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Efforts to realize video streaming over Mobile Ad hoc Networks (MANETs) meet many challenges, which are addressed by different techniques. In the highly dynamic and unpredictable environment of MANETs, cross-layer mechanisms seem to be the most suitable for optimising video streaming. This paper presents a survey of 44 studied papers on the area, comparing tools, parameters and metrics used for their evaluation. It also indicatively describes in more detail some of these proposals. [ABSTRACT FROM PUBLISHER]

When a passenger in a vehicle wants to watch video during movement, he may request video through cellular network, e.g., 3G or 3.5G network. However, due to the characteristics of vehicular networks, the limited bandwidth of 3G/3.5G network is not enough to support high resolution or high video quality. In order to improve the quality of video playback, this vehicle, which is defined as requester in this paper, may try to ask other members of the same fleet to download video cooperatively. In other words, other members would download parts of requested video through their 3G/3.5G network individually and then forward video data hop by hop to the requester using the DSRC ad-hoc network. In order to smooth the DSRC ad-hoc network, we propose and discuss two k-hop packet forwarding schemes for the aforementioned cooperative video streaming over vehicular networks in this paper. Each intermediary node of the forwarding route must decide how to deliver buffered video data through the limited DSRC network. Finally, the NS2 simulation tool is adopted to evaluate the proposed schemes. Based on the simulation results, the Playback Priority First (PPF) scheme is performed better than the First-In First-Out (FIFO) scheme. [ABSTRACT FROM PUBLISHER]

The technology of sensor devices and networks is evolving rapidly with significant advances in size, processing power, memory, and energy efficiency. In addition, the cost of sensors is constantly decreasing making it possible to use large quantities of these sensors in a wide variety of important applications in environmental, military, commercial, health care, and other fields. In order to monitor certain types of infrastructures. Many of these applications involve lining up the sensors in a linear form, making a special class of these networks which are defined in this work as Linear Sensor Networks (LSNs). In a previous paper, we introduced the concept of LSNs along with a classification of the different types of LSNs, a sample of their applications and the motivation for designing specialized protocols that take advantage of the linearity of the network to enhance their communication efficiency, reliability, fault tolerance, energy savings, and network lifetime. This paper presents a distributed topology discovery algorithm for a hierarchical two-level LSNs. New definitions for important structure and design parameters are introduced. The proposed protocol allows the nodes to construct an ordered list of the nodes in the network which can be used to create an efficient routing table. In addition, it would be useful for simplifying, and enhancing the reliability and robustness of the routing process by taking advantage of the linear alignments of the nodes. Furthermore, the protocol does not require the nodes to have location detection capabilities such as GPS, which would lead to a more complex design and higher cost of the sensor nodes. [ABSTRACT FROM PUBLISHER]

Self organizing mobile Ad-Hoc networks have gained much attention in the last decade particularly due to their ease of deployment in war zones and natural disasters. Because of the fact that the Ad-Hoc network is a virtual network created by the participating nodes, this approach can be applied to remote areas with no fixed networking capability, and is ideal for coordination in remote locations. Considering the sophistication of equipment capable of handling MIMO techniques and inbuilt GPS receivers, a simple two-stage method of forwarding the message is proposed in this paper. A low frequency broadcast containing GPS coordinates of the nodes is used for node discovery which is then followed by a directional narrow beam at higher frequency for data transfer. The knowledge of GPS location combined with directional transmission is expected to increase the performance of the network. The intent of the paper is to propose a simplified location-based Ad-Hoc routing mechanism and to examine its performance when combined with MIMO space time coding technique. The space time codes are evaluated over a Flat Slow Fading channel using various modulation schemes. The basic premise of the proposed scheme is simplicity and robustness. [ABSTRACT FROM PUBLISHER]

The main study of traditional probability coverage problem in wireless sensor networks (WSNs) is aiming at two-dimensional space, however, most practical applications of wireless sensor network is placed in a three-dimensional sensor networks. Therefore, probability model is introduced for three-dimensional WSNs. This paper presents a method that using Voronoi divide to control the Scheduling of the probability model nodes in the target area. Also, a coverage control algorithm based on probability model (PMCCA) is proposed. We verify the effectiveness and the practice of PMCCA algorithm by comparing PMCCA algorithm to another algorithm in simulation experiment. [ABSTRACT FROM PUBLISHER]

