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Abstract With the emergence of ad-hoc networks, the communication methods in the field of wireless have greatly developed. A great deal of research has been conducted, especially in mobile nodes or mobile ad hoc networks (MANETs). The greatest advantage of MANETs is that they don't require predefined infrastructures, such as router link, hub etc. The nodes in a MANET are capable of forming a network which is time-dependent but not permanent to establish communication based on the allocated path. Routing attacks can cause great damage to MANETs. In the past few years, the research work has proposed a special intrusion detection mechanism to detect these attacks, resulting in eliminating malicious nodes in the network. The proposed work in this research paper addresses an efficient fuzzy clustering based algorithm for intrusion detection of a MANET implementation in a cloud storage environment. This paper has presented a model and experimental justifications for improving the efficiency. [ABSTRACT FROM AUTHOR]

The previous studies almost focus on the fairness problem of the uplink traffic in wireless mesh networks. This paper studies the fairness problem for bidirectional traffic in multi-hop wireless mesh networks containing selfish nodes. Unlike the transmission of uplink traffic, where transit packets are dropped at intermediate Transit Access Points (TAPs), almost all downlink traffic is dropped at the gateway. To resolve the problem, this paper presents an incentive-based mechanism (IBM) under which the optimal strategies of selfish TAPs and the gateway are the corresponding actions that enforce fairness. Moreover, this paper formulates the target throughput of each TAP in the network, proves the feasibility of the target throughputs for the uplink and downlink traffic of each TAP, and uses IBM to ensure that all selfish TAPs and the gateway follow the fairness model truthfully. Finally, the simulation results show that the proposed mechanisms are accurate and truthful. [ABSTRACT FROM AUTHOR]

Abstract: In wireless networks other than source and destination nodes, intermediate nodes play a major role for routing and other control transfer functions. Hence the network must be formed by self-organized intermediate nodes. This feature of the node is also used to protect the network from uncertainties like link, node failures. The main objective of this paper is to give the characteristics of intermediate nodes; how they support the quality of service issues. Existing research work in this area mainly concentrates on backbone construction and there is no solution for self-organized backbone formation. A new distributed localized algorithm is proposed to construct and maintain the backbone network named as SOB-T or M (self-organized backbone- tree or mark), which means that tree or marking scheme are used to construct the backbone network. The QoS parameters like throughput, delay and number of control messages are analyzed in this paper. [Copyright &y& Elsevier]

• The presented exposition introduces mobile resource Mutual exclusion (MRME) problem in FANET. • A novel token-based algorithm to solve the MRME problem has also been proposed. • The proposed algorithm is fault-tolerant as it handles token-loss. • The paper proves the correctness properties of the problem. • The static and dynamic performance analysis of the procedure has also been provided. Mutual exclusion (ME) is a highly researched problem in distributed computing systems. In the mutual exclusion problem, no two nodes can use critical resource simultaneously. Numerous protocols have been proposed for various types of static as well as mobile distributed systems, namely, Mobile Ad Hoc Networks (MANET), Vehicular Ad Hoc Networks (VANET) and cellular networks. The flying ad hoc networks (FANET) is an interesting variant of distributed systems and, to the best of our knowledge, no protocol exists in the literature for mutual exclusion in FANETs. In FANETs, the critical resource is mounted on an unmanned aerial vehicle (UAV) and user nodes are assumed in the transmission range of the UAV. Ours is the first algorithm to ensure ME in FANETs. The algorithm is token-based and we name it Mobile Resource Mutual Exclusion (MRME) algorithm. Unlike other ad hoc networks, due to swift mobility of nodes as well as resource, the FANETs topology is highly dynamic and fault prone. The MRME algorithm handles it successfully. Further, we present the correctness proof, complexity analysis and simulation results. The worst-case complexity of MRME is O(n) and synchronization delay is T, where T is message propagation delay. [ABSTRACT FROM AUTHOR]

The optimal path problem can be considered as a type of discrete optimization, which enables reliable and QoS-aware data dissemination in Vehicular Ad Hoc Networks (VANETs). The optimal path is of great importance in vehicular communication due to frequently disconnected network, dynamic topology, and limited bandwidth of wireless interface. In this paper, multi-valued Discrete Particle Swarm Optimization (DPSO), including encoding and decoding phase, is used to optimize the process of identification of an optimal path for efficient data dissemination in VANETs. The proposed algorithm includes link stability calculated by Euclidean distance in the polar coordinate system and the probability of occurrence of obstacles as objective. Extensive simulations are utilized to analyze the effectiveness of the proposed technique on the metrics such as packet delivery ratio, average throughput, and routing overhead. The results obtained demonstrate that the proposed algorithm is better than the other related schemes in the existing literature. [ABSTRACT FROM AUTHOR]

