Wireless Access In Vehicular Environments Research Articles

WAVE 통신 시스템을 위한 차량 보안 통신 프로토콜의 설계 및 구현

The WAVE(Wireless Access in Vehicular Environments) communication system supports wireless communication environments between vehicles. As the utilization of wireless communication has been increased, attack methods have been varied. There is a high risk on packet manipulations conducted by third party. In this paper, we have designed a secure communication protocol between CA and vehicles. Our designed protocol uses a ECIES(Elliptic Curve Integrated Encryption Scheme) for vehicle authentication and AES(Advanced Encryption Standard) algorithm for protecting packet integrity and confidentiality.

Improving aggregate utility in IEEE 802.11p based vehicle-to-infrastructure networks

IEEE802.11p, also known as wireless access in vehicular environment defines amendments to IEEE 802.11 to support intelligent transportation systems applications, by enabling both vehicle-to-vehicle and vehicle-to-infrastructure (V2I) communications. The medium access control layer in IEEE 802.11p is based on IEEE 802.11e enhanced distributed channel access, while the physical layer is based on IEEE 802.11a standard. This paper investigates the problem of improving the aggregate utility in IEEE 802.11p based V2I networks, while ensuring fairness among the competing vehicles. Firstly, we consider a V2I network in drive-thru Internet scenario, formed by vehicles moving on a multi-lane highway with different mean velocities in different lanes, in which all the competing vehicles use the same data rate. For error-prone channels, we derive analytical expressions for the class specific optimal minimum contention window ($$CW_{\min }$$CWmin) values that simultaneously maximize the aggregate data transferred and provide fairness among vehicles belonging to distinct mean velocity classes in the sense of equal chance of communicating with the road side units. We also obtain an analytical expression for the maximum aggregate data transferred in the presence of channel error. In the second part, we extend the analytical model to compute the amount of successfully transferred data in a multi-rate multi-lane V2I network. In addition to the unfairness problem caused by the distinct velocities, vehicles in such networks suffer from a performance anomaly problem as well, due to the use of distinct data rates. We determine analytical expressions for the $$CW_{\min }$$CWmin values required to simultaneously resolve both the problems. Results show that, with proper tuning of $$CW_{\min }$$CWmin the aggregate data transferred in the network improves significantly. The analytical results are corroborated using extensive simulation studies.

An Enhanced Message Priority Mechanism in IEEE 802.11p Based Vehicular Networks

IEEE 802.11p is a standard MAC protocol for wireless access in vehicular environments (WAVEs). If a packet collision happens when a safety message is sent out, IEEE 802.11p chooses a random back-off counter value in a fixed-size contention window. However, depending on the random choice of back-off counter value, it is still possible that less important messages are sent out first while more important messages are delayed longer until sent out. In this paper, we present a new scheme for safety message scheduling, called the enhanced message priority mechanism (EMPM). It consists of the following two components: the benefit-value algorithm, which calculates the priority of the messages depending on the speed, deceleration, and message lifetime; and the back-off counter selection algorithm, which chooses the non-uniform back-off counter value in order to reduce the collision probability and to enhance the throughput of the highly beneficial messages. Numerical results show that the EMPM can significantly improve the throughput and delay of messages with high benefits when compared with existing MAC protocols. Consequently, the EMPM can provide better QoS support for the more important and urgent messages.

Impact of 802.11p Channel Hopping on VANET Communication Protocols

Vehicular Ad-Hoc Networks (VANETs) are a specific type of moving networks in which the nodes are vehicles with processing, storage and wireless communication capacity. The Wireless Access in Vehicular Environments (WAVE) presents an architecture, based on a division into multiple channels with each channel set certain types of application and that uses a switching mechanism for the selection of channels, since only one channel is active at a given time. However, in certain scenarios, this channel switching mechanism approach used in WAVE introduces an undesirable effect that allows different vehicles to transmit simultaneously, resulting in collisions. In this work, we propose a solution to this problem, with the development of a mechanism based on recalculation of transmission delay to ensure greater performance in transmissions. The mechanism proposed, named as Desync, was evaluated in two different data dissemination protocols, ABSM and AID. The simulation results show that the Desync is effective in reducing collisions and maximizing the delivery rate.

