Time division multiple access scheduling strategies for emerging vehicular ad hoc network medium access control protocols: a survey

[EN] Vehicular ad hoc network (VANET) is an emerging and promising technology, which allows vehicles while moving on the road to communicate and share resources. These resources are aimed at improving traffic safety and providing comfort to drivers and passengers. The resources use applications that have to meet high reliability and delay constraints. However, to implement these applications, VANET relies on medium access control (MAC) protocol. Many approaches have been proposed in the literature using time division multiple access (TDMA) scheme to enhance the efficiency of MAC protocol. Nevertheless, this technique has encountered some challenges including access and merging collisions due to inefficient time slot allocation strategy and hidden terminal problem. Despite several attempts to study this class of protocol, issues such as channel access and time slot scheduling strategy have not been given much attention. In this paper, we have relatively examined the most prominent TDMA MAC protocols which were proposed in the literature from 2010 to 2018. These protocols were classified based on scheduling strategy and the technique adopted. Also, we have comparatively analyzed them based on different parameters and performance metrics used. Finally, some open issues are presented for future deployment.Tambawal, AB.; Noor, RM.; Salleh, R.; Chembe, C.; Anisi, MH.; Michael, O.; Lloret, J. (2019). Time division multiple access scheduling strategies for emerging vehicular ad hoc network medium access control protocols: a survey. Telecommunication Systems. 70(4):595-616. https://doi.org/10.1007/s11235-018-00542-8S59561670

TDMA Slot Reservation in Cluster-Based VANETs

Vehicular Ad Hoc Networks (VANETs) are a form of Mobile Ad Hoc Networks (MANETs) in which vehicles on the road form the nodes of the network. VANETs provide several services to enhance the safety and comfort of drivers and passengers. These services can be obtained by the wireless exchange of information among the vehicles driving on the road. In particular, the transmission of two different types of messages, safety/update and non-safety messages. The transmission of safety/update message aims to inform the nearby vehicles about the sender\u27s current status and/or a detected dangerous situation. This type of transmission is designed to help in accident and danger avoidance. Moreover, it requires high message generated rate and high reliability. On the other hand, the transmission of non-safety message aims to increase the comfort on vehicles by supporting several non-safety services, from notifications of traffic conditions to file sharing. Unfortunately, the transmission of non-safety message has less priority than safety messages, which may cause shutting down the comfort services. The goal of this dissertation is to design a MAC protocol in order to provide the ability of the transmission of non-safety message with little impact on the reliability of transmitting safety message even if the traffic and communication densities are high. VANET is a highly dynamic network. With lack of specialized hardware for infrastructure and the mobility to support network stability and channel utilization, acluster-based MAC protocol is needed to solve these overcomes. This dissertation makes the following contributions: 1. A multi-channel cluster-based TDMA MAC protocol to coordinate intracluster communications (TC-MAC) 2. A CH election and cluster formation algorithm based on the traffic flow and a cluster maintenance algorithm that benefits from our cluster formation algorithm 3. A multi-channel cluster-based CDNIA/TDMA hybrid MAC protocol to coordinate inter-cluster communications I will show that TC-MAC provides better performance than the current WAVE standard in terms of safety/update message reliability and non-safety message delivery. Additionally, I will show that my clustering and cluster maintenance protocol provides more stable clusters, which will reduce the overhead of clusterhead election and re-clustering and leads to an efficient hierarchical network topology

TDMA-based MAC Protocols for Vehicular Ad Hoc Networks: A Survey, Qualitative Analysis and Open Research Issues

International audience—Vehicular Ad-hoc NETworks (VANETs) have attracted a lot of attention in the research community in recent years due to their promising applications. VANETs help improve traffic safety and efficiency. Each vehicle can exchange information to inform other vehicles about the current status of the traffic flow or a dangerous situation such as an accident. Road safety and traffic management applications require a reliable communication scheme with minimal transmission collisions, which thus increase the need for an efficient Medium Access Control (MAC) protocol. However, the design of the MAC in a vehicular network is a challenging task due to the high speed of the nodes, the frequent changes in topology, the lack of an infrastructure, and various QoS requirements. Recently several Time Division Multiple Access (TDMA)-based medium access control protocols have been proposed for VANETs in an attempt to ensure that all the vehicles have enough time to send safety messages without collisions and to reduce the end-to-end delay and the packet loss ratio. In this paper, we identify the reasons for using the collision-free medium access control paradigm in VANETs. We then present a novel topology-based classification and we provide an overview of TDMA-based MAC protocols that have been proposed for VANETs. We focus on the characteristics of these protocols, as well as on their benefits and limitations. Finally, we give a qualitative comparison, and we discuss some open issues that need to be tackled in future studies in order to improve the performance of TDMA-based MAC protocols for vehicle to vehicle (V2V) communications

TDMA scheduling strategies for vehicular ad hoc networks: from a distributed to a centralized approach

International audienceVehicular Ad hoc NETworks, known as VANETs, are deployed to reduce the risk of road accidents as well as to improve passenger comfort and safety by allowing vehicles to exchange different kinds of data. Medium Access Control protocols, namely those that are based on TDMA technique play a primary role in providing bounded transmission delay while minimizing data packet loss. However, due to mobility constraints and frequent changes in topology, slot scheduling is a more challenging task in VANETs than in other networks. Many MAC protocols based on TDMA for vehicular networks have been proposed to date. Among them, CTMAC is a centralized scheduling mechanism, while DTMAC, VeMAC and AD-HOCMAC are three distributed TDMA based MAC protocols. In this paper, we evaluate and analyze the performance these four protocols. The scenarios used in the simulation experiments take into account density variation factor that influences protocol performance. We use the MOVE and SUMO tools to generate realistic mobility scenarios. Performance metrics such as access collision, merging collision rate, packet loss and overhead are evaluated using NS-2.34

