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Using directional antennas in wireless Ad hoc networks has many superiorities, including reducing interference, extending transmission range, and increasing space division multiplexing. However, directional transmission introduces two problems: deafness and directional hidden terminals problems. We observe that these problems result in saturation throughput disparity among the competing flows in directional CSMA/CA based Ad hoc networks and bring challenges for modeling the saturation throughput of the flows. In this article, we concentrate on how to model and analyze the saturation throughput disparity of different flows in directional CSMA/CA based Ad hoc networks. We first divide the collisions occurring in the transmission process into directional instantaneous collisions and directional persistent collisions. Then we propose a four-dimensional Markov chain to analyze the transmission state for a specific node. Our model has three different kinds of processes, namely back-off process, transmission process and freezing process. Each process contains a certain amount of continuous time slots which is defined as the basic time unit of the directional CSMA/CA protocols and the time length of each slot is fixed. We characterize the collision probabilities of the node by the one-step transition probability matrix in our Markov chain model. Accordingly, we can finally deduce the saturation throughput for each directional data stream and evaluate saturation throughput disparity for a given network topology. Finally, we verify the accuracy of our model by comparing the deviation of analytical results and simulation results. [ABSTRACT FROM AUTHOR]

Information-Centric Networking (ICN) has emerged as a paradigm to cope with the lack of built-in security primitives and efficient mechanisms for content distribution of today's Internet. However, deploying ICN in a wireless environment poses a different set of challenges compared to a wired environment, especially when it comes to security. In this article, we present the security issues that may arise and the attacks that may occur from different points of view when ICN is deployed in wireless environments. The discussed attacks may target both applications and the ICN network itself by exploiting elements of the ICN architecture, such as content names and in-network content caches. Furthermore, we discuss potential solutions to the presented issues and countermeasures to the presented attacks. Finally, we identify future research opportunities and directions. [ABSTRACT FROM AUTHOR]

For improving the throughput while simultaneously enhancing the security in aeronautical ad-hoc networking (AANET), a channel quality indicator (CQI)-mapped spatially modulated sparse code multiple access (SM-SCMA) scheme is proposed in this paper. On one hand, we exploit the joint benefits of spatial modulation and SCMA for boosting the data rate. On the other hand, a physical-layer secret key is generated by varying the SM-SCMA mapping patterns based on the instantaneous CQI in the desired link. This guarantees the security of AANETs, since this secret key is not exchanged between the source aeroplane and its destination. Due to the line-of-sight (LoS) propagation in the AANET, other aeroplanes or eavesdroppers may detect the signals delivered in the desired link. However, they are unable to translate the detected signals into the original confidential information, even if multiple copies of the signals are recoined over multiple hops of the AANET, because they have no knowledge of the CQI-based SM-SCMA mapping pattern. The performance of the CQI-mapped SM-SCMA is evaluated in terms of both its bit error rate and its ergodic secrecy rate, which substantiates that the proposed scheme secures the confidential information exchange in the multi-hop AANET. [ABSTRACT FROM AUTHOR]

Ad hoc networks are vulnerable to numerous attacks due to its infrastructure-less nature, one of these attacks is the Sybil attack. Sybil attack is a severe attack on vehicular ad hoc networks (VANET) in which the intruder maliciously claims or steals multiple identities and uses these identities to disturb the functionality of the VANET network by disseminating false identities. Many solutions have been proposed in order to defend the VANET network against the Sybil attack. In this research a hybrid algorithm is proposed by combining footprint and privacy-preserving detection of abuses of pseudonyms (P2DAP) methods. The hybrid detection algorithm is implemented using the ns2 simulator. The proposed algorithm works as follows. P2DAP acts better than the footprint algorithm when the number of vehicles increases. On the other hand, the footprint algorithm acts better when the speed of vehicles increases. The hybrid algorithm depends on encryption, authentication and on the trajectory of the vehicle. The scenarios will be generated using SUMO and MOVE tools. [ABSTRACT FROM AUTHOR]

Efficient routing and broadcasting among a set of nodes play a critical role in wireless adhoc networks. for energy efficient routing, a connected dominating set (CDS) based virtual backbone is a promising approach. In the network, one-hop neighbors are selected as multi point relay (MPR) by each node to cover all its two-hop neighbors for the purpose of broadcasting and 2-hop repair. To improve the network lifetime, energy efficient MPR based CDS construction has been proposed by considering the node degree, energy level, node ID and velocity of the node. We also propose a route discovery protocol to relay route request messages, which makes use of the CDS nodes to obtain a stable routing path; 2-hop repair for route maintenance, which reduces the path damage (reduced control packets with lesser consumption of bandwidth) and broadcast storm problem. The simulation results show that the proposed protocol increases the network lifetime up to 30% than other works and effectively repair damaged routes by reducing control packets. [ABSTRACT FROM AUTHOR]

