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IEEE 802.11ad defines a new physical and medium access control layer for IEEE 802.11 networks to operate in the unlicensed 60 GHz millimeter wave spectrum for multi-gigabit wireless communications. Higher frequency waves have higher propagation loss but smaller antenna size. Hence, for millimeter wave networks, higher number of antennas can be packed together, enabling beamforming with very large gains. In this paper, we propose a novel Directional MAC protocol for Basic Stations (DMBS) with the goal of fully leveraging spatial reusability, and limiting deafness and hidden terminal problems with minimal overhead, and without using any complicated hardware for localization. The distinguishing features of DMBS are threefold. First, DMBS extends the association beamforming training time (A-BFT) of IEEE 802.11ad, during which the stations perform initial beamforming training with the access point (AP), by an intelligent listening mechanism. This mechanism allows the stations to passively learn about the best direction of the neighboring stations, decreasing the associated beamforming training overhead. Second, DMBS determines the best transmission direction by using multi-directional sequential (circular) RTS/CTS (Request To Send/ Clear To Send) (CRTS/CCTS) packets, and tracks the best direction by updating its beamforming table upon reception of every RTS/CTS packet, without requiring any additional hardware for localization. If the location information of the destination is up-to-date, the source station only transmits directional RTS/CTS (DRTS/DCTS) in the known direction. Third, DMBS uses two network allocation vectors (NAVs). The first NAV, denoted by NAV1, is used to reduce deafness by determining the busy nodes upon the reception of every RTS/CTS packet. The second NAV, called NAV2, is used to limit hidden terminal problem while maximizing spatial reusability by determining whether a transmission can interfere with active communication links. If NAV2 is set, then the node defers its multi-directional communication but still communicates directionally. We provide a novel Markov chain based analytical model to calculate the aggregate network throughput of DMBS. We demonstrate via extensive simulations that DMBS performs better than existing directional communication protocols in terms of throughput for different network sizes, mobilities and number of receivers. [ABSTRACT FROM AUTHOR]

This paper proposes a large-scale wireless powered communication network (WPCN), which consists of a hybrid access point (H-AP) and numerous nodes. The H-AP broadcasts energy to all nodes, and the nodes harvest the energy and then use the harvested energy to transmit information. For the large-scale WPCN, we also propose a novel hybrid multiple access protocol, termed hybrid multiple access-based dual harvest-then-transmit. The proposed protocol utilizes both time division multiple access (TDMA) and carrier-sense multiple access (CSMA), in order to deal with various traffic patterns and transmission reliability of different applications in large-scale networks. We consider a dual wireless energy transfer (WET) at the H-AP. The main WET is performed in TDMA and the other WET is performed at space holes in CSMA, to increase the channel utilization and harvested energy. For the considerations, we study the sum-throughput maximization in the large-scale WPCN based on hybrid multiple access-based dual harvest-then-transmit. Simulation results show that the proposed protocol outperforms the conventional protocol in large-scale WPCN. [ABSTRACT FROM AUTHOR]

We consider the secrecy rate for the multiple-input single-output optical wireless scattering communication, where the detected signal can be characterized by discrete photoelectrons. Assuming a legitimate receiver and an eavesdropper, we propose two secure communication protocols, the non-jamming protocol, and the cooperative jamming protocol, where for the former the transmitter does not send jamming signals but for the latter the transmitter sends jamming signals. We formulate the corresponding power and duty cycle optimization problems for both protocols. We also analyze the properties on the optimal solution, and adopt the alternating optimization to obtain a tractable solution. Moreover, we analyze the condition on the positive secrecy rate for the case where all the sub-channels to the receiver are weaker than their counterparts to the eavesdropper, where the secrecy transmission cannot be realized via a non-jamming protocol. The performance of the proposed two protocols is evaluated by numerical results. It is seen that for the iterative optimization solution, two to three iterations suffice for the convergence of the secrecy rate. [ABSTRACT FROM AUTHOR]

We investigate the pairwise error probability (PEP) performance degradation of dual phase multiple relay C(0) cooperation protocol due to imperfect channel state information (CSI) and mobility of nodes. We analyze PEP performance of C (0) protocol over time selective independent, but not identically distributed MIMO channel fading links. Our analysis reveals that because of the mobility of nodes, the PEP performance is severely degraded and in some specific system conditions, encounter asymptotic floor. Moreover, when both the destination-node (DN) and the source-node (SN) are static, the PEP upper union bound performance does not experience error floor limit regardless of the fact that the relay-nodes (RNs) are mobile. In addition, except the scenario when the RNs are static, the mobility of either the DN or the SN basically influences the performance of the wireless network due to error floors limits. Simulation outcomes prove that system achieves full diversity order (DO) when all nodes are static and perfect CSI. Simulation outcomes confirm the accuracy of the derived theoretical formulations. [ABSTRACT FROM AUTHOR]

In the area of wireless sensor networks the network is composed of a significant number of nodes deployed in an extensive area in which not all nodes are directly connected. The sensor nodes are generally unattended after their deployment in hazardous, hostile or remote areas. But the thing is that ,"how nodes share the channel" and "how it will work at low energy" are the two main design goal. Contention-based vs. Scheduled-based protocols are used to avoid above problems. In this paper, we present the challenges in the design of the energy efficient protocols and for the wireless sensor network. We describe several Contention-based and Scheduledbased protocols for the WSNs emphasizing their strength and weakness wherever possible. At the end, we discuss the future research directions in the MAC protocol design. [ABSTRACT FROM AUTHOR]