Abstract In vehicular networks, protocols and algorithms rely on the in-network status information and its delivery via control messages for their operations. Using the same wireless channel for data and control message transmissions consume significant channel capacity and time, thus resulting in performance degradation. In this paper, a multi-tiered, heterogeneous vehicular network architecture is considered consisting of mainly two radio access technologies, i.e., ad hoc and cellular. Based on the concept of infrastructure-assistance , we suggested offloading control messages over the cellular network and data over the ad hoc network. Next, an efficient broadcast algorithm is proposed that exploits predicted connectivity information to decide on transmit power levels for each vehicle. Finally, a joint transmit power adaptation, and routing algorithm is implemented to disseminate data over a multi-hop network. Through extensive simulations, we reported significant performance gains in terms of delay, collision rate, and packet delivery ratio while maintaining lower communication overhead. [ABSTRACT FROM AUTHOR]

Abstract An energy efficient content distribution technique in mobile ad hoc networks is proposed in this paper. Based on bit rate, remaining energy and maximum allowable delay, a fitness value is evaluated for each node in the network. A set of nodes having maximum fitness values are elected as cluster heads. It is determined by applying teaching learning based optimization technique, only after the nodes satisfy an energy constraint. The clusters of nodes are formed by assigning the remaining nodes to their corresponding cluster heads. The cluster heads can receive the required packets from the base station via long range communication and forward the same to the cluster members. Efficient energy expenditure by this approach leads to an increased network lifetime. The experimental results show effectiveness of the proposed approach over K-means Clustering and U+M techniques in terms of reduced energy consumption and improved network lifetime. [ABSTRACT FROM AUTHOR]

Abstract The dynamic nature of Mobile Ad hoc Networks (MANET) poses many challenges including effective management of scarce resources such as energy. Overall energy consumption of a network depends upon the transmission power of its constituent nodes and decides network lifetime. In this paper, a clustering based scalable topology control method, Optimized Power Control (OPC) is proposed to determine the optimal transmission power of nodes with the help of modified Gabriel Graph (GG) algorithm. OPC is tested for its efficiency in terms of various network parameters such as transmission power, per node energy consumption and network delay. Simulation results show that the proposed scheme is scalable and outperforms the existing schemes such as Local Tree based Reliable Topology (LTRT) and Distributed Power Management (DISPOW) in terms of the above-mentioned network parameters. Additionally, per node power level decision using OPC has been improved by approximately 7% in comparison to LTRT and DISPOW. [ABSTRACT FROM AUTHOR]

Abstract In recent years, various types of applications have emerged from Vehicular Ad hoc Networks (VANETs) for safety, infotainment, rescue and security purposes. Safety applications have their own strict communication requirements, and they require reliable and timely data communication within networks. Due to a variety of network applications, safety applications have been negatively impacted by communication channel congestion issues. Channel congestion leads to packet loss, delay and unreliability issues, and has a serious impact on vehicular traffic, including road accidents, road jams, and wrong traffic decisions. In addressing these issues, this paper's authors have proposed a Dynamic Congestion Control Scheme (DCCS) as a means of reliable and timely data delivery, in safety applications. The proposed scheme is designed for communication channels, as a means of broadcasting safety messages, and to ensure the reliable and timely delivery of messages to all neighbours in a network. The DCCS scheme is designed for inter-vehicle communication, without fixed infrastructure. Comprehensive simulation is conducted, in order to evaluate the performance of a proposed scheme, and to compare it with other state of the art schemes. [ABSTRACT FROM AUTHOR]

Abstract: In Mobile Ad hoc Network (MANET), mobility, traffic and node density are main network conditions that significantly affect performance of routing protocols. Much of the previous research in MANET routing have focused on developing strategies, which suit one specific networking scenario. Therefore, there is no existing protocol that can work well in all different networking scenarios. This paper reviews characteristics of several different classes of routing protocols. Moreover, most of current routing protocols assume homogeneous networking conditions where all nodes have the same capabilities and resources. This paper presents extensive studies simulations for DSR, AODV, LAR1, FSR and WRP in homogenous and heterogeneous networks that consist of different nodes with different resources. The results showed that while all protocols perform reasonably well in homogenous networking conditions, their performance suffer significantly over heterogonous networks. [Copyright &y& Elsevier]

