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Recent physical-layer designs capable of decoding multi-packet collisions demonstrate great potential for improving the network performance. Current network protocols, however, tailor the traditional physical layer to avoid collisions and thus cannot fully exploit the benefits of concurrent transmission techniques. In this paper, we propose an innovative generic concurrent transmission aware routing design called mShare. The mShare design exploits the benefits of these techniques by scheduling concurrent senders to utilize co-owned receiver(s) in parallel. This design significantly increases the available number of routing choices and thus improves the network performance. To illustrate the versatility of our design, we test mShare in three settings: unicast, opportunistic routing, and data collection (convergecast). The performance of mShare is evaluated with physical testbed experiments running on USRP and simulations. The experimental results show that compared to conventional designs, mShare: 1) improves 277% of the throughput in unicast; 2) saves 78% of transmissions in opportunistic routing; and 3) reduces 70% of the delivery delay in data collection. [ABSTRACT FROM AUTHOR]

Abstract Offloading data traffic from Infrastructure-to-Device (I2D) to Device-to-Device (D2D) communications is a powerful tool for reducing congestion, energy consumption, and spectrum usage of mobile cellular networks. Prior network-level studies on D2D data offloading focus on high level performance metrics as the offloading efficiency , and take into account the radio propagation aspects by using simplistic wireless channel models. In this work, we consider a D2D data offloading protocol tailored to highly dynamic scenarios as vehicular environments, and evaluate its performance focusing on physical layer aspects, like energy consumption and spectral efficiency. In doing this, we take into account more realistic models of the wireless channel, with respect to the simplistic ones generally used in the previous studies. Our objective is twofold: first, to quantify the performance gain of the considered D2D offloading protocol with respect to a classic cellular network, based on I2D communications, in terms of energy consumption and spectral efficiency. Second, to show that using simplistic channel models may prevent to accurately evaluate the performance gain. Additionally, the use of more elaborated models allows to obtain insightful information on relevant system-level parameters settings, which would not be possible to obtain by using simple models. The considered channel models range from widely used models based on deterministic path loss formulas, to more accurate ones, which include effects like multipath fading and the associated frequency selectivity of wideband channels. These models have been proposed and validated, in the recent years, through large-scale measurements campaigns. Our results show that the considered protocol is able to achieve a reduction in the energy consumption of up to 35%, and an increase in the system spectral efficiency of 50%, with respect to the benchmark cellular system. The use of different channel models in evaluating these metrics may result, in the worst case, in a sixfold underestimation of the achieved improvement. [ABSTRACT FROM AUTHOR]

Abstract In this work, we investigate the pilot contamination problem in multi-cell massive multi-input multi-output (MIMO) systems. The conventional approaches to address pilot contamination for multi-cell MIMO systems impose orthogonal pilots constraint across multiple users and cells, which leads to bandwidth inefficiency under large number of active users. We propose an uplink (UL) transmission protocol in which the pilot segments of users partially overlap across cells and even overlap with data from other cells, which provides more freedom in system designing. We also apply semi-blind algorithms at base station (BS) in order to separate the data streams of each user. Our analysis shows that semi-blind receiver removes pilot contamination effectively under large UL data length. The simulation results demonstrate that the performance of the proposed protocol with semi-blind receiver employing Constant Modulus Algorithm (CMA) is superior as compared to the existing schemes. [ABSTRACT FROM AUTHOR]

