scholarly journals Vehicle Density Based Forwarding Protocol for Safety Message Broadcast in VANET

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Jiawei Huang ◽  
Yi Huang ◽  
Jianxin Wang
Keyword(s):  
Vehicular Ad Hoc Networks ◽  
Ad Hoc ◽  
Mac Protocol ◽  
Medium Access ◽  
Safety Message ◽  
Vehicle Density ◽  
Multihop Broadcast ◽  
Hoc Networks ◽  
Time Critical ◽  
Safety Applications

In vehicular ad hoc networks (VANETs), the medium access control (MAC) protocol is of great importance to provide time-critical safety applications. Contemporary multihop broadcast protocols in VANETs usually choose the farthest node in broadcast range as the forwarder to reduce the number of forwarding hops. However, in this paper, we demonstrate that the farthest forwarder may experience large contention delay in case of high vehicle density. We propose an IEEE 802.11-based multihop broadcast protocol VDF to address the issue of emergency message dissemination. To achieve the tradeoff between contention delay and forwarding hops, VDF adaptably chooses the forwarder according to the vehicle density. Simulation results show that, due to its ability to decrease the transmission collisions, the proposed protocol can provide significantly lower broadcast delay.

Medium Access Protocols for Cooperative Collision Avoidance in Vehicular Ad-Hoc Networks

2013 ◽  
pp. 354-375
Author(s):  
Md. Imrul Hassan ◽  
Hai L. Vu ◽  
Taka Sakurai
Keyword(s):  
Collision Avoidance ◽  
Road Safety ◽  
Vehicular Ad Hoc Networks ◽  
Ad Hoc ◽  
Mac Protocol ◽  
Dynamic Networks ◽  
Medium Access ◽  
Vehicle To Vehicle ◽  
Hoc Networks ◽  
Safety Applications

It is envisaged that supporting vehicle-to-vehicle and vehicle-to-infrastructure communications with a Vehicular Ad-Hoc Network (VANET) can improve road safety and increase transportation efficiency. Among the candidate applications of VANETs, cooperative collision avoidance (CCA) has attracted considerable interest as it can significantly improve road safety. Due to the ad hoc nature of these highly dynamic networks, no central coordination or handshaking protocol can be assumed and safety applications must broadcast information of interest to many surrounding cars by sharing a single channel in a distributed manner. This gives rise to one of the key challenges in vehicle-to-vehicle communication systems, namely, the development of an efficient and reliable medium access control (MAC) protocol for CCA. In this chapter, we provide an overview of proposed MAC protocols for VANETs and describe current standardization activities. We then focus on the performance of the IEEE 802.11 carrier sense multiple access (CSMA) based MAC protocol that is being standardized by the IEEE standards body for VANET applications. In particular, we review prominent existing analytical models and study their advantages, disadvantages and their suitability for performance evaluation of the MAC protocol for VANETs. After a discussion of the shortcomings of these models, we develop a new analytical model in the second half of the chapter. Explicit expressions are derived for the mean and standard deviation of the packet delay, as well as for the packet delivery ratio (PDR) at the MAC layer in an unsaturated network formed by moving vehicles on a highway. We validate the analytical results using extensive simulations and show that good accuracy can be achieved with the proposed model for a range of topologies and traffic load conditions. More importantly, using the model, we show that hidden terminals can have a severe, detrimental impact on the PDR, which may compromise the reliability required for safety applications.