Graphical abstract Abstract This paper presents a Gauss Markov Mobility-based Affinity Propagation-driven Distributed (GMM-APD) clustering approach which primarily tackles the greedy clustering heuristics in MANETs. GMM-APD addresses two fundamental short-comings of greedy approach namely: (a) Use of local optima concept and (b) frequent event-driven broadcasts by mapping evolution of the network topology into clusters. Node mobility is considered as the proximity criteria while the node movement pattern is represented as a Gauss Markov (GM) distribution. The temporal dependency of GM distribution is used to compute the proximity criteria which is further optimised by allowing the network to evolve using a modified Affinity Propagation technique; followed by the clustering decisions. An analytical model to explain the dynamics of GMM-APD is also presented describing the occurrences of various events taking place on the timeline of cluster and node. Finally, GMM-APD clustering technique is represented as an Integer Linear Problem formulation focussing on minimising the dominating set. The simulations carried out using NS-2 reveal that GMM-APD generates a quasi-optimal set of cluster heads and exhibits enhanced performance as compared to some of the existing clustering techniques in terms of cluster stability, quality and cost. [ABSTRACT FROM AUTHOR]

The vehicle routing in real-life transportation, distribution and logistics may change with time, especially when there is existing technology that can produce real-time routing data. In this paper, a metaheuristic procedure based on an Adaptive Large Neighborhood Search (ALNS) algorithm is proposed to solve the Dynamic Vehicle Routing Problem (DVRP) with limited vehicles and hard-time windows. The ALNS involves ad hoc destroy/repair heuristics and a periodic perturbation procedure. In addition, an efficient feasibility check has been designed for inserting customer. By conducting several computational experiments with Lackner's benchmark, we show that the present approach can solve real-time problems within a very short time while improving the quality of the solution. The average number of vehicles is smaller than that of existing algorithms, the maximum average error of the vehicle traveling distance is reduced, and the average computation time remains the same. [ABSTRACT FROM AUTHOR]

The Internet of Things (IoT) is a collection of heterogeneous, interconnected mobile ad-hoc networks (MANETs) devices. High-level security is always required to protect sensitive information travelling over MANET-IoT networks. IoT security ensures the privacy, confidentiality, and security of the users, infrastructure, and data. The Enhanced Multi-Level Intelligent Trust Scheme (EMITS) initially designs to authenticate and validate the data for the Mobile IoT (MIoT) ecosystem. The proposed model used the AODV (Adhoc On-Demand Distance Vector Routing) routing protocol with an intelligent trust scheme. This paper aims to present a MANET-IoT-based model combined with a hybrid cryptographic scheme that ensures secure communication between mobile IoT ecosystems against the black hole attack. The performance of the proposed EMITS-MIoT model is verified based on the packet delivery ratio (PDR), packet loss ratio (PLR), false positive ratio (FPR), false negative ratio (FNR), and attack detection rate (DR). The EMTS-IoT technique shows a 3–5% success in data transmission over existing techniques. [ABSTRACT FROM AUTHOR]

Mobile ad hoc networks (MANETs) are one of the emerging technologies of wireless communication, in which each node in the MANET acts as a router. In an ad hoc network, any node can communicate with any other node in the network. However, this infrastructure of mobile nodes makes this system more vulnerable to various types of attacks. A black hole attack is one such attack in which the packet is dropped maliciously. In this paper, we propose a security solution known as the honeypot-based dynamic anomaly detection using cross-layer security (HBDADCS). The proposed technique detects and isolates black hole attacks from the ad hoc network. In this work, various novel algorithms are used which involve honeypot methodology. These technologies are proposed in order to detect and isolate black hole attacks from the network. Simulation-based results prove that the proposed technique has better packet delivery and end to end to delay with a decreased network load solely due to control packets compared to the other existing techniques. [ABSTRACT FROM AUTHOR]