Energy harvesting (EH) combined with cooperative relying plays a promising role in future wireless communication systems. We consider a wireless multiple EH relay system. All relays are assumed to be EH nodes with simultaneous wireless and information transfer (SWIPT) capabilities, which means the relays are wirelessly powered by harvesting energy from the received signal. Each EH node separates the input RF signal into two parts which are, respectively, for EH and information transmission using the power splitting (PS) protocol. In this paper, a closed-form outage probability expression is derived for the cooperative relaying system based on the characteristic function of the system's probability density function (PDF) with only one relay. With the approximation of the outage probability expression, three optimization problems are built to minimize the outage probability under different constraints. We use the Lagrange method and Karush-Kuhn-Tucker (KKT) condition to solve the optimization problems to jointly optimize the relay's PS factors and the transmit power. Numerical results show that our derived expression of the outage probability is accuracy and gives insights into the effect of various system parameters on the performance of protocols. Meanwhile, compared with the no optimal condition, our proposed optimization algorithms can all offer superior performance under different system constraints. [ABSTRACT FROM AUTHOR]

The world of connected devices has led to the rise of the Internet of Things paradigm, where applications rely on multiple devices, gathering and sharing data across highly heterogeneous networks. The variety of possible mechanisms, protocols, and hardware has become a hindrance in the development of architectures capable of addressing the most common IoT use cases, while abstracting services from the underlying communication subsystem. Moreover, the world is moving toward new strict requirements in terms of timeliness and low latency in combination with ultra-high availability and reliability. Thus, future IoT architectures will also have to support the requirements of these cyber-physical applications. In this regard, edge computing has been presented as one of the most promising solutions, relying on the cooperation of nodes by moving services directly to end devices and caching information locally. Therefore, in this article, we propose a modular and scalable architecture based on lightweight virtualization. The provided modularity, combined with the orchestration supplied by Docker, simplifies management and enables distributed deployments, creating a highly dynamic system. Moreover, characteristics such as fault tolerance and system availability are achieved by distributing the application logic across different layers, where failures of devices and micro-services can be masked by this natively redundant architecture, with minimal impact on the overall system performance. Experimental results have validated the implementation of the proposed architecture for on-demand services deployment across different architecture layers. [ABSTRACT FROM AUTHOR]

We propose a Context-aware Smallworld routing protocol for wireless ad-hoc networks which finds efficient routes to the destination nodes often through a very short chain of intermediate nodes, without using any routing table. This protocol exploits the “small-world” phenomenon of social networks where source-destination pairs typically get connected through few intermediate friends and the individuals can collectively discover such short paths. The key idea behind our routing protocol is that for forwarding an incoming packet to the destination, a node picks the next hop from among the one-hop neighbor from its one-hop neighborhood that is closest to the destination, and multiple randomly selected long-distance neighbor(s), i.e., from outside of its one-hop neighborhood, based on which of these neighbors is closest to the destination. The long-distance neighbors are selected by using their contextual information through a probabilistic mapping. We provide the theoretical foundations behind our protocol. This simple but effective algorithm can meet performance objectives for most scenarios by reducing loss and latency. Simulation results, using synthetic network topologies, have demonstrated that the routing performance of context-aware Smallworld is better than geographical (distance-based) Smallworld and other standard proactive routing protocols (e.g., OLSRv2) when metrics, such as packet losses, end-to-end delays, hop-counts, connectivity drops, and control traffic generated, are used as the key performance indicators. We also show that the proposed protocol is resilient to dynamic topology changes. [ABSTRACT FROM AUTHOR]

The rapid urbanisation has transformed cities to the preferential human settlement and allowed cities to quietly witness all range of human activities. As the key enabler in the information and communications technology industry, cellular networks play a decisive role in delivering communication messages and entertainment content. In particular, cellular network operators respond to human initiated service requests by gradually deploying necessary infrastructure and calibrating transmission protocols. Hence, cellular network records encompass the interesting interaction between human-initiated messages and network-triggered responses. In this study, the authors collect the 'big data' in urban cellular networks and try to dig out the human and urban planning properties. Specifically, they focus on the statistical modelling of three representative scenarios like spatial deployment density of base stations, packet length or traffic volume of mobile services, as well as inter-arrival time and dwell time of human mobility. Through extensive data mining, they validate the heavy-tailed feature universally existing in these scenarios. Afterwards, they discuss the implications of this heavy-tailed feature and talk about its fundamental contribution to intelligent resource adjustment, proactive content caching, and enhanced connection management in cellular networks. Finally, they highlight the applications of this feature towards smarter cellular networks and cities. [ABSTRACT FROM AUTHOR]

