Broadcast In Vehicular Networks Research Articles

Fast Message Broadcasting in Vehicular Networks: Model Analysis and Performance Evaluation

The pervasive use of technology in the urban environment requires evolved algorithms able to deliver messages across vehicular ad-hoc networks (VANETs). These networks could be exploited to run a vast plethora of applications, including critical ones such as emergency message distribution. The state-of-the-art broadcasting solutions are based on providing vehicles with different probabilities of forwarding the message in order to reduce message collisions and the number of hops to cover a certain area of interest. In this article, we examine a class of these propagation algorithms, discussing their model analysis and performance evaluation. Furthermore, we propose a possible algorithm’s extension introducing a dynamic setting of parameters according to the vehicular network’s conditions.

A Novel Hybrid MAC Protocol for Basic Safety Message Broadcasting in Vehicular Networks

Basic Safety Messaging plays a crucial role to provide road safety in vehicular ad-hoc networks (VANETs). To avoid potential accidents, vehicles periodically broadcast safety information to neighboring vehicles. However, due to transmission collisions, fading channels and other factors, vehicular networks usually suffer a low packet delivery ratio (PDR) and a large delay, which are intolerant of many safety applications. To tackle these issues, this paper proposes a hybrid medium access control (MAC) protocol for basic safety message (BSM) dissemination based on the framework of Dedicated Short-Range Communication (DSRC). Its partially centralized and partially distributed characteristic not only can effectively suppress the collisions, but keep compatibility with IEEE 802.11p. In addition, the integration of Physical-Layer Network Coding (PNC) and Random Linear Network Coding (RLNC) further strengthens the reliability and efficiency for BSM dissemination. Both the theoretical analysis and comprehensive simulations indicate that, compared with existing schemes, the proposed protocol can significantly improve the PDR by a range of 20% to 300%. Meanwhile, in terms of normalized throughput, it increases by varying percent between 20% and 160% in different scenarios.

Cooperative Cache Transfer-based On-demand Network Coded Broadcast in Vehicular Networks

Real-time traffic updates, safety and comfort driving, infotainment, and so on, are some envisioned applications in vehicular networks. Unlike traditional broadcast, network-coding-assisted broadcast can satisfy multiple vehicles with different data items in a coded form. However, server side encoding requires the prior knowledge about vehicles’ cache information for the successful decoding at the vehicles’ sides. The explicit cache upload from vehicles to Road Side Unit (RSU) wastes upload bandwidth. In multi-RSU vehicular networks, we propose a Cooperative Cache Transfer-based On-demand Network Coded Broadcast called CCTCB. In the proposed CCTCB approach, vehicles do not need to upload their cache information to the server, rather the RSU server learns the vehicles’ cache intrinsically. We derive a probabilistic model to analyze the coding opportunity in the proposed cooperative cache transfer mechanism incorporating vehicle mobility. The comprehensive simulation results validate the superiority of the proposed approach.

A cooperative V2X MAC protocol for vehicular networks

In support of traffic safety applications, vehicular networks should offer a robust Medium Access Control (MAC) layer protocol that can provide a reliable delivery service to safety-related messages. As the safety applications generally use broadcasting to propagate their messages, a reliable broadcast protocol is essential. In general, however, broadcast is considered as unreliable by nature in contrast to unicast. This paper introduces a novel MAC protocol, called a Hybrid Cooperative MAC (HCMAC), which can substantially enhance the reliability of broadcast in vehicular networks by employing a notion of channelization. HCMAC introduces a hybrid protocol that combines a time slot allocation of Time Division Multiple Access (TDMA) and a random-access technique of Carrier Sense Multiple Access (CSMA) and thus minimizes the probability of data collisions. In addition, its feedback strategy further enhances the system performance by preventing transmissions during time slots that experience collisions. Through analysis and simulations, we compare the performance of HCMAC with VeMAC, an existing TDMA protocol. The results demonstrate that HCMAC can offer substantially faster channel access and lower collision rate compared with VeMAC.