A mobile ad hoc network (MANET) is a temporary network where nodes are free to move in a given area. Due to this dynamic nature, links in the routes break. Often backup routing is used as a solution in which alternate route tables are used to continue the data transfer. In this paper, we discuss the shortcomings of the existing backup routing, which is due to their inadequate ways of updating alternate route table information by route maintenance. In several routing protocols, hello messages are periodically broadcasted to update the neighbour table entries which help in detecting link failure. We propose an efficient route maintenance mechanism in AODV routing protocol employing the benefits offered by hello messages. Simulation results show that our proposed modified route maintenance (MRM) scheme significantly improves the performance of MANET. [ABSTRACT FROM AUTHOR]

Mission-critical military operations with dismounted soldiers are frequently characterized by high battlefield dynamics. In such scenarios a mobility model can manage soldiers’ movements dynamically especially under enemy attacks. This paper presents a group mobility model simulating realistic soldier and leader battlefield behaviors. Our model analyzes communication between a group of dismounted soldiers deployed in a mobile ad hoc network (MANET) and their leader under several perturbation factors (e.g., noise and enemies attacks) which affect movements and topology connectivity. Results show that the dismounted soldiers’ collective movement improves the capacity of communication channels, whereas noise uncertainty may dramatically destroy the network. Moreover, the enemy’s presence, another disorder parameter, changes qualitatively and quantitatively the army’s wireless communication topology. Enemy numbers decrease almost linearly the throughput at the sink node (commander). A discussion of results follows, using distributions of path lifetimes, path lengths, packet delivery and group sizes in the communication soldiers’ network. [ABSTRACT FROM AUTHOR]

Code Division Multiple Access, which allows multiple users to access and transmit data over wireless channel simultaneously, is implemented using different code assignment schemes including Pair-wise Code Assignment. In this paper, the existing pair-wise code assignment procedure is enhanced and a new such scheme is presented with at most ∆ codes, where ∆ is the maximum degree of a network. In addition, a co-channel interference called secondary interference that exists in the existing schemes has been addressed and an interference free pair-wise code assignment procedure is proposed with at most ∆ 2 - c codes, where c is a constant. On simulation over different synthesized, actual and random networks, it is found that our scheme improves successful transmission rate and blocking probability by 17% and 12.5% respectively. Although the code requirement of the proposed interference free scheme is increased by 40%, it would improve the network performance. [ABSTRACT FROM AUTHOR]

A Mobile Ad hoc Network (MANET) is an infrastructure-less collection of nodes that are powered by portable batteries. Consumption of energy is the major constraint in a wireless network. This paper presents a new algorithm called Energy-Aware Span Routing Protocol (EASRP) that uses energy-saving approaches such as Span and the Adaptive Fidelity Energy Conservation Algorithm (AFECA). Energy consumption is further optimized by using a hardware circuit called the Remote Activated Switch (RAS) to wake up sleeping nodes. These energy-saving approaches are well-established in reactive protocols. However, there are certain issues to be addressed when using EASRP in a hybrid protocol, especially a proactive protocol. Simulation results for the EASRP protocol show an increase in energy efficiency of 12.2% and 17.45% compared with EAZRP and ZRP, respectively. The EASRP protocol also proves to be effective in by producing a better packet delivery ratio for low- and high-density networks as measured by the NS-2 simulation tool. [ABSTRACT FROM AUTHOR]

Advances in wireless ad-hoc network techniques have spurred the development of new approaches to increase network efficiency. One of the more popular approaches is swarm intelligence. Swarm intelligence imitates the collective behavior of biological species to solve network routing problems. Meanwhile, weakly connected dominating sets (WCDS) can serve as auxiliary structures for clustering nodes in the network. This paper uses the clustering concept of WCDS to propose an improved ant-based on-demand clustering routing (AOCR) protocol for wireless ad-hoc networks. Network states’ information is obtained from the Forward_Ant, and is only broadcast by the head of every cluster, thus decreasing the overhead required to transmit ant packets. To increase network efficiency, the pseudo-random-proportional-selection strategy is used to evaluate the best path from the source node to the destination node by the Backward_Ant. [ABSTRACT FROM AUTHOR]

Cooperative ad-hoc networks are popular because of their ability to provide reliable communication. In this paper, we consider a cooperative ad-hoc network consisting of a source, two decode-and-forward relays and a destination. The source intends to transmit its data to the destination directly as well as through relays. We employ a weighted selection combining at the destination which chooses either the weighted source-to-relay1-to-relay2-to-destination link or source-to-destination link depending upon the instantaneous signal-to-noise-ratio. We derive the end-to-end symbol error probability (SEP) of a triple-hop cooperative network with binary phase-shift keying for a flat, slow Rayleigh fading channel. Further, we develop an algorithm which investigates the performance of this cooperative ad-hoc network in terms of SEP. Results show that the cooperation among the nodes and weighted selection combining improves the performance of ad-hoc networks when compared to a point-to-point link and conventional selection combining. [ABSTRACT FROM AUTHOR]