We consider a scenario of broadcasting information over a network of nodes connected by noiseless communication links. A source node in the network has some data packets to broadcast. It encodes these data packets into $n$ coded packets in such a way that any node in the network that receives any $k$ out of the $n$ coded packets will be able to retrieve all the original data packets. The source transmits the $n$ coded packets to its one-hop neighbours. Every other node in the network follows a probabilistic forwarding protocol, in which it forwards a previously unreceived packet to all its neighbours with a certain probability $p$. We say that the information from the source undergoes a “near-broadcast” if the expected fraction of nodes that receive at least $k$ of the $n$ coded packets is close to 1. The forwarding probability $p$ is chosen so as to minimize the expected total number of transmissions needed for a near-broadcast. We study how, for a given $k$ , this minimum forwarding probability and the associated expected total number of packet transmissions varies with $n$. We specifically analyze the probabilistic forwarding of coded packets on two network topologies: binary trees and square grids. For trees, our analysis shows that for fixed $k$ , the expected total number of transmissions increases with $n$. On the other hand, on grids, a judicious choice of $n$ significantly reduces the expected total number of transmissions needed for a near-broadcast. Behaviour similar to that of the grid is also observed in other well-connected network topologies such as random geometric graphs and random regular graphs. [ABSTRACT FROM AUTHOR]

Communications and routing protocols for vehicular ad-hoc networks (VANETs) are affected by dynamic vehicular constraints like high mobility, efficient delivery, reliable path, and trustworthiness. We propose a novel “VAR2” scheme that enables autonomous trust and selects routes with the longest connectivity time to efficiently deliver messages. In multi-hop and multi-path VANETs, the proposed scheme ensures reliability by selecting compatible and trustworthy routes with minimum additional communications. Our Python simulations on sparse and dense SUMO traffic traces show that the proposed VAR2 routes have 100~400s connectivity with only 3~4 hops and achieve 6~15% PDR, which are comparatively more efficient results than that of existing schemes. [ABSTRACT FROM AUTHOR]

This letter proposes a new approach to the reliability analysis of IEEE 802.11 one-dimensional (1-D) broadcast mobile ad hoc networks. The approach finds a simple and effective way to derive the distribution of signal-to-interference-to-noise ratio (SINR) on each receiver, which is required for evaluation of the reliability metrics and the channel capacity. Having observed that the effective interference area depends on a given SINR threshold, the SINR distribution derivation is converted to estimating the SINR threshold related interference areas that are dynamically changed in a communication channel. The analysis is applied to two network configurations for example, and it is cross validated by the extensive simulations. Compared with the previous models, the new approach is more general, more precise, and faster. [ABSTRACT FROM AUTHOR]

In this letter, we study wireless broadcast schemes based on online fountain codes. We first propose and analyze an online fountain code based-broadcast scheme, where the coded symbol degree is updated based on the decoding states of all receivers. Then we propose and analyze an improved broadcast scheme by taking advantage of the received coded symbols that are not immediately decodable. Simulation results demonstrate that our proposed scheme has better performance compared to other broadcast schemes based on feedback fountain codes. [ABSTRACT FROM AUTHOR]

Fog computing is a disruptive technology in the big data analytics area. Smartphone users and organizations use cellular services, which can support decision-making in disaster scenarios with the data that have been collected. Nevertheless, the regular communication infrastructure can be damaged by disasters. NTT provided an easily deployable solution to construct an emergency communication network (ECN), but ECNs are slow at propagating big data due to their limited transmission capabilities. One major issue is efficiently integrating data processing in the ECN to realize effective data processing and transmission in disaster scenarios. In this paper, we present—a detailed mathematical model to represent data processing and transmission in an ECN fog network; an NP-hard proof for the problem of optimizing the overall delay; and a novel algorithm to minimize the overall delay for wirelessly-networked disaster areas that can be run in real-time. We evaluated the systems across various transmission speeds, processing speeds, and network sizes. We also tested the calculation time, accuracy, and percent age error of the systems. Through evaluation, we found that the proposed disaster area adaptive delay minimization (DAADM) algorithm showed to have a reduced overall delay over various network sizes when compared with some conventional solutions. The proposed DAADM algorithm matched the curve of the genetic algorithm (GA), even if its results did not yield delays as small as the GA. The DAADM had one major advantage over the GA which was the processing time, which allows the DAADM to be implemented in a real-time system, where a GA solution would take far too much time.

Reconfigurable wireless networks, such as ad hoc or wireless sensor networks, do not rely on fixed infrastructure. Nodes must cooperate in the multi-hop routing process. This dynamic and open nature make reconfigurable networks vulnerable to routing attacks that could degrade significantly network performance. Intrusion detection systems consist of a set of techniques designed to identify hostile behavior. In this paper, there are several approaches for intrusion detection in reconfigurable network routing such as collaborative, statistical, or machine learning-based techniques. In this paper, we introduce a new approach to intrusion detection for reconfigurable network routing based on linear systems theory. Using this approach, we can discriminate routing attacks by considering the system's z-plane poles. The z-plane can be thought of as a two dimensional feature space that arises naturally. It is independent of the number of network attack detection metrics and does not require extra dimensionality reduction. Two different host-based intrusion detection techniques, inspired by this new linear systems perspective, are presented and analyzed through a case study. The case study considers the effects of attack severity and node mobility to the attack detection performance. High attack detection accuracy was obtained without increasing packet overhead for both techniques by analyzing locally available information.

