High Mobility Of Nodes Research Articles

Routing Protocols for the Aircraft AD HOC Networks

The communication between the aircraft-to-aircraft and aircraft-to-ground can be established with the support of Aircraft Ad hoc Networks (AANET). Routing in the aircraft ad hoc networks is a challenging task due to its unique attributes such as very high mobility of the aircraft nodes and dynamic topology. Few research works had developed routing environment and protocols for the dynamic topology based AANET. This paper analyses the developments of the routing protocols for the aircraft ad hoc networks. This paper extensively discusses the routing protocols and comparative analyses of the performance metrics namely throughput, packet delivery ratio, end to end delay, routing overhead, and number of handoffs. Further, this work deliberates the aircraft ad hoc networks simulation environment, aircraft’s velocity, different radio propagation models of aircraft simulation model. Various challenges and issues of routing protocols are extensively analyzed and compared with existing methodologies in this paper.

Intrusion Detection for Mobile Ad Hoc Networks Based on Node Reputation

The mobile ad hoc network (MANET) is more vulnerable to attacks than traditional networks, due to the high mobility of nodes, the weakness of transmission media and the absence of central node. To overcome the vulnerability, this paper mainly studies the way to detect selfish nodes in the MANET, and thus prevent network intrusion. Specifically, a data-driven reputation evaluation model was proposed to detect selfish nodes using a new reputation mechanism. The mechanism consists of a monitoring module, a reputation evaluation module, penalty module and a response module. The MANET integrated with our reputation mechanism was compared with the traditional MANET through simulation. The results show that the addition of reputation mechanism can suppress the selfish behavior of network nodes and enhance network security.

Efficient data dissemination protocol based on complex networks\u2019 metrics for urban vehicular networks

Services that aim to make the current transportation system more secure, sustainable, and efficient constitute the Traffic Management Systems (TMS). Vehicular Ad hoc Networks (VANETs) exert a strong influence for TMS applications, due to TMS services require data, communication, and processing for operation. Besides, VANET allows direct communication between vehicles, and data are exchanged and processed between them. Several TMS services require disseminated information among decision-making vehicles. However, such dissemination is a challenging task, due to the specific characteristics of VANETs, such as short-range communication and high node mobility, resulting in several variations in their topology. In this article, we introduce an extensive analysis of our proposed data dissemination protocol based on complex networks’ metrics for urban VANET scenarios, called DDRX. Each vehicle must build a subgraph to identify the relay node to continue the dissemination process. Based on the local graph, it is possible to select the relay nodes based on complex networks’ metrics. Simulation results show that DDRX offers high efficiency in terms of coverage, number of transmitted packets, delay, and packet collisions compared to well-known data dissemination protocols. Also, DDRX provides significant improvements to a TMS that needs efficient data dissemination.

Speed Adaptive Beacon Broadcast for Information Dissemination in Vehicular Ad hoc Networks

Vehicular Ad hoc Network has been a key component of the Intelligent Transport System. An efficient mechanism for dissemination of information in VANETs is a challenging task. The high mobility of vehicular nodes and varying traffic flows makes selection of best relay vehicle to disseminate information a taxing task. Periodic beaconing for gathering information about the vehicles in the vicinity is though commonly employed in VANETs, but it degrades the performance resulting in channel contention and collisions. This paper presents a Speed Adaptive Beacon Broadcast approach that controls the beaconing rate depending upon the speed at which the vehicle is moving in comparison to the other vehicles in its locality. The selection of the relay vehicle is done keeping in consideration its distance from the source, local density and priority is given to the vehicle at an intersection. The approach is evaluated for both highway and urban scenario and simulation outcome reveals that SABB performs well in comparison to some of the existing approaches.

Reward Function Learning for Q-learning-Based Geographic Routing Protocol

This letter proposes a new scheme that uses Reward Function Learning for Q-learning-based Geographic routing (RFLQGeo) to improve the performance and efficiency of unmanned robotic networks (URNs). High mobility of robotic nodes and changing environments pose challenges for geographic routing protocols; with multiple features simultaneously considered, routing becomes even harder. Q-learning-based geographic routing protocols (QGeo) with preconfigured reward function encumber the learning process and increase network communication overhead. To solve these problems, we design a routing scheme with an inverse reinforcement learning concept to learn the reward function in real time. We evaluate the performance of the RFLQGeo in comparison with other protocols. The results indicate that the RFLQGeo has a strong ability to organize multiple features, improve network performance, and reduce the communication overhead.