A wireless ad hoc network consists of a set of wireless devices. The wireless devices are capable of communicating with each other without the assistance of base stations. Space Division Multiple Access (SDMA) is a new technology designed to optimize the performance of current and future mobile communication systems. In this paper, an SDMA-based MAC protocol (S-MAC) for wireless ad hoc networks with smart antennas is proposed. The proposed protocol exploits the SDMA system to allow reception of more than one packet from spatially separated transmitters. Using SDMA technology provides collision-free access to the communication medium based on the location of a node. The proposed protocol solves the hidden terminal problem, the exposed terminal problem, and the deafness problem. Simulation results demonstrate the effectiveness of the proposed S-MAC in improving throughput and increasing spatial channel reuse. [ABSTRACT FROM AUTHOR]

In this paper, we focus on constructing a mobile social network over a mobile ad hoc network. Although some mobile social networks have been proposed to address contents sharing and search in mobile ad hoc networks, most existing methods incur either high network management overheads or low efficiency of contents search. The proposed method constructs a mobile social network according to user interests and location information. Since the mobile nodes with nearby positions are linked together, the network management overhead of the proposed method is decreased. The contents search can be performed by using the constructed social links with low communication cost and high success rate. The various experimental results based on the synthetic datasets and real datasets have showed that the proposed method has a great advantage comparing to existing methods. [ABSTRACT FROM AUTHOR]

Highlights: [•] Hybrid routing intelligent algorithm is proposed in this paper. [•] The hybrid routing intelligent algorithm improves the end-to-end delay and power consumption. [•] The proposed hybrid routing intelligent algorithm approach has a tendency to find the optimal route. [Copyright &y& Elsevier]

Abstract: An unreliable wireless communication environment and limited energy resources have a severe impact on the Quality of Service (QoS) of Mobile Ad Hoc Networks (MANETs). To improve network performance, an Energy-balanced Cooperative Media Access Control (EC-MAC) protocol in MANETs is proposed in this paper. It adopts the best partnership selection algorithm based on opportunistic relaying to select the cooperative node with the best channel conditions, highest transmission rate and most balanced energy consumption. The simulation results of EC-MAC, Cooperative MAC (CoopMAC) and IEEE 802.11 Distributed Coordination Function (DCF) protocols show that EC-MAC outperforms the other two protocols in terms of the packet delivery ratio, network throughput and network lifetime under two distinct channel noise levels, especially under the bad channel condition. Meanwhile, the EC-MAC protocol does not increase the average end-to-end delay compared with IEEE 802.11 DCF. [Copyright &y& Elsevier]

Abstract: In cognitive radio (CR) networks, a static activity model fails to capture the dynamic and time-varying behavior of the licensed or primary users (PUs). In this paper, a distributed scheme is proposed that allows mobile CR users to learn about the activity of the PUs, and disseminate this information to the neighboring nodes that also function as information repositories. In order to guarantee sensing precision and transmission efficiency, the proposed method switches between time-intensive “fine sensing” and quick “normal sensing”. Our approach uses the maximum likelihood estimator to learn average busy and idle periods in the fine sensing stage. These identified activity patterns are then used during normal sensing, where the mean square error (MSE) value of PU on–off times is continuously monitored to ensure that the estimation is sufficiently accurate. When PU activity changes significantly, the MSE is considered as the indicator to re-start the fine sensing. Simulation results reveal that our proposed method can efficiently track the dynamics of the PU activity. [Copyright &y& Elsevier]

Abstract: The wireless world is migrating towards an era that will comprise wireless network infrastructure, as well as more temporary structures which, for instance, can be called Opportunistic Networks (ONs). ONs can comprise various terminals, potentially organized in an ad-hoc mode, and be terminated at a set of access points of the infrastructure-based network. In this context, an operator, owning a wireless network infrastructure, can exploit ONs for complementing the infrastructure, e.g., in order to resolve coverage expansions or for achieving green targets. Given the existence of opportunities in terms of available nodes and spectrum, the suitability of creating an ON can be determined by the type of involved applications and mobility levels. The decision to create or not an ON will be dynamic, should respect traffic and mobility aspects and should also envisage anticipated QoS and energy related benefits for the whole network. Framed within this statement, this paper aims at the investigation of those conditions under which the creation of an ON will be beneficiary for the overall network. This investigation is based on extensive network simulations and under certain circumstances the scheme may designate solutions that can offer adequate QoS. [Copyright &y& Elsevier]

