Geographic routing protocols for Vehicular Ad hoc NETworks (VANETs): A survey

In urban vehicular ad hoc networks (VANETs), due to the high mobility and uneven distribution of vehicles, how to select an optimal relaying node in an intra-street and how to determine a street selection at the intersection are two challenging issues in designing an efficient routing protocol in complex urban environments. In this paper, we build a link model with a Wiener process to predict the probability of link availability, which considers the stable and unstable vehicle states according to the behavior of vehicles. We introduce a novel concept called the link correlation which represents the influence of different link combinations in network topology to transmit a packet with less network resource consumption and higher goodput. Based on this concept, we design an opportunistic routing metric called the expected transmission cost over a multi-hop path (ETCoP) implemented with our link model as the selection guidance of a relaying node in intra-streets. This metric can also provide assistance for the next street selection at an intersection. Finally, we propose a street-centric opportunistic routing protocol based on ETCoP for VANETs (SRPE). Simulation results show that our proposed SRPE outperforms the conventional protocols in terms of packet delivery ratio, average end-to-end delay, and network yield.

A Street-Centric Opportunistic Routing Protocol Based on Link Correlation for Urban VANETs

Vehicular ad-hoc NETworks (VANETs) have received considerable attention in recent years, due to its unique characteristics, which are different from mobile ad-hoc NETworks, such as rapid topology change, frequent link failure, and high vehicle mobility. The main drawback of VANETs network is the network instability, which yields to reduce the network efficiency. In this paper, we propose three algorithms: cluster-based life-time routing (CBLTR) protocol, Intersection dynamic VANET routing (IDVR) protocol, and control overhead reduction algorithm (CORA). The CBLTR protocol aims to increase the route stability and average throughput in a bidirectional segment scenario. The cluster heads (CHs) are selected based on maximum lifetime among all vehicles that are located within each cluster. The IDVR protocol aims to increase the route stability and average throughput, and to reduce end-to-end delay in a grid topology. The elected intersection CH receives a set of candidate shortest routes (SCSR) closed to the desired destination from the software defined network. The IDVR protocol selects the optimal route based on its current location, destination location, and the maximum of the minimum average throughput of SCSR. Finally, the CORA algorithm aims to reduce the control overhead messages in the clusters by developing a new mechanism to calculate the optimal numbers of the control overhead messages between the cluster members and the CH. We used SUMO traffic generator simulators and MATLAB to evaluate the performance of our proposed protocols. These protocols significantly outperform many protocols mentioned in the literature, in terms of many parameters.

Performance Improvement of Cluster-Based Routing Protocol in VANET

Location based routing protocols in VANET: Issues and existing solutions

An adaptive relay nodes selection scheme for multi-hop broadcast in VANETs

Robust and efficient data delivery in vehicular ad hoc networks (VANETs) with high mobility is a challenging issue due to dynamic topology changes and unstable wireless links. The opportunistic routing protocols can improve the reliability of routing by making full use of the broadcast characteristics and assist in data transmission through additional backup links. In this paper, we propose a Link State aware Geographic Opportunistic routing protocol (LSGO) which exploits a combination of geographic location and the link state information as the routing metric. The LSGO aims to improve the reliability of data transmission in a highly dynamic environment, which selects the forwarders and prioritizes them based on the vehicle’s geographic location and the link’s quality. We compare the performance of LSGO with GpsrJ + which removes the unnecessary stop at a junction and greedy traffic aware routing protocol (GyTAR) using network simulator ns-2. The simulation results show that it opens more nodes to participate in the opportunistic data forwarding and increases a connection’s throughput while using no more network capacity than traditional routing. In the simulation, compared with other two protocols, when the number of vehicles and the average vehicle velocity increase, LSGO’s packet dropping rate is reduced and the network throughput is improved.