Continuously increasing the data rate in wireless networks is required to satisfy the ever-increasing service demands. Full-duplex (FD), a promising technology for wireless networks, is able to double the data rate theoretically. Although several researchers study the physical (PHY) and medium access control (MAC) protocols of FD technology, there are few study focusing on the multiuser MAC protocol design for the next generation wireless networks. In this paper, a power control (PC) based multiuser FD MAC protocol, named PC MU-FuPlex, is proposed. Moreover, the probability of establishing FD link is formulated specifically. The simulation results demonstrate that the proposed MAC protocol significantly improves the saturation throughput up to 200% compared to that without PC in higher modulation. [ABSTRACT FROM AUTHOR]

During the last two decades, there has been a tremendous growth in the use of MANETs, not only due to the development of the technology but also due to their high flexibility. MANETs have challenges and limitations and among the major challenge is the routing process because of high dynamic topology and distributed nature. This is the main reason for quick depletion of network resources. Thus, there is a need to develop a routing protocol to fulfill various application requirements and enhance routing paths according to the topology change. In this paper, two protocols are proposed in order to optimally utilize the constrained network resources and reliably detect high-quality links. They are Hybrid Geo-cast Routing (HGR) protocol and Signal Strength and Congestion Avoidance protocol (SSCA). The optimal and adaptive HGR protocol utilizes geographical location information to limit search area during route discovery process by including only promising search paths to minimize control overhead. Meanwhile, adaptive SSCA uses SSCA mechanism in order to enhance link and node quality detection and reduce packet drop. The experimental results show that the proposed HGR protocol is able to reduce up to 46.67% control overhead. Meanwhile, the proposed adaptive SSCA protocol reduces packet drop to 71.20%. [ABSTRACT FROM AUTHOR]

This paper describes Census, a protocol for data aggregation and statistical counting in MANETs. Census operates by circulating a set of tokens in the network using biased random walks such that each node is visited by at least one token. The protocol is structure-free so as to avoid high messaging overhead for maintaining structure in the presence of node mobility. It biases the random walks of tokens so as to achieve fast cover time; the bias involves short albeit multi-hop gradients that guide the tokens towards hitherto unvisited nodes. Census thus achieves a cover time of O(N) and message overhead of O(Nlog(N)) where N is the number of nodes. Notably, it enjoys scalability and robustness, which we demonstrate via simulations in networks ranging from 100 to 4000 nodes under different network densities and mobility models. We also observe a speedup by a factor of k when k different tokens are used (1≤k≤N). [ABSTRACT FROM AUTHOR]

The existing RFID (Radio Frequency Identification) security protocol lacks the key establishment mechanism, assuming only that both parties of the authentication protocol have shared their respective session keys. However, key establishment is an integral part of the RFID security system. This article first introduces the elliptic curve related mathematical theory foundation. Then we establish the key negotiation mechanism, and analyze the correctness and rationality of the negotiation mechanism. Finally, we design the authentication protocol based on elliptic curve in mobile RFID system, analyze the protocol authentication process, and compare the security and performance with other protocols, which shows that the authentication protocol has more efficient performance and the ability to resist all kinds of attacks. [ABSTRACT FROM AUTHOR]