Abstract: Localization based services rely on Global Positioning System (GPS) receivers embedded in the network nodes, but the satellite signal availability is often limited in indoors environment. Collaborative network-assisted GPS algorithms addressed this issue by communicating various assistance data between the nodes or transforming open-sky nodes into virtual GPS satellite transmitters (pseudolites). Even though such approach improves the coverage, the crosscorrelation problem surfaces due to masking of relatively weak available satellite signals by stronger pseudolites. This paper proposes reduced complexity algorithms to mitigate such a self-jamming (near/far) effect in ad hoc networks. The idea is based on adaptive modifications of dispreading GPS codes in receiver nodes to minimize interference caused by strong pseudolite signals. An optimization problem is formulated for the minimization of interference using mean squared error (MSE) as a cost function. Then computational optimization is achieved through adaptive implementation and parameterized dimension reduction of the optimization problem. [Copyright &y& Elsevier]

Abstract: Wireless mesh network (WMN) is a promising solution for last mile broadband internet access. Mesh nodes or mesh routers are connected via wireless links to form a multi-hop backbone infrastructure and improving throughput is the primary goal. While previous works mainly focused on either link level protocol design or complex mathematical model, in this paper, we investigate the performance gains from jointly optimizing scheduling and routing in a multi-radio, multi-channel and multi-hop wireless mesh network. Then, two optimization objectives are addressed by considering wireless media contention and spatial multiplexing. The first objective is to maximize throughput by exploiting spatial reuse while the second one is to ensure fairness among different links. We design a cross-layer algorithm by considering both MAC layer and network layer. Simulation results show that our joint optimization algorithm can significantly increase throughput as well as fairness. [Copyright &y& Elsevier]

Abstract: With the expanding of applications, the demand of quality of service (QoS) has become strongly increased in ad hoc networks. Since the efficient and reasonable MAC protocol is a key factor for providing QoS in ad hoc networks, in this paper we propose an adaptive QoS MAC protocol (AMP) based on IEEE 802.11. In AMP, we introduce the concept of transmission license, where only the node which holds transmission license can participate in the channel contention for changing the number of licenses according to the load of the network adaptively, controlling the number of the nodes that participate in the channel contention, and ensuring the nodes with licenses share the channels through contention. In addition, AMP assigns different priority classes for different traffic according to the special characteristics and performance types of the different networks, and it sets the different contention parameters for the different priorities services for guaranteeing these services performances to have advantages in the channel contention. Simulation shows that compared to IEEE 802.11 protocol, AMP not only can meet the QoS requirement with high priority in the networks but also can well solve the hidden terminal problems and the fairness issues between different network nodes; that is, it can satisfy the high efficiency, pertinence, spatial-reuse, etc. to the largest extent at the same time in limited channels. [Copyright &y& Elsevier]

Abstract: Multi-hop wireless networks (MHWN) have emerged to be a promising cost effective paradigm for the next-generation wireless technology. However, the unique characteristics of nowadays MHWN, such as distributed and dynamic network architecture, broadcast nature of wireless medium and stringent resource constraints of wireless devices, makes it extremely attractive and vulnerable to malicious attacks. So how to ensure continuous network service becomes a critical problem especially in jammed situations. Although some research has been conducted on countering jamming attacks, few works consider jamming dynamics. In this paper, interference avoidance mechanisms are well concerned and a proactive multi-path routing mechanism based on measuring jamming dynamic is presented. In our proposed solutions, the novel mechanism defines a new metric for routing known as the degree of interference activity (IA) to represent the jamming dynamic on a node. A comprehensive simulation study is conducted to evaluate the performance of the proposed scheme. Performance results show that our solution outperforms existing ad hoc routing protocols in terms of packet delivery and average end-to-end delay in the presence of jammers. [Copyright &y& Elsevier]