Mobile ad hoc networks (MANETs) are mobile networks, which are automatically outspread on a geographically limited region, without requiring any preexisting infrastructure. Mostly, nodes are both self-governed and self-organized without requiring a central monitoring. Because of their distributed characteristic, MANETs are vulnerable to a particular routing misbehavior, called wormhole attack. In wormhole attack, one attacker node tunnels packet from its position to the other attacker nodes. Such wormhole attack results in a fake route with fewer hop count. If source node selects this fictitious route, attacker nodes have the options of delivering the packets or dropping them. For this reason, this paper proposes an improvement over AODV routing protocol to design a wormhole-immune routing protocol. The proposed protocol called defending against wormhole attack (DAWA) employs fuzzy logic system and artificial immune system to defend against wormhole attacks. DAWA is evaluated through extensive simulations in the NS-2 environment. The results show that DAWA outperforms other existing solutions in terms of false negative ratio, false positive ratio, detection ratio, packet delivery ratio, packets loss ratio and packets drop ratio. [ABSTRACT FROM AUTHOR]

RFID is one of the most important automatic identification techniques in the future IoT world. Compared with the other techniques, RFID has various advantages such as no requirement of line of sight, the capability of wireless communication, low cost, small size, and so on. This article discusses two types of anomaly tags, i.e., missing tags and unknown tags, which usually appear due to theft or product misplacement. Generally, there are two categories of anomaly tag pinpointing protocols: boolean detection, which aims at probabilistically determining whether there exist anomaly tags or not; and exact identification, which aims at identifying all anomaly tag IDs. This article first conducts a comprehensive survey of the existing anomaly tag pinpointing protocols, particularly emphasizing their evolution road. After that, we also conduct a taxonomy of the existing protocols and summarize their pros and cons. Finally, we discuss some technical challenges and problems that have not been covered yet, and point out the potential opportunities in RFID research and applications. [ABSTRACT FROM AUTHOR]

Driven by the increasing demand on marine exploration, UWANs are confronted with the rigorous challenge of improving network throughput. To deal with this challenge, this article proposes to apply the IBFD technique to UWANs. The IBFD technique can potentially double link capacity by simultaneously transmitting and receiving on the same frequency band, which has been recently demonstrated to be feasible for wireless communications. In this article, novel MAC protocols are specifically proposed for the acoustic IBFD network to overcome the inherent issues in underwater acoustic communications, such as long packet delay, large node collision probability, and high power consumption. Numerical results verify that our proposals can effectively mitigate these effects and improve the overall performance of the UWANs. [ABSTRACT FROM AUTHOR]

In this paper, a secure cross-layer-based routing technique (SCLARDI) for a mobile ad hoc network (MANET) is proposed. This technique makes use of ad hoc on-demand routing protocol (AODV) algorithms and honey pot technology to detect and isolate black hole attacks from MANETs. This novel system is compared with the single-layer design techniques and existing cross-layer detection techniques. Out of the tested models, the proposed cross-layer design is the most suitable for MANET security. First, the vulnerabilities of the AODV routing protocol against black hole attacks are analyzed. Second, a secure cross-layer-based AODV routing technique is proposed. The proposed SCLARDI technique detects and isolates black hole attacks from MANET. Finally, the results are compared with the existing techniques. The simulations are done using NS-2. The simulation results show that the proposed technique improves the packet delivery ratio and reduces network overhead, normalized routing load, and packet drop ratio compared to other existing single-layer and cross-layer techniques. [ABSTRACT FROM AUTHOR]

Current networking technologies are not perfectly equipped to support Quality of Service (QoS), which is vital for real-time multimedia applications in Wireless Community Mesh Networks (WCNs). Therefore, there is a need to devise innovative routing algorithms to support QoS on top of existing standards. Thus, this paper presents a cross layer relay node selection model for routing protocols in order to offer optimal routes to real-time applications. To the best of our knowledge, our two proposed routing metrics, Packet Priority-Oriented routing metric (PPO) and Packet Priority-oriented QoS routing metric (PP-QoS) , are the first to provide differentiated priorities and service levels to applications with different needs. PPO considers the application priority. Moreover, PP-QoS also considers the channel busy level to improve the performance of path selection. The simulation confirms the superiority of the proposed model against a number of existing counterparts. [ABSTRACT FROM AUTHOR]

This study proposes a novel square-circle structure fractal multibroadband planar antenna, similar to an ancient Chinese coin-like structure, for second generation (2G), third generation (3G), fourth generation (4G), WLAN, and navigation wireless applications. The device is based on the principles and structural features of conventional monopole antenna elements, combined with the advantages of microstrip antennas and fractal geometry. A fractal method was presented for circular nested square slotted structures, similar to an ancient Chinese copper coin. The proposed antenna adapted five iterations on a fractal structure radiator, which covers more than ten mobile applications in three broad frequency bands with a bandwidth of 70% (1.43–2.97 GHz) for DCS1800, TD-SCDMA, WCDMA, CDMA2000, LTE33-41, Bluetooth, GPS (Global Positioning System), BDS (BeiDou Navigation Satellite System), GLONSS (Global Navigation Satellite System), GALILEO (Galileo Satellite Navigation System), and WLAN frequency bands, 16.32% (3.32–3.91 GHz) for LTE42, LTE43, and WiMAX frequency bands, and 10.92% (4.85–5.41 GHz) for WLAN frequency band. The proposed antenna was fabricated on a 1.6 mm thick G10/FR4 substrate with a dielectric constant of 4.4 and a size of 88.5 × 60 mm2. The measurement results reveal that the omnidirectional radiation patterns achieve a gain of 1.16–3.75 dBi and an efficiency of 40–72%. The good agreement between the measurement results and simulation validates the proposed design approach and satisfies the requirements for various wireless applications. [ABSTRACT FROM AUTHOR]