Medium Access Protocols for Cooperative Collision Avoidance in Vehicular Ad-Hoc Networks

2010 ◽  
pp. 97-119
Author(s):  
Md. Imrul Hassan ◽  
Hai L. Vu ◽  
Taka Sakurai
Keyword(s):  
Collision Avoidance ◽  
Road Safety ◽  
Vehicular Ad Hoc Networks ◽  
Ad Hoc ◽  
Mac Protocol ◽  
Dynamic Networks ◽  
Medium Access ◽  
Vehicle To Vehicle ◽  
Hoc Networks ◽  
Safety Applications

It is envisaged that supporting vehicle-to-vehicle and vehicle-to-infrastructure communications with a Vehicular Ad-Hoc Network (VANET) can improve road safety and increase transportation efficiency. Among the candidate applications of VANETs, cooperative collision avoidance (CCA) has attracted considerable interest as it can significantly improve road safety. Due to the ad hoc nature of these highly dynamic networks, no central coordination or handshaking protocol can be assumed and safety applications must broadcast information of interest to many surrounding cars by sharing a single channel in a distributed manner. This gives rise to one of the key challenges in vehicle-to-vehicle communication systems, namely, the development of an efficient and reliable medium access control (MAC) protocol for CCA. In this chapter, we provide an overview of proposed MAC protocols for VANETs and describe current standardization activities. We then focus on the performance of the IEEE 802.11 carrier sense multiple access (CSMA) based MAC protocol that is being standardized by the IEEE standards body for VANET applications. In particular, we review prominent existing analytical models and study their advantages, disadvantages and their suitability for performance evaluation of the MAC protocol for VANETs. After a discussion of the shortcomings of these models, we develop a new analytical model in the second half of the chapter. Explicit expressions are derived for the mean and standard deviation of the packet delay, as well as for the packet delivery ratio (PDR) at the MAC layer in an unsaturated network formed by moving vehicles on a highway. We validate the analytical results using extensive simulations and show that good accuracy can be achieved with the proposed model for a range of topologies and traffic load conditions. More importantly, using the model, we show that hidden terminals can have a severe, detrimental impact on the PDR, which may compromise the reliability required for safety applications.

scholarly journals An Accurate Performance Analysis of Hybrid Efficient and Reliable MAC Protocol in VANET under Non-saturated Conditions

2017 ◽  
Vol 7 (2) ◽  
pp. 999 ◽  
Author(s):  
Akram A. Almohammedi ◽  
Nor K. Noordin ◽  
A. Sali ◽  
Fazirulhisyam Hashim ◽  
Abdulmalek Al-Hemyari
Keyword(s):  
Vehicular Ad Hoc Networks ◽  
Ad Hoc ◽  
Mac Protocol ◽  
Packet Delivery Ratio ◽  
Ieee 802.11P ◽  
Accurate Estimation ◽  
Delivery Ratio ◽  
Medium Access ◽  
Packet Delivery ◽  
Safety Applications

Vehicular Ad Hoc Networks (VANETs) is a technology supporting two types of applications, safety and service applications with higher and lower priorities respectively. Thereby, Medium Access Control (MAC) protocol is designed to provide reliable and efficient data broadcasting based on prioritization. Different from the IEEE 1609.4 (legacy), HER-MAC protocol is a new multi-channel MAC proposed for VANETs, offering remarkable performance with regards to safety applications transmission. This paper focuses on the analysis of packet delivery ratio of the HER-MAC protocol under non-saturated conditions. 1-D and 2-D Markov chains have been developed for safety and non-safety applications respectively, to evaluate mathematically the performance of HER-MAC protocol. The presented work has taken into account the freezing of the backoff timer for both applications and the backoff stages along with short retry limit for non-safety applications in order to meet the IEEE 802.11p specifications. It highlights that taking these elements into consideration are important in modeling the system, to provide an accurate estimation of the channel access, and guarantees that no packet is served indefinitely. More precise results of the system packet delivery ratio have been yield. The probability of successful transmission and collisions were derived and used to compute the packet delivery ratio. The simulation results validate the analytical results of our models and indicate that the performance of our models outperformed the existing models in terms of the packet delivery ratio under different number of vehicles and contention window.