In ad hoc networks that allow devices to dynamically configure networks via wireless communication, a secure routing protocol is a technology that guarantees the validity of routing with the use of cryptographic authentication. The secure DSR with ID-based sequential aggregate signatures (ISDSR) is a recently introduced secure routing protocol with “cryptographically compact chain,” where each device signs both the routing information and signatures generated by the previous device without increasing the size of signatures and the ID information propagated via packets can be utilized as a public key. However, ISDSR requires communication with a centralized key generation center (KGC), and thus a new device may experience difficulties in joining the protocol. Moreover, the implementation results of ISDSR have not been presented. In this work, we present ISDSR+, a new secure routing protocol without a centralized KGC that uses distributed key generation and the conventional features of ISDSR. ISDSR+ relies on a novel signature scheme where any node can receive a secret key as long as the number of available KGCs is more than a certain threshold. In other words, even if several KGCs are unavailable, the remaining available KGCs can still provide secret keys. We furthermore show promising results of ISDSR+ via a prototype implementation on Raspberry Pis. The results show the computational time of 0.1 s for both the secret key generation and the round trip time (RTT) of routing information under reasonable settings. The RTT of ISDSR+ is better than that of a naive secure routing protocol with RSA signatures.

Vehicular ad hoc network (VANET) is a specialized form of wireless network that is solely intended for collaboration between vehicles. Several studies have shown that standard routing protocols cannot be implemented in VANETs because of their unique characteristics such as their significant count of vehicles on the network and the rapid evolution of the network’s design. Because VANET communication links are broken very frequently, it is necessary to address the routing consistency of these highly dynamic networks. The transmission of VANET data may result in a substantial amount of overhead in the routing process; thus, it is vital to address the issue of overhead to enhance the overall network performance. The proposed protocol named compacted area with effective links (CAEL) is designed to focus on decreasing overhead to achieve an enhancement in PDR performance inside the network. The communication between selected nodes that have been judged to be dependable in terms of geographical location and appropriate existing links between vehicles is focused on achieving this goal. With the inclusion of the reliability factor, it is possible to complete the important step of removing extraneous nodes, with the selection of the trustworthy nodes being made based on the link expiration time during the whole routing procedure. When compared to our previously published protocols, i.e., Dynamic Trilateral Enrollment (DyTE) and Reliable Group of Vehicles (RGoV), the results of the simulations demonstrate that CAEL has achieved an overall improvement in the performance of the network.

Purpose - This paper aims to introduce vehicular network platform, routing and broadcasting methods and vehicular positioning enhancement technology, which are three aspects of the applications of intelligent computing in vehicular networks. From this paper, the role of intelligent algorithm in the field of transportation and the vehicular networks can be understood. Design/methodology/approach - In this paper, the authors introduce three different methods in three layers of vehicle networking, which are data cleaning based on machine learning, routing algorithm based on epidemic model and cooperative localization algorithm based on the connect vehicles. Findings - In Section 2, a novel classification-based framework is proposed to efficiently assess the data quality and screen out the abnormal vehicles in database. In Section 3, the authors can find when traffic conditions varied from free flow to congestion, the number of message copies increased dramatically and the reachability also improved. The error of vehicle positioning is reduced by 35.39% based on the CV-IMM-EKF in Section 4. Finally, it can be concluded that the intelligent computing in the vehicle network system is effective, and it will improve the development of the car networking system. Originality/value - This paper reviews the research of intelligent algorithms in three related areas of vehicle networking. In the field of vehicle networking, these research results are conducive to promoting data processing and algorithm optimization, and it may lay the foundation for the new methods.

This study seeks to conduct analytical investigation into Congestion Control models to determine the effects of parameters inherent in mitigating traffic flow density in a congested network. The spatial temporal variations in the value of λ affects vehicular traffic flow. This study proposed a Congestion Control Model and perform simulation in MATLAB. In this model, vehicular density and number of vehicles were held constant while varying the value of λ from 1 to 10. The simulation result reveals the vehicle trajectories as the value of λ increases with time. The outcome of this study indicates that there is no need increasing the value of λ beyond 12, since further increases would only increase the number of vehicles leading to traffic jam. In principle, it is very important to use 1≤ λ ≤12 in designing traffic models in VANETs. The analytical result proved that the Congestion Control Model for the four-lane may be the most appropriate model to be adopted and use in designing VANETs networks.

Recently, flying ad hoc networks (FANETs) have been broadly applied to various civilian and military applications. Medium access control (MAC) protocols have attracted significant attention because of their impact on overall network performance. Owing to peculiar features such as high mobility and dynamic topology, however, the design of a MAC protocol for FANETs confronts challenges. Several MAC protocols for FANETs have been reported in literature. In early MAC protocols for FANETs, delay, throughput, and collision detection were the key design concerns. Recently, however, the design of an energy-efficient MAC protocol has become a new research focus. To the best of the authors’ knowledge, there exists no survey on MAC protocols for FANETs. This study extensively investigates the existing MAC protocols for FANETs. In this paper, the MAC design issues in FANETs are presented first. Subsequently, the existing MAC protocols are reviewed and discussed from the perspective of major features, operational principles, advantages, and limitations. The MAC protocols are then qualitatively compared in terms of major features, characteristics, and performance factors. Furthermore, open issues and research challenges are summarized and discussed. [ABSTRACT FROM AUTHOR]

