Delivery Of Safety Messages Research Articles

What is a shore dump?: Exploring Australian university students’ beach safety knowledge and their perceptions of Australian beach safety signage

BackgroundOn average 122 coastal drownings deaths are recorded in Australia every year. Typically, young adult beachgoers (15–34 years old), many of whom were born overseas, account for 25 % of these fatalities. This study identifies university students as appropriate subjects for investigating typical interpretations of beach safety messages and signage among this high-risk demographic. MethodsThis study involved an online survey of Australian university students (domestic: n = 136 international: n = 84). The survey comprised both closed and open-ended questions about beach safety terms and signage. Participants were recruited through university newsletters, course announcements, social media, and at beach safety workshops. Data were analysed with SPSS for descriptive analyses and Pearson Chi-Square to test for statistical differences between domestic and international students. ResultsOver 55% of domestic and over 75% of international students did not understand the common safety terms shore dump and shore break and approximately half of both groups misunderstood the sign, always swim between the flags, believing that surfers should also stay between the flags. Concerningly, 21% of international students perceived this meant that beachgoers who don’t or can’t swim need to stay outside the flags. So what?Existing beach safety signage is not as effective as authorities assume due to linguistic and translation challenges. Some terms are improperly translated into Japanese and Chinese in the current search on Google Translate. Such linguistic issues must be addressed so as to improve the delivery of coastal safety messages.

A metaheuristic MAC protocol for safety applications in cognitive vehicular networks

In a dynamic cognitive vehicular network (CVN) environment, ensuring reliable data delivery of safety messages (sm) is crucial. However, fast-moving vehicles and rapidly changing channel accessibility make sm broadcasting challenging. To address this issue, we propose a cooperative make-up technique, which leverages the 2-Hop Harris Hawks Optimization (HHO) algorithm to choose an optimal helper for sm retransmission in case of failed direct transmission. Our simulations using the Network Simulator version 2 with SUMO demonstrate that the proposed approach achieves cooperative communication within the tight 100ms sm broadcast time frame and outperforms contemporary CVN protocols regarding throughput and packet delivery ratio. Our results suggest that our approach holds great promise for reliable and efficient data delivery in CVNs.

A TDMA-Based MAC Protocol for Mitigating Mobility-Caused Packet Collisions in Vehicular Ad Hoc Networks.

An autonomous driving environment poses a very stringent requirement for the timely delivery of safety messages in vehicular ad hoc networks (VANETs). Time division multiple access (TDMA)-based medium access control (MAC) protocols are considered a promising solution because of their time-bound message delivery. However, in the event of mobility-caused packet collisions, they may experience an unpredicted and extended delay in delivering messages, which can cause catastrophic accidents. To solve this problem, a distributed TDMA-based MAC protocol with mobility-caused collision mitigation (MCCM-MAC) is presented in this paper. The protocol uses a novel mechanism to detect merging collisions and mitigates them by avoiding subsequent access collisions. One vehicle in the merging collisions retains the time slot, and the others release the slot. The common neighboring vehicles can timely suggest a suitable new time slot for the vacating vehicles, which can avoid access collisions between their packet transmissions. A tie-breakup mechanism is employed to avoid further access collisions. Simulation results show that the proposed protocol reduces packet loss more than the existing methods. Consequently, the average delay between the successfully delivered periodic messages is also reduced.

An Analysis on Contemporary MAC Layer Protocols in Vehicular Networks: State-of-the-Art and Future Directions