Performance Analysis of a Flexible MAC Protocol for Real-Time Services in Vehicular Ad-Hoc Networks

2005 ◽  
Vol 12 (3) ◽  
pp. 147-157
Author(s):  
Giuseppe Caizzone ◽  
Paolo Giacomazzi ◽  
Luigi Musumeci ◽  
Gabriella Saddemi ◽  
Giacomo Verticale
Keyword(s):  
Performance Analysis ◽  
Ad Hoc Networks ◽  
Real Time ◽  
Vehicular Ad Hoc Networks ◽  
Ad Hoc ◽  
Mac Protocol ◽  
Hoc Networks

scholarly journals METRICS FOR PERFORMANCE EVALUATION OF SAFETY APPLICATIONS IN VEHICULAR AD HOC NETWORKS

Transport ◽  
2008 ◽  
Vol 23 (4) ◽  
pp. 291-298 ◽  
Author(s):  
Saleh Yousefi ◽  
Mahmood Fathy
Keyword(s):  
Performance Evaluation ◽  
Ad Hoc Network ◽  
Vehicular Ad Hoc Networks ◽  
Ad Hoc ◽  
Road Traffic ◽  
Real Life ◽  
Message Exchange ◽  
To Come ◽  
Hoc Networks ◽  
Safety Applications

In the recent years, direct message exchange between vehicles in order to improve the safety of road traffic has been attracting lots of interest in both networking and road safety communities. While travelling on a road, vehicles form an ad hoc network called Vehicular Ad hoc NETwork (VANET) and deploy life safety applications. Evaluating the performance of these applications is primordial for realizing VANETs in real life. Current literature lacks efficient ways to evaluate the performance of safety applications and mostly leverages on classical networking metrics like delay, delivery rate etc. In this paper, we consider both networking and safety concerns simultaneously to come up with more efficient methods. In particular, we first point out the significance of fairness and coverage from safety viewpoint. Then, we introduce two new metrics called beaconing rate and effective range aiming at providing more facilities for safety performance evaluation in VANET s research. Furthermore, realizing special characteristics of safety applications while disseminating beacon messages, we study the way that beacon dissemination protocols affect the performance of safety applications. We then conduct extensive simulation study to show the usefulness of the introduced metrics and derive some insights on the feasibility of driver‐assistant safety applications. Our evaluation also shows that sending the aggregated status of neighbouring vehicles in addition to vehicle's own status, and instead, increasing beacon transmission interval may be invoked in order to assist safety applications in providing satisfactory services to drivers.

A Power Optimization Algorithm for Ad Hoc Networks with Variable Rate Control

2013 ◽  
Vol 470 ◽  
pp. 611-616
Author(s):  
Xuan Jie Ning ◽  
Hai Zhao ◽  
Mao Fan Yang ◽  
Dan Wu
Keyword(s):  
Ad Hoc Networks ◽  
Rate Control ◽  
Ad Hoc ◽  
Transmission Rate ◽  
Mac Protocol ◽  
Network Capacity ◽  
Data Rate ◽  
Medium Access ◽  
High Data ◽  
Hoc Networks

This paper is concerned with the capacity of ad hoc networks employing pure ALOHA medium access control (MAC) protocol under the effect of different transmission power levels and variable data rate control. The data rate of a certain link is related to the signal to interference plus noise ratio (SINR), and SINR is, in turn, related to the transmitted power and link distance. The increasing power conducts a high data rate, resulting in the high interference of networks. Consequently, the optimum power that yields maximum network throughput is a tradeoff between transmission rate and network interference. Mathematical model analysis for the ad hoc network capacity are presented in the paper. A revised expression to the approximate calculating of the capture probability in networks is proposed.

scholarly journals A routing protocol for urban vehicular ad hoc networks to support non-safety applications

2018 ◽  
Vol 4 (3) ◽  
pp. 189-199 ◽  
Author(s):  
S.K. Bhoi ◽  
P.M. Khilar ◽  
M. Singh ◽  
R.R. Sahoo ◽  
R.R. Swain
Keyword(s):  
Ad Hoc Networks ◽  
Routing Protocol ◽  
Vehicular Ad Hoc Networks ◽  
Ad Hoc ◽  
Hoc Networks ◽  
Safety Applications
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