Performance Analysis of MAC with DCF on CCH and Reservation for Multi-Channel for IEEE 802.11p/1609.4 WAVE Networks

We propose and analyze a MAC Protocol for multiple service channels (SCHs) based on reservation by distributed coordination function (DCF) on control channel (CCH) for IEEE 802.11p and IEEE 1609.4 wireless access in vehicular environments (WAVE) networks. Specifically each user sends a request for service (RFS) packet to the Road-Side Unit (RSU) on the CCH by DCF method in order to reserve one SCH over which a data file is transmitted at a once. We construct a Markov Chain to find collision probability of RFS packet. We obtain probability of successful delivery and head-of-line (HOL) delay of RFS packet, and service time of data file.

A Video-Analysis-Based Railway–Road Safety System for Detecting Hazard Situations at Level Crossings

Safety and security are the most discussed topics in the road and railway transportation field. Latest security initiatives in the field of railway transportation propose to implement video surveillance at level crossing (LC) environments. In this paper we explore the possibility of implementing a smart video surveillance security system that is tuned toward detecting and evaluating abnormal situations induced by users (pedestrians, vehicle drivers, and unattended objects) in LCs. This intelligent security system starts by detecting, separating, and tracking moving objects shot in the LC. Then, a hidden Markov model is developed to estimate ideal trajectories, allowing the detected targets to discard dangerous situations. After that, the level of risk of each target is instantly estimated by using the Dempster-Shafer data fusion technique. The proposed analysis allows for also recognizing hazard scenarios. The video surveillance system is connected to a communication system (the Wireless Access for Vehicular Environment), which takes the information on the dynamic status of the LC (safe or presence of a dangerous situation) and sends it to users approaching the LC. Four hazard scenarios are tested and evaluated with different real video image sequences: presence of the obstacle in the LC, presence of the stopped vehicles line, vehicle zigzagging between two closed half barriers, and pedestrian crossing the LC area.

Efficiency Improvement of Vehicular Antenna Systems for Ubiquitous Intelligent Systems

This paper describes the design of a high-efficiency vehicular roof-mounted antenna for wireless access for vehicular environment (WAVE) communication systems used for ubiquitous intelligent systems. The main objective of the ubiquitous intelligent system’s automotive IT technology is to enhance the connectivity among vehicles to ensure seamless communication and to reduce the initial access time using high-performance antenna systems. The efficiency of WAVE communication systems used for ubiquitous intelligent systems depends on the antenna efficiency. The proposed vehicular antenna for WAVE communication systems shows an improvement of approximately 4.77 dB in the return loss, as compared with a conventional antenna system.

An infrastructure-aided cooperative spectrum sensing scheme for vehicular ad hoc networks

The Wireless Access in Vehicular Environments (WAVE) protocol stack has been recently defined to enable vehicular communication on the Dedicated Short Range Communication (DSRC) frequencies. Recent studies have demonstrated that the Control Channel (CCH) of the DSRC protocol on which all vehicular safety messages are sent might not provide sufficient spectrum for reliable exchange of safety information over congested urban scenarios. In this paper, we develop a scheme that calls for collecting spectrum sensing measurements by cars and then aggregating these measurements by Road Side Units (RSUs) to assess the state of the spectrum on road segments. We propose to opportunistically use the white spaces in the spectrum as an extension of the crowded Control Channel (CCH) for the next passing cars. A blind detector is applied and tested on the cars level, which takes advantage of their mobility to span a large area of the roads and deliver more accurate decisions in dynamic vehicular environments. To ensure homogeneity in the sensing samples among cars, we make the sensing rate of the cars dependent on their traveling speed. A fusion and decision algorithm is employed by Road Side Units (RSUs) to aggregate the individual sensing data and decide on the vacancy of the sensed frequency bands. The performance of the sensing and decision algorithms are evaluated and tested in various vehicular scenarios using the network simulator ns2. The obtained results prove the effectiveness of the system in detecting available ISM channels.