Traffic density around the globe is increasing on a day-to-day basis, resulting in more accidents, congestion, and pollution. The dynamic vehicular environment induces challenges in designing an efficient and reliable protocol for communication. Timely delivery of safety and non-safety messages is necessary for traffic congestion control and for avoiding road mishaps. For efficient resource sharing and optimized channel utilization, the media access control (MAC) protocol plays a vital role. An efficient MAC protocol design can provide fair channel access and can delay constraint safety message dissemination, improving road safety. This paper reviews the applications, characteristics, and challenges faced in the design of MAC protocols. A classification of the MAC protocol is presented based on contention mechanisms and channel access. The classification based on contention is oriented as contention-based, contention-free, and hybrid, whereas the classification based on channel access is categorized as distributed, centralized, cluster-based, cooperative, token-based, and random access. These are further sub-classified as single-channel and multi-channel, based on the type of channel resources they utilize. This paper gives an analysis of the objectives, mechanisms, advantages/disadvantages, and simulators used in specified protocols. Finally, the paper concludes with a discussion on the future scope and open challenges for improving the MAC protocol design.

An Enhancement for IEEE 802.11p to Provision Quality of Service with Context Aware Channel Access for the Forward Collision Avoidance Application in Vehicular Ad Hoc Network.

Key application of an intelligent transportation system is traffic safety, and it provides driver assistance. Safety messages are of two types, beacon messages and event messages. The nodes broadcast these messages in the vehicular networks. The system must rely on a robust medium access control (MAC) protocol to support delivery of safety messages. The standard medium access scheme that is used in vehicular networks to provide service differentiation to support various applications is IEEE 802.11p. The emergency event messages should reach the drivers immediately to take necessary steps to avoid casualties on the road. In IEEE 802.11p, both of these messages are considered with the same priority so that no separate differentiation is created. The proposed work focuses on improving the quality of service for forward collision warning applications in intelligent transportation systems. The scheme proposes a priority-based cooperative MAC (PCMAC) for channel access that works on the context of information. Simulation and analytical results validate improved performance of PCMAC in terms of packet delivery ratio, throughput, and average packet delivery delay, as compared with other eminent MAC protocols. The simulation results show that it has a 9% higher improvement in throughput than IEEE 802.11p and has better performance in the increasing number of emergency messages.

Distribution of Safety Messages Using Mobility-Aware Multi-Hop Clustering in Vehicular Ad Hoc Network

Reliability and security when distributing safety messages among vehicles in an extremely mobile environment are prominent issues in Vehicular Ad-Hoc Networks (VANETs). In VANET, data transfer becomes challenging because of inherent features such as excessive speed, geographically constrained topologies, unsteady communication links, diversity in the capacity of the channel, etc. A major challenge in the multi-hop framework is maintaining and building a path under such a rigid environment. With VANET, potency in the traffic safety applications has performed well because of the proper design of medium access control (MAC) protocols. In this article, a protocol is proposed pertaining to the distribution of safety messages named mobility-aware multi-hop clustering-based MAC (MAMC-MAC) to accomplish minimum communication overhead, high reliability, and delivery of safety messages in real-time environments. MAMC-MAC has the ability to establish clustering-based multi-hop sequence using the time-division multiple access (TDMA) technique. The protocol was specially developed for highway outlines to achieve network enhancement and efficient channel usage and guarantees integrity among the vehicles. The performance of the proposed protocol is evaluated using Network Simulator (NS-2), and it demonstrates its superiority over various standard protocols in terms of a number of quality-of-service (QoS)-based parameters. The criteria to select and assess these parameters are their sensitivity and importance to the safety-based applications they provide.

Efficient VANET safety message delivery and authenticity with privacy preservation

Vehicular ad-hoc networks (VANETs) play an essential role in the development of the intelligent transportation system (ITS). VANET supports many types of applications that have strict time constraints. The communication and computational overheads are minimal for these computations and there are many security requirements that should be maintained. We propose an efficient message authentication system with a privacy preservation protocol. This protocol reduces the overall communication and computational overheads. The proposed protocol consists of three main phases: the group registration phase, send/receive messages phase, and the leave/join phase. For cryptography algorithms, we combined symmetric and asymmetric key algorithms. The symmetric key was generated and exchanged without using the Diffie–Hellman (DH) protocol. Furthermore, we used an efficient version of the RSA algorithm called CRT-RSA. The experimental results showed that the computational overhead in the registration phase was significantly reduced by 91.7%. The computational overhead for sending and receiving the non-safety message phase was reduced by 41.2% compared to other existed protocols. Moreover, our results showed that the time required to broadcast a safety and non-safety group message was below 100 ms and 150 ms, respectively. The average computational time of sending and receiving a one-to-one message was also calculated. The proposed protocol was also evaluated with respect to performance and security and was shown to be invulnerable to many security attacks.

