Performance and fairness in VANETs

This paper presents performance and fairness analysis of the 802.11p Medium Access Control (MAC) in one-hop periodic broadcast V2V communication used in cooperative driving applications aimed for improving vehicle safety and traffic efficiency. We show that both performance and fairness strongly dependent on the random relative phasing (F0) of the vehicles and on the impact of Hidden Nodes (HNs)

Performance and fairness in VANETs

This paper presents performance and fairness analysis of the 802.11p Medium Access Control (MAC) in one-hop periodic broadcast V2V communication used in cooperative driving applications aimed for improving vehicle safety and traffic efficiency. We show that both performance and fairness strongly dependent on the random relative phasing (F0) of the vehicles and on the impact of Hidden Nodes (HNs)

Application level phase adjustment for maximizing the fairness in VANET

Proposed safety applications for vehicle-to-vehicle (V2V) communication rely mostly on periodic broadcasting. In this work we analyze the performance and fairness aspects of such an one-hop periodic broadcast communication. We show that communication reliability is greatly dependent on the random relative phasing of the communicating vehicles and on the impact of hidden nodes. For a random initial phasing some vehicles suffer from consecutive packet losses thereby becoming invisible to neighboring vehicles for a long time, whereas some other vehicles have no packet loss at all. We propose a simple and effective approach to provide fair transmission opportunities and show the improvements through simulations

Model, analysis, and improvements for inter-vehicle communication using one-hop periodic broadcasting based on the 802.11p protocol

Many future vehicle safety applications will rely on one-hop periodic broadcast communication (oPBC). The key technology for supporting this communication system is the new standard IEEE 802.11p which employs the carrier sense multiple access/collision avoidance (CSMA/CA) mechanism to resolve channel access competition. In this work, we first aim at understanding the behavior of such oPBC under varying load conditions by considering three important quality aspects of vehicle safety applications: reliability, fairness, and delay. Second, we investigate possible improvements of these quality aspects. We start with a clear mathematical model which gives the foundation for making an accurate simulation model as well as for defining new appropriate metrics to judge the aforementioned quality aspects. We evaluate oPBC with a strictly periodic broadcasting scheme, i.e., each vehicle broadcasts messages in a strictly periodic manner. The evaluation reveals that the hidden terminal, or Hidden Node (HN), problem is the main cause of various quality degradations especially when the network is unsaturated. To be more specific, the HN problem reduces the message reception ratio (i.e., reliability degradation) and causes unfair message reception ratios for vehicles (i.e., fairness degradation). Moreover, it causes long-lasting consecutive message losses (i.e., delay degradation) between vehicles while they are encountering each other, i.e., entering their Communication Ranges (CRs). In some serious cases, a certain vehicle could not successfully deliver any of its messages to a particularly destination vehicle throughout an entire encounter interval of these two vehicles. We propose three simple, but effective broadcasting schemes, to alleviate the impact of the HN problem. Though these solutions do not affect the message reception ratio (i.e., reliability) of the entire network, they do improve the fairness and delay aspects. These solutions are fully compatible with the IEEE 802.11p standard, i.e., they are application-level solutions and can be easily introduced in practice

Establishing fairness and minimizing blackout periods in broadcast based vehicle to vehicle communication using application-level phase adjustments

A method for a station to periodically broadcast messages over a wireless channel to communicate to multiple other stations who transmit on the same channel, the station becomes ready to broadcast at successive message activation times, at a message activation time the station performing a Multiple Access mechanism (930) to resolve channel access competition and the station subsequently starting transmission of a message, wherein at least two successive message activation times differ a random time interval

Model, analysis, and improvements for inter-vehicle communication using one-hop periodic broadcasting based on the 802.11p protocol

Many future vehicle safety applications will rely on one-hop Periodic Broadcast Communication (oPBC). The key technology for supporting this communication system is the new standard IEEE 802.11p which employs the Carrier Sense Multiple Access/Collision Avoidance (CSMA/CA) mechanism to resolve channel access competition. In this work, we first aim at understanding the behavior of such oPBC under varying load conditions by considering three important quality aspects of vehicle safety applications: reliability, fairness, and delay. Second, we investigate possible improvements of these quality aspects. We start with a clear mathematical model which gives the foundation for making an accurate simulation model as well as for defining new appropriate metrics to judge the aforementioned quality aspects. We evaluate oPBC with a strictly periodic broadcasting scheme, i.e., each vehicle broadcasts messages in a strictly periodic manner. The evaluation reveals that the hidden terminal, or Hidden Node (HN), problem is the main cause of various quality degradations especially when the network is unsaturated. To be more specific, the HN problem reduces the message reception ratio (i.e., reliability degradation) and causes unfair message reception ratios for vehicles (i.e., fairness degradation). Moreover, it causes long lasting consecutive message losses (i.e., delay degradation) between vehicles while they are encountering each other, i.e., entering their Communication Ranges (CRs). In some serious cases, a certain vehicle could not successfully deliver any of its messages to a particularly destination vehicle throughout an entire encounter interval of these two vehicles. We propose three simple but effective broadcasting schemes to alleviate the impact of the HN problem. Though these solutions do not affect the message reception ratio (i.e., reliability) of the entire network, they do improve the fairness and delay aspects. These solutions are fully compatible with the IEEE 802.11p standard, i.e., they are application-level solutions and can be easily introduced in practice

Model, analysis, and improvements for inter-vehicle communication using one-hop periodic broadcasting based on the 802.11p protocol

Many future vehicle safety applications will rely on one-hop periodic broadcast communication (oPBC). The key technology for supporting this communication system is the new standard IEEE 802.11p which employs the carrier sense multiple access/collision avoidance (CSMA/CA) mechanism to resolve channel access competition. In this work, we first aim at understanding the behavior of such oPBC under varying load conditions by considering three important quality aspects of vehicle safety applications: reliability, fairness, and delay. Second, we investigate possible improvements of these quality aspects. We start with a clear mathematical model which gives the foundation for making an accurate simulation model as well as for defining new appropriate metrics to judge the aforementioned quality aspects. We evaluate oPBC with a strictly periodic broadcasting scheme, i.e., each vehicle broadcasts messages in a strictly periodic manner. The evaluation reveals that the hidden terminal, or Hidden Node (HN), problem is the main cause of various quality degradations especially when the network is unsaturated. To be more specific, the HN problem reduces the message reception ratio (i.e., reliability degradation) and causes unfair message reception ratios for vehicles (i.e., fairness degradation). Moreover, it causes long-lasting consecutive message losses (i.e., delay degradation) between vehicles while they are encountering each other, i.e., entering their Communication Ranges (CRs). In some serious cases, a certain vehicle could not successfully deliver any of its messages to a particularly destination vehicle throughout an entire encounter interval of these two vehicles. We propose three simple, but effective broadcasting schemes, to alleviate the impact of the HN problem. Though these solutions do not affect the message reception ratio (i.e., reliability) of the entire network, they do improve the fairness and delay aspects. These solutions are fully compatible with the IEEE 802.11p standard, i.e., they are application-level solutions and can be easily introduced in practice