Runtime validation of wireless protocol implementations cannot always employ direct instrumentation of the device under test (DUT). The DUT may not implement the required instrumentation, or the instrumentation may alter the DUT’s behavior when enabled. Wireless sniffers can monitor the DUT’s behavior without instrumentation, but they introduce new validation challenges. Losses caused by wireless propagation prevent sniffers from perfectly reconstructing the actual DUT packet trace. As a result, accurate validation requires distinguishing between specification deviations that represent implementation errors and those caused by sniffer uncertainty. We present a new approach enabling sniffer-based validation of wireless protocol implementations. Beginning with the original protocol monitor state machine, we automatically and completely encode sniffer uncertainty by selectively adding non-deterministic transitions. We characterize the NP-completeness of the resulting decision problem and provide an exhaustive algorithm for searching over all mutated traces. We also present practical protocol-oblivious heuristics for searching over the most likely mutated traces. We have implemented our framework and show that it can accurately identify implementation errors in the face of uncertainty. [ABSTRACT FROM AUTHOR]

The state of the art in wireless communication is highly spectrum efficient but performs poorly in terms of energy efficiency. With widespread deployment, battery operated devices, escalating energy cost, and inherent energy inefficiency of the Carrier Sense Multiple Access protocol in wireless, it is of prime importance today to look for improved energy efficiency in wireless communication. One promising solution is to use multi clock-rate sampling devices in conjunction with frequency agnostic preamble detection. This reduces the power consumed by wireless devices in idle listening, without significantly affecting the throughput and spectrum efficiency. In this paper, we model such a device as a Markov chain and determine its performance in terms of power consumption and goodput, and discuss the elemental trade-off between the two. The analytical results are verified using extensive simulation and compared with existing techniques. A preamble construction scheme that allows devices with different downclocking levels to coexist in the same network is also explored. Finally, we propose a novel preamble compression scheme based on Robust Header Compression to provide improved performance and scalability. [ABSTRACT FROM AUTHOR]

This paper considers a wireless powered communication network, where a multiantenna power beacon (PB) is employed to assist an energy constrained source to establish secure communications with a destination in the presence of multiple eavesdroppers. We propose a two-phase communication protocol termed as accumulate then transmit to enhance network secrecy. In the energy harvesting phase, the PB transfers radio frequency energy to charge the source; then in the information transmission phase, the PB acts as a friendly jammer to protect the source transmission against eavesdropping. We study the dynamic energy state transitions at the source using an energy discretization method and a finite-state Markov chain. Closed-form expressions are derived for connection outage probability, secrecy outage probability, and effective secrecy throughput, with the aim to evaluate both reliability and security of the proposed protocol. Furthermore, numerical results reveal the impacts of various system parameters on the secrecy performance and demonstrate the superior performance of our proposed protocol over an existing scheme. [ABSTRACT FROM AUTHOR]

An opportunistic network is a wireless ad hoc network that has frequently intermittent connectivity due to nodes’ mobility. These spare, unpredictable networks aim to solve the prolonged delay paths by a store-carry-forward scheme. It is difficult to determine the appropriate nodes to forward the messages since there are few opportunistic contacts. The nodes might decide based on the obtained data of the network as a guide to reach a destination. The aforementioned technique is not helpful in case the rate of change in the network topology is higher than the rate of data gathering due to usage restrictions and uncertain available information/knowledge of the future contacts. In this paper, to cope with the challenges imposed by the un-deterministic environment, a risk assessment strategy is considered to evaluate the short and long-term impact of each decision to find the optimal node/paths. This routing scheme can take advantage of the unanticipated connection to make the routing more flexible in short time and with less buffer usage. Our proposed risk assessment algorithms that are based on MALP are mixed with the knowledge about buffer management and network capacity. The prioritized messages to be disseminated as well as better decision to take a risk are the main contributions of this paper. Moreover, the self-adaptive threshold, distributed PID controller, is considered to tackle different threshold levels for each node individually. Numerical results prove that the proposed method drastically increases the delivery ratio and also minimizes the risk of exceeding resource consumption and packet loss. [ABSTRACT FROM AUTHOR]