High-Performance Vehicle Streams: Communication and Control Architecture

This paper presents the overall framework for high-performance vehicle streams that integrates the transportation and the communication layered architectures together. It shows the process in establishing an infrastructure for high-performance vehicles and the theoretical development and deployment of cooperative adaptive cruise control (CACC) for heterogeneous vehicles that is integrated with lateral control. The system is designed to be fault tolerant and uses the concept of subplatoons. Our framework is based on integrating a transportation layered architecture with the Wireless Access in Vehicular Environment (WAVE) communication protocol.

Circular polarization‐agile microstrip antenna for wireless access in vehicular environments

ABSTRACTIn this article, a new reconfigurable microstrip antenna with circular polarization‐agile capability is presented for wireless access in vehicular environments (WAVE). The proposed antenna consists of a circular microstrip radiator on a back‐sided circular slot with an adding tab and a trimmed slot with two PIN diodes. The circular slot in the ground acts as a perturbing element to generate both left‐ and right‐handed circular polarization without shifting the resonant frequency. Both of circular polarization senses can be successfully alternated by controlling the states of diodes. The implemented antenna shows a good agreement with the simulation results and excellent controllability with symmetrical radiation at the identical resonant frequency. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2310–2313, 2014

Exploiting Context Severity to Achieve Opportunistic Service Differentiation in Vehicular Ad hoc Networks

Wireless Access in Vehicular Environment (WAVE) dictates primitives for intelligent transportation system (ITS) applications and services. The medium access control (MAC) layer in WAVE facilitates service differentiation. This offers quality of service (QoS) by prioritizing traffic through different access categories (ACs), which are based on application-requested priorities. However, it is oblivious to network load, to delay requirements for ITS safety applications, and to the “severity” of vehicles. In this paper, we propose a novel opportunistic service differentiation (OSD) scheme as an enhancement to WAVE. We define a fuzzy inference system (FIS) to deduce a context severity metric (CSM) that relates the driving behavior of a vehicle to its environment. Our OSD traffic distribution heuristic prioritizes vehicle traffic, with respect to CSM, and accounts for network load and link layer bounds. Furthermore, the OSD scheme guarantees that ACs do not exceed maximum allowable delay for ITS applications. Our methodology entails defining and designing a linear programming (LP) model for verification and validation of the OSD scheme. We perform a comparative study of OSD-enhanced WAVE and classical WAVE analytically and in a vehicular ad hoc network (VANET) simulator. We show that both simulation and analytical results substantiate our claim of improvement in performance of OSD-enhanced WAVE over classical WAVE.

Counting vehicles: Learning from animal population estimation

In the soon-to-be realized IEEE Wireless Access in Vehicular Environment (WAVE) system, vehicles are supposed to broadcast their movement information periodically. Although this beaconing mechanism has been designed mainly to reduce the risk of vehicle crashes in various driving contexts, it can easily be exploited for implementing many other applications. In particular, applications such as traffic situation monitoring and safety message overload control can be enabled by just counting the beacons. Counter to our intuition, however, simple counting is inadequate to enumerate the real vehicle population and generally leads to underestimation. This article first sheds light on this aspect, and then discusses how it can be overcome by drawing from experiences in wild animal counting in ecological studies.