In this paper, a link-layer synchronization and medium access control (MAC) protocol for very-high-speed wireless communication networks in the Terahertz (THz) band is presented. The protocol relies on a receiver-initiated handshake to guarantee synchronization between transmitter and receiver. Two scenarios are considered, namely, a macroscale scenario, where nodes utilize rotating directional antennas to periodically sweep the space while overcoming the distance problem at THz frequencies, and a nanoscale scenario, where nano-devices require energy harvesting systems to operate. Both scenarios are implemented on a centralized and an ad-hoc network architecture. A carrier-based physical layer is considered for the macro-scenario, whereas the physical layer for the nano-scenario is based on a femtosecond-long pulse-based modulation scheme with packet interleaving. The performance of the proposed MAC protocol is analytically investigated in terms of delay, throughput and probability of successful packet delivery, and compared to that of an adapted Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) with and without handshake. The results are validated by means of extensive simulations with ns-3, in which all the necessary THz elements have been implemented. The results show that the proposed protocol can maximize the successful packet delivery probability without compromising the achievable throughput in THz-band communication networks. [ABSTRACT FROM AUTHOR]

In this study, Internet of Things (IoT) based firing zone monitoring and firefighter surveillance system (IoT-FFM) is developed with IEEE 802.15.6 standard and Ad hoc On-Demand Distance Vector (AODV) routing protocol. Fireground coordinates, fire temperature, and gas type in the environment are collected, and also, respiration rate, heart rate, pulse oximeter of the firefighter, and nearest firefighter number are gathered with the proposed IoT-FFM wireless communication system. The gathered data are saved in InfluxDB database with Node-RED programming tool and monitored in real-time with Grafana monitoring system at the remote control center. End-to-end delay, throughput, and energy consumption parameters are considered for performance evaluation of the IoT-FFM. The Nakagami channel model is used for a more realistic wireless environment and compared with the Free Path Loss model. Thanks to the IoT-FFM, the health conditions of firefighters can be kept under control, and information about the fire zone can be mapped, and the fire can be intervened appropriately. [ABSTRACT FROM AUTHOR]

With the technology of data storage and shared services in the cloud, users can easily share data or revoke from their groups. To ensure the accuracy of the shared data, the key is used for group users to calculate the authenticators of the shared data and audit the data's integrity remotely. However, high-speed mobile terminals have posed challenges to key management in Vehicle Ad-hoc networks (VANETs). Besides, to maintain the integrity of the shared data, the computation and communication overheads must be increased in the revocation process when a vehicle user is removed from a group. For such, a new shared data auditing scheme is proposed in this paper, which supports user revocation by combining the existing certificateless signcryption method with a fog architecture. This scheme improves the efficiency of auditing and user revocation since it reduces many time-consuming operations, as well as features such as public auditing, mutual authentication, efficient and secure revocation are presented. Security analysis and experimental results demonstrate that the proposed scheme is both correct and safe, has more comprehensive functions and better efficiency than other existing ones. [ABSTRACT FROM AUTHOR]

An intelligent transportation system in a metropolitan area is dynamic and prone to many external and internal attacks. These attacks result into modification, controlling, accessing, and altering private and public information of transport depots and their communicating agents. In this article, we have proposed a novel agent pseudonymous authentication with a conditional privacy preservation scheme in a metropolitan area. The proposed scheme utilizes identity-based encryption and a Boneh–Lynn–Shacham signature scheme for authentication, pseudonyms based for privacy preservation, and public key cryptography for pseudonyms generation. It achieves privacy preservation of depot's information. The primary objective of the proposed scheme is to protect privacy of communicating agents of transport depots during exchange of information (such as surplus and deficit vehicles and vehicles dispatch allocation and revocation). The proposed scheme is capable of avoiding the presence of impersonate genuine and malicious agents at transport depot. The proposed scheme uses an emergent intelligence technique for collecting, sharing, and analyzing transportation information. In addition, it also takes dynamic decisions for protecting privacy of transport depot's communicating agents. In this article, first, formal security proofs of the proposed scheme has been carried out using ProVerif tool, and second, Crypto++ package is used for the experimental and performance analysis. The experimental results reveal that the proposed scheme efficiently preserves privacy of transport depots’ communicating agents. [ABSTRACT FROM AUTHOR]

Smart, and green cities impose stringent requirements on spectral efficiency (SE), and energy efficiency (EE) of vehicular networks. For the current vehicular ad-hoc networks (VANETs), vehicle's mobility leads to rapid topology changes, and high channel uncertainty. However, clustering schemes for establishing stable clusters, and robust power control (RPC) combating with channel fluctuation are investigated independently. In this paper, joint clustering, and RPC schemes are proposed to optimize the SE, and EE of the involved VANETs. Via the same fixed-length slot, the synchronized interference constraints of cluster heads (CHs) are formed, and offer conditions for RPC. Due to the random channel fluctuations, all CHs’ synchronized interference constraints are formulated as probability constraints. Besides, a pricing-based utility which avoids the separate optimization between SE, and EE is introduced, and the price's impact on the tradeoff between them is involved. Since the probability constraints are intractable, and the unified utility is nonconvex, the Bernstein approximation, and successive convex approximation (SCA) are used to transform the problem into a tractable convex one. Through dual decomposition, two RPC algorithms are proposed to determine the optimal solutions for the fixed price C, and the optimal price C*, respectively. Numerical simulations are used to evaluate the algorithmic performances in high-dynamic system, and the results show that the proposed algorithms are effective. The validity of the clustering method, and the proposed RPC scheme is further verified by comparisons. [ABSTRACT FROM AUTHOR]