A vehicular ad hoc network (VANET) is a type of mobile ad hoc network (MANET) that provides an exchange of messages between vehicles. VANETs encourage researchers to create safety and comfort applications that will lead to intelligent transport systems. Conventional ad hoc routing methods may cause ooding of packets to find routes in a VANET. Hence, finding a route from the source to the destination vehicle by local broadcast techniques in densely populated urban areas may create a broadcast storm and network bandwidth is unnecessarily wasted to discover routes between source and destination vehicles. In this paper, an efficient routing protocol (ERP) is proposed to utilize the network bandwidth efficiently by avoiding unnecessary rebroadcast. This new protocol finds a minimum connected dominating set of vehicles (MCDSV) and treats them as a virtual backbone for communication in VANETs. Vehicles in the virtual backbone act as forwarders and are responsible for local broadcasting in the network. Vehicles that are not in the MCDSV are not allowed to broadcast packets as forwarders and hence the bandwidth utilization is minimized. The proposed protocol has been implemented in NS2 and its performance is compared with other routing protocols for packet delivery ratio, control overhead ratio, and average end-to-end delay. [ABSTRACT FROM AUTHOR]

This paper presents the Reliable Bidirectional Control Protocol (RBCP) protocol, which is a transport protocol for Wireless Sensor Networks (WSN), focused on managing sensors' behaviour. It aims to be a utility for reliable control data transferring from source to destination unit in the network. Considering the related studies on transport protocols, which are mostly dedicated to a single-direction reliable data transport, RBCP is the answer for the lack of control mechanisms in WSNs based on bidirectional communication. The first part of this paper is focused on general presentation of the proposed solution. In the next part, evaluation of the idea and final functionality are discussed. It will finally show the results of undergone testing stage. [ABSTRACT FROM AUTHOR]

Abstract: Full duplex wireless communication is one of the enabling technologies of the fifth generation (5G) mobile telecommunication networks. It boosts up the bandwidth by enabling simultaneous data transmission and reception on a single channel. In this paper, we design a suitable medium access control (MAC) protocol for 5G networks to realize the benefit of full duplex communication. We also develop an analytical model to evaluate the performance of our proposed MAC protocol. [ABSTRACT FROM AUTHOR]

During the last few years, wireless low-power communications experienced an increasing coexistence and traction as a result of the higher demand posed by power constrained applications. On the other hand, this increasing wireless coexistence is a growing concern and Low-power wireless communication protocols have been shown to experience a significant timeliness and reliability degradation under certain interference profiles. Therefore, the support of real-time communications over license-free bands in open environments, encompassing multiple real-time stations with an unknown number of unconstrained stations, is a challenging task. Provided that this impairment has hindered their wide adoption in demanding real-time scenarios, the Wireless Flexible Time Triggered (WFTT) protocol has been recently proposed targeting applications with stringent timeliness requirements. This protocol works on the medium access determinism granted by the bandjacking technique in open environments, where different technologies may contend for the medium. Besides providing a deeper definition of the WFTT architecture and protocol operation, this paper presents a thorough analysis addressing its specifications, implementation feasibility and testbed based results. These provide strong evidence that the WFTT protocol is able to support real-time communications, even in environments affected by high levels of interference from neighboring contention-based communication technologies such as Wi-Fi. [ABSTRACT FROM AUTHOR]

This paper investigates a protocol so-called Adaptive Harvest Then Transmit (AHTT) for wireless powered communication networks (WPCNs) in multiple-input single-output (MISO) downlink systems, which assists in transmitting signals from a multi-antenna transmitter to a single-antenna receiver. Particularly, the power constrained relay is supplied with power by utilizing radio frequency (RF) signals from the source. In order to take advantage of multiple antennas, two different linear processing schemes, including Maximum Ratio Combining (MRC) and Selection Combination (SC) are studied. The system outage capacity and ergodic capacity are evaluated for performance analysis. Furthermore, the optimal power allocation is also considered. Our numerical and simulation results prove that the implementation of multiple antennas helps boost the energy harvesting capability. Therefore, this paper puts forward a new way to the energy efficiency (EE) enhancement, which contributes to better system performance. [ABSTRACT FROM AUTHOR]

Wireless powered communication networks (WPCNs) have attracted much research interest in fifth generation (5G) wireless networks. With the help of WPCN, the reliability and battery life of wireless low-power devices can be enhanced. In this paper, we investigate throughput and ergodic capacity in WPCN-assisted amplify-and-forward relaying systems considering two transmission modes, including delay-tolerant and delay-limited. More importantly, we propose energy harvesting protocol so-called hybrid time switching-based and power splitting-based relaying (HTPSR) protocol in order to achieve optimal throughput. In particular, both time switching-based and power splitting-based coefficients in this scheme are considered. Unlike most previous works, we further focus on the impact of outdated channel state information (CSI) in WPCN. In order to evaluate information processing efficiency, the performance can be substantially improved by optimizing harvesting time and power coefficients of the received signal at the relay node for energy and information extraction. Thanks to Monte Carlo simulations, it is confirmed that the system performance is more sensitive to CSI estimation error, noise variance and signal-to-noise ratio which enable us in reasonable computations of HTPSR to obtain QoS requirement. [ABSTRACT FROM PUBLISHER]

Similar to terrestrial networks, underwater wireless networks (UWNs) also aid several critical tasks including coastal surveillance, underwater pollution detection, and othermaritime applications. Currently, once underwater sensor nodes are deployed at different levels of the sea, it is nearly impossible or very expensive to reconfigure the hardware, for example, battery. Taking this issue into account, considerable amount of research has been carried out to ensure minimum energy costs and reliable communication between underwater nodes and base stations. As a result, several different network protocols were proposed for UWN, including MAC, PHY, transport, and routing. Recently, a new paradigm was introduced claiming that the intermittent nature of acoustic channel and signal resulted in designing delay tolerant routing schemes for the UWN, known as an underwater delay tolerant network. In this paper, we provide a comprehensive survey of underwater routing protocols with emphasis on the limitations, challenges, and future open issues in the context of delay tolerant network routing. [ABSTRACT FROM AUTHOR]