This paper proposes a social distribution mechanism for finding, connecting and propagating contents in social networks using context and communication history of users together with meta information about the content. The proposed mechanism operates by propagating invitation messages to a prioritized group of users to build up an ad-hoc social network from the original social network while at the same time preventing spamming the users with unwanted invitation messages. The proposed mechanism makes it possible to implement and deploy a wide variety of services targeting the specific needs of a user. As a proof-of-concept, the paper shows how the proposed social distribution mechanism can be used to invite users to a shared space, which can contain various kinds of collaboration tools allowing a group of users to communicate and solve problems together. In order to investigate the efficiency of the proposed mechanism, the paper also presents result from a simulation study. The result shows that the social distribution mechanism should consider both social strength and context for propagating social media contents as some of the recipients may have equal interest of the social media but different level of trust about the originator. [ABSTRACT FROM PUBLISHER]

In this paper, we propose a novel end-to-end QoS guaranteed approach in Cognitive Mobile Ad hoc Networks (MANETs). A "black box" concept is adopted in our approach. End-to-end QoS condition is reflected by some typical QoS parameters, QoS guaranteed is implemented by the adjustments of the tunable parameters in protocol stack and the complex mechanism inside MANETs is transparent to applications and users. Multi-object genetic algorithm is used to deal with the relation between the QoS parameters and tunable parameters. QoS parameters form the fitness function and tunable parameters are encoded to the chromosome. This algorithm aims at searching the tunable parameter values which can optimize the QoS parameters. To verify the performance of genetic algorithm, its convergence is discussed in this paper. The whole approach is designed based on the cognitive method, which can enhance the adaption of our approach. In order to evaluate our approach, we design two groups of simulations based on different node mobile speed. The results show that our approach is effective and works well when topology change is rapid. [ABSTRACT FROM PUBLISHER]

The deployment of wireless ad-hoc networks compared to traditional infrastructure based networks offers several advantages such as fully distributed mobile operation, easy discovery of joining wireless devices and quick cheap network setup. The design of an effective routing protocol is one of the main challenges in the ad-hoc networking paradigm and the utilisation of an adequate link cost metric is essential. In this paper, the validity of ETX (Expected Transmission Count) as a link cost metric is investigated by studying its behaviour in real-time testbeds. In our performance evaluation, the ETX performance was studied in different distance scenarios. Subsequently, the main observation was that ETX values was not steady over time and usually fluctuated for a fixed scenario. Fluctuation in the ETX values affects a routing protocol in wrongly identifying the best path based on current ETX link cost and therefore new methods for ETX calculation are proposed in this paper. These different methods for ETX link cost calculation are compared with each other and the best link cost formula has been proposed as a new method for ETX calculation towards the end of the paper. The new ETX calculation is called AETX that could be used as a link cost in routing protocols that reflects the balance required between the consistency of a link metric value over time for fixed scenarios and the flexibility required to detect actual changes in link metric values. We finally provide conclusions about our research and some avenues for future work. [ABSTRACT FROM PUBLISHER]

Wireless mesh networks (WMNs) offer dependable and scalable solutions for services utilizing large bandwidth. Enhancement in the deployed number of applications based on wireless mesh networks necessitated a corresponding increased demand for higher bandwidth. This paper proposes a framework for effective management of bandwidth in WMNs making use of the concepts of cross layer design and ant colony methods. [ABSTRACT FROM PUBLISHER]

In the standard AODV protocol, the shortest path is always selected. But this shortest path is the easiest broken one. In this paper, we propose an improvement of AODV protocol called AMAODV(Adaptative Mobility aware AODV). This protocol is based on considering the distance and relative velocity between each node and one hop neighbor. Which permits to avoid losing route. Through the simulation, it is confirmed that this improvement has higher package delivery fraction than basic AODV protocol. [ABSTRACT FROM PUBLISHER]

Cluster-based wireless sensor network is considered in this paper. In wireless sensor network, every node wants to send data to a certain gateway node, or command node in case of military sensor network. Cluster-based communication enables effective power control, while the power budget of wireless sensor nodes is limited. In the conventional clustering algorithm, there is the cluster header node which has comparatively large capacity. However, in most cases, every node has the same power budget and all nodes behave symmetrically. It is necessary to design cluster based on this equivalent node condition. In this paper, we design optimal cluster size based on the outage probability under Rayleigh fading channel. A node who wants to send data to the gateway node adaptively constructs a cluster based on joint power minimization problem of cluster size and resource allocation. After making the cluster, the header node can cooperatively send packets with the member nodes of its cluster. This optimized cluster design shows outstanding power reduction compared to conventional clustering algorithm in which cluster header node directly transmits to the gateway node. [ABSTRACT FROM PUBLISHER]