Millimeter Wave (mmWave) communications are evolving as a potential and promising technology to address the ever increasing mobile data rate requirements. This paper addresses fair scheduling in directional antenna based mmWave wireless personal and local area networks with non-uniform traffic demand. Due to their small wavelength, mmWave signals are susceptible to blockage. The proposed fair schedulers handle the link blockage problem through relaying, and are capable of providing end-to-end fair bandwidth allocation to relay flows. To achieve differentiated and fair service allocation to various regions of the network while using only limited flow related information, a service tag based scheduler is proposed in this paper. Then, the performance bounds on the minimum throughput and unfairness of this scheduler are obtained. To approximate the performance of the service tag based scheduler while minimizing the control overhead, a heuristic fair scheduler is also proposed. Results from extensive simulations conducted in a mmWave WPAN deployed to support high data rate applications show the performance advantages of the proposed schedulers, compared to existing fair schedulers, in terms of throughput and fairness. [ABSTRACT FROM AUTHOR]

With the popularization of smart devices and social platforms (Facebook, Instagram and etc.), content transmission is becoming an increasingly prevalent form of human interaction with transmission time being a critical issue in miscellaneous applications. Extensive works have been devoted to this problem with the typical assumption that the network is non-evolving. In contrast, real-world networks which the transmission runs through are widely observed to be evolving over time and thus display distinctive properties. In this paper, we make the first study of content transmission in evolving networks. Particularly, we focus on the specific transmission time of the content, which is an important performance metric. For a comprehensive analysis, we consider both static and mobile cases. The network evolves in the following sense: each new user randomly chooses a geographic location while establishing social relations with existing users according to the evolving model, called Affiliation Networks. The transmission scheme running on the network exploits both social relationships and geographic information. While revealing the microscopic property of evolving social networks as the basis, in both static and mobile cases we manage to bound the transmission time in evolving networks which departs from results in non-evolving networks. In both cases, we find that the transmission time in evolving networks is smaller than the non-evolving counterpart under our scheme, and the gap is constantly increasing over time. Especially, the mobile case obtains such gain with less geographic knowledge. The theoretical findings are confirmed by experiments on both synthetic and real networks under different settings. We find that transmission time in evolving networks is smaller than non-evolving counterparts under the tested settings, and our proposed algorithms outperform the baselines. [ABSTRACT FROM AUTHOR]

Preventing the source-destination network flow information from being disclosed is pivotal for anonymous wireless network applications. However, the advance of network inference, which is able to obtain the flow information without directly measuring it, poses severe challenges towards this goal. Randomized routing is capable of hiding the flow information by injecting substantial errors to the network inference process. In this paper, we systematically study the behavior of randomized routing protocols, and categorize them into three templates, $k$ -random-relay, $k$ -random-neighbor and $k$ -random-path based on their routing behaviors. We propose technical models to characterize these templates in terms of their induced inference errors and their delay costs. We also use simulations to validate the theoretical results. Our work provides the first systematic study on understanding both the benefit and the cost of using randomized routing to hide the flow information in wireless networks. [ABSTRACT FROM AUTHOR]

The idea of aggregate signcryption was first proposed by Selvi. The aggregation process reduces the communication overhead and hence, it is efficient in low‐bandwidth communication networks such as wireless sensor networks and vehicular ad‐hoc network VANET. The goal of this study is to propose a secure provably identity based aggregate signcryption scheme ID‐ASC without pairings over the elliptic curve cryptography. The proposed scheme is provable secure against confidentiality and unforgeability under random oracle model. Moreover, the proposed ID‐ASC reduced the computational complexity when compared to other schemes in literature. [ABSTRACT FROM AUTHOR]

A wireless ad hoc network consisting of one‐hoping relay channel and some interfering nodes with possible arbitrary correlation between wireless channels coefficients is studied. By exploiting a novel approach called Copula theory, enabling us to describe joint probability distribution function for arbitrarily correlated random variables, the authors derive a closed‐form expression for success probability in different dependence structures of channels. Specifically, by applying the Farlie–Gumbel–Morgenstern (FGM) Copula and the popular Archimedean (Clayton, Gumbel, and Frank) Copulas, they analyse the network performance in terms of success probability, and show that the channels correlation improves the performance of success probability so that whenever the dependence structure tends to higher values, the performance improvement is increased. Besides, it is found that the investigation of channel correlation effects by FGM Copula is more tangible compared to Archimedean Copulas. Finally, the efficiency of the analytical results is illustrated numerically. [ABSTRACT FROM AUTHOR]

In recent years, the need for high security with reliability in the wireless network has tremendously been increased. To provide high security in reliable networks, mobile ad hoc networks (MANETs) play a top role, like open network boundary, distributed network, and fast and quick implementation. By expanding the technology, the MANET faces a number of security challenges due to self-configuration and maintenance capabilities. Besides, traditional security solutions for wired networks are ineffective and inefficient because of the nature of highly dynamic and resource-constrained MANETs. In this paper, the researchers focus on improving reliable data transmission with high security in the MANET using an optimization technique. In the proposed MANET system, the nodes are clustered by utilizing an energy-efficient routing protocol. Then, the modified discrete particle swarm optimization is used to select the optimal cluster head. A secured routing protocol and a signcryption model can be used to improve the transmission security of the reliable MANET. The signcryption algorithm encrypts the digital signature, which can enhance the overall efficiency and confidentiality. The security-based analysis is performed on the basis of packet delivery ratio, energy consumption, network lifetime, and throughput. Finally, the result demonstrates that the MANET with optimization techniques achieves a high transmission rate and improves the reliable data security. [ABSTRACT FROM AUTHOR]