Nowadays, wireless LAN has become the most widely deployed technology in mobile devices for providing Internet access. Operators and service providers remarkably increase the density of wireless access points in order to provide their subscribers with better connectivity and user experience. As a result, WLAN users usually find themselves covered by multiple access points and have to decide which one to associate with. In traditional implementations, most wireless stations would select the access point with the strongest signal, regardless of traffic load on that access point, which might result in heavy congestion and unfair load. In this paper, we propose a novel on-line association algorithm to deal with any sequence of STAs during a long-term time such as one day. the performance of our algorithm is evaluated through simulation and experiments. Simulation results show that our algorithm improves the overall WLAN throughput by up to 37%, compared with the conventional RSSI-based approach. Our algorithm also performs better than SSF (Strongest Signal First) and LAB (Largest Available Bandwidth) in the experiments. [ABSTRACT FROM AUTHOR]

Mobility management is classified into two parts such as location management and handoff management. The earlier one concentrates on location update whereas the later one manages continuous Internet connectivity while the Mobile Router (MR) changes its single point of attachment to the network. Therefore, frequent movement of the MR is one of the significant characteristics in Network Mobility (NEMO) environment. Because, in accordance with the standard Network Mobility Basic Support Protocol (NEMO BSP), the MR utilizes single Interface to attach to the access link. MR requires changing its Care of Address (CoA) when it moves among different wireless access networks. As a result, it can directly influence the performance of the mobility management protocols during inter technology handoff of multi-interfaced MR. This paper proposed a multi-interfaced fast handoff scheme in Proxy NEMO (PNEMO) environment. After that, it represents a comparative analysis between the proposed multiinterfaced scheme, NEMO BSP and the PNEMO scheme respectively. The performance disparities of these schemes are estimated and analyzed via both numerical and simulation approaches. The simulation is performed through NS-3 network simulator. The performance metrics estimated for evaluation are mainly handoff delay and packet loss. It has been perceived that, the proposed scheme performs better compared to the PNEMO scheme and NEMO BSP. [ABSTRACT FROM AUTHOR]

We present a distributed stable protocol for local broadcast in multi-hop wireless networks, where packets are injected to the nodes continuously, and each node needs to quickly disseminate the injected packets to all its neighbors within a given communication range $R$. We investigate the maximum packet injection rate and the minimum packet latency that can be achieved in a stable protocol. This paper assumes the signal-to-interference-plus-noise-ratio (SINR) interference model, which reflects more accurately the physical characteristics of the wireless interference, such as fading and signal accumulation, than conventional local interference models, e.g., graph-based models. More specifically, we present a stable protocol that can handle both stochastic and adversarial injection patterns. The protocol is asymptotically optimal in terms of both injection rate and packet latency. To the best of our knowledge, this paper is the first one studying the properties of stable protocols for the basic primitive of local broadcast in a multi-hop setting under SINR. Our proposed protocol utilizes a static local broadcast algorithm as a subroutine. This static algorithm is of independent interest, and it closes the $O(\log n)$ gap between the upper and lower bounds for static local broadcast. Simulation results indicate that our proposed algorithms can perform well in realistic environments. [ABSTRACT FROM AUTHOR]

Wireless sensor networks (WSNs) are finding application in numerous fields. For many of these applications, some or all of the sensor nodes are mobile. Mobility management in WSNs is a challenging and has been the subject of intensive research. In this paper, we propose an IP-based mobility management protocol named Fast handover Proxy Mobile IPv6 for Sensor networks (FPMIPv6-S). FPMIPv6-S provides network-based mobility support for 6LoWPAN WSN when a sensor node moves between two Personal Area Networks. It is an improved version of the PMIPv6 protocol proposed for mobility management in IPv6 networks. FPMIPv6-S messages are carried by RPL protocol. Analytical evaluation of the proposed protocol shows significantly improved performance with respect to network mobility cost (signalling traffic) when compared to PMIPv6 and RPL alone. We also integrated the FPMIPv6-S protocol in the NS-3 simulator and performed a thorough performance comparison of FPMIPv6-S and RPL. [ABSTRACT FROM AUTHOR]