Resolving the Unfairness of Distributed Rate Control in the IEEE WAVE Safety Messaging

In the IEEE Wireless Access in Vehicular Environment (WAVE), the periodic broadcast of the basic safety message (BSM) enables proximity awareness in the vehicle-to-vehicle (V2V) context. To maximize the level of awareness and consequently the driving safety, the BSM transmission at the highest allowed rate is desired in principle. A caveat, however, is controlling the BSM traffic within the given channel capacity because otherwise it can actually lower the delivery probability due to message collisions. To avoid such a congestion situation, a traditional mode of control is regulating the frequency of the BSM transmission based on the channel load. In this paper, we shed light on the pitfalls that lurk in exercising adaptive rate control based on an observed global state such as the channel load. Specifically, we show that straightforward threshold- or hysteresis-based controls can irrevocably render the rate assignments irrelevant to the given vehicle density pattern. As a solution, we show that distributed but coordinated control provably leads to stability and relevance to the given vehicle density pattern.

On the coexistence of IEEE 802.11ac and WAVE in the 5.9 GHz Band

The IEEE Wireless Access in Vehicular Environment, or WAVE, system uses 5.9 GHz band. Recently, however, the FCC announced its intention to share the band for WLANs based on new standards such as IEEE 802.11ac. In this article, we discuss the problems in the possible coexistence scenario of WAVE and WLAN, such as direct competition between WLAN and WAVE devices for bandwidth and the hidden terminal problem. The problems are exacerbated by the different bandwidth used by the two technologies, so the only usable sensing method between them is energy detection. In this article, we consider one way to address the problems within the current standards framework, which is the combined control of interframe space and the receiver sensitivity on the WLAN devices cued by the energy detection.

MAC 계층에서의 IEEE 802.11p 기반 WAVE 통신 시스템의 성능 평가

Vehicular communications have been receiving much attention in intelligent transport systems(ITS) by combining communication technology with automobile industries. In general, vehicular communication can be used for vehicle-to-vehicle(V2V) and vehicle-to-infrastructure( V2I) communication by adopting IEEE802.11p/1609 standard which is commonly known as wireless access in vehicular environment(WAVE). WAVE system transmits signal in 5.835~5.925 GHz frequency band with orthogonal frequency division multiplexing(OFDM) signaling. In this paper, after 32 bit processed the channel monitoring in MAC(Media Access Control) layer of WAVE system implemented according to IEEE 802.11p standard, data were received and we evaluated the performance, we built the test bed consisting of OBU(On Board Unit) in the real expressway. We transmitted WSM(WAVE Short Message) and received WSM between OBU wirelessly. And then, we calculated channel occupancy time per one frame and throughput, and evaluated the performance.

Radio Channel Model Suitable for the Next Generation Wireless Access Vehicular Environment Technology

차세대 차량무선통신시스템의 성능개선에 대한 보다 정확한 평가나 교통의 안전성을 확보하기 위해서는, 무엇보다 중요한 것은 V2I(vehicle to infrastructure) 과 V2V(vehicle to vehicle) 무선통신 채널에 대한 보다 정확한 채널 모델링의 적용이다. 이는 차세대 차량용 무선통신기술(WAVE) 개발에 있어서 교통의 안전성과 효율성에 직결되기 때문이다. 본 논문에서는 차량용 무선통신기술에 있어서 교통의 안전성을 보장하고 그 성능을 정확히 평가할 수 있는 무선전파모델의 미시적 효과에 대하여 해석하였다. 우선 기존의 대표적인 시가지 무선전파의 경험적 모델을 정의하고, 거시적 전파특성과 미시적 전파특성에 대한 데이터 전송특성과 교통의 안전성 감지특성에 대하여 해석하였다. 컴퓨터 시뮬레이션 해석 결과, 차량용 무선통신기술에 적합한 무선전파 채널모델링은 경로손실특성, 새도우 페이딩(shadow fading), 그리고 고속 페이딩(fast fading) 효과 등을 함께 고려해야 함을 알 수 있었다.

Network performance analysis and manuever model for overtaking assistant service using wave

We present network requirements for an overtaking assistant service using wireless access in vehicular environment (WAVE). Currently, DNPW has been proposed as a representative overtaking assistant service with vehicle-tovehicle (V2V) communication. In order to analyze its network performance, we construct a maneuver model for an overtaking system. According to this model, we configured a scenario for network simulation based on the 802.11p WAVE standard. The results confirm that a radio range for overtaking needs only a single hop without routing methods. Moreover, we propose an additional safe distance for the communication delay generated by an increase in the numbers of neighboring vehicles. And for high priority activity of safety services, we present a proper access category (AC) of enhanced distributed channel access (EDCA). These analysis results should be tested considered in real safety service systems that use V2V communication.