In this paper, we introduce a GPS spoofing attack on the time synchronization in wireless networks. As a case study, the frequency hopping code division multiple access (FH-CDMA) based ad hoc network relying on the GPS signal is investigated. The GPS spoofing attack, which is more malicious than other attacks such as jamming, could lead to the loss of network-wide synchronization as well as the loss of synchronization in FH code. The performance degradation in terms of symbol error rate (SER) of the FH-CDMA based ad hoc network under such an attack is evaluated. Then, to detect the spoofing attack efficiently, we propose to employ a quick detection technique, i.e., CUSUM test algorithm, by observing the dynamic range of the successful detection rate. Simulation results show that GPS spoofing attack on network performance is a long-term impact and more pernicious threat compared to the jamming; moreover, our proposed CUSUM scheme is an effective method to detect the GPS spoofing attack. [ABSTRACT FROM PUBLISHER]

MANETs (mobile ad-hoc networks) are already starting to get deployed in tactical settings. In such networks, where capacity is limited compared to wired networks, QoS mechanisms are needed in order to serve high priority traffic with acceptable quality under both light and heavy load conditions. A crucial part of a QoS architecture is the admission control mechanism, making decisions on whether new flows may be admitted into the network based on the current traffic situation. The IETF is currently standardizing an architecture for admission control and flow termination for wired DiffServ domains, named Pre-congestion Notification (PCN). In this paper the possibility of applying the PCN mechanisms to wireless MANETs is studied. MANET specific challenges are discussed, as well as necessary modifications to the PCN mechanisms. Simulation results are presented, identifying the introduction of probing as a key measure in order to reduce the amount of signaling and to base admission decisions on fresh network status information. [ABSTRACT FROM PUBLISHER]

Routing path restitution approach to control and tolerate the congestion in routing models for mobile ad hoc networks is proposed in this paper. Packet loss in network routing is primarily due to link failure and congestion. The majority of present congestion control solutions do not possess the ability to distinguish between packet loss due to link failure and packet loss due to congestion. Here in this paper we propose route discovery and congestion handling algorithms. The proposed cross layer model includes network, MAC and transport layers. In the proposed model the MAC and network layers are having active role in congestion detection and regularization, in contrast the network and transport layers are active in congestion endurance. The experimental and simulation results show that a better congestion control and endurance is possible for this protocol. [ABSTRACT FROM PUBLISHER]

Wireless sensor network is a kind of data centric network, which transmit sensing data to sink nodes. Considering energy constraints, how to make full use of the limited energy to work reliably becomes a main research area in wireless sensor networks. In this paper, we propose a vote based cluster head election algorithm. In this algorithm, nodes vote to others who owning more remaining energy, and the process is carried among neighbors. According to the voting rules, nodes owning more energy and more neighbors will get more votes. Conversely, nodes owning less energy and less neighbors will get fewer votes. Cluster heads are specified based on the number of the votes. Several experiments have been done to validate the algorithm. [ABSTRACT FROM PUBLISHER]

Vehicular ad hoc networks (VANETs), which are a class of Mobile ad hoc networks, have recently been developed as a standard means of communication among moving vehicles. Congestion is one of the key issues which can restrict the Network performance, and it is no exception for VANETs. Congestion control mechanisms include three phases: congestion detection, congestion notification and rate adjustment. Congestion detection is the first stage of congestion control mechanisms, and it is also the content what this paper focuses on. Because the available resources are limited, and the network topology and node density change over time, applying conventional congestion detection protocols to VANETs can be problematic. To address this challenge, this paper proposes an aggregate parameter based on weights for congestion detection, which can monitor the network performance from the four aspects: Messages Delivered Ratio (MDR), Average Delay (AD), Throughput and Overhead Ratio (OR), so as to achieve the purpose of the congestion detection. In addition, we introduce the method of normalizing the above four parameters, which make the aggregate parameter more accurate. Finally, simulation results show that the aggregate parameter is correct and effective. [ABSTRACT FROM PUBLISHER]

In this paper, we designed the digital narrowband communication system. It can apply at the special field in wireless channel environments. Also, It is a narrowband wireless communication system which uses UHF band. Thus, A system analysis performed using channel equalization and signal acquisition scheme for the effect of a fading and Frequency offset. [ABSTRACT FROM PUBLISHER]

Vehicular Ad Hoc Networks (VANETs) is derived from Mobile Ad Hoc Networks (MANETs) that recently attracts attention of research community. Active road safety application is one of the types of VANETs applications that is very important. It reduces the probability of traffic accident on the road and save human life. Besides that, it has a specific characteristic such as hard delay constraint compared to another type of VANETs applications. Therefore, performance simulation and analysis for this application are critical and require an unique approach also. In this paper, we compared and evaluated the performance of AODV, DSDV and OLSR in a safety application scenario using NS-3. Simulation result show that despite DSDV is originally a MANETs protocol, but it could adapt to the requirement of safety application consistently, whilst OLSR and AODV failed to achieve the expected performance. [ABSTRACT FROM PUBLISHER]

