimize the cellular service in that area.Comment: 14 pages, submitted for publication to ETT Transactions on Emerging Telecommunications Technologie

자율주행을 위한 V2X 기반 차량 CDN 설계

학위논문 (석사) -- 서울대학교 대학원 : 공학전문대학원 응용공학과, 2021. 2. 김성우.Recent technical innovation has driven the evolution of autonomous vehicles. To improve safety as well as on-road vehicular experience, vehicles should be connected with each other or to vehicular networks. Some specification groups, e.g., IEEE and 3GPP, have studied and released vehicular communication requirements and architecture. IEEEs Wireless Access in Vehicular Environment focuses on dedicated and short-range communication, while 3GPPs New radio V2X supports not only sidelink but also uplink communication. The 3GPP Release 16, which supports 5G New Radio, offers evolved functionalities such as network slice, Network Function Virtualization, and Software-Defined Networking. In this study, we define and design a vehicular network architecture compliant with 5G core networks. For localization of autonomous driving vehicles, a high-definition map needs to contain the context of trajectory . We also propose new methods by which autonomous vehicles can push and pull map content efficiently, without causing bottlenecks on the network core. We evaluate the performance of V2X and of the proposed caching policy via network simulations. Experimental results indicate that the proposed method improves the performance of vehicular content delivery in real-world road environments.최근들어 기술의 혁신은 자율주행 자동차의 발전을 가속화 하고 있다. 보다 높은 수준의 자율 주행을 구현하기 위해서, 차량은 네트워크를 통해 서로 연결되어 있어야 하고 차량의 안전과 편의성을 향상 시킬 수 있도록 정보를 공유 할 수 있어야 한다. 표준화 단체인 IEEE와 3GPP는 차량 통신 요구사항, 아키텍처를 연구하고 개정해왔다. IEEE가 전용 채널을 통한 근접 지역 통신에 초점을 맞추는 반면에, 3GPP의 New Radio V2X는 Sidelink 뿐만 아니라 Uplink 통신을 동시에 지원한다. 5G 통신을 지원하는 3GPP Release 16은 Network Slice, NFV, SDN과 같은 새로운 통신 기능들을 제공한다. 이 연구에서는 새롭게 정의된 5G Core Network Architecture를 바탕으로 차량 네트워크를 정의하고 설계하였다. 자율주행 자동차의 측위를 위해서, 고해상도 지도는 각 구성요소들의 의미와 속성을 자세하게 포함하고 있어야 한다. 우리는 이 연구에서 V2X 네트워크 상에 HD map을 중계할 수 있는 Edge Server를 제안 함으로써, 중앙에서 발생할 수 있는 병목현상을 줄이고 전송 Delay를 최소화한다. 또한 Edge의 컨텐츠를 등록하고 삭제하는 정책으로 기존의 LRU, LFU가 아닌 새로운 컨텐츠 교체 알고리즘을 제안하였다. 실제 주행 시험과 시뮬레이션을 통한 실험을 통해 전송 품질을 향상시켰으며, Edge 컨텐츠의 활용도를 높였다.I. Introduction 1 II. Related Works 6 2.1 V2X Standardization 6 2.1.1 IEEE WAVE 6 2.1.2 3GPP C-V2X 9 2.2 Geographic Contents 14 2.3 Vehicular Content Centric Network 17 III. System Modeling 20 3.1 NR-V2X Architecture Analysis 20 3.2 Caching Strategy for HD Map Acquisition 23 IV. Evaluation 30 4.1 Contents Replacement Strategy 30 4.2 V2X Characteristics 36 4.3 Edge Performance in Driving on the Road 38 4.4 Edge Performance on 3D Point Clouds Caching for Localization 44 V. Conclusion 47 Bibliography 49 Abstract 54Maste