Deployment and Analysis of Cooperative Intelligent Transport System Pilot Service Alerts in Real Environment

The industry is providing vehicles with advanced features and technologies that allows vehicles to connect and communicate with their nearby environment. These technologies' umbrella term, Cooperative Intelligent Transportation Systems (C-ITS) are aimed to enhance road traffic efficiency, safety and assist the drivers in multiple ways. The C-ITS communication system should be able to offer the functional benefits to different sets of use-cases, each having a particular sub-set of requirements. In this paper some of the relevant use-case scenarios utilizing road weather and traffic information are studied in terms of communication technology. The key requirements for C-ITS use-case scenarios are analyzed and an evaluation of the ITS-G5 protocol stack is performed. The performance of ITS-G5 in use-case scenarios is considered testing messages (alerts) on road weather and traffic information in realistic environments. The results indicate that the performance of ITS-G5 in tested use-case scenarios offers 90-98% success rate in the delivery of safety messages at a transmission frequency of 10Hz. Also, ITS-G5 delivers safety alerts with a minimum delay so that it satisfies the C-ITS use-case requirements in real environments. The C-ITS pilot platform also performs efficiently in terms of transmitting packets from a safe distance with minimum network latency and packet loss between vehicles and infrastructure. C-ITS pilot use-cases were tested on the platform developed and tailored by the Finnish Meteorological Institute (FMI).

MC-Safe

In a Vehicular Cyber Physical System (VCPS), ensuring the real-time delivery of safety messages is an important research problem for Vehicle to Vehicle (V2V) communication. Unfortunately, existing work relies only on one or two pre-selected control channels for safety message communication, which can result in poor packet delivery and potential accident when the vehicle density is high. If all the available channels can be dynamically utilized when the control channel is having severe contention, then safety messages can have a much better chance to meet their real-time deadlines. In this article, we propose MC-Safe, a multi-channel V2V communication framework that monitors all the available channels and dynamically selects the best one for safety message transmission. During normal driving, MC-Safe monitors periodic beacons sent by other vehicles and estimates the communication delay on all the channels. Upon the detection of a potential accident, MC-Safe leverages a novel channel negotiation scheme that allows all the involved vehicles to work collaboratively, in a distributed manner, for identifying a communication channel that meets the delay requirement. MC-safe also features a novel coordinator selection algorithm that minimizes the delay of channel negotiation. Once a channel is selected, all the involved vehicles switch to the same selected channel for real-time communication with the least amount of interference. Our evaluation results both in simulation and on a hardware testbed with scaled cars show that MC-Safe outperforms existing single-channel solutions and other well-designed multi-channel baselines by having a 23.4% lower packet delay on average compared with other well-designed channel selection baselines.

ALMS: Asymmetric Lightweight Centralized Group Key Management Protocol for VANETs

Vehicular ad hoc networks (VANETs) were initially designed to assist in traffic management and delivery of safety messages. Due to the significant evolution in modern vehicles, the features offered by VANETs have expanded to include comfort and entertainment relevant services. This expansion has further increased the need to secure them. The security of VANETs is mainly dependent on sharing a cryptographic group key confidentially. Due to the frequent change in group membership, there is a need to update the group key repeatedly, which is difficult in highly dynamic networks like VANETs. Therefore, designing a secure, scalable, and efficient group key management protocol is challenging. Existing group key management protocols introduce a variety of limitations, including high computational cost for both group key computation and retrieval, additional computational and communication overhead when the membership in the group changes, and collusion among receiving vehicles. To overcome these limitations, this paper introduces a novel group key management protocol, ALMS. Performance analysis reveals that, compared to existing protocols, ALMS is more scalable since it introduces a low computational overhead for both the Trusted Authority (TA) and the receiving vehicles. Also, it does not suffer from the key distribution limitation as symmetric key management protocols do. Moreover, ALMS introduces only a light overhead on the TA for group membership change. This is achieved by decoupling the initialization from group key computation and performing it offline without affecting the size of the encrypted group key.