RFID applications such as monitoring an object for a long time need to identify tags repeatedly within the scope of the reader. Re-identification process can be improved using the information obtained from the previous tag identification process. Couple-resolution blocking (CRB) protocol utilizes the blocking technique that prevents staying tags from being collided by newly arriving tags. Staying tags can be efficiently re-identified by utilizing the retained information. After staying tags are separately all identified, arriving tags are identified. In this paper, we argue that CRB may work more poorly than other protocols which do not consider the repeated tag identification, such as query tree (QT) and collision tree (CT) protocol, when only few tags stay. To tackle the problem, we propose an adaptive CRB (ACRB) protocol. In ACRB, the reader estimates the tag staying ratio during the re-identification process for staying tags. If the estimated ratio is lower than a certain threshold, the blocking technique is immediately abandoned. Instead, staying tags and arriving tags are identified together without considering the retained information. In addition, we propose to improve CRB further using CT protocol, instead of QT protocol. Through computer simulation, we show that ACRB improves the identification efficiency of CRB, especially when the tag staying ratio is low. [ABSTRACT FROM AUTHOR]

A Wireless Sensor Network (WSN) link layer security protocol called TeenySec is proposed in this paper. WSNs are caused by a lot of vulnerability because of factors such as hardware constraints of the sensor nodes, wireless communication medium, real-time computing, heterogeneous structure, large number of nodes, scalability, mobility, weight and cost requirements of application environment. In sensitive WSN applications like surveillance of enemy lines or border areas, security protocols must be used which provide confidential data transfer from sensors to base station. In this study, a new data link layer protocol is developed which is called TeenySec. The TeenySec combines the advantageous aspects of the Corrected Block Tea Algorithm (XXTEA) with the Offset Codebook Mode (OCB) approaches. TeenySec provides data confidentiality, data integrity, data freshness and data authentication and is also energy efficient. Moreover, proposed protocol has been implemented on the TelosB nodes. The security has been increased in the developed protocol. Also, better results have been obtained than TinySec, MiniSec and SNEP in energy consumption and memory usage which are very important for WSNs. Copyright © 2017 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Underwater sensor networks have enabled a new era in scientific and industrial underwater monitoring and exploration applications. However, these networks are energy-constrained and, more problematically, energy-hungry, as a consequence of the use of underwater acoustic links. In this work, we thoroughly review potential techniques for greening underwater sensor networks. In a top-down approach, we discuss the principal design and challenges of the appealing highlighted techniques. We also exemplify their use by surveying recent proposals in underwater sensor networks. Finally, we describe potential future research directions for energy conservation in underwater networks. [ABSTRACT FROM PUBLISHER]

Recently, there has been an increasing need for secure, efficient, and simple notification methods for wireless systems. Such systems are meant to provide users with precise tools best suited for work or leisure environments, and a lot of effort has been put into creating a multitude of applications. At the same time, however, not much research has been made into determining which of the available protocols are best suited for each individual task. A number of basic notification methods are presented here, and tests have been performed for the most-promising ones. An attempt has been made to determine which of the methods have the best throughput, latency, security, and other characteristics. A comprehensive comparison is provided, which can be used to select the right method for each individual project. Finally, conclusions are provided, and the results from all of the tests conducted are discussed. [ABSTRACT FROM AUTHOR]

Mobile Ad hoc Network (MANET) is a rapidly growing wireless technology with wide range of applications. MANET routing faces challenges due to their Ad hoc nature, and many routing algorithms have been proposed. Reactive routing protocols are preferred due to less control overhead and scalability, but they suffer from frequent link breakages due to the high-mobility of the nodes. To reduce the link breakages and get a stable route, a new reactive routing protocol is proposed that is tree-based mobility-aware. The proposed Mobility and Direction Aware Ad-hoc On Demand Distance Vector routing protocol (MDA-AODV) aims to handle the mobility and direction factors in ad-hoc networks. MDA-AODV guides the route discovery and route reply depending on the speed of the participating nodes and their directions. Qualnet simulator version 7.1, using two offered load simulations (packet-rate and CBR connections), was used to investigate the effect and the advantages of MDA-AODV over AODV protocol. The simulation results show that the proposed scheme decreases control overhead by (4.6 ÷ 5.2%). It also accomplishes (37 ÷ 41%) lower route losses compared to AODV. The delivery ratio is increased by (29 ÷ 47%). The consumed energy and end-to-end delay of the proposed protocol is also compared to that of AODV. [ABSTRACT FROM AUTHOR]

Mobile multihop relay (MMR) WiMAX networks have attracted lots of interest in the wireless communication industry recently because of its scalable coverage, improved data rates, and relatively low cost. However, security of MMR WiMAX networks is the main challenge to be addressed. In this paper, we first identify several possible attacks on MMR WiMAX networks in which a rogue base station (BS) or relay station (RS) can get authenticated and gain control over the connections and show that the current standard does not address this problem well. We then propose a set of new authentication protocols for protecting MMR WiMAX networks from rogue BS attack, rogue RS attack, and suppress-replay attack. Our protocols can provide centralized authentication by using a trusted authentication server to support mutual authentication between RS and BS, between RS and RS, and between mobile station (MS) and RS. Moreover, our protocols can also provide distributed authentication with a license issued by the trusted server. We use a formal tool called Scyther to analyze and verify the security properties of our protocols. The results show that our protocols can counter rogue BS and RS attacks and suppress-replay attack and are not susceptible to any known attacks. [ABSTRACT FROM AUTHOR]

Key distribution is essential for providing secure communication between commercial and sensitive applications of wireless sensor and actor networks (WSANs). It becomes more challenging when any of the intermediate sensor nodes is compromised by the adversaries as the messages carrying secure keys will be exposed and links will be unreliable. This paper presents a Disjoint Key Establishment Protocol (DKEP) that does not require transmitting keys across the nodes. In DKEP, each node is preloaded with one row and one column from a matrix. After the deployment, indices for row and column are exchanged between the two nodes and values at intersection of row and column index will be used to calculate the key on each node. DKEP is verified by performing formal analysis using Rubin Logic and validated using simulations in NS-2. Simulation results demonstrate the effectiveness and efficiency of DKEP compared to contemporary schemes in terms of reducing storage and communication cost and improving resilience against node compromise attacks. Moreover, the proposed scheme is implemented in a group-based mobile application scenario for secure message exchange. [ABSTRACT FROM AUTHOR]