Empirical Performance Models of MAC Protocols for Cooperative Platooning Applications

Vehicular ad-hoc networks (VANET) enable vehicles to exchange information on traffic conditions, dynamic status and localization, to enhance road safety and transportation efficiency. A typical VANET application is platooning, which can take advantage of exchanging information on speed, heading and position to allow shorter inter-vehicle distances without compromising safety. However, the platooning performance depends drastically on the quality of the communication channel, which in turn is highly influenced by the medium access control protocol (MAC). Currently, VANETs use the IEEE 802.11p MAC, which follows a carrier sense multiple access with collision avoidance (CSMA/CA) policy that is prone to collisions and degrades significantly with network load. This has led to recent proposals for a time-division multiple access (TDMA)-based MAC that synchronize vehicles’ beacons to prevent or reduce collisions. In this paper, we take CSMA/CA and two TDMA-based overlay protocols, i.e., deployed over CSMA/CA, namely PLEXE-slotted and RA-TDMAp, and carry out extensive simulations with varying platoon sizes, number of occupied lanes and transmit power to deduce empirical models that provide estimates of average number of collisions per second and average busy time ratio. In particular, we show that these estimates can be obtained from observing the number of radio-frequency (RF) neighbours, i.e., number of distinct sources of the packets received by each vehicle per time unit. These estimates can enhance the online adaptation of distributed applications, particularly platooning control, to varying conditions of the communication channel.info:eu-repo/semantics/publishedVersio

A secured privacy-preserving multi-level blockchain framework for cluster based VANET

© 2021 by the authors. Licensee MDPI, Basel, Switzerland. Existing research shows that Cluster-based Medium Access Control (CB-MAC) protocols perform well in controlling and managing Vehicular Ad hoc Network (VANET), but requires ensuring improved security and privacy preserving authentication mechanism. To this end, we propose a multi-level blockchain-based privacy-preserving authentication protocol. The paper thoroughly explains the formation of the authentication centers, vehicles registration, and key generation processes. In the proposed architecture, a global authentication center (GAC) is responsible for storing all vehicle information, while Local Authentication Center (LAC) maintains a blockchain to enable quick handover between internal clusters of vehicle. We also propose a modified control packet format of IEEE 802.11 standards to remove the shortcomings of the traditional MAC protocols. Moreover, cluster formation, membership and cluster-head selection, and merging and leaving processes are implemented while considering the safety and non-safety message transmission to increase the performance. All blockchain communication is performed using high speed 5G internet while encrypted information is transmitted while using the RSA-1024 digital signature algorithm for improved security, integrity, and confidentiality. Our proof-of-concept implements the authentication schema while considering multiple virtual machines. With detailed experiments, we show that the proposed method is more efficient in terms of time and storage when compared to the existing methods. Besides, numerical analysis shows that the proposed transmission protocols outperform traditional MAC and benchmark methods in terms of throughput, delay, and packet dropping rate

An active signaling mechanism to reduce access collisions in a distributed TDMA based MAC protocol for vehicular networks

International audienceA Vehicular Ad-Hoc NETwork (VANET) is an emerging technology consisting in a set of vehicles, mobile devices and an infrastructure, which uses wireless transmission technologies to enable real-time communication between them. VANETs help to improve traffic safety and efficiency by enabling each vehicle to exchange information about vehicle positions , speeds and the state of the road. Due to its promising applications, this type of network has attracted a lot of attention in the research community, including those in the domain of Medium Access Control (MAC). In fact, an efficient MAC protocol design in VANETs is crucial to guarantee safety-critical message broadcasting with high reliability and minimum delay. A Time Division Multiple Access (TDMA)-based MAC protocol is advantageous in VANETs thanks to its ability to prevent the hidden node problem, and to guarantee high quality of service for real-time applications. However, time slot assignments to vehicles could suffer from the access collision problem which can frequently occur between vehicles trying to access the same time slots. This problem is mainly due to the lack of infrastructure and potentially high density of vehicles in VANETs. In this paper, we focus on the problem of access collision in the time slot assignments of the DTMAC protocol, and present an enhanced version based on active signaling (AS-DTMAC, i.e. Active Signaling-DTMAC). Extensive simulations are conducted considering various traffic densities to demonstrate the performance of AS-DTMAC

A Fully Distributed TDMA based MAC Protocol for Vehicular Ad Hoc Networks

—The Vehicular Ad-Hoc NETwork (VANET) consists of a set of vehicles moving on roads which can communicate with each other through ad hoc wireless devices. VANET has attracted a lot of attention in the research community in recent years with the main focus on its safety applications. One of the challenges for vehicular network is the design of an efficient Medium Access Control (MAC) protocol due to the hidden node problem, the high speed of the nodes, the frequent changes in topology, the lack of an infrastructure, and various QoS requirements. Motivated by this observation, we design a fully distributed and location-based TDMA scheduling scheme for VANETs networks, named DTMAC. The main goal of this work is to propose a MAC protocol that can provide fairness in accessing the transmission medium, as well as reduce access collision and merging collision under various conditions of vehicular density without having to use expensive spectrum and complex mechanisms such as CDMA or OFDMA. An analytical model of the average access collision probability and throughput are derived which can be used to evaluate the performance of DTMAC protocol as well as to validate the simulation results under different traffic conditions