Distance and signal quality aware next hop selection routing protocol for vehicular ad hoc networks

Newly emerged and integrated data communication technologies have changed the traditional processes and improve the quality of services. Wireless networks also provide efficient, low cost, fast and reliable solutions for different fields of life. Vehicular ad hoc networks are intended with various new smart features and make the inter communication systems for transportation and provide safety and comfort on the roads and establish the communication platform. However, because of unpredictable dense and sparse traffic conditions in urban areas, data communication is a challenging task for effective and reliable data links. Various topology-, location- and cluster-based protocols have been adopted to deal with high mobility of nodes and dynamic nature of network topologies. This paper presents a distance and signal quality aware routing (DSQR) protocol to deal with vehicular networks. The propose protocol initiates its forwarding decision based on Mid-Area node selection by evaluating direction and distance of neighbour nodes and also taking link quality into account and selects the best next forwarder node towards the destination node. The performance of DSQR is evaluated carrying out with vehicle speed and traffic density in realistic environment. Performance comparisons evaluation indicated the higher performance of propose protocol compared with existing protocols and reduces packet dropping and link failure issues.

Hybrid Type-2 Fuzzy Based Channel Estimation for MIMO-OFDM System with Doppler Offset Influences

The channel estimation methods track and predict the variation in channel characteristics, so that the original signal can be obtained after nullifying the channel induced influences. The channel estimation methods impact the overall performance of the MIMO-OFDM system. When the communicating nodes are mobile, a complete estimation of the fast time varying channel is accomplished if the Doppler offset is evaluated along with the channel gain. However, most of the channel estimation approaches proposed in literature for MIMO-OFDM systems assume that the Doppler offset contributed by highly mobile communicating nodes is already known to the receiver. The estimation of the Doppler offset with the channel coefficients renders the channel estimation problem non linear. In this paper, the issue of this non linear channel estimation for high mobility communicating nodes with associated dynamic Doppler offset in a MIMO-OFDM system is addressed. In order to obtain complete information of the channel which includes the channel coefficients and the associated Doppler offsets, a hybrid interval type-2 fuzzy aided Kalman filter for channel estimation is proposed. The type-2 fuzzy based membership functions are used here opposed to the type-1 fuzzy membership functions because the type-2 fuzzy membership functions are capable of effective modeling even under high degree of uncertainties. Furthermore, a detailed computational complexity analysis of the proposed algorithm is presented which shows that the algorithm has moderate computational complexity and has good performance in fast time varying channel conditions with high node mobility in a MIMO-OFDM system.

UAV-Assisted Supporting Services Connectivity in Urban VANETs

To keep the services and applications of intelligent transportation system stable and active, vehicular ad hoc networks (VANETs) are considered as an essential building block to maintain and manage its features. A wide deployment of VANETs is possible only after addressing numerous research challenges. One of the most complicated issues consists of designing a routing strategy, taking into consideration several serious constraints, and especially in a network such as VANET. The severity of these issues would be increased significantly when a VANET is deployed over an urban area, where we distinguish the high mobility of nodes and existing obstructions (e.g., buildings, bridges, tunnels, etc.). In this paper, an efficient routing solution based on a flooding technique is conceived to make the data delivery more reliable and to guarantee robust paths. Vehicles can cooperate in ad hoc fashion with existing unmanned aerial vehicles (UAVs). This kind of collaboration provides reliable routing paths and ensures alternative solutions in the case of path failures. Furthermore, a prediction technique is used to expect the expiration time of each discovered path. To limit the overhead over the network, all control packets are characterized by their static size making the originality of this work. Based on the simulation outputs, we discuss the performances of the proposed approach as compared with other dedicated previous schemes in terms of several metrics. The obtained results demonstrate that the hybrid communication between vehicles and UAVs based on the proposed flooding technique is perfectly suited to improve the data delivery process.