Transmission of system-critical control information plays a key role in efficient management of limited wireless network resources and successful reception of payload data information. This paper uses an orthogonal frequency division multiplexing (OFDM) architecture to investigate the detection performance of a time-domain approach used to detect deterministic control signalling information. It considers a type of control information chosen from a finite set of information, which is known at both transmitting and receiving wireless terminals. Unlike the maximum likelihood (ML) estimation method, which is often used, the time-domain detection technique requires no channel estimation and no pilots as it uses a form of time-domain correlation as the means of detection. Results show that when compared with the ML method, the time-domain approach improves detection performance even in the presence of synchronisation error caused by carrier frequency offset. [ABSTRACT FROM AUTHOR]

In the near future, wireless networks will be one of the key technologies for road traffic management in smart cities. Vehicles and dedicated roadside units should be interconnected through wireless technologies such as IEEE 802.11p (WAVE). Traffic lights and road signs may also take their place in this architecture, forming a large-scale network of small devices that report measurements, take orders from a control center, and are able to take decisions autonomously based on their local perception. Such a network shares many similarities with classical wireless sensor and actuator networks, starting with its distributed organization and with the role of the control center. However, its topology, and, subsequently, the appropriate selection of protocols and algorithms, will be strongly influenced by each city's characteristics. In this paper, we characterize and discuss probable topologies of these networks. The aim of this work is to provide network models that can be used to evaluate protocols and algorithms using realistic scenarios in place of generic random graphs. We deploy such networks over 52 city maps extracted from OpenStreetMap and characterize the resulting graphs, with particular focus on the connectivity aspects (degree distribution and connected components). The tools, the complete data sets, and OMNeT++ network models are freely available online. [ABSTRACT FROM AUTHOR]

VANETs have emerged as an exciting research and application area. Increasingly vehicles are being equipped with embedded sensors, processing and wireless communication capabilities. This has opened a myriad of possibilities for powerful and potential life-changing applications on safety, efficiency, comfort, public collaboration and participation, while they are on the road. Although, considered as a special case of a Mobile Ad Hoc Network, the high but constrained mobility of vehicles bring new challenges to data communication and application design in VANETs. This is due to their highly dynamic and intermittent connected topology and different application’s QoS requirements. In this work, we survey VANETs focusing on their communication and application challenges. In particular, we discuss the protocol stack of this type of network, and provide a qualitative comparison between most common protocols in the literature. We then present a detailed discussion of different categories of VANET applications. Finally, we discuss open research problems to encourage the design of new VANET solutions. [ABSTRACT FROM AUTHOR]

We present the Extended Minimum Estimated Expected Delay (EMEED) protocol for routing in wireless mobile Delay-Tolerant Networks (DTNs) comprising very large numbers of nodes with nonuniform, correlated mobility patterns. Under EMEED, packets are routed on graphs that are created taking into account (i) estimates of the expected delays until node pairs are within R C hops of each other and (ii) information on which node pairs are currently within R C hops of each other — R C is a tunable parameter. EMEED is inspired by the Minimum Estimated Expected Delay (MEED) protocol; it may be viewed as an extension of the basic routing method of MEED coupled with a suite of mechanisms that maintain the resulting control overhead at manageable levels. Packet replication is not employed. We evaluate the performance of EMEED through simulations in a pocket switched network and a vehicular DTN, comparing it with MEED, BUBBLE, Spray & Wait and flooding. We find that EMEED is superior to these other protocols in terms of jointly optimizing the packet delivery rate and the wireless channel usage efficiency. [ABSTRACT FROM AUTHOR]

This paper presents the design of triple band compact microstrip patch antenna with fractal elements. The antenna has been designed on FR4 substrate with thickness 1.6mm, dielectric constant 4.4 and resonant frequency of antenna is 3.2GHz. Gain of antenna is improved by addition of fractal elements to the nine corners of the nonagon patch. Introduction of fractal elements improved the gain from 1.24dB to 7.96dB and miniaturization takes place due to the decrease in resonant frequency from 3.38GHz to 2.88GHz on increasing the iteration number. The three iterations of antenna is designed and simulated by using HFSS V13 software and the designed antennas covers the frequency bands of WLAN, WiMax and other wireless applications which comes under the frequency ranges of S-band, C-band and X-band. [ABSTRACT FROM AUTHOR]

Buffer sizing is an important network configuration parameter that impacts the quality of service characteristics of data traffic. With falling memory costs and the fallacy that "more is better," network devices are being overprovisioned with large buffers. This may increase queueing delays experienced by a packet and subsequently impact stability of core protocols such as TCP. The problem has been studied extensively for wired networks. However, there is little work addressing the unique challenges of wireless environments such as time-varying channel capacity, variable packet inter-service time, and packet aggregation, among others. In this article we discuss these challenges, classify the current state-of-the-art solutions, discuss their limitations, and provide directions for future research in the area. [ABSTRACT FROM PUBLISHER]

The recent increase in the use of wireless networks for video transmission has led to the increase in the use of rate-adaptive protocols to maximize the resource utilization and increase the efficiency in the transmission. However, a number of these protocols lead to interactions among the users that are subjective in nature and affect the overall performance. In this paper, we present an in-depth analysis of interplay between the wireless network dynamics and video transmission dynamics in the light of subjective perceptions of the end users in their interactions. We investigate video exchange applications in which two users interact repeatedly over a wireless relay channel. Each user is driven by three conflicting objectives: maximizing the Quality of Service (QoS) and Quality of Experience (QoE) of the received video, while minimizing the transmission cost. Non-cooperative repeated games model precisely interactions among users with independent agendas. We show that adaptive video exchange is impossible if the duration of the interaction is determined. However, if the users interact indefinitely, they achieve cooperation via exchange of video streams. Our simulations evidence the tradeoff between users' QoS and QoE of their received video. The expected duration of the interaction plays a role and draws the region of solution trade-offs. We propose further means of shaping this region using Pareto optimality and user-fairness arguments. This work proposes a concrete game theoretical framework that allows the optimal use of traditional protocols by taking into account the subjective interactions that occur in practical scenarios. [ABSTRACT FROM AUTHOR]

