To date, many VEHICULAR ad hoc NETWORK unicast routing protocols have been proposed to support efficient packet transmission between vehicles in urban environments. However, when there is insufficient vehicle density during non-rush hour times, the VEHICULAR ad hoc NETWORK is often intermittently connected. These unicast routing protocols, therefore, perform poorly when forwarding packets over this VEHICULAR disruption TOLERANT NETWORK. This paper adopts the controlled replication approach, in a proposed IG-Ferry routing protocol, to spray a limited number of packet copies, denoted by packet token values, to relay vehicles in a VEHICULAR disruption TOLERANT NETWORK. We then identify three kinds of relay vehicle, i.e. direct buses, non-direct buses and private cars according to their travel itineraries. Based on the proposed DELAY evaluation function for the three types of intermediate vehicle, the IG-Ferry packet spraying mechanism, instead of that of traditional binary spraying, can efficiently spray appropriate packet tokens to vehicles. Finally, intensive NS2 simulations are conducted using the realistic Shanghai city vehicle traffic trace, IEEE 802.11p protocol, with EDCA and the Nakagami radio propagation model, to show that IG-Ferry outperforms three well-known VDTN routing protocols, in terms of average packet delivery ratios, end-to-end transmission DELAYs and packet replication overheads, with respect to various combinations of five communication parameters.

The conventional routing protocols are not able to handle intermittent mobile NETWORKs, since because of deficiency of nodes’ density, mobility, instability of radio connections, most of the times no path exists among the source and destination nodes. DELAY TOLERANT NETWORKs (DTN) is a solution in which communications become feasible in intermittent mobile NETWORKs by tolerating long DELAYs. Routing methods in DTN use the idea of spreading packets among the mobile nodes for transporting information toward the destinations. In order to achieve a good performance, it is necessary to control the workload of the NETWORK by limiting the number of copies. In this paper, a novel method for packet copying process is proposed which improves the throughput significantly while controlling the workload of the NETWORK. The key idea behind the proposed method is to prioritize the buffered packets at each node in order to avoid excessive repetitions of packets and stop wasteful workload grow. The packets are prioritized based on the source nodes, the ages, and their remaining lifetimes. Our simulation results indicate that the proposed method can improve packet delivery ratio by 40 to 60 percent in comparison with Spray and Binary Wait, and Direct delivery routing methods.

In this paper, a new virtual leader following consensus protocol is introduced to perform the internal (asymptotic) stability analysis of longitudinal platoon of vehicles under generic NETWORK topology. In all previous studies on multi-agent systems with generic NETWORK topology, the control parameters are strictly dependent on eigenvalues of NETWORK matrices (adjacency or Laplacian). Since some of these eigenvalues are complex, the stability analysis with the presented methods is very hard or even impossible for large scale or time-varying NETWORKs. A new approach is introduced in this paper to decouple the large dimension closed-loop dynamics to individual third-order linear differential equations. A new spacing policy function assuring safety and increasing the traffic capacity is introduced to adjust the inter-vehicle spacing. The stable regions of communication and parasitic DELAYs are calculated by employing the cluster treatment characteristic roots (CTCR) method. It will be shown that the presented approach assures the internal stability of large-scale platoon of vehicles with generic NETWORK topology. The most important privilege of the presented method compared with the previous approaches, is that the control gains are independent on NETWORK structure. This new finding, simplifies the stability analysis and control design specially for large scale platoons and time-varying NETWORKs. Several simulation results are provided to show the effectiveness of the proposed approaches.

The DELAY TOLERANT Mobile Sensor NETWORKs (DTMSNs) distinguish themselves from conventional sensor NETWORKs by means of some features such as loose connectivity, node mobility, and DELAY tolerability. It needs to be acknowledged that traditional end-to-end routing protocols cannot be applied usefully in such challenging NETWORK conditions because of intermittent connections and/or long DELAYs. Hence, this research is intended to propose a Unicast Tree-based Data Gathering protocol (UTDG) to resolve this problem. A UTDG includes 3 phases: tree formation phase, data collection and data transmission phase, and finally the updating phase. The proposed protocol constructs a tree in each community on the basis of transmission ranking, contact probability and the link expiration time. The selection of the next-hop node is based on the tree structure rather than forwarding the message to the neighbor node directly. Each node unicasts the data to its parent in the related community, and the root of the tree successively sends the data to the sink node. The authors contend, based on the simulation results of the study, that the proposed protocol can gain significantly higher message delivery rates with lower transmission overhead and also lower DELAY in data delivery than the other existing DTMSNs routing protocols in some applications.

The DELAY TOLERANT Mobile Sensor NETWORKs (DTMSNs) distinguish themselves from conventional sensor NETWORKs by means of several features such as node mobility, loose connectivity, and DELAY tolerability. In comparison with conventional NETWORKs, prominent feature of these NETWORKs is that there is not end-to-end path between source and destination. Due to energy limitation, one of the crucial issues in large-scale NETWORKs is energy storage that can be overcome this problem by distribution of multi-sink in a NETWORK at the same time. In this paper, in order to covering large area, we determine a new radio range to sink nodes that prevents the presence of nodes in the radio range of multiple sinks and sending data to a large number of sinks. Then, we represent Replica Adaptive Data Gathering Protocol. Simulation results indicate that the proposed protocol significantly improves message delivery rate with lower transmission overhead and also lower DELAY in data delivery than the other existing DTMSNs routing protocols.

The NETWORK overhead and multiple NETWORKs disconnection faults are the main challenges of anonymous servers implemented in VANETs. The block chain technology has been entered into the wide range of preserving privacy. The robust anonymity mechanism existence and the traceability of all transactions are the main advantages of this technology. The primary model of the block chain was able to complete the process with the anonymity stored data. In distributed models, the authentication, storage and retrieval of transactions are applied by all user’ s consensus. The asymmetric cryptography, preserves the identity anonymity and aggregating transactions of different users into a block which is ready to send, preserves the path anonymity. The proposed method is aimed to ensure anonymity by mounting the block chain on VANETs. Before delivering any transaction to the block chain, the risk of user’ s privacy is high. To achieve low risk, we combine the graph processing methods with Silent Period, Cloaking-Region and Dummy Node methods. The block chain simulation on VANET is driven by python and the anonymity risks are simulated with ARX. The results suggest that the block chain is stabled and the optimal risk reduction is achieved on the VANET.

Efficient message delivery in city environment is required to ensure driver’ s safety and passenger’ s comfortability. In cities of developed nations, routing of data in VEHICULAR Ad hoc NETWORK (VANET) faces many challenges such as radio obstacles, mobility constraints and uneven nodes distribution. These factors primarily makes communication between vehicles complex. To overcome and transmit data traffic effectively in city environment in the presence of abovementioned challenges, evaluation of some NETWORK parameters conducted. The selected metrics are packet delivery ratio (PDR), end-to-end DELAY and routing overhead. These are based on three performance of position-based routing protocols: Anchor– based Street and Traffic Awareness Routing (A-STAR), Greedy Perimeter Coordinator Routing (GPCR) and Contention Based Forwarding (CBF) with the help of Simulation of Urban Mobility (SUMO) to generates vehicle mobility in city environment and NETWORK simulator (OMNeT++) to creates and calculates needed components. The speed of the vehicles and node density were varied in this process, and the simulated results showed that CBF outperforms significantly than A-STAR and GPCR in terms of packet delivery ratio as the speed varied and with a better end-to-end DELAYs and routing overhead at a lower speed. In addition, CBF performs better than A-STAR and GPCR in terms of packet delivery ratio as the node varied with a better end-to-end DELAY, and a better routing overhead at a lower node density.