In recent years, the issue of location verification system (LVS) has received significant attention in wireless communication networks, especially in Intelligent Transportation Systems (ITSs) and vehicular technology, where the location information is important for users’ safety and security. In this article, we consider a vehicular network and analyze a more general Information Theoretic (ITc) study of LVS, specifically, aiming at finding an optimum decision threshold for detection a spoofed location and increasing the system ability in correctly detecting malicious users. For this purpose, we propose different information theoretic measures (Renyi divergence, Renyi mutual information, Kullback–Leibler divergence, Kullback–Leibler mutual information and Jensen-Shannon divergence) for identifying malicious user. Simulation results and comparison between proposed measures show that the optimum decision threshold can be achieved by applying the Jensen-Shannon divergence measure. [ABSTRACT FROM AUTHOR]

Futuristic communication network formed by autonomously operated, unmanned aerial vehicles, has piqued researchers interests in highly mobile wireless networks. Exchanging safety critical information, with low latency and high throughput, in such systems is of paramount importance. We study the broadcast capacity and minimum delay scaling laws for such highly mobile wireless networks, in which each node has to disseminate packets to all other nodes in the network. In particular, we consider a cell partitioned network under an IID mobility model, in which each node chooses a new position at random, every time slot. We derive scaling laws for broadcast capacity and minimum delay as a function of the network size. We propose a simple first-come-first-serve flooding scheme, which nearly achieve both capacity and minimum delay scaling. Thus, in contrast to what has been speculated in the literature, we show that there is nearly no tradeoff between capacity and delay. Our results also show that high mobility does not improve broadcast capacity. Our analysis makes use of the theory of Markov Evolving Graphs (MEGs), and develops two new bounds on flooding time in MEGs by relaxing the previously required expander property assumption. Simulation results verify our analysis, and throw up interesting open problems. [ABSTRACT FROM AUTHOR]

Water distribution systems have a safety-critical role and are vulnerable to a range of intentional threats. Committing to emergency preparedness, critical and missing metrics are the residual water storage in tanks and the estimated operative autonomy (in hours). This article presents a high-fidelity simulator developed to calculate the mentioned metrics and to evaluate the impact of adverse events, such as faults and/or cyber-attacks on a real water distribution system. This simulator utilizes a refined model of the network for accurate results; a commercial simulator to trustworthily solve the hydraulic equations; and an ad-hoc module to follow the evolution in time of the event. A large real water distribution network has been modeled thanks to real data provided by an operator and used as a case study. A comprehensive impact analysis of the single failure has been carried out. Results show that the simulator has been able to elicit unforeseen use cases and correctly quantify the required metrics. This article has been implemented in the framework of the European project ATENA. [ABSTRACT FROM AUTHOR]

Managing trust in mobile networks necessitates dealing with uncertainty, resulting from incomplete, duplicate or conflicting evidence. In this work, possibility theory is used to deal with uncertainty, and a trust model is developed that includes the network nodes’ integrity, their competency and that of the connections among them. Evidence obtained by direct observation (‘passive’) is integrated with that solicited from other nodes (‘active’) to generate possibility distributions, or trust profiles, that can be combined, updated and discounted. Simulations of mobile ad hoc networks show that the inclusion of these trust profiles in routing decisions conserves network resources and limits data exposure by directing packets over reliable links through uncompromised nodes. Possibility theory enables the information gain provided by different forms of evidence to be evaluated, and this is used to explore the benefits of different sources of active trust evidence. It is seen that passive evidence is not sufficient to maintain trust profiles with low uncertainty, and that active trust evidence obtained by authentication requests provides higher informational value than that received using reputation solicitation. [ABSTRACT FROM AUTHOR]

Protecting the location privacy is one of the main challenges in vehicular ad-hoc networks (VANETs). Although, standardization bodies, such as IEEE and ETSI, have adopted a pseudonym-based scheme as a solution for this problem, an efficient pseudonym changing and management is still an open issue. In this paper, we propose PRIVANET, a complete and efficient pseudonym changing and management framework. The PRIVANET has a hierarchical structure and considers the vehicular geographic area as a grid. Each cell of this grid contains one or many logical zones, called vehicular location privacy zones (VLPZs). These zones can easily be deployed over the widespread roadside infrastructures (RIs), such as gas stations, to provide a secure changing and management of pseudonyms. The proposed framework consists of different building blocks: 1) an effective VLPZ-based pseudonym changing strategy; 2) a reputation-based mechanism to motivate selfish vehicles to enter VLPZs; 3) an adapted user-centric privacy model; 4) a secure hybrid mechanism for the distribution of pseudonyms sets and CRLs; 5) a method to generate the IP and MAC addresses from the pseudonym; 6) a stochastic model to estimate the number of VLPZs required at a given cell; and 7) a mathematical model for an optimal placement of the VLPZs over RIs to reduce the transportation cost of vehicles in terms of time. An extensive simulation study using a realistic map and with real traffic mobility measurements is carried out to evaluate and validate the performance of the PRIVANET. The simulation results demonstrate the effectiveness of the proposed framework. [ABSTRACT FROM AUTHOR]