Abstract: With the introduction of Mobile Ad Hoc Networks (MANETs), nodes are able to participate in a dynamic network which lacks an underlying infrastructure. In this paper, we present a novel approach to improve the search efficiency and scalability of MANETs by clustering nodes based on trust mechanism. In our method, the trust relationship is formed by evaluating the level of trust using Bayesian statistic analysis, and clusters can be formed and maintained autonomously by nodes with only partial knowledge. Simulation results show that each node can form and join proper clusters based on their trust degree, and the cluster-based search algorithm with trust mechanism outperforms over those in current popular clustering models. [Copyright &y& Elsevier]

Abstract: This paper discusses some aspects related to Wireless Sensor Networks over the IEEE 802.15.4 standard, and proposes, for the very first time, a mesh network topology with geographic routing integrated to the open Freescale protocol (SMAC – Simple Medium Access Control). For this is proposed the SMAC routing protocol. Before this work the SMAC protocol was suitable to perform one hop communications only. However, with the developed mechanisms, it is possible to use multi-hop communication. Performance results from the implemented protocol are presented and analyzed in order to define important requirements for wireless sensor networks, such as robustness, self-healing property and low latency. [Copyright &y& Elsevier]

Abstract: In recent years, Spatial Wireless Ad Hoc (SWAH) networks constructed in the near spatial region by connecting various pieces of spatial and ground communication equipment have become the focus for developing future information networks. Due to their special characteristics, the traditional routing protocols in fixed networks and ad hoc networks cannot be used directly in SWAH networks. Therefore, the design of a special routing protocol for SWAH networks has become a challenge. In this paper, we propose a new Hybrid On-demand Distance Vector Multi-path (HODVM) routing protocol that divides the SWAH networks into backbone and non-backbone networks to perform static routing and dynamic routing, respectively. To provide load balancing, HODVM can adaptively establish and maintain multiple node-disjoint routes by multi-path routing. Simulation results show that, compared to traditional routing protocol, HODVM not only has better performance in terms of scalability and survivability but can also balance the network load well. [Copyright &y& Elsevier]

Abstract: Performance of ad hoc networks dramatically declines as network grows. Cluster formation in which the network hosts are hierarchically partitioned into several autonomous non-overlapping groups, based on proximity, is a promising approach to alleviate the scalability problem of ad hoc networks. In this paper, we propose a localized learning automata-based clustering algorithm for wireless ad hoc networks. The proposed clustering method is a fully distributed algorithm in which each host chooses its cluster-head based solely on local information received from neighboring hosts. The proposed algorithm can be independently localized at each host. This results in a significantly reduction in message overhead of algorithm, and allows cluster maintenance can be locally performed only where it is required. To show the performance of proposed algorithm, obtained results are compared with those of several existing clustering methods in terms of the number of clusters, control message overhead, clustering time, and load standard deviation. [Copyright &y& Elsevier]

Abstract: Path compression techniques are efficient on-demand routing optimizing techniques for mobile Ad Hoc networks. However, there is no efficient model for path compression techniques. This paper analyzed the principles and characteristics of path compression algorithms and proposed dynamic model which provided theoretical basis to improve or propose path compression algorithms. This model took the mobility and expansibility of Ad Hoc networks into account and was efficient to analyze or evaluate path compression algorithms. The quantitative relationship and probability expression for pivotal compression events were given based on the model. The simulation results of SHORT (self-healing and optimizing routing techniques) and PCA (path compression algorithm) show that it is a correct and efficient dynamic model for path compression. Finally, some suggestions and application scenarios about the model were proposed. [Copyright &y& Elsevier]

Abstract: Wireless multicast for multihop ad-hoc networks ensures that the same information is delivered efficiently to multiple recipients simultaneously. However, existing protocols ignore the real-time nature of many wireless applications such as real-time video and audio communications in mesh and ad-hoc networks. Further, devices in such networks are typically energy-constrained, i.e., multicast protocols have to trade off timeliness with energy efficiency. This paper presents RTMC, a real-time multicast protocol for wireless multihop networks that allows receivers to specify their individual real-time constraints and establishes multicast trees such that receivers’ deadlines are met and overall energy consumption in the network is reduced. Toward this end, RTMC relies on dynamically prioritized packet scheduling on forwarding nodes, prioritized channel access at the MAC layer, feedback control for latency management, tree adaptations to address mobility, dynamic subscriptions and unsubscriptions, and adaptations to address link breakages. Simulation results show that, compared to non-real-time multicast techniques, RTMC can provide user-specific latency management while reducing the energy consumption in the network. [Copyright &y& Elsevier]