A Cooperative and Reliable RSU-Assisted IEEE 802.11P-Based Multi-Channel MAC Protocol for VANETs

Vehicle ad-hoc networks (VANETs), which support various important applications for intelligent transportation systems (ITSs), consist of vehicle-to-vehicle and vehicle-to-infrastructure communications based on vehicles and roadside units (RSUs). Medium access control (MAC) plays a critical role in providing efficient broadcast services for VANETs. Unlike other types of networks, VANETs suffer from rapid changes in topology, resulting in frequent network disconnections caused by the high mobility of nodes. Hence, adaptive MAC protocols, which dynamically adjust the interval according to the traffic conditions, are essential to VANETs. This study proposes a cooperative and reliable RSU-assisted IEEE 802.11p-based multi-channel MAC protocol for VANETs, called RAM. In our proposal, an RSU is used to both calculate the optimized interval and keep track of the safety packet transmission. We also present a cooperative scheme for the retransmission of safety packets that failed to broadcast because of hidden nodes. The simulation results show that the RAM not only allows safety packets to be broadcast more efficiently using the existing MAC protocols, but also outperforms the existing MAC protocols in terms of the packet delivery ratios for safety and control packets.

An Efficient and Reliable QoF Routing for Urban VANETs With Backbone Nodes

Because of the dynamic topology, high mobility of nodes, and complicated channel environments in urban areas, existing routings methods are susceptible to frequent link interruptions and channel congestions. To address these issues, a Quality of Forwarding (QoF)-based reliable geographic routing (QFRG) in urban vehicular ad hoc networks (VANETs) is proposed, where the best route is determined by guaranteeing the QoF and satisfying the link reliability requirement. Two theoretical models for QoF and link reliability analysis are first presented. Taking into consideration the transmission cost and the packet delivery ratio, the QoF is, then, employed to provide the quantitative evaluation to the road segments through the presented road weight evaluation (RWE) scheme, which takes into account the impact of the relative position of links on the network performance. Next, to accommodate the network scale of an urban city, the city map is divided into smaller grid zones. Based on the position of the destination, different transmission strategies are presented for packet forwarding. The extensive simulations demonstrate our protocol’s superiority in both transmission delay and packet delivery ratio compared with the existing schemes.

A Qualitative Assessment of VANET Routing Protocols Under Different Mobility Models

Vehicular Ad-hoc Networks (VANET) is an advanced wireless network that came to increase traffic safety, efficiency and to improve driving experience. The high mobility of nodes is the major characteristic in these networks. The aim of this paper is to figure out the impact of various mobility models on the performance of Ad-hoc On-demand Distance Vector (AODV), Cluster-Based Directional Routing (CBDR) and Greedy Perimeter Stateless Routing (GPSR) protocols. In this study, we analyze the performance of these routing protocols in different mobility models namely: Street Random Waypoint (STRWP), Gauss Markov and Freeway having varying speed. The simulation results show that STRWP provides a good performance with the three routing protocols in terms of packet delivery ratio, throughput and end to end delay.

Performance improvement of vehicular ad-hoc network with nature inspired biological computing algorithm

VANET is a hybrid ad-hoc network between vehicles and road side units. Due to the high mobility of nodes, to find a stable data communication route in VANET is an open challenge. This paper introduces a new hybrid routing algorithm to find a stable route by using zone-based routing (ZBR), fuzzy logic, and NIBC algorithm. In proposed algorithm ZBR is used to divide the network into small and stable zones, fuzzy logic is used to find the quality of links between nodes, and NIBC to find the stable route in short time. Six techniques for the VANET has been implemented and compared in this paper. NS2.34 network simulator is used for simulations. Simulations were carried out for variable transmission rate and variable speed. Five performance parameters have been taken to analyse the results. Simulation results have shown that NIBC algorithms improve the performance of VANET.

A novel energy-efficient probabilistic routing method for mobile opportunistic networks