Wireless networks using mobile relays are widely used by urban vehicles, where throughputs and transmission delays are critically performance metrics. Even though there are several wireless routing protocols, the proper data forwarding algorithm should be carefully selected based on their characteristic in various situations. This paper provides extensive NS-2 based performance evaluation of three essential wireless data forwarding algorithms used in popular Mobile Ad Hoc Networks (MANET): Ad hoc on Demand Distance Vector (AODV), Destination-Sequenced Distance Vector (DSDV), and Dynamic Source Routing (DSR). We investigate throughputs, packet drop rate, and transmission delay with various numbers of mobile nodes and realistic mobility models, and provide a useful reference guideline to determine the best wireless data forwarding protocol for vehicles in urban areas. According to our performance study, AODV is the most effective algorithm in terms of throughput and data transmission delay for mobile environments. [ABSTRACT FROM PUBLISHER]

Security is a major concern while implementing Mobile Ad Hoc Networks (MANET) for communication in an adverse environment. The dynamism in network topology and the absence of centralized administration, MANET is susceptible to security attacks from malicious users. This paper introduces the concept of anonymity for an informant who identifies and discloses anonymously the malicious behavior of other users in the network. This paper proposes the Trust-Based Anonymous Communication Technique (TACT) to provide anonymity for an informant and liability for the malicious users who attempt to misuse the anonymity property. The TACT restrains the misuse of anonymity in such a way that any user not sending cooperation message utmost once, upon receiving warnings two times is identified and also any user sending multiple cooperation messages per warning per malicious behavior type will also be termed as malicious user. The proposed technique is designed based on “broadcast with trapdoor information” a cryptography concept to monitor the users and to report malicious users to the network anonymously. The simulation results prove the necessity of anonymity in MANET and the effectiveness of this protocol in achieving such anonymity. [ABSTRACT FROM PUBLISHER]

In emergency scenarios, when multiple rescue and security actors have to quickly deploy their networks in the same area, interference among networks and lack of frequency resources could strongly impact networks activities and be at the origin of less efficient emergency operations. More generally, to allow the coexistence of mobile autonomous ad hoc networks that share the same frequency resources is a crucial problem to solve, that can be very challenging due to interference they might generate to each other. The introduction of Radio Environment Map (REM) concept can be a helpful mean to face this problem. In this paper we propose an adaptation of the REM concept to the ad hoc constraints. We elaborate a REM-based system architecture and we develop a protocol that enables the deployment and the coexistence of several ad hoc networks that share a limited amount of frequency resources in the same area. The need to optimize the use of frequency resources by reducing signalling load, coupled with the objective to keep networks autonomous, led us to the elaboration of a two-level REM based architecture. In addition to a Global REM (G-REM), to which all networks can have access in order to report and obtain data, each network has a Local REM (L-REM), that pilots nodes with measurement capabilities (MCDs), collecting and processing information and interfacing (when necessary) with G-REM. A protocol that permits to construct and to feed the L-REM as well as to pilot the measurement activities of the nodes is developed in the paper. The proposed protocol takes also into account the problem of coordination of resource allocation activities in each network through a Radio Resource Manager (RRM), integrating in the defined signalling messages both RRM and L-REM operations. [ABSTRACT FROM PUBLISHER]

It is highly desired to minimize power consumption, because battery power is one of the most critical resources for mobile devices. Significant energy of a mobile device battery is expended by the activated wireless interface embedded while it is not only in transmit/receive mode but also in idle mode. Therefore, it is energy efficient to turn the wireless interface off or in doze mode while it is not used. However, required energy and time for turning the wireless interface are not negligible. Most of recent works have been trying to enhance the hardware architecture or network/MAC protocols. In this paper, we present an energy efficient policy that turns on the wireless interface only when predefined threshold is exceeded and transmits all awaited data. We propose two kinds of threshold - deadline and sending data queue size. For the practical evaluation, we conduct not only simulations but also experimental measurements by implementing on a real test bed. [ABSTRACT FROM PUBLISHER]