Low-Power Wide-Area Networks (LPWANs) have recently emerged as appealing communication systems in the context of the Internet of Things (IoT). Particularly, they proved effective in typical IoT applications such as environmental monitoring and smart metering. Such networks, however, have a great potential also in the industrial scenario and, hence, in the context of the Industrial Internet of Things (IIoT), which represents a dramatically growing field of application. In this paper we focus on a specific LPWAN, namely, LoRaWAN, and provide an assessment of its performance for typical IIoT employments such as those represented by indoor industrial monitoring applications. In detail, after a general description of LoRaWAN, we discuss how to set some of its parameters in order to achieve the best performance in the considered industrial scenario. Subsequently we present the outcomes of a performance assessment, based on realistic simulations, aimed at evaluating the behavior of LoRaWAN for industrial monitoring applications. Moreover, the paper proposes a comparison with the IEEE 802.15.4 network protocol, which is often adopted in similar application contexts. The obtained results confirm that LoRaWAN can be considered as a strongly viable opportunity, since it is able to provide high reliability and timeliness, while ensuring very low energy consumption. [ABSTRACT FROM AUTHOR]

In vehicle-to-vehicle (V2V) communications, achieving reliable physical layer performance is a challenging task due to the highly dynamic nature of V2V propagation channels. Frame timing estimation, as one of the most critical signal processing procedures that rely on channel statistics, has to be appropriately enhanced to tackle this challenge. This study presents a novel frame timing estimation scheme based on both the available periodical preambles in IEEE 802.11p standard. By designing the fourth-order statistics-based correlation and differential normalisation functions, the proposed timing metric not only is capable of possessing an extensible correlation length, but also achieves the robustness to multipath effect and large carrier frequency offset. From the standpoints of hypothesis testing and classification, the proposed approach can effectively increase the distinction between correct and wrong timing indexes in terms of the class-separability criteria, and consequently has a significantly improved timing estimation performance compared with the existing methods. Simulation results consist with theoretical analysis under the typical V2V channel model, and demonstrate that the proposed method can significantly reduce both the probabilities of false alarm and missed detection, and make the selection of a suitable threshold for frame detection much easier. [ABSTRACT FROM AUTHOR]

Peer-sampling protocols constitute a fundamental mechanism for a number of large-scale distributed applications. The recent introduction of WebRTC facilitated the deployment of decentralized applications over a network of browsers. However, deploying existing peer-sampling protocols on top of WebRTC raises issues about their lack of adaptiveness to sudden bursts of popularity over a network that does not manage addressing or routing. Spray is a novel random peer-sampling protocol that dynamically, quickly, and efficiently self-adapts to the network size. Our experiments show the flexibility of Spray and highlight its efficiency improvements at the cost of small overhead. We embedded Spray in a real-time decentralized editor running in browsers and ran experiments involving up to 600 communicating Web browsers. The results demonstrate that Spray significantly reduces the network traffic according to the number of participants and saves bandwidth. [ABSTRACT FROM AUTHOR]

To provide a tool for performance evaluation of IEEE 802.15.4 with sleep mode enabled, a novel model based on real time queueing analysis is proposed in this paper. A low-rate wireless personal area network (LR-WPAN), composed of multiple nodes which send packets to the coordinator, is considered. The queueing behaviour of IEEE 802.15.4 node with sleep mode enabled differs from others because the packet arrivals in sleep period accumulate at the beginning of the active period, which makes a heavier load in the beginning than at any other time. This model analyses this behaviour by dividing the active portion of the superframe into backoff slots and then using an embedded discrete-time Markov chain model. The concept of virtual service time is introduced into this model which makes the proposed queueing model novel and different from typical ones. The accuracy of the proposed model is validated by Monte Carlo simulations in existing typical application scenarios, which indicates that the proposed queueing model can accurately evaluate the performance of IEEE 802.15.4 in the context of the application scenarios described in the simulations. [ABSTRACT FROM AUTHOR]