Modelling a vehicle‐ID‐based IEEE 802.11OCB MAC scheme for periodic broadcast in vehicular networks

Periodic broadcast of cooperative awareness messages (CAMs) is of great importance considering safety-related applications, for a network like VANET. This study proposes a vehicle-identifier (ID)-based MAC scheme for the periodic broadcast of CAMs in a vehicular network. Each CAM generated by a vehicle is associated with a unique ID. This study uses this attribute of CAM messages while participating in the channel assessment procedure. Each vehicle weighs the random back-off number with the unique ID incorporated in their respective CAM. This eventually leads to the selection of a vehicle-ID-based random back-off number, mitigating all possible probabilities of collision due to same back-off number selection. The simulation is performed considering saturated traffic conditions, to analyse its behaviour under most critical situations. The proposed model eliminates the chances of selecting zero as the initial back-off number, eliminating any chances of consecutive freeze process. The proposed one-dimensional Markovian model is validated by MATLAB. The proposed model provides a clear depiction that it performs better than the traditional IEEE 802.11OCB used for VANET. Also, it is worth noting that the achieved results outperform the existing work in terms of average packet delay since nearly one-fourth of the contention window size is utilised throughout the simulation.

Efficient Real-Time Coding-Assisted Heterogeneous Data Access in Vehicular Networks

Through the embedded processors and communication technologies, vehicles are increasingly being connected with the Internet of Things. Recently, much attentions have been paid to network-coding-assisted data broadcast in vehicular networks. However, majority of the works consider all the accessed data items are the same size. In this paper, we have studied the network coding-assisted heterogeneous on-demand real-time data access in vehicular networks. First, we have investigated the less efficiency of conventional coding assisted approach in accessing heterogeneous data items in real-time vehicular environment. Due to ignoring the impact of heterogeneous data items in decoding, the conventional coding does not achieve expected performance in accessing data items with diverse size. Second, based on our observations, for efficiently serving heterogeneous data items, we have proposed a dynamic threshold-based coding-assisted real-time data broadcast approach called earliest deadline first <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Θ</sub> . Third, we have derived the probabilistic analysis of the system performance of the proposed approach and the state-of-the-art approaches. Fourth, based on our further investigations, we have proposed another approach, called inverse of slack time multiply distance with THRESHOLD (Θ) (ISXD <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Θ</sub> ). The proposed network coding-assisted ISXD <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Θ</sub> exploits the different modulation and coding scheme of IEEE 802.11p physical layer for leveraging the variable serving rate considering the dynamic positions of vehicles along with the vehicle mobility. The comprehensive simulation results demonstrate the efficacy of the proposed approaches over the state-of-the-art approaches in terms of improving the on-demand requests serving capability and reducing the system response time.

A Network Coverage Algorithm for Message Broadcast in Vehicular Networks

In the recent years, ICT use in vehicular technology has expanded very fast. Inter-vehicle communication (IVC) is seen as the natural next step in this evolution whose availability will give rise to the next generation of smart vehicles. As this technology is deployed, a wide range of services varying from safety to entertainment will become factually accessible to passengers. Many of these envisaged services require a one-to-many communication model which demand for intelligent solutions able to propagate the message in areas of the network where it has not been heard before. To this end, we propose an enhancement of an existent optimal message propagation scheme proposed in the context of one dimensional vehicular networks, namely Fast-Broadcast. Our proposal generalizes the former with the objective of guiding message dissemination to an entire area of interest in generic road topologies. Our proposed scheme exploits bloom filter properties to further advance message propagation into the network. We contrast our approach with the original, lightweight state-of-the-art proposal, showing that it fulfills its design objectives.

Editorial for SM 160 – Design and Implementation of Mobile Smart Objects Special Issue

Editorial: This special issue features six selected high quality papers from SMARTOBJECTS 2015, a Workshop on experiences with the design and implementation of smart objects, held of September 7th, 2015 in Paris, FRANCE. It focuses on experiences with the design, implementation, deployment, operation and evaluation of novel communication approaches and systems for smart objects in the emerging cooperative environments. In the first article, BAn NFC Anti-Counterfeiting Framework for ID Verification and Image Protection^, Wei Hsun Lee, Chien Ming Chou, and Szu Wen Wang propose an NFC anti-counterfeiting framework with a two-layered digital image protection mechanism. In this system, an application certificate signed by the service provider and image metadata are hidden in the personal digital image using digital watermarking, and the image metadata is protected by the secure element in the NFC device. Several procedures are designed to ensure the originality of the photo and signature images, so that the process of digital image authentication is as secure and practical as using printed images on a plastic card. The second article titled BThe Coordinated Vehicle Recovery Mechanism in City Environments^, by GwoJiun Horng, presents the design and analysis of an innovative, optimized and coordinated vehicle recovery network system. This system safeguards private property for all citizens, significantly enhances an existing vehicle recovery and anti-theft system, and improves the success rate for vehicle recovery. This study is not only applicable to a single vehicle but also considers the entire vehicle anti-theft communication network and connects all individual vehicles to an innovative, optimized and coordinated vehicle recovery network. The next article BA Network Coverage Algorithm for Message Broadcast in Vehicular Networks^, by Armir Bujari, proposes an enhancement of an existent optimal message propagation scheme proposed in the context of one dimensional vehicular networks, namely Fast-Broadcast. This proposal generalizes the former with the objective of guiding message dissemination to an entire area of interest in generic road topologies. The proposed scheme exploits bloom filter properties to further advance message propagation into the network. The fourth article is titled BWearable HUD for Ecological Field Research Applications: A Development Experience on the Design of a Wearable Mobile System^. Its authors, Saul Delabrida, Thiago D’Angelo, Ricardo Augusto Rabelo Oliveira, and Antonio Alfredo F. Loureiro, overview wearable architectures found in the literature and present a novel wearable device for monitoring ecological environments. The wearable includes a Head-UP Display (HUD) assembled with Google Card* Pietro Manzoni pmanzoni@disca.upv.es