In mobile opportunistic networks (MONs), a large number of intelligent devices carried by moving people can conduct message transmission without the support of communication infrastructures. Routing is one of the concerning and challenging research hotspots in MONs because of nodes’ mobility, intermittent connectivity, limited nodes’ energy, and the dynamic changing quality of the wireless channel. However, only one or several of the above factors are considered in most current routing methods. Moreover, owing to the high mobility of nodes, it is particularly important to decide the time when to make the forwarding decision and which nodes can be selected as the relay nodes. Additionally, due to the dynamic changing quality of the wireless channel, the predetermined relay nodes for the next hop may not receive the message. In this paper, we propose a novel energy-efficient probabilistic routing method for MONs, in which energy and mobility of nodes and the quality of wireless channel are all taken into account. Firstly, we explore the regularity of nodes’ mobility and the encounter probability among nodes to decide the time when to forward messages to other nodes. Secondly, by maintaining the energy fairness among nodes, the network lifetime can be prolonged. Thirdly, by fully taking the dynamic changing quality of the wireless channel into consideration, the retransmission number of messages can be effectively reduced. Additionally, we adopt a forwarding authority transfer policy for each message, which can effectively control the number of replicas for each message. The extensive simulation results show that the proposed method outperforms the existing routing algorithms in terms of the delivery ratio and the overhead ratio.

Performance Evaluation of Routing Protocols for Voice and Video Traffics

Wireless networks are comprised of nodes which are high in mobility and are adhoc natured where centralized access point is not required. Each node will have particular transmission range in which the data transmits from source to destination in that transmission range. Route construction for transmission of data from source to destination is tough due to high node mobility and dynamic nature of network. Many routing protocols are proposed and implemented in networks to reduce such mobility and dynamic difficulties for route construction. These routing protocols construct a route from source to destination based on availability of network nodes. Adhoc On demand Distance vector (AODV) is a self-starting dynamic network, Dynamic source routing (DSR) and Temporally Ordered Routing Algorithm (TORA) are most frequent used ones for dynamic route construction. Voice and Video are two mostly used applications nowadays as the users are immensely using them. In this paper, a comparison is made in performances of AODV, DSR and TORA for the traffics of voice and video. The performance is evaluated in terms of delay, throughput and packet delivery ratio. Simulations are conducted using network simulator NS 2.35.

VANETs QoS-based routing protocols based on multi-constrained ability to support ITS infotainment services

Vehicular ad hoc networks (VANETs) present an intriguing platform for several applications on e.g., intelligent transportation system (ITS) and infotainment applications aspire to be the main pattern of communication among vehicles while travelling. This can significantly impact on the amount of data exchanged by vehicles, increasing the contention on communication links and thus, degrading the quality of service of these applications. So, discrimination of data becomes imperative and forwarding critical information on suitable routes becomes decisive. Hence, a quality of service (QoS)-driven mechanism is needed to handle and assign network resources according to the stringent application data traffic demands. But, VANETs high node mobility and frequent link failure, stuck a big challenge in implementing an effective policy to meet and enforce these QoS requirements. A promising way to tackle this issue is to enforce QoS at the network layer, since it is the crucial point in VANETs’ communication. So, over the years, many QoS-aware routing protocols were specifically conceived for VANETs. In this paper, we present a comprehensive survey of QoS-aware routing protocols in VANETs’ literature. We examined the protocols based on their ability to support ITS infotainment services, their multi-constraint path problem (MCP), protocol’s functionality and weakness, objectives and design challenges. This way, we outline future directions for VANETs QoS-aware protocol research.

A mobility-aware approach for distributed data update on unstructured mobile P2P networks

In unstructured mobile peer-to-peer systems (MP2P), the frequent link breakages lead frequent topology mismatching problems and data transmission failures due to high mobility of nodes. The overhead of data transmission and synchronization cannot be neglected. In order to keep the data consistent, flooding is a fundamental and straightforward data synchronization mechanism since a mobile node does not know which else has the same shared data item. However, data flooding causes the broadcast storm problem. In this paper, we propose a mobility-aware data update approach (MADU) to improve the data dissemination and to reduce the overhead of maintaining the consistency of shared data items in an MP2P network. We use safe-time which is derived from the neighbor’s location and speed to determine the time for a node to do the checking and updating between the neighbor nodes and itself. We also consider the network connectivity of a mobile node and access frequency of a data item as the factors to trigger the update process. By combining the mobility information of nodes, network connectivity, and access frequency of data items, we set a reasonable data update mechanism, which can significantly decrease the number of retransmissions and redundant messages so as to reduce the overhead of maintaining the data consistency.