The finite wireless range and fixed location of service networks could render them unable to provide services in certain situations where a dense zone of users is created in the area. This could be in the event of a conference or a festival. Alternatively in extreme cases, the network may not be able to serve anyone at all in the case of a major power shutdown or network collapse. To deal with such situations, we propose to explore establishing a service network through cyber foraging when no service network is functioning properly in an area. To effectively establish a network based on cyber foraging, service nodes need to be placed at strategic points in the service area. This paper presents the first step in our approach. In this initial work, we present how to gather current information on users density in the area. The intended service area mapped with this information could help in identifying the strategic points to place service nodes to enable establishing a network through cyber foraging. We present a scanning algorithm that provides an approximate distribution of users within an area. This paper presents our approach, explains the algorithm in details and presents simulation results to show how the approach could be used. [ABSTRACT FROM PUBLISHER]

Wireless sensor networks (WSN) are highly distributed self-organized systems, the associated research being growing at a tremendous pace, and targeting various application domains. The successful implementation of such networks is dependent on the enabling technologies (such as digital electronics and wireless communications), as well as the provisioning of Quality of Service (QoS) and various security features in the networks. This paper focuses on the main characteristics and the current development status of the: management and monitoring, security and QoS topics, an overview of the recent progress being given. The paper examines and discusses the challenges of an adaptive monitoring framework (WSeH framework) with enhanced security and QoS support for WSNs, proposing a generic architecture and opening research issues. [ABSTRACT FROM PUBLISHER]

The present world has been dominated by wireless ad hoc communication network. Having understood the purpose of ad hoc scenario in this real world, the establishment of network without clustering will not fall down to the line of expectation. Thus, the cluster formation algorithm has been an essential step towards making the network to perform efficiently. This paper proposes Ex-PAC as a cluster formation procedure and its performance has been compared against K-means. The programming language C++ has been used to implement these two algorithms and the results are tabulated. Obviously the findings say, Ex-PAC has an edge over K-means in terms of computation time and handling large sets of data in the process of making clusters. [ABSTRACT FROM PUBLISHER]

Cognitive radio ad hoc networks (CRAHNs) are multi-hop, dynamic and self-configurable networks, which can communicate without any infrastructure support. Most of the research in CRAHNs has been already carried out on physical and media access control layers, but without effective routing protocols we cannot take full advantage of CRAHNs. In this paper, we discuss the problems in already proposed routing protocols for cognitive radio networks and proposed a novel protocol: Delay and Energy based Spectrum Aware Routing Protocol (DESAR), which consider both delay and energy for the computation of efficient path between source and destination. Simulation results show that DESAR protocol performs better than existing protocol in term of end-to-end delay. [ABSTRACT FROM PUBLISHER]

In the previous work, we propose a node localization scheme based on three dimensional optimum space step distance in wireless sensor networks (WSNs) which is called 3D-OSSDL for short. By optimizing distances from the network model, the optimum space step distance from nodes to anchors is obtained and the coordinates of unknown nodes are derived finally. In this paper, in order to overcome the defects of OSSDL, an optimum anchor selection mechanism is added into it without inducing any extra requirements. Actually by using the optimum space step distance and optimum anchor selection, the whole scheme operates well and simulation results show better performances by 20%-30% than 3D-OSSDL on the localization error and much better than that of DV-Hop algorithm. In this paper comprehensive analysis about the mechanism is proposed and experiments prove the validity of it. [ABSTRACT FROM PUBLISHER]

In this paper, we analyze the performance of cooperative content caching in vehicular ad hoc networks (VANETs). In particular, we characterize, using analysis and simulations, the behavior of the probability of outage (i.e. not finding a requested data chunk at a neighbor) under freeway vehicular mobility. First, we introduce a formal definition for the probability of outage in the context of cooperative content caching. Second, we characterize, analytically, the outage probability under vehicular and random mobility scenarios. Next, we verify the analytical results using simulations and compare the performance under a number of plausible mobility scenarios. This provides key insights into the problem and the involved trade-offs and enable us to assess the potential opportunity offered by the, somewhat structured, vehicular mobility that can be exploited by cooperative content caching schemes. The presented numerical results exhibit complete agreement between the analytical and simulation studies. Finally, we observe that vehicular mobility creates opportunities for enhanced outage performance under practically relevant scenarios. [ABSTRACT FROM PUBLISHER]

This paper reviews a range of problems in the road transport field and the potential role of vehicular ad-hoc network systems (VANETs) in helping to solve them. In reality, the communications requirements vary widely from one application to the next, in terms of range, latency, and connectivity together with vehicle and roadside hardware. Based on the nature of the wireless channel, this presents some challenges for communication to security. The paper concludes with a summary of the current state of VANET technology and presents a summary of the challenges to be found in each approach. [ABSTRACT FROM PUBLISHER]