Quality of service aware data dissemination in vehicular Ad Hoc networks

Des systèmes de transport intelligents (STI) seront éventuellement fournis dans un proche avenir pour la sécurité et le confort des personnes lors de leurs déplacements sur les routes. Les réseaux ad-hoc véhiculaires (VANETs) représentent l'élément clé des STI. Les VANETs sont formés par des véhicules qui communiquent entre eux et avec l'infrastructure. En effet, les véhicules pourront échanger des messages qui comprennent, par exemple, des informations sur la circulation routière, les situations d'urgence et les divertissements. En particulier, les messages d'urgence sont diffusés par des véhicules en cas d'urgence (p.ex. un accident de voiture); afin de permettre aux conducteurs de réagir à temps (p.ex., ralentir), les messages d'urgence doivent être diffusés de manière fiable dans un délai très court. Dans les VANETs, il existe plusieurs facteurs, tels que le canal à pertes, les terminaux cachés, les interférences et la bande passante limitée, qui compliquent énormément la satisfaction des exigences de fiabilité et de délai des messages d'urgence. Dans cette thèse, en guise de première contribution, nous proposons un schéma de diffusion efficace à plusieurs sauts, appelé Dynamic Partitioning Scheme (DPS), pour diffuser les messages d'urgence. DPS calcule les tailles de partitions dynamiques et le calendrier de transmission pour chaque partition; à l'intérieur de la zone arrière de l'expéditeur, les partitions sont calculées de sorte qu'en moyenne chaque partition contient au moins un seul véhicule; l'objectif est de s'assurer que seul un véhicule dans la partition la plus éloignée (de l'expéditeur) est utilisé pour diffuser le message, jusqu'au saut suivant; ceci donne lieu à un délai d'un saut plus court. DPS assure une diffusion rapide des messages d'urgence. En outre, un nouveau mécanisme d'établissement de liaison, qui utilise des tonalités occupées, est proposé pour résoudre le problème du problème de terminal caché. Dans les VANETs, la Multidiffusion, c'est-à-dire la transmission d'un message d'une source à un nombre limité de véhicules connus en tant que destinations, est très importante. Par rapport à la diffusion unique, avec Multidiffusion, la source peut simultanément prendre en charge plusieurs destinations, via une arborescence de multidiffusion, ce qui permet d'économiser de la bande passante et de réduire la congestion du réseau. Cependant, puisque les VANETs ont une topologie dynamique, le maintien de la connectivité de l'arbre de multidiffusion est un problème majeur. Comme deuxième contribution, nous proposons deux approches pour modéliser l'utilisation totale de bande passante d'une arborescence de multidiffusion: (i) la première approche considère le nombre de segments de route impliqués dans l'arbre de multidiffusion et (ii) la seconde approche considère le nombre d'intersections relais dans l'arbre de multidiffusion. Une heuristique est proposée pour chaque approche. Pour assurer la qualité de service de l'arbre de multidiffusion, des procédures efficaces sont proposées pour le suivi des destinations et la surveillance de la qualité de service des segments de route. Comme troisième contribution, nous étudions le problème de la congestion causée par le routage du trafic de données dans les VANETs. Nous proposons (1) une approche de routage basée sur l’infonuagique qui, contrairement aux approches existantes, prend en compte les chemins de routage existants qui relaient déjà les données dans les VANETs. Les nouvelles demandes de routage sont traitées de sorte qu'aucun segment de route ne soit surchargé par plusieurs chemins de routage croisés. Au lieu d'acheminer les données en utilisant des chemins de routage sur un nombre limité de segments de route, notre approche équilibre la charge des données en utilisant des chemins de routage sur l'ensemble des tronçons routiers urbains, dans le but d'empêcher, dans la mesure du possible, les congestions locales dans les VANETs; et (2) une approche basée sur le réseau défini par logiciel (SDN) pour surveiller la connectivité VANET en temps réel et les délais de transmission sur chaque segment de route. Les données de surveillance sont utilisées en entrée de l'approche de routage.Intelligent Transportation Systems (ITS) will be eventually provided in the near future for both safety and comfort of people during their travel on the roads. Vehicular ad-hoc Networks (VANETs), represent the key component of ITS. VANETs consist of vehicles that communicate with each other and with the infrastructure. Indeed, vehicles will be able to exchange messages that include, for example, information about road traffic, emergency situations, and entertainment. Particularly, emergency messages are broadcasted by vehicles in case of an emergency (e.g., car accident); in order to allow drivers to react in time (e.g., slow down), emergency messages must be reliably disseminated with very short delay. In VANETs, there are several factors, such as lossy channel, hidden terminals, interferences and scarce bandwidth, which make satisfying reliability and delay requirements of emergency messages very challenging. In this thesis, as the first contribution, we propose a reliable time-efficient and multi-hop broadcasting scheme, called Dynamic Partitioning Scheme (DPS), to disseminate emergency messages. DPS computes dynamic partition sizes and the transmission schedule for each partition; inside the back area of the sender, the partitions are computed such that in average each partition contains at least a single vehicle; the objective is to ensure that only a vehicle in the farthest partition (from the sender) is used to disseminate the message, to next hop, resulting in shorter one hop delay. DPS ensures fast dissemination of emergency messages. Moreover, a new handshaking mechanism, that uses busy tones, is proposed to solve the problem of hidden terminal problem. In VANETs, Multicasting, i.e. delivering a message from a source to a limited known number of vehicles as destinations, is very important. Compared to Unicasting, with Multicasting, the source can simultaneously support multiple destinations, via a multicast tree, saving bandwidth and reducing overall communication congestion. However, since VANETs have a dynamic topology, maintaining the connectivity of the multicast tree is a major issue. As the second contribution, we propose two approaches to model total bandwidth usage of a multicast tree: (i) the first approach considers the number of road segments involved in the multicast tree and (ii) the second approach considers the number of relaying intersections involved in the multicast tree. A heuristic is proposed for each approach. To ensure QoS of the multicasting tree, efficient procedures are proposed for tracking destinations and monitoring QoS of road segments. As the third contribution, we study the problem of network congestion in routing data traffic in VANETs. We propose (1) a Cloud-based routing approach that, in opposition to existing approaches, takes into account existing routing paths which are already relaying data in VANETs. New routing requests are processed such that no road segment gets overloaded by multiple crossing routing paths. Instead of routing over a limited set of road segments, our approach balances the load of communication paths over the whole urban road segments, with the objective to prevent, whenever possible, local congestions in VANETs; and (2) a Software Defined Networking (SDN) based approach to monitor real-time VANETs connectivity and transmission delays on each road segment. The monitoring data is used as input to the routing approach