Interconnection has a great importance to provide a high bandwidth communication among parallel systems. On multi-core context, Network-on-Chip is the default intra-chip interconnection choice, providing low contention and high bandwidth between the processing elements. However, the communication outside the chip commonly uses high performance links which have the entire communication protocol stack overhead. This paper introduces the Expansible NoC concept and architecture, which is formed by wired and wireless NoC components in order to provide a low overhead interconnection for intra-chip and inter-chip communication. ENoC couples both networks with the same simplified protocol, enabling the transmission of parallel messages directly in the NoC level. The ability of identifying new communicant on-the-fly increases its flexibility, expanding the system boundaries every time a new system is connected. The ENoC inter-chip wireless link reaches short distances working at 60 GHz with Orthogonal Frequency Division Multiplexing with Quadrature Amplitude Modulation, enabling high bandwidth communication for systems inside a single cluster rack. Experimental evaluations were performed using the Noxim simulator executing computational fluid dynamics benchmark applications. Results show that the proposed architecture improves up to 38% the performance when compared to the newest related work. [ABSTRACT FROM AUTHOR]

Global Mobility Networks(GLOMONETs) in wireless communication permits the global roaming services that enable a user to leverage the mobile services in any foreign country. Technological growth in wireless communication is also accompanied by new security threats and challenges. A threat-proof authentication protocol in wireless communication may overcome the security flaws by allowing only legitimate users to access a particular service. Recently, Lee et al. found Mun et al. scheme vulnerable to different attacks and proposed an advanced secure scheme to overcome the security flaws. However, this article points out that Lee et al. scheme lacks user anonymity, inefficient user authentication, vulnerable to replay and DoS attacks and Lack of local password verification. Furthermore, this article presents a more robust anonymous authentication scheme to handle the threats and challenges found in Lee et al.’s protocol. The proposed protocol is formally verified with an automated tool(ProVerif). The proposed protocol has superior efficiency in comparison to the existing protocols. [ABSTRACT FROM AUTHOR]

A cooperative wireless-powered communication network protocol is proposed, in which user far away from a hybrid access point (H-AP) is capable of harvesting wireless powers by overhearing the uplink signals of users that are relatively nearer to the H-AP, in addition to downlink signal broadcast by the H-AP. In this setting, time allocations for the downlink transmission of the H-AP and the uplink transmission for the users are jointly optimized for two different purposes. First, the weighted sum-rate maximization problem is solved for a given total transmission time. Then, the total transmission time is minimized under a minimum rate constraint, and an efficient algorithm is also presented to solve the optimal solution by a line search strategy. Numerical results demonstrate that the proposed schemes significantly increase the far user's rate, which in turn improves user fairness and transmission delay. [ABSTRACT FROM PUBLISHER]

Efficient and scalable media access control (MAC) protocol design is crucial to guarantee the reliable broadcast of safety messages in vehicular ad hoc networks. To devise a MAC for safety message broadcasting with reliability and minimum delay, in this paper, we propose a novel time slot-sharing MAC, referred to as SS-MAC, which can support diverse periodical broadcasting rates. In specific, we first introduce a circular recording queue to online perceive time slot occupying status. We then design a distributed time slot sharing (DTSS) algorithm and random index first fit (RIFF) algorithm, to efficiently share the time slot and make the online vehicle-slot matching, respectively. We prove theoretically the efficacy of DTSS algorithm, and evaluate the efficiency of RIFF algorithm by using MATLAB simulations. Finally, we conduct extensive simulations considering various driving scenarios and resource conditions to demonstrate the SS-MAC performance. [ABSTRACT FROM PUBLISHER]