IRDT (Intermittent Receiver-driven Data Transmission) realizes low-power communication between neighbor sensor nodes. This paper proposes combination IRDT-GEDIR of IRDT and GEDIR which is an on-demand location-based ad-hoc routing protocol. Here, pseudo speed of data message transmission is applied for next-hop selection in an intermediate node and on-line determination of its next-hop node is realized by calculation of expectation of pseudo speed provided by its neighbor nodes which have not yet enter their active mode. This paper discusses how the expected pseudo speed and the reduction of data message transmission delay is evaluated. In addition, the performance of IRDT-GEDIR is evaluated in simulation experiments. [ABSTRACT FROM PUBLISHER]

Effect of additive white Gaussian noise on accuracy performance of a six-port reflectometer (SPR) is presented in this paper. Three six-port circuits (sampling line, five-port ring and ideal design) calibrated with different calibration techniques (five and seven standard loads based) are investigated. Mathematical model of a SPR is developed and simulated. To evaluate the accuracy performance of a SPR at a certain signal-to-noise ratio, a mean absolute error is computed from mean distance between exact and predicted reflection coefficients for all possible passive loads. Validity of this work is proven with some experimental results at 1 GHz SPRs. [ABSTRACT FROM PUBLISHER]

This paper considers cases where a specific number of nodes in an ad hoc network broadcast video and audio streams over the entire network. For the purpose, we have proposed Load and Battery Charge oriented Flooding (LBF), which reduces degradation in delivery quality, and energy consumption, and prevents nodes from being interrupted due to the complete discharge of their batteries. This paper describes an evaluation of the proposed method through network simulation. The simulation results indicate that the proposed method can prolong network running time without degradation of delivery quality. [ABSTRACT FROM PUBLISHER]

The importance of resources and services availability in Ad Hoc networks has already been proved several times in the past. It concerns, essentially, node availability as well as routing and forwarding actions accessibility. Unfortunately, nodes' lifetimes may be reduced or even depleted which leads to route failure, packets loss, QoS deterioration, etc. This is mainly due to a battery problem that can be caused by a legitimate consumption or by an attacker. To mitigate this problem and in order to allow nodes perpetuity and to face up any unavailability or flinching, a sharing of nodes' permissions can be used. Delegation is a common practice that is used to simplify and to manage this kind of sharing. Our proposition is then, to use a delegation process in order to enhance the QoS of Ad hoc networks by allowing the perpetuity of routes without stopping the packets transfer nor the re-calculation of a novel route. In view of the importance of the issue, we propose to base delegation on trust relations. Trust is a security concept generally used to provide collaborating network entities with a mean to counter their uncertainty. The main contribution in this paper is then, the proposition of a trust based delegation model for Ad Hoc networks in order to enhance QoS and specially routes availability. [ABSTRACT FROM PUBLISHER]

Vehicle trajectories information can enable many promising applications, but obtaining the information is very challenging. Road-side infrastructure can collect trajectory data from vehicles in the area through wireless communication in addition to many other functionalities. In this paper, we suggest the deployment of roadside infrastructure for vehicle trajectory collection. More specifically, we select intersections to install access points for collecting moving trajectory of all the vehicles in the area, while at the same time minimize the number of selected intersections. We prove the intersection selection problem is NP-complete and propose a greedy heuristic to approximately address it. The performance, efficiency and practical issues such as broadcast intervals of the scheme are analyzed in this paper. The simulation shows that our greedy approach solves the intersection selection problem efficiently and effectively. [ABSTRACT FROM PUBLISHER]

Ad hoc networks have emerged from wireless technology, which consist of wireless nodes with absence of a stationary infrastructure. These networks are inherently vulnerable to security attacks from malicious users. Therefore, providing distinct security for ad hoc networks becomes a primary concern and requires several challenges to be achieved. One main challenge is how to manage public keys' certificates among ad hoc nodes. This paper introduces a fast and secure clustering scheme by select candidate's nodes using voting method, This method is to select certificates management node which manages certificates on behave of other nodes in ad hoc network. [ABSTRACT FROM PUBLISHER]

Authentication protocols are very much essential for secure communication in mobile ad hoc networks (MANETs). A number of authentication protocols for MANETs have been proposed in the literature which provide the basic authentication service while trying to optimize their performance and resource consumption parameters. A problem with most of these protocols is that the underlying networking environment on which they are applicable have been left unspecified. As a result, lack of specifications about the networking environments applicable to an authentication protocol for MANETs can mislead about the performance and the applicability of the protocol. In this paper, we first characterize networking environment for a MANET as its 'Membership Model' which is defined as a set of specifications related to the 'Membership Granting Server' (MGS) and the 'Membership Set Pattern' (MSP) of the MANET. We then identify various types of possible membership models for a MANET. In order to illustrate that while designing an authentication protocol for a MANET, it is very much necessary to consider the underlying membership model of the MANET, we study a set of six representative authentication protocols, and analyze their applicability for the membership models as enumerated in this paper. The analysis shows that the same protocol may not perform equally well in all membership models. In addition, there may be membership models which are important from the point of view of users, but for which no authentication protocol is available. [ABSTRACT FROM PUBLISHER]