Broadcasting with Prediction and Selective Forwarding in Vehicular Networks

Broadcasting in vehicular networks has attracted great interest in research community and industry. Broadcasting on disseminating information to individual vehicle beyond the transmission range is based on inter-vehicle communication systems. It is crucial to broadcast messages to other vehicles as fast as possible because the messages in vehicle communication systems are often emergency messages such as accident warning or alarm. In many current approaches, the message initiator or sender selects the node among its neighbors that is farthest away from it in the broadcasting direction and then assigns the node to rebroadcast the message once the node gets out of its range or after a particular time slot. However, this approach may select a nonoptimal candidate because it does not consider the moving status of vehicles including their moving directions and speeds. In this paper, we develop a new approach based on prediction of future velocity and selective forwarding. The current message sender selects the best candidate that will rebroadcast the message to other vehicles as fast as possible. Key to the decision making is to consider the candidates' previous moving status and predict the future moving trends of the candidates so that the message is spread out faster. In addition, this approach generates very low overhead. Simulations demonstrate that our approach significantly decreases end-to-end delay and improves message delivery ratio.

Performance Analysis for Priority-Based Broadcast in Vehicular Networks

Transportation safety is one of the most important applications of vehicular ad hoc networks which is based on IEEE 802.11p. When a vehicle is in an emergency situation, a safety-related message is transmitted to the neighboring vehicles and infrastructures. Vehicles and infrastructures exchange periodic messages on vehicle position, traffic information, and so forth to provide various services. When the traffic load is very high, the emergency message cannot be delivered immediately. To overcome this situation, a priority-based transmission scheme is considered to guarantee the transmission of the emergency message. In this paper, the performance of vehicular communication networks is analyzed in two perspectives. Firstly, an analytical Markov chain model for vehicle-to-vehicle (V2V) ad hoc communication networks is proposed for broadcasting messages with priority based on the IEEE 802.11p wireless access for vehicular environments (WAVE) standard. Secondly, an analytic queuing model for vehicular communication networks is proposed to evaluate the network performance to deal with safety and nonsafety messages.

The Dynamic Counting Broadcast in Vehicular Networks

An interesting application of wireless MANETs that is emerging with a high potential for research and development is the inter-vehicle communication where nodes collect and distribute traffic information while moving in urban areas. Broadcasting is a key component to vehicular communication with the aim of high coverage and low medium consumption. Existing broadcasting schemes, however, result in redundancy and medium contention. In this paper a broadcasting scheme with intelligent neighbourhood sensing is produced and tested in two Vehicle Ad Hoc Network (VANET) contexts. Simulation results show that our scheme reduces the amount of unneeded transmissions through the medium even under high density with high traffic loads while maintaining comparable network coverage.

Black-Burst-Based Multihop Broadcast Protocols for Vehicular Networks

In this paper, two IEEE 802.11-based multihop broadcast protocols, namely urban multihop broadcast and ad hoc multihop broadcast, are proposed to address the broadcast storm, hidden node, and reliability problems of multihop broadcast in vehicular networks. In the proposed protocols, the functions of forwarding and acknowledging the broadcast packet are assigned to only one vehicle by dividing the road portion inside the transmission range into segments and choosing the vehicle in the furthest nonempty segment without a priori topology information. The simulation results confirm that our protocols have very high success rate and efficient channel utilization when compared with other flooding-based protocols. It is also concluded that there is no need for infrastructure support unless the line of sight among different road segments incident to an intersection is blocked with obstacles.