Crash Risk-Based Prioritization of Basic Safety Message in DSRC

Dedicated short-range communications (DSRC) is one of the key technologies enabling safety-critical applications for intelligent transportation system (ITS). Considering the significance of such safety-of-life applications, it is of utmost importance to guarantee reliable delivery of basic safety messages (BSMs). However, in accordance with a V2X network being inherently dynamic in key aspects such as vehicle density and velocity, the networking behavior of a DSRC system is usually highly complicated to analyze. In addition, the United States Federal Communications Commission (US FCC) recently proposed the so-called “5.9 GHz band innovation,” which includes a plan to reduce bandwidth for DSRC to 10 MHz at best from 75 MHz. Motivated from these challenges, the necessity of “lightening” load of a DSRC network has become essential to keep safety-related operations from performance deterioration. To this end, this paper proposes a protocol that prioritizes transmission of a BSM from a vehicle according to the level of accident risk of the vehicle. The proposed protocol uses the distance of a vehicle from a danger source as the metric to determine the priority for transmission. Our results show that this protocol effectively prioritizes the transmission opportunity for dangerous vehicles, and hence results in higher performance in terms of key metrics–i.e., average latency, packet delivery rate ( $\mathsf {PDR}$ ), and inter-reception time ( $\mathsf {IRT}$ ).

QoS Routing Protocol (QoRP) to Enhance Road Safety in VANETs

Vehicular Ad Hoc Network (VANET) communication promises a vast array of applications ranging from road safety and driving comfort. Safety message broadcasting plays a significant role in highway safety in which the safety alert messages have to be delivered immediately to the vehicles located in the risk boundary area. Most of the current research attempt to select optimal relayer for safety message rebroadcasting. However, relayer selection models are not efficient, especially in a high-density VANET, as they cause a high delay in safety message delivery and lead to multiple accidents at the incident spot. To avert these issues, this work proposes a QoS Routing Protocol (QoRP) that aims to enhance the road safety in both sparse and dense VANETs.

Real-Time Detection of DoS Attacks in IEEE 802.11p Using Fog Computing for a Secure Intelligent Vehicular Network

The vehicular ad hoc network (VANET) is a method through which Intelligent Transportation Systems (ITS) have become important for the benefit of daily life. Real-time detection of all forms of attacks, including hybrid DoS attacks in IEEE 802.11p, has become an urgent issue for VANET. This is due to sporadic real-time exchange of safety and road emergency message delivery in VANET. Sporadic communication in VANET has the tendency to generate an enormous amount of messages. This leads to overutilization of the road side unit (RSU) or the central processing unit (CPU) for computation. Therefore, efficient storage and intelligent VANET infrastructure architecture (VIA), which includes trustworthiness, are required. Vehicular Cloud and Fog Computing (VFC) play an important role in efficient storage, computation, and communication needs for VANET. This research utilizes VFC integration with hybrid optimization algorithms (OAs), which also possess swarm intelligence, including Cuckoo/CSA Artificial Bee Colony (ABC) and Firefly/Genetic Algorithm (GA), to provide real-time detection of DoS attacks in IEEE 802.11p, using VFC for a secure intelligent vehicular network. Vehicles move ar a certain speed and the data is transmitted at 30 Mbps. Firefly Feed forward back propagation neural network (FFBPNN) is used as a classifier to distinguish between the attacked vehicles and the genuine vehicles. The proposed scheme is compared with Cuckoo/CSA ABC and Firefly GA by considering jitter, throughput, and prediction accuracy.