Geographic routing has been considered as an attractive approach for wireless mobile ad hoc and sensor networks due to its effectiveness and scalability. Over the past few decades, numerous geographic routing protocols have been proposed extensively in 2D space. However, these protocols are no longer valid if ad hoc or sensor networks are distributed in 3D environments, such as space, atmosphere, and ocean. Because of the surprisingly difficulty of designing geographic routing protocols for 3D networks compared to 2D networks, only a few prior studies have focused on 3D geographic routing specifically designed for ad hoc and sensor networks. In this article, we first illustrate the principles of 3D geographic routing, and categorize current research work based on different criteria. Then we compare the 3DGR protocols under study through comprehensive analysis. Finally, we point out the open issues and opportunities for further research. [ABSTRACT FROM AUTHOR]

Although widely used, TCP has many limitations in meeting the throughput and latency requirements of applications in wireless networks, high-speed data center networks, and heterogeneous multi-path networks. Instead of relying purely on retransmission upon packet loss, coding has potential to improve the performance of TCP by ensuring better transmission reliability. Coding has been verified to work well at the link layer but has not been fully studied at the transport layer. There are many advantages but also challenges in exploiting coding at the transport layer. In this article, we focus on how to leverage end-to-end coding in TCP. We reveal the problems TCP faces and the opportunities coding can bring to improve TCP performance. We further analyze the challenges faced when applying the coding techniques to TCP and present the current applications of coding in TCP. [ABSTRACT FROM AUTHOR]

The most widespread wireless technology for mobile ad-hoc networks nowadays is Wi-Fi based on the IEEE 802.11 standard. The working procedure of this protocol produces various problems when multiple sub-networks are merged. The main drawbacks that may cause inability to communicate are the IP duplication and the existence of sub-networks in different channels. This paper proposes a practical solution to these problems, which does not cause any network overload and does not affect the data management of connections. Furthermore, it has been fully implemented in a new tool developed to create a vehicular ad-hoc network using only smartphones. Both a straightforward deterministic algorithm and a more complex scheme taking into account the interferences between wireless channels from a fuzzy logic point of view are defined here. Promising results regarding performance and security have been obtained from the analysis of large-scale NS2 simulations based on data got from implementations with real devices. [ABSTRACT FROM AUTHOR]

RFID is one of the most prominent identification schemes in the field of pervasive systems. Nonline of sight capability makes RFID systems much better choice than its contended systems (such as barcode, magnetic tape, etc.). Since the RFID uses wireless channel for communication with its associated devices, there should be some optimal encryption methods to secure the communicating data from adversaries. Several researchers have proposed ultralightweight mutual authentication protocols (UMAPs) to secure the RFID systems in cost effective manner. Unfortunately most of the previously proposed UMAPs are later found to be vulnerable against various desynchronization, Denial of Service (DoS), traceability, and full disclosure attacks. In this paper, we present a more sophisticated UMAP to provide Strong Authentication and Strong Integrity (SASI) using recursive hash function. The proposed protocol incorporates only simple bitwise logical operators XOR, Rot, and nontriangular function (recursive hash) in its design, which can be efficiently implemented with a low cost passive RFID tag. The performance analysis of the protocol proves the conformation of the proposed protocol with EPC-C1G2 passive tags. In addition to privacy and security, small chip area (miniaturization) is another design constraint (which is mandatory requirement for a protocol to be considered as ultralightweight authentication protocol). We have also proposed and implemented the efficient hardware design of the proposed protocol for EPC-C1G2 tags. Both the FPGA and ASIC implementation flows have been adopted. The FPGA flow is primarily used to validate the functionality of the proposed hardware design whereas ASIC flow (using TSMC 0.35 μm library) is used to validate the gate count. To the best of our knowledge, this is the first FPGA and ASIC implementation of any ultralightweight RFID authentication protocol. [ABSTRACT FROM AUTHOR]

IEEE 802.15.4 standard specifies the Medium Access Control (MAC) and Physical (PHY) layer for wireless sensor networks (WSN) applications with limited power and low data rate. This standard supports time critical applications by allowing TDMA based access in beacon enabled networks. In these networks, the PAN coordinator exchanges data with the end devices through guaranteed time slots (GTS). The PAN coordinator can allocate GTS on a first come first serve (FCFS) basis in response to the requests by end devices. In original standard, the coordinator can assign up to the maximum seven GTSs. This fixed number of GTS allocation may result in inefficient utilization of channel bandwidth. In this paper, we propose a new GTS allocation scheme that will set the GTS size adaptively in accordance with the data size of the end device. We call it as GTS Size Adaptation Algorithm (GSAA) and it will optimally use the GTS resources. Simulations have been performed to validate the proposed GSAA. [ABSTRACT FROM AUTHOR]

Authentication protocol plays an important role in the short-range wireless communications for the Near Field Communication (NFC) technology. Due to the shared nature of wireless communication networks, there are several kinds of security vulnerabilities. Recently, a pseudonym-based NFC protocol (PBNFCP) has been proposed to withstand the security pitfalls found in the existing conditional privacy preserving security protocol (CPPNFC). However, this paper further analyzes PBNFCP and shows that it still fails to prevent the claimed security properties, such as impersonation attacks against an adversary, who is a malicious registered user having a valid pseudonym and corresponding private key. In order to overcome these security drawbacks, this paper proposes a secure and efficient authentication protocol (SEAP) for NFC applications using lifetime-based pseudonyms. The proposed SEAP is simulated for the formal security verification using the widely-accepted AVISPA (Automated Validation of Internet Security Protocols and Applications) tool. The simulation results show that SEAP is secure. The rigorous security and performance analysis shows that the proposed SEAP is secure and efficient as compared to the related existing authentication protocols for NFC applications. [ABSTRACT FROM PUBLISHER]