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LSGO: Link State aware Geographic Opportunistic routing protocol for VANETs

The characteristics of vehicular ad hoc networks VANETs make the design of routing protocol a great challenge. In this paper, we propose a vehicle density and load aware routing protocol for VANETs called VDLA. VDLA adopts sequential selection of junctions to construct the route. The selection is based on the real-time vehicle density, the traffic load, and the distance to the destination. The network information is collected by a decentralized mechanism. Through factoring in these metrics, the packets are avoided being sent to roads where network is disconnected, and the network load is balanced to mitigate network congestion. The intermediate junctions are selected before the packet reaches a junction to reduce the unnecessary hops. Our study also investigates the impact of the high mobility of the nodes. An analytical framework is proposed to analyze the mobility. Based on the analysis, the traditional Hello scheme is enhanced to improve the accuracy of the neighbor table. In the simulation, we compare VDLA with greedy perimeter coordinator routing and GpsrJ+, which are geographic routings protocols proposed for VANETs. The results validate the superiority of VDLA in terms of end-to-end delay and packet delivery rate. And the superiority holds in different scenarios. Copyright © 2013 John Wiley & Sons, Ltd.

Geographic routing protocol for vehicular ad hoc networks in city scenarios: a proposal and analysis

The invention discloses a prediction-based routing method at an intersection in a vehicle self-organizing network, and mainly solves the problem that when a packet is routed at the intersection, a link is unstable in the prior art. The scheme for implementing the method is that: when the packet arrives at a previous hop node of the intersection, the node predicts the next intersection to which the packet is transmitted; a weight of each adjacent intersection is calculated according to the density of adjacent road sections and a distance from the next intersection to a destination, and the intersection with the largest weight is selected as the next temporary destination for transmitting the packet; and when the packet is forwarded in a greedy mode in the road section, if the selected nodeis positioned in the boundary of the transmission range and is opposite to a driving direction of the transmitting node, a node secondarily nearest to the destination is selected, otherwise the packet is directly forwarded to the selected node. Compared with the geographic routing in city scenarios (GPCR) protocol and the greedy perimeter stateless routing for wireless networks in urban vehicularscenarios (GpsrJ+ protocol), the method has the advantages that: the transmission rate of the packet is increased, the transmission time delay of the packet is reduced, and the method can be applicable to the vehicle self-organizing network.

Prediction-based routing method at intersection in vehicle self-organizing network

Due to the characteristics of Vehicular Ad Hoc Networks (VANETs), i.e. highly dynamic network topology, large network size and non-uniform node distribution, it is a great challenge to develop a routing protocol to ensure efficient data transmission. In this paper, we propose a Vehicle Density and Load Aware routing protocol for VANETs called VDLA. VDLA adopts sequential selection of junctions to construct the route. The selection is based on the real-time vehicle density, the traffic load of the corresponding road segment and the distance to the destination. The network information is collected by a decentralized mechanism. Through factoring in these metrics, the packets are avoided being sent to roads where network is disconnected and the network load is balanced to mitigate network congestion. Thereby VDLA can improve the efficiency of data transmission. By virtue of the information collected at every junction, the decision about which junction the packet should forward to is made before the junctions to reduce the unnecessary hops. In the simulation, we compare VDLA with GPCR, one of the most widely used routing protocols in VANET. The results show the superiority of VDLA in terms of average end to end delay and packet delivery ratio over GPCR.

A vehicle density and load aware routing protocol for VANETs in city scenarios

In vehicular ad hoc networks (VANETs), the communication links are inherently unstable due to vehicles’ mobility and various impairment of radio signal. Existing geographic routing protocols often choose the next hop according to the greedy forwarding, regardless of the link’s quality and transmission reliability. The successful packet delivery rate is decreased in non-ideal communication links. Consequently, the reliability of data transmission is worse and the network throughput is declined. In this paper, we propose a routing protocol called link state aware geographic routing protocol (LSGR) for VANETs. In LSGR, a routing metric called expected one-transmission advance (EOA) is contrived to improve the greedy forwarding algorithm by explicitly incorporating the link state and packet’s advance. Routing with the EOA metric, one can improve the transmission efficiency by diminishing transmission failures. Simulation results show that LSGR can achieve a higher throughput and packet delivery rate than the geographic routing protocols that adopt the traditional greedy forwarding.

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Chunchun Zhao

Papers

LSGO: Link State aware Geographic Opportunistic routing protocol for VANETs

Geographic routing protocol for vehicular ad hoc networks in city scenarios: a proposal and analysis

Prediction-based routing method at intersection in vehicle self-organizing network

A vehicle density and load aware routing protocol for VANETs in city scenarios

A link state aware geographic routing protocol for vehicular ad hoc networks