Congestion Control in V2V Safety Communication: Problem, Analysis, Approaches

The emergence of Vehicular Ad Hoc Networks (VANETs) is expected to be an important step toward achieving safety and efficiency in intelligent transportation systems (ITS). One important requirement of safety applications is that vehicles are able to communicate with neighboring vehicles, with very low latency and packet loss. The high mobility, unreliable channel quality and high message rates make this a challenging problem for VANETs. There have been significant research activities in recent years in the development of congestion control algorithms that ensure reliable delivery of safety messages in vehicle-to-vehicle (V2V) communication. In this paper, we present a comprehensive survey of congestion control approaches for VANET. We identify the relevant parameters and performance metrics that can be used to evaluate these approaches and analyze each approach based a number of factors such as the type of traffic, whether it is proactive or reactive, and the mechanism for controlling congestion. We conclude this paper with some additional considerations for designing V2V communication protocols and interesting and open research problems and directions for future work.

MPMAC: Clustering Based MAC Protocol for VANETs

Vehicular safety messaging is warranted mostly in turbulent traffic situations in which even cluster based MAC protocols are beset by problems of cluster rupture, which leads to non-availability of channels to vehicles even when channels are idle. To solve this, motion parameters based cluster medium access (MPMAC) protocol is presented in this paper. The vehicles organize themselves into headless clusters without any messaging. The members of a cluster are not spatially bunched and may belong to different lanes. Each cluster has channels earmarked with the flexibility of utilizing idle channels belonging to other clusters. Safety messages are accorded higher priority with one channel dedicated exclusively for these messages. To enhance channel utilization and avoid the hidden station problem, the RSU monitors the channels and periodically advertises the channel usage map. The MPMAC protocol increases the system’s throughput by enhancing channel utilization and facilitates the availability of channels during traffic conditions like phantom jams, lane changing and congestion. The delivery of safety messages to intended vehicles is ensured make provisions for flexible and prioritized channel access in addition to an earmarked channel. Simulation results show that the proposed MPMAC protocol is able to provide sufficient channels for dissemination of safety and other messages with enhanced throughput, fair access, and increased channel utilization while minimizing cluster formation overheads.

Secure Intelligent Vehicular Network Using Fog Computing

VANET (vehicular ad hoc network) has a main objective to improve driver safety and traffic efficiency. The intermittent exchange of real-time safety message delivery in VANET has become an urgent concern due to DoS (denial of service) and smart and normal intrusions (SNI) attacks. The intermittent communication of VANET generates huge amount of data which requires typical storage and intelligence infrastructure. Fog computing (FC) plays an important role in storage, computation, and communication needs. In this research, fog computing (FC) integrates with hybrid optimization algorithms (OAs) including the Cuckoo search algorithm (CSA), firefly algorithm (FA), firefly neural network, and the key distribution establishment (KDE) for authenticating both the network level and the node level against all attacks for trustworthiness in VANET. The proposed scheme is termed “Secure Intelligent Vehicular Network using fog computing” (SIVNFC). A feedforward back propagation neural network (FFBP-NN), also termed the firefly neural, is used as a classifier to distinguish between the attacking vehicles and genuine vehicles. The SIVNFC scheme is compared with the Cuckoo, the FA, and the firefly neural network to evaluate the quality of services (QoS) parameters such as jitter and throughput.