Vehicular ad hoc networks (VANETs) have recently received considerable attentions for both safety and commercial applications. In this paper, we address popular content distribution (PCD) in VANETs, in which a popular file is downloaded by a group of on-board units (OBUs) passing by a roadside unit (RSU). Due to high speeds and channel fadings, the OBUs may not finish downloading the entire file from the RSU, but only possess several content pieces. In this paper, we propose a cooperative approach using coalitional graph game to establish a peer-to-peer (P2P) network among the OBUs, in which content pieces are exchanged to complete the file downloading process. Further, we adopt cognitive radio (CR) technique for implementing vehicle-to-vehicle (V2V) transmissions. Simulation results show that the proposed algorithm enjoys a better performance in various conditions, compared to the non-cooperative approach, where OBUs randomly response to content requests from other OBUs. [ABSTRACT FROM PUBLISHER]

Mesh Client (MC) may be frequently move from the current SMAP to another SMAP in the Wireless Mesh Networks (WMN). The most of the present research papers on WMN assume that the MC is static or quasi static. However, MC may constantly move actually, which connection interruption and packet loss may occur. To solve these problems this paper presents a mobility support strategy for WMN, which consists of two parts: address assignment and mobility management. [ABSTRACT FROM PUBLISHER]

The open access and limited resources of WSNs make the network vulnerable to all kinds of attacks, and for this reason it requires effective intrusion detection technology to detect and identify various security threat. This paper firstly gives a brief introduction of the present intrusion detection system, and then discusses the various threats faced of WSNs, at last this paper points out that the comprehensive use of various technologies is the trend of the intrusion detection system of WSNs. [ABSTRACT FROM PUBLISHER]

Mobile ad-hoc network technology has gained popularity in recent years by researchers on account of its flexibility, low cost and each of deployment. The objective of this paper is to model the behavior of routing metrics in MANET for different protocols. These metrics have been generated by Network Simulator NS 2.34 tools and the node movement has been generated using Bonmotion 1.4. The metrics behavior for each protocol is hypothesized to be dependent on node density, pause time, number of packets transferred, and the number of connection. A statistical model is implemented on MATLAB 7.0 and the model is found to be satisfactory with fitness value almost ideal value (1.0). [ABSTRACT FROM PUBLISHER]

Apple Wireless Direct Link (AWDL) is a proprietary and undocumented IEEE 802.11-based ad hoc protocol. Apple first introduced AWDL around 2014 and has since integrated it into its entire product line, including iPhone and Mac. While we have found that AWDL drives popular applications such as AirPlay and AirDrop on more than one billion end-user devices, neither the protocol itself nor potential security and Wi-Fi coexistence issues have been studied. In this paper, we present the operation of the protocol as the result of binary and runtime analysis. In short, each AWDL node announces a sequence of Availability Windows (AWs) indicating its readiness to communicate with other AWDL nodes. An elected master node synchronizes these sequences. Outside the AWs, nodes can tune their Wi-Fi radio to a different channel to communicate with an access point, or could turn it off to save energy. Based on our analysis, we conduct experiments to study the master election process, synchronization accuracy, channel hopping dynamics, and achievable throughput. We conduct a preliminary security assessment and publish an open source Wireshark dissector for AWDL to nourish future work. [ABSTRACT FROM AUTHOR]

In a cooperative wireless network all the nodes will cooperate for the transmission of all other nodes. But there may be some malicious nodes which does not comply with the cooperation rule and act as selfish to reserve its resources for its own use. In this paper we present a review of the various approaches that are used to detect and eliminate the malicious nodes. We concentrated our review mainly on approaches that gave good results and which have to be improved. We provided our simulation result using NS2 with some routing protocols. [ABSTRACT FROM PUBLISHER]

The ad-hoc network is a collection of wireless mobile nodes without any support of a stationary infrastructure. Due to the node's mobility and the network topology changes to be kinetic, the network disconnection occur frequently. This paper proposes a variation of the AODV protocol, which selects CORE nodes using path's accumulation information, and then establishes multi paths based on CORE-node's information. When network is disconnected, our proposed protocol saves path reset time and reduces the reset control messages by using the information held by the CORE-node. [ABSTRACT FROM PUBLISHER]