Until recently, Industrial Automation and Control Systems (IACS) were largely isolated from corporate systems by means of proprietary protocols, which facilitated their protection against cyber-attacks under the principle of security through obscurity. However, the widespread adoption of the new communication technologies, such as the Internet protocols and wireless communications has changed this scenario. In recent years there have been many evidences of cyberattacks to IACS that exploit their vulnerabilities. Unfortunately, these attacks have increased significantly during the last five years, and quite clearly only the tip of the iceberg comes to the public knowledge. The purpose of this article is twofold: (1) to raise awareness about the security vulnerabilities that most companies are facing at their IACS and (2) to propose a roadmap that seeks to guide designers and programmers in the new and complex world of industrial cyber-security. [ABSTRACT FROM AUTHOR]

Address autoconfiguration of resource constrained MANETs is a challenging issue for decades. The heterogeneity, multi-interfaces, extreme resource constrains and miniaturization of the nodes participating in multiple networks affects the autoconfiguration schemes. The significant roles of resource utilization caused by multiple communications and its challenges to autoconfiguration have not drawn attention. A cross layer approach called Selective address allocator configuration protocol (SAACP) has been proposed to enhance the service responsiveness and continuity of the autoconfiguration scheme used for resource constrained nodes. The SAACP protocol is a stateful autoconfiguration protocol which selects the address allocator using a weighing algorithm. The algorithm derives weightage for the nodes based on the node's resource utilization information collected from different layers of network stack. The cost and performance of the proposed scheme has been analyzed using mathematical formulations and simulations respectively. The simulation results show that the proposed scheme reduces address allocation latency, packet losses and protocol overhead and correspondingly increases successful allocation ratio. The scheme proves to perform well even in high resource constraints, node mobility, network merging and partitioning. [ABSTRACT FROM AUTHOR]

Opportunistic forwarding has emerged as a promising technique to address the problem of unreliable links typical in wireless sensor networks and improve energy efficiency by exploiting multiuser diversity. Timer-based solutions, such as timer-based contention, form promising schemes to allow opportunistic next hop relay selection. However, they can incur significant idle listening and thus reduce the lifetime of the network. To tackle this problem, we propose to exploit emerging wake-up receiver technologies that have the potential to considerably reduce the power consumption of wireless communications. A careful design of MAC protocols is required to efficiently employ these new devices. In this work, we propose Opportunistic Wake-Up MAC (OPWUM), a novel multihop MAC protocol using timer-based contention. It enables the opportunistic selection of the best receiver among its neighboring nodes according to a given metric (e.g., the remaining energy), without requiring any knowledge about them. Moreover, OPWUM exploits emerging wake-up receivers to drastically reduce nodes power consumption. Through analytical study and exhaustive networks simulations, we show the effectiveness of OPWUM compared to the current state-of-the-art protocols using timer-based contention. [ABSTRACT FROM AUTHOR]

The Internet is used by more than two billion customers around the world and is expected to serve as a global platform for interconnecting cyber-physical objects that form the Internet of Things (IoT). Within the next decade, traffic demands are expected to increase a thousand-fold. This challenge can be addressed by introducing and expanding heterogeneous wireless technologies, which provide higher network capacity, wider coverage and higher quality of service (QoS). However, the heterogeneity and complexity of these networks are a major challenge for traditional control and management systems. Therefore, there is a need for self-manageable and self-configurable networks that support the data produced by the different IoT devices and provide opportunities for data analytics. In this work, a cognitive network framework is proposed, in which the network protocol stack is integrated with a semantic system. The proposed framework provides the bases for building smart networks that observe data from different layers in the network protocol stack and represents it in a hierarchical structure in a knowledge base. The framework employs an ontology that provides an abstraction model for the different heterogeneous wireless devices. The ontology determines the relationships between technology-dependent parameters in the network protocol stack and enables, through the use of inferences, the utilization of the observed data from the network. The use of a cognitive network framework with the network protocol stack allows adding ontologies to describe the data, a solution which could solve the problem of analysing, searching or visualising data. [ABSTRACT FROM AUTHOR]

With ever growing mobile Internet and the explosion of its applications, users are experiencing abundant services from different content providers via different network service providers in the heterogeneous network. The information-centric network (ICN) advocates getting rid of the current host-centric network protocol because information dissemination rather than end-to-end communication contributes to the majority of today's network traffic. Furthermore, it is better for network entities to converge as a whole in order to take advantage of open, scalable, and smart traffic transmission. The cloud radio access network is one of the emerging architecture evolutions on the wireless side for easier infrastructure deployment and network management. Therefore, when the information-centric network meets the C-RAN in the Het-Net, it is worthwhile and consequential to integrate ICN protocol with C-RAN architecture to achieve more efficient communication and information management. Moreover, SDN has been recognized as another promising architecture evolution to achieve the flexibility and reconfigurability of dense HetNets; its inherent advantage lies in global uniform control of the wired network. Thus, any of ICN, C-RAN and SDN is the complementary to the others. In this article, we contribute to a fresh proposal for and elaboration of the integration of the ICN, CRAN, and SDN for the HetNet to achieve a win-win situation. The vision of the proposed system is demonstrated, followed by the advantages and challenges. We further present a hybrid system in a large-scale wireless heterogeneous campus network. [ABSTRACT FROM PUBLISHER]

While energy consumption is widely considered the primary challenge of wireless networked devices, energy harvesting emerges as a promising way of powering the Internet of Things (IoT). In the Medium Access Control (MAC) layer of the communication stack, energy harvesting introduces spatial and temporal uncertainty in the availability of energy. In this context, this paper focuses on the design and implementation of the MAC layer of wireless embedded systems that are powered by energy harvesting; providing novel protocol features and practical experiences to designers of consumer electronics who opt for tailoring their own protocol solutions instead of using the standards. [ABSTRACT FROM AUTHOR]