A Semi-Empirical Performance Study of Two-Hop DSRC Message Relaying at Road Intersections

This paper is focused on a vehicle-to-vehicle (V2V) communication system operating at a road intersection, where the communication links can be either line-of-sight (LOS) or non-line-of-sight (NLOS). We present a semi-empirical analysis of the packet delivery ratio of dedicated short-range communication (DSRC) safety messages for both LOS and NLOS scenarios using a commercial transceiver. In a NLOS scenario in which the reception of a safety message may be heavily blocked by concrete buildings, direct communication between the on-board units (OBUs) of vehicles through the IEEE 802.11p standard tends to be unreliable. On the basis of the semi-empirical result of safety message delivery at an intersection, we propose two relaying mechanisms (namely, simple relaying and network-coded relaying) via a road-side unit (RSU) to improve the delivery ratio of safety messages. Specifically, we designed RSU algorithms to optimize the number of relaying messages so as to maximize the message delivery ratio of the entire system in the presence of data packet collisions. Numerical results show that our proposed relaying schemes lead to a significant increase in safety message delivery rates.

Reliability and energy-efficiency analysis of safety message broadcast in VANETs

Safety applications in vehicular ad hoc networks (VANETs) rely heavily on broadcast schemes for the exchange of status messages. Reliable and on-time delivery of safety messages is critical in VANETs that requires extremely efficient broadcast models. In this paper, we model the reliability of flooding used as the underlying data dissemination protocol for time-critical safety messages. We consider a multi-hop VANET and model end-to-end reliability provided by the network layer. The analytical results unleash important insights about the flooding mechanism. For instance, the reliability drops exponentially beyond a certain threshold value of packet loss probability. Secondly, the impact of hop length on reliability can be catastrophic if not handled appropriately. Keeping in view of the fact that energy-efficient protocols is a key requirement in the upcoming Internet of Vehicles (IoV), we also show that restrictive flooding is more energy-efficient than plain flooding under the same reliability constraint. We validate our theoretical findings through simulations and propose modifications to plain flooding to make it more reliable.

Determining vehicles’ radio transmission range for increasing cognitive radio VANET (CR-VANET) reliability using a trust management system

As a part of an intelligent transportation system, a Vehicular Ad-Hoc Network (VANET) requires reliability by way of an essential need. Timely and accurately delivering safety messages in VANET is one of the reliability issues affected by different factors such as the lack of frequency spectrum as well as nodes’ inabilities or misbehaviors. To overcome spectrum shortage, Cognitive Radio (CR) has been proposed while employing a trust mechanism can lessen any damage caused to reliability by incapable or misbehaver nodes. An effective trust management system can analyze ‘agree’ and ‘disagree’ messages and decide about an event to increase reliability. However, message transmission based on trust assessment imposes an extra decision delay causing a reliability cutback, especially in delay-sensitive safety messages. In this research, an effective trust management system for CR-VANET is proposed and analyzed based on a Birth and Death Process (BDP) model to evaluate the average delay imposed by the decision-making process. The probability of event occurrence is also derived in terms of arrival message rate. Moreover, the minimum and maximum permissible range of radio transmission to reach an acceptable degree of reliability, based on the above analysis, is determined. Our statistical analysis in base of 2k factorial methodology shows that determining the radio transmission range has a major impact on decision-making delay. Using the proposed radio transmission range, simulation results also show that reliability can be improved as well as increasing the accuracy of event detection and reducing decision-making and safety message delivery delays.

A Review of Congestion Control Schemes for Vehicular Ad-Hoc Network (VANET) Communication

Intelligent Transportation Systems (ITS) are built on top of self-organizing networks, known as Vehicular Ad hoc Networks (VANET). In VANET, each vehicle equipped with communication devices represents a node and is allowed to send and receive safety messages through wireless communication channels. These messages are either periodic (beacons) or event-driven. Beacons are transmitted periodically while the event-driven messages are generated when an abnormal condition or an imminent danger is detected. The event-driven messages should be delivered to neighbouring nodes with high reliability and limit time as a single delayed or lost message could result in loss of lives. In dense network, the periodic messages broadcast lead to broadcast storm/blind flooding problem in VANETs. It is very important to keep the communication channel free from congestion in order to ensure timely and reliable delivery of event-driven safety messages. This study presents a review of existing congestion control schemes for VANETs with the aim of discussing the contributions and drawbacks of the algorithms.