Abstract: Reliability is an important research topic of distributed systems. To achieve fault-tolerance in the distributed systems, healthy processors need to reach a common agreement before performing certain special tasks, even if faults exist in many circumstances. This problem is called as the Byzantine Agreement (BA) problem and it must be addressed. In general, the traditional BA problem is solved in well-defined networks. However, the MANETs (Mobile Ad-hoc Network) are increasing in popularity and its network topology is dynamic in nature. In this paper, the BA problem is re-examined in MANETs. Our protocol uses the minimum number of message exchanges to reach an agreement within the distributed system while tolerating the maximum number of faulty processors in MANETs. [Copyright &y& Elsevier]

Abstract: Topological changes in mobile ad hoc networks frequently render routing paths unusable. Such recurrent path failures have detrimental effects on quality of service. A suitable technique for eliminating this problem is to use multiple backup paths between the source and the destination in the network. Most of the proposed on-demand routing protocols however, build and rely on single route for each data session. Whenever there is a link disconnection on the active route, the routing protocol must perform a path recovery process. This paper proposes an effective and efficient protocol for backup and disjoint path set in an ad hoc wireless network. This protocol converges into a highly reliable path set very fast with no message exchange overhead. The paths selection according to this algorithm is beneficial for mobile ad hoc networks, since it produces a set of backup paths with much higher reliability. Simulations are conducted to evaluate the performance of our algorithm in terms of route numbers in the path set and its reliability. In order to acquire link reliability estimates, we use link expiration time (LET) between each two nodes. In another experiment, we save the LET of entire links in the ad hoc network during a specific time period, then use them as a data base for predicting the probability of proper operation of links. Links reliability obtains from LET. Prediction is done by using a multi-layer perceptron (MLP) network which is trained with error back-propagation error algorithm. Experimental results show that the MLP net can be a good choice to predict the reliability of the links between the mobile nodes with more accuracy. [Copyright &y& Elsevier]

• Opportunistic routing is a new routing paradigm for wireless ad-hoc networks. • Quality-of-service based routing improves network delay and throughput. • Links quality and nodes congestion are considered to form the QoS routing metric. • Queue length can be a network congestion indicator. • The links' data rate can be a channel quality indicator. Opportunistic routing (OR) is a new routing paradigm in which the next hop forwarders are not fixed. A group of network nodes called forwarder set is considered as potential forwarders from which the next hop will be selected. Although OR can improve network performance, network resources are allocated to the flows, regardless of their quality-of-service (QoS) needs. This paper proposes a QoS-aware opportunistic routing that considers QoS levels of the flows in passing them over appropriate paths. To achieve this goal, we propose a method that selects and prioritizes the forwarder set based on the flow's QoS levels. This policy leads to a more uniform distribution of traffic in the network. Consequently, the average queue length, the average queuing delay, and packet loss are reduced. The simulation results imply that the proposed algorithm makes traffic distribution more uniform so that the network performance is improved in terms of average throughput and end-to-end delay. [ABSTRACT FROM AUTHOR]

• A comprehensive classification of VANET clustering algorithms: strength and weakness. • Intelligence-based VANET clustering including machine learning and fuzzy logic. • The distinction between vehicle mobility as well as network mobility strategies. • A detail study of VANET multi-hop clustering strategies. Clustering is an important concept in vehicular ad hoc network (VANET) where several vehicles join to form a group based on common features. Mobility-based clustering strategies are the most common in VANET clustering; however, machine learning and fuzzy logic algorithms are also the basis of many VANET clustering algorithms. Some VANET clustering algorithms integrate machine learning and fuzzy logic algorithms to make the cluster more stable and efficient. Network mobility (NEMO) and multi-hop-based strategies are also used for VANET clustering. Mobility and some other clustering strategies are presented in the existing literature reviews; however, extensive study of intelligence-based, mobility-based, and multi-hop-based strategies still missing in the VANET clustering reviews. In this paper, we presented a classification of intelligence-based clustering algorithms, mobility-based algorithms, and multi-hop-based algorithms with an analysis on the mobility metrics, evaluation criteria, challenges, and future directions of machine learning, fuzzy logic, mobility, NEMO, and multi-hop clustering algorithms. Image, graphical abstract [ABSTRACT FROM AUTHOR]