Routing selection and supporting Quality of Service (QoS) are fundamental problems in Mobile Ad Hoc Network (MANET). Many different protocols have been proposed in the literature and some performance simulations are made to address this challenging task. This paper discusses the performance evaluation and comparison of two typical routing protocols; Ad Hoc On-Demand Distance Vector (AODV) and Destination-Sequenced Distance- Vector (DSDV) based on measuring the power consumption in network with varing of the QoS parameters. In this paper, we have studied and analyzed the impact of variations in QoS parameter combined with the choice of routing protocol, on network performance. The network performance is measured in terms of average throughput, packet delivery ratio (PDR), average jitter and energy consumption. The simulations are carried out in NS-3. The simulation results show that DSDV and AODV routing protocols are less energy efficient. The main aim of this paper is to highlight the directions for the future design of routing protocol which would be better than the existing ones in terms of energy utilization and delivery ratio. [ABSTRACT FROM AUTHOR]

Mobile ad-hoc cloud can exploit the computing resources (e.g., smartphones, vehicles, and unmanned systems) scattered in the mobile environment to form a self-organized ad-hoc local resource pool for providing opportunistic computing services. However, the highly dynamic and distributed characteristics of the mobile ad-hoc network environment bring great challenges in privacy and security in such opportunistic resource sharing. In this article, we first discuss the attractive features of blockchain for providing such resource sharing services in the mobile ad-hoc network environment in a secure and trustful way and then discuss the problems caused when using existing consensus protocols in such an environment. We accordingly devise a blockchain based trustful mobile ad-hoc cloud architecture, AdChain cloud. We describe the functions at different layers in this architecture, including the network layer, blockchain layer, and smart contract layer. To adapt to the high dynamics of the mobile ad-hoc network environment, we design a stability-aware consensus protocol at the blockchain layer. Simulation results show that our solution can achieve improved performance as compared with existing work. [ABSTRACT FROM AUTHOR]

The rapid development of Space-Air-Ground integrated network, IoT, and swarm-based robotic systems has promoted the transformation of traditional single drone toward drone swarm. Compared to the traditional single drone, drone swarm can collaboratively complete complex tasks with higher efficiency and lower cost, especially in harsh environments. Communication and networking techniques are essential to enabling collaborate information sharing, coordinating multiple drones, and achieving autonomous drone swarm. However, the traditional communication technologies on fixed networks or slowly moving networks cannot address the unique characteristics of drone swarm, such as high dynamic topology, intermittent links and capability constraints. Two kinds of networking techniques fit for different drone swarm tasks are investigated, and the performance indexes of several wireless technologies suitable for drone swarm are also analyzed. Considering that drone swarm would usually be deployed in dire circumstances and the network may get frequently partitioned, the robustness of drone swarm becomes crucial. Based on the Molloy-Reed criterion, a swarm intelligent robust solution for drone swarm is proposed by using the consensus method and grey prediction, which has advantages of small overhead and local information exchanging. The simulation results corroborate that the robustness to node failure of drone swarm can be effectively improved by the proposed method. [ABSTRACT FROM AUTHOR]

Due to the requirement of real time controlling on the vehicular ad-hoc networks (VANETs), the security measure should be fast, lightweight, and strong. In this paper, we investigate the secure communication between the on-board unit and the roadside unit which has strong computing ability to remedy the insufficient computing power of on-board unit. The novel schemes are developed to guarantee both security and energy harvest. Specifically, a muti-antenna roadside unit (PT) conveys a secret message to a muti-antenna primary on-board unit (PR) intercepted by multiple muti-antenna adversaries (Eves). Simultaneously, a secondary roadside unit (ST) adopts simultaneous wireless information and power transfer (SWIPT) strategy to send secret-free data embeded with energy-carrying artificial noise (AN) to its service subscriber (SR), by which secrecy guarantee is provided for the primary on-board unit and the quality of service (QoS) is satisfied, i.e., data traffic and harvested energy. Technically, considering the secondary link's data transmission rate, harvested energy, and transmit power, we propose joint power allocation designs for the nonconvex secrecy rate maximization (SRM) problems under either perfect channel state information (CSI) or norm-bounded channel uncertainty model. Simulation results show that the proposed secondary link-aided secrecy designs can achieve better performance in terms of secrecy rate and energy efficiency. [ABSTRACT FROM AUTHOR]

The performance of existing coded caching schemes is sensitive to the worst channel quality, a problem which is exacerbated when communicating over fading channels. In this paper, we address this limitation in the following manner: in short-term, we allow transmissions to subsets of users with good channel quality, avoiding users with fades, while in long-term we ensure fairness among users. Our online scheme combines (i) the classical decentralized coded caching scheme with (ii) joint scheduling and power control for the fading broadcast channel, as well as (iii) congestion control for ensuring the optimal long-term average performance. We prove that our online delivery scheme maximizes the alpha-fair utility among all schemes restricted to decentralized placement. By tuning the value of alpha, the proposed scheme can achieve different operating points on the average delivery rate region and tune performance according to an operator’s choice. We demonstrate via simulations that our scheme outperforms two baseline schemes: (a) standard coded caching with multicast transmission, limited by the worst channel user yet exploiting the global caching gain; (b) opportunistic scheduling with unicast transmissions exploiting the fading diversity but limited to local caching gain. [ABSTRACT FROM AUTHOR]