Analysis of Position Based Routing Protocols in VANET using NS2 Simulator

Vehicular Ad hoc Network can ease our life by making driving safe in near future. To make it successful, efficient routing protocols need to be used for communication among vehicles. This communication can be direct within vehicles and can be through road side units (RSUs). In this paper we are exploiting the GPSR, ASTAR and BMFR position based routing protocol by comparing their performances with respect to throughput, end to end delay and number of packets drops during communication. We are using IEEE 802.11p as a standard protocol for Vehicular Ad hoc Network and simulated the framework through NS2 network simulator. Keywords-Vehicular Ad Hoc Network (VANET), Road Side Units (RSUs), Dedicated Short Range Communication (DSRC), Wireless Access in Vehicular Environment (WAVE), Intrusion Detection System (IDS).

Prioritized Optimal Channel Allocation Schemes for Multi-Channel Vehicular Networks

The IEEE 1609.4 standard has been proposed to provide multi-channel operations in wireless access for vehicular environments (WAVE), where all channels are periodically synchronized into control and service intervals. Communication device in each vehicle will stay at the control channel for negotiation and contention during the control interval, and thereafter switch to one of the service channels for data transmission in the service interval. In this paper, based on the concept of cognitive radio (CR), the vehicles are categorized into primary providers (PPs) that intend to transmit safety-related messages and secondary providers (SPs) with non-safety information to be delivered. The prioritized optimal channel allocation (POCA) approaches are proposed to improve channel utilization of IEEE 1609.4 standard for multi-channel vehicular networks. Prioritized channel access is analyzed in the POCA schemes in order to increase the transmission opportunity of PPs. Moreover, depending on whether the CR network is distributed or centralized, the optimal channel-hopping sequence and optimal channel allocation is assigned for SPs based on dynamic programming and linear programming technique, respectively. These schemes are designed to consider optimal load balance between both channel availability and channel utilization within the throughput constraints of PPs. With the adoption of proposed POCA schemes, simulation results show that maximum throughput of SPs can be achieved with guaranteed quality-of-service requirement for PPs.

WAVE 하드웨어 암호 라이브러리에 적합한 효율적인 AES-CCM 구조 설계

차량에서의 무선통신의 발달과 함께 WAVE(Wireless access in vehicular environments) 상에서도 보안에 대한 위험성이 증가하였다. 이를 위해 IEEE 1609.2로 스누핑, 도청과 같은 공격으로부터 메시지를 보호하기 위한 보안 서비스를 규정하였다. 이를 보안 라이브러리를 하드웨어 형태로 구현 가능하며 본 논문에서는 이에 적합한 AES-CCM 구조를 설계하였다. 동일 FPGA에서 비교 논문의 구조와 비교하여 27 % 적은 slice를 사용하였으며 기존 라이브러리모듈에서 레지스터를 공유하였을 경우를 고려하면 약 45 % 적은 slice를 사용한다. 또한 xc5vlx110t-2ff1136 상에서 1355 Gbits/s의 처리량을 보인다. According to developing wireless communications in vehicle, various security threat in the WAVE(Wireless access in vehicular environments) is increased. To protect this, IEEE 1609.2 specify services as for prevent message from attacks such as spoofing, eavesdropping and replay. It is possible to implement a hardware library for defending these attacks. In this paper, we proposed a efficient AES-CCM architecture for the hardware library in the WAVE. We compare our architecture to the previous one in the same FPGA. And our design uses less slices than 27 % of it and less slices than 45 % of it if we share registers that were used by other modules in the library. We also achieves a throughput of 1355 Gbits/s in xc5vlx110t-2ff1136.