Station association information, such as an associated mesh router is required to support communication between legacy stations in Wireless Mesh Networks (WMN). Current IEEE 802.11s draft standard specifies two mechanisms to maintain the station association information: Proxy Registration Procedure (PRP) and Association Discovery Protocol (ADP). Each of them has structural limitations in that mesh routers always maintain a station association information table. Consequently, the more the number of station and mobility increases, the more management overhead increases. In this paper, we propose the method of station association information and forwarding frame using MAC subnet addressing without a station association information table. According to simulations, we results in significant improvement in terms of management frame overhead and frame transmission delay. [ABSTRACT FROM PUBLISHER]

Mobile Ad-hoc Networks (MANETs) require a dynamic and efficient routing protocol that can responds quickly to network topology changes. Ad hoc routing protocols for MANETs are classified into: (a) proactive, (b) reactive and (c) hybrid approaches. In general, proactive routing is more suitable for a stationary network, while reactive routing is better for a mobile network with a high mobility. In many applications, a node in a MANET is mobile, yet it can also fluctuate between being mobile and being stationary. Thus, a hybrid routing approach with the ability to adapt according to the node mobility could improve the performance of MANETs. However, existing hybrid protocols (e.g. the Tooska scheme) do not consider node mobility. Therefore, this paper, proposes a Mobility-Aware Hybrid Routing (MAHR) approach for MANETs, which varies its routing between a reactive and proactive approach according to the node mobility. While the proposed scheme is similar to the Tooska scheme, it selects the core nodes based on the ratio of changing neighbor nodes to take account of the node mobility. Simulation results show that the proposed routing protocol outperformed three other routing protocols, i.e., the Tooska scheme, AODV, and OLSR. [ABSTRACT FROM PUBLISHER]

The IEEE 802.11p wireless access in vehicular environments (WAVE) is defined to provide a networked environment supporting very high speed transactions to enable safety and mobility applications. Adaptive Enhanced Distributed Channel Access (EDCA) mechanism based on IEEE 802.11p WAVE for vehicular ad-hoc network (VANET) to improve medium access ratio is proposed in this paper. The priority categories are re-classified from safety information for driver life to non-safety information. When the existing IEEE 802.11 EDCA mechanism operates, it will be referred by priority level. In case of collision, the Contention Window (CW) values increase. But this concept is designed to control CW depending on the density of the vehicles for improving throughput of each access category. [ABSTRACT FROM PUBLISHER]

In this paper, the authors describe a management method for home wireless networks that provides robust connectivity and stable transmission. [ABSTRACT FROM PUBLISHER]

On the basis of the characteristics of Ad Hoc Networks, from the perspective of the authentication and key agreement between nodes, this paper puts forward Ad Hoc Networks key cluster management solution based on the hash function. By introducing a clustering technology, this solution reduces the amount of computation and communication between nodes, improves the efficiency of authentication, and achieves effective communication between nodes authentication, digital signatures and other functions. [ABSTRACT FROM PUBLISHER]

In the absence of multi-user detection techniques in ad hoc networks, interference management is done through MAC scheduling by creating suitable exclusion zones around active receivers. Applying MAC mechanisms alters the spatial distribution Φi of parent contending nodes to thinned daughter distribution Φs. The knowledge of post-MAC geometrical distribution of nodes is important for efficient MAC implementation. The paper provides a thinning model to capture the MAC implementation in ad hoc networks and investigates the stochastic geometry of thinned nodes. It is shown that the thinning process results in different spatial distributions that is sensitive to the robustness of the physical layer. [ABSTRACT FROM PUBLISHER]

The use of beamforming antennas has received significant attention over the last decade. We consider beamforming applied to dynamic operations such as networked UAV hubs which interconnect with users on the ground. The key problem involves scheduling these communications with users serviced by different beam patterns. This paper develops a linear program to optimally allocate time to beams for client specific traffic for such an application in order to maximize client throughput. It also incorporates l1 norm regularization to help allocate time for non-linear factors such as beam-switching while still maintaining optimality. Furthermore this paper implements delay constraints and verifies the program's performance. A shortest path first approach is presented that optimally schedules the order of the beam switches such that inter-switch delay, and associated protocol specific overhead, is minimized. We show how we implement, and then test, a multi-UAV scenario where the separate UAVs service their respective users while being interconnected in an ad hoc network. Finally, we present a working prototype implementation incorporating this work. [ABSTRACT FROM PUBLISHER]