The ever-increasing demand for media streaming together with limited backhaul capacity renders developing efficient file-delivery methods imperative. One such method is femto-caching, which, despite its great potential, imposes several challenges such as efficient resource management. We study a resource allocation problem for joint caching and transmission in small cell networks, where the system operates in two consecutive phases: (i) cache placement, and (ii) joint file- and transmit power selection followed by broadcasting. We define the utility of every small base station in terms of the number of successful reconstructions per unit of transmission power. We then formulate the problem as to select a file from the cache together with a transmission power level for every broadcast round so that the accumulated utility over the horizon is maximized. The former problem boils down to a stochastic knapsack problem, and we cast the latter as a multi-armed bandit problem. We develop a solution to each problem and provide theoretical and numerical evaluations. In contrast to the state-of-the-art research, the proposed approach is especially suitable for networks with time-variant statistical properties. Moreover, it is applicable and operates well even when no initial information about the statistical characteristics of the random parameters such as file popularity and channel quality is available. [ABSTRACT FROM AUTHOR]

The ad hoc network is an emerging wireless communication technology. Recently, the reliability of ad hoc networks has attracted increasing attention in the literature. In this paper, the reliability of such networks is analyzed by incorporating the impacts of node failures and interference, because node failures usually obstruct the achievement of the intended function of a network, and interference is a key factor that degenerates the communication quality. We consider a general case that an ad hoc network is functional if at least k arbitrary nodes are operational and connected. Accordingly, two novel reliability indices, the generalized k-terminal reliability and the average generalized k-terminal reliability, are proposed, and their calculation methods are provided based on the Laplace transformation technique and the graph theory. For optimizing the design of an ad hoc network, a multiobjective optimization problem is investigated to maximize the reliability level and minimize the cost. The optimization problem is handled by the weighted sum method, and the most suitable solution is selected by the fuzzy satisfying approach. Finally, a numerical example is given to demonstrate the application of the proposed methods. [ABSTRACT FROM AUTHOR]

In the event of a natural disaster, communications infrastructure plays an important role in organizing effective rescue services. However, the infrastructure-based communications are often affected during severe disaster events such as earthquakes, landslides, floods, and storm surges. Addressing this issue, the article proposes a novel drone-based cellular infrastructure to revive necessary communications for out-of-coverage user equipment (UE) which is in the disaster area. In particular, a matching game algorithm is proposed using one-to-many approach wherein several drone small cells (DSCs) are deployed to match different UEs to reach a stable connection with optimal throughput. In addition, a medium access control framework is then developed to optimize emergency and high priority communications initiated from the rescue workers and vulnerable individuals. The simulation results show that the throughput for the out-of-coverage UEs are significantly improved when the DSCs are deployed in public safety network while the channel access delay is also notably reduced for emergency communications within the affected areas. [ABSTRACT FROM AUTHOR]

Clustering based vehicular Ad-hoc Network (CAN) is being considered as the most viable solution to integrate milimeter wave (mmWave) and sub-6 GHz interface in vehicular communication. In CAN, the data path contains two cascaded links, mostly mmWave link for vehicular to vehicular (V2V) connectivity and sub-6 GHz link for vehicular to infrastructure (V2I) connectivity. In this letter, we have introduced diverted path approach (DPA) to enhance V2V communication reliability. In addition, the notion of back-up link has been introduced to enhance V2I communication reliability. Then, through simulation results, it is shown that DPA can significantly improve V2V communication reliability. Further, it is shown that the incorporation of both the proposed schemes with the existing CAN, significantly enhances the overall vehicular (V2V+V2I) communication reliability. [ABSTRACT FROM AUTHOR]

Communication problems in ad hoc wireless networks have been already widely studied under the SINR model, but a vast majority of results concern networks with constraints on connectivity, so called strongly-connected networks. In such networks, connectivity is defined based on highly reliable links, that is, where both ends are located far closer from their transmission boundaries. What happens if the network is not strongly-connected, e.g., it contains some long but still viable "shortcut links" connecting transmission boundaries? It is known that even a single broadcast in such ad hoc weakly-connected networks with uniform transmission powers requires Ω (n) communication rounds, where n is the number of nodes in the network. The best up-to-date (randomized) distributed algorithm, designed by Daum et al. [1] , accomplishes broadcast task in O (n log 2 ⁡ n) communication rounds with high probability. In this work, inspired by the work on broadcasting, we show a novel deterministic distributed implementation of token traversal — a fundamental tool in distributed systems — in the SINR model with uniform transmission powers and no restriction on connectivity. We show that it is efficient even in a very harsh model of weakly-connected networks without GPS, carrier sensing and other helping features. We apply this method to span a traversal tree and accomplish broadcast in O (n log ⁡ N) communication rounds, deterministically, provided nodes are equipped with unique IDs in the range [ 1 , N ] for some integer N ≥ n. This result implies an O (n log ⁡ n) -round randomized solution that does not require IDs, which improves the result from [1]. The lower bound Ω (n log ⁡ N) for deterministic algorithms proved in our work shows that our result is tight without randomization. Our implementation of token traversal routine, efficient in terms of time and memory, is based on a novel implicit algorithmic carrier sensing method and a new type of selectors, which might be of independent interest and applicable to other communication tasks in distributed ad hoc setting. [ABSTRACT FROM AUTHOR]