5G NR-V2X: Towards Connected and Cooperative Autonomous Driving

This paper is concerned with the key features and fundamental technology components for 5G New Radio (NR) for genuine realization of connected and cooperative autonomous driving. We discuss the major functionalities of physical layer, Sidelink features and its resource allocation, architecture flexibility, security and privacy mechanisms, and precise positioning techniques with an evolution path from existing cellular vehicle-to-everything (V2X) technology towards NR-V2X. Moreover, we envisage and highlight the potential of machine learning for further enhancement of various NR-V2X services. Lastly, we show how 5G NR can be configured to support advanced V2X use cases in autonomous driving

A trajectory-driven opportunistic routing protocol for VCPS

By exploring sensing, computing and communication capabilities on vehicles, Vehicular Cyber-Physical Systems (VCPS) are promising solutions to provide road safety and traffic efficiency in Intelligent Transportation Systems (ITS). Due to high mobility and sparse network density, VCPS could be severely affected by intermittent connectivity. In this paper, we propose a Trajectory-Driven Opportunistic Routing (TDOR) protocol, which is primarily applied for sparse networks, e.g., Delay/Disruption Tolerant Networks (DTNs). With geographic routing protocol designed in DTNs, existing works primarily consider the proximity to destination as a criterion for nexthop selections. Differently, by utilizing GPS information of onboard vehicle navigation system to help with data transmission, TDOR selects the relay node based on the proximity to trajectory. This aims to provide reliable and efficient message delivery, i.e., high delivery ratio and low transmission overhead. TDOR is more immune to disruptions, due to unfavorable mobility of intermediate nodes. Performance evaluation results show TDOR outperforms well known opportunistic geographic routing protocols, and achieves much lower routing overhead for comparable delivery ratio