Mobile and wireless networks permit to widen traditional internet applications to this kind of networks. Furthermore, with the dramatic increase in their capabilities, mobile devices are becoming one of the main processing devices for users. However, they still lack resources compared to traditional processing devices. Integration between mobile devices over mobile ad hoc networks and Cloud computing is addressed in various studies. The goal of this paper is to propose a protocol for the deployment of an ad hoc mobile cloud over MANETs. This scenario has multiple advantages such as ubiquity, availability, affordability, opportunity and spontaneity. The proposed system is composed of two types of nodes: Providers and Customers. A group of nodes with sufficient resources (Providers) collaborate to set up an IAAS like cloud and provides their services to a set of nodes (Customers) requesting resources. The protocol permits a dynamic management of provider and customer nodes. [ABSTRACT FROM AUTHOR]

Recently, the IEEE 802.15.6 Task Group introduced a new wireless communication standard that provides a suitable framework specifically to support the requirements of wireless body area networks (WBANs). The standardization dictates the physical (PHY) layer and medium access control (MAC) layer protocols for WBAN-based communications. Unlike the pre-existing wireless communication standards, IEEE 802.15.6 standardization supports short-range, extremely low power wireless communication with high quality of service and support for high data rates upto 10 Mbps in the vicinity of living tissues. In this work, we construct a discrete-time Markov chain (DTMC) that efficiently depicts the states of an IEEE 802.15.6 CSMA/CA-based WBAN. Following this, we put forward a thorough analysis of the standard in terms of reliability, throughput, average delay, and power consumption. The work concerns non-ideal channel characteristics and a saturated network traffic regime. The major shortcoming of the existing literature on Markov chain-based analysis of IEEE 802.15.6 is that the authors did not take into consideration the time spent by a node awaiting the acknowledgement frame after transmission of a packet, until time-out occurs. Also, most of the work assume that ideal channel characteristics persist for the network which is hardly the case in practice. This work remains distinctive as we take into account the waiting time of a node after it transmits a packet while constructing the DTMC. Based on the DTMC, we perform a user priority (UP)-wise analysis, and justify the importance of the standard from a medical perspective. [ABSTRACT FROM AUTHOR]

Wireless technologies have evolved very rapidly in recent years. In the future, operators will need to enable users to use communication services independently of access technologies, so they will have to support seamless handovers in heterogeneous networks. In this paper we present a novel adaptive congestion aware Session Initiation Protocol (SIP) based procedure for handover in heterogeneous networks. In the proposed algorithm the handover decision is based in addition to signal strength, also on target network congestion status, which is tested during the conversation. As SIP protocol was used, the proposed procedure is independent of access technologies. For performance evaluation of proposed procedure we developed a purpose built simulation model. The results show that the use of the proposed adaptive procedure significantly improves the QoE of VoIP users, compared to reference scenario, in which only signal strength was used as the trigger for handover decision. [ABSTRACT FROM AUTHOR]

ITU-R M.1842-1, as a well-known specification dedicated to maritime mobile applications, has standardized wireless transmission protocols according to the particular characteristics of a maritime communications scenario. A time division multiple access (TDMA) frame structure, along with modulation schemes to achieve a high data rate, has been described clearly in ITU-R M.1842-1. However, several specification items are still under "to be decided" status, which brings ambiguity to research works. In addition, the current version of ITU-R M.1842-1 is focused mainly on maritime transmissions in open-sea areas, where the cyclic prefix (CP) is set to zero and only 16-QAM is used in the multi-carrier (MC) system. System performance might be dramatically degraded in coastline areas due to the inter-symbol interference (ISI) caused by selective fading. This is because there is a higher probability that the signal will be reflected by obstacles in coastline areas. In this paper, we introduce the transmission resource block (TRB) dedicated to ITU-R M.1842-1 for a ship ad-hoc network (SANET), where the pilot pattern of TRB is based on the terrestrial trunked radio (TETRA). After that, we evaluated SANET performance under the maritime channel model in a coastline area. In order to avoid noise amplification and to overcome the ISI caused by selective fading, several strategies are suggested and compared in the channel estimation and equalization procedures, where the link-level simulation results finally validate our proposals. [ABSTRACT FROM AUTHOR]

In this paper, we analyze the impact of hardware impairments at relay node and source node (i.e. imperfect nodes) on network performance by evaluating outage probability based on the effective signal to noise and distortion ratio (SNDR). Especially, we propose energy harvesting protocol at the relay and source nodes, namely, power switching imperfect relay (PSIR) and power switching imperfect source (PSIS). Aiming to determine the performance of energy constrained network, we first derive closed-form expressions of the outage probability and then the throughput can be maximized in delay-limited transmission mode. The simulation results provide practical insights into the impacts of hardware impairments and power switching factors of the energy harvesting protocol on the performance of energy harvesting enabled two-way relaying network. [ABSTRACT FROM AUTHOR]

Wireless technology will be widely used in libraries with the development of the mobile network in the near future. This paper focuses on MAC protocol for wireless network based on ultra-wideband band (UWB) to solve the problems of real-time and reliability in the wireless transmitting. According to the particular signal characteristics such as low energy consumption and excellent location, we propose a multichannel MAC protocol (UWBIMAC) based on status-adaptive to choose the channel mechanism. Simulation results show that the protocol had the ability of stronger antijamming, improved network throughput, and provided better average delay performance than IEEE802.15.4 MAC, IEEE802.11 MAC, and other UWBIMAC protocols. This method could be used in the process of wireless transmission service in the library or other similar scenarios. To a certain extent, it solves the problem of real-time and reliable performance in the process of wireless communication. [ABSTRACT FROM AUTHOR]