Toward a lightweight and efficient UAV‐aided VANET

AbstractConnectivity in a smart vehicular network is quite sensitive and highly affected by its dynamic network topology. Issues related to the intermittent nature of connectivity may arise due to the high mobility of nodes and network heterogeneity. In sparse areas, a vehicular network is basically a disruption‐tolerant network suffering from frequent disconnections, long delays, and messages loss. Facing these issues, and specifically for time‐sensitive applications, Unmanned Aerial Vehicle (UAV) can provide valuable assistance to Vehicular Ad Hoc Network (VANET) by assuming a relay node role between disconnected segments in the road. In such scenarios, effective communication is either between vehicles (V2V) or between vehicles and UAVs (V2U), which would form subsequently a UAV‐assisted vehicular network. In the present paper, we propose a new framework for using small UAVs as mobile infrastructure nodes in order to enhance the connectivity between vehicles. The first part of this framework accurately predicts the disconnected segments such that drones can be deployed to reestablish lost links. We have implemented a theoretical game for this prediction process. Furthermore, since the battery reserves of the UAVs are limited, we have proposed a mitigation technique based on game theory to reduce the power draining effects that a broadcast storm would have on the energy consumption of the network. For the validation of the proposed UVE (UAV‐aided VANET framework, with energy‐conscious constraints), we conducted thorough simulation scenarios with Network Simulator 3. The obtained performances are promising in the sense that our approach achieves high packet delivery ratio, low end‐to‐end delay, and low overhead communication costs.

High Speed Realistic Mobility Model for TN-Multi Lane Highway Environment

Vehicular Ad-hoc Networks (VANETs) are self-forming networks built from moving vehicles. The most important quality of VANETs is the high mobility of nodes, which makes the mobility model as one of the most important parameters. The mobility pattern in the mobility models is used to simulate the movement of the vehicles, which plays an important role in developing an effective communication for the vehicular network. The challenge is to generate suitable microscopic mobility model from the correct and realistic dataset. In this paper, the work analyses the different type of data sources in terms of various mobility models. Finally, it proposes the effective mobility model for the high speed multi-lane highway scenario. Then the performance metrics are analyzed for this proposed model using mobility and network simulators.

Fault Tolerance and QoS based Pervasive Computing using Markov State Transition Model

Fault-tolerance is significant in pervasive computing environments. Recently, few research works has been developed for reducing the fault, occurring in pervasive computing. However, there is a need for a fault tolerance mechanism to reduce the link failures and unwanted mobile node access (in pervasive computing environment). In order to overcome these limitations, Markov State Transition Based Fault Tolerance (MST-FT) Model is proposed. The main objective of MST-FT Model is to achieve resource efficient QoS in pervasive computing environment by avoiding the link failures and unwanted mobile node usages. Initially, the optimization of link failures is achieved by maintaining Markov chain of high energy mobile nodes on the wireless network communication path. The mobile nodes with higher energy and minimal drain rate are combined to form a chain in its corresponding path of communication in order to minimize the link failures in pervasive computing. Next, the inappropriate mobile node usage is avoided by selecting only the authorized mobile nodes for Markov chain construction to effective network communication, which resulting in improved fault tolerant rate. Therefore, MST-FT Model provides higher resource efficient QoS as compared to existing works. The performance of MST-FT Model is measured in terms of fault tolerant rate, execution time, energy consumption rate and quality of service level. The simulation results show that the MST-FT Model is able to improve the fault tolerant rate by 13% and also reduces the energy consumption rate of resource efficient QoS by 25%, when compared to previous works.

Source Coding Options to Improve HEVC Video Streaming in Vehicular Networks

Video delivery in Vehicular Ad-hoc NETworks has a great number of applications. However, multimedia streaming over this kind of networks is a very challenging issue because (a) it is one of the most resource-demanding applications; (b) it requires high bandwidth communication channels; (c) it shows moderate to high node mobility patterns and (d) it is common to find high communication interference levels that derive in moderate to high loss rates. In this work, we present a simulation framework based on OMNeT++ network simulator, Veins framework, and the SUMO mobility traffic simulator that aims to study, evaluate, and also design new techniques to improve video delivery over Vehicular Ad-hoc NETworks. Using the proposed simulation framework we will study different coding options, available at the HEVC video encoder, that will help to improve the perceived video quality in this kind of networks. The experimental results show that packet losses significantly reduce video quality when low interference levels are found in an urban scenario. By using different INTRA refresh options combined with appropriate tile coding, we will improve the resilience of HEVC video delivery services in VANET urban scenarios.