In this paper, we study simultaneous wireless information and power transfer (SWIPT) in relay interference channels (ICs), where energy-constrained relays harvest energy from sources’ radio-frequency signals and use the harvested energy to forward the information to destinations. We adopt the power splitting (PS) relay protocol and the interference alignment (IA) technique to jointly realize energy transfer and interference management. We propose two novel transmission schemes for the SWIPT in relay IC networks, namely, one-stage PS IA scheme and two-stage PS IA scheme. For both schemes, we investigate the optimal PS ratios that maximize the network sum rate. We obtain the closed-form optimal PS ratios for the two-stage PS IA scheme and develop a distributed and iterative algorithm to derive the optimal PS ratios for the one-stage PS IA scheme. We further study the optimal design of the IA precoding and decoding matrices. Based on the Grassmann manifold approach, we present an algorithm to obtain the optimal IA matrices for both schemes. The optimality of the designs of both the PS ratios and the IA matrices is then verified by simulations. Our results show that the proposed schemes effectively improve the performance of the network and significantly outperform benchmark schemes. [ABSTRACT FROM PUBLISHER]

Fiber-Wireless (FiWi) networks typically combine an optical access network with a wireless access network so as to build on the respective strengths of the optical and wireless network technologies. Prior analytical throughput-delay studies of FiWi networks have typically considered heavy-loaded traffic models, i.e., constantly backlogged source nodes. In contrast, in this paper we present a more general comprehensive FiWi network throughput-delay analysis that encompasses Poisson (non-heavy) as well as heavy-loaded input traffic models. In addition, our analysis covers bandwidth assignments of wireless channels both at the hop distance level and at the node level, as well as a queuing model of dynamic bandwidth allocation in the optical access network. Our analysis provides insightful guidelines for setting the channel access probabilities for source traffic and relay traffic in FiWi networks. Our numerical evaluations demonstrate that prior studies which considered only heavy traffic loads gave misleading results for the delay performance of well-known access probability assignments. We correct and clarify these misleading results with our more general analysis for non-heavy traffic. [ABSTRACT FROM AUTHOR]

Wireless object-tracking applications are gaining popularity and will soon utilize emerging ultra-low-power device-to-device communication. However, severe energy constraints require much more careful accounting of energy usage than what prior art provides. In particular, the available energy, the differing power consumption levels for listening, receiving, and transmitting, as well as the limited control bandwidth must all be considered. Therefore, we formulate the problem of maximizing the throughput among a set of heterogeneous broadcasting nodes with differing power consumption levels, each subject to a strict ultra-low-power budget. We obtain the oracle throughput (i.e., maximum throughput achieved by an oracle) and use Lagrangian methods to design EconCast—a simple asynchronous distributed protocol in which nodes transition between sleep, listen, and transmit states, and dynamically change the transition rates. EconCast can operate in groupput or anyput mode to respectively maximize two alternative throughput measures. We show that EconCast approaches the oracle throughput. The performance is also evaluated numerically and via extensive simulations and it is shown that EconCast outperforms prior art by $6\times $ – $17\times $ under realistic assumptions. Moreover, we evaluate EconCast’s latency performance and consider design tradeoffs when operating in groupput and anyput modes. Finally, we implement EconCast using the TI eZ430-RF2500-SEH energy harvesting nodes and experimentally show that in realistic environments it obtains 57%–77% of the achievable throughput. [ABSTRACT FROM AUTHOR]

The popularization of wireless networks and mobile applications has increased the importance of RFID technologies. However, since wireless networks does not guarantee transmission channel security, putting private user information at risk for unintentional disclosure. Previous research has introduced a security mechanism to provide privacy and authentication. This mechanism is based on quadratic residue, does not require a secure channel and fits EPC Class-1 Gen-2 specifications. However, this mechanism cannot resist replay attacks, and lacks an efficient means of its server is not able to find determining validating values, making it difficult to implement. This paper proposes an improvement scheme that uses virtual IDs and time parameters. It does not need a secure channel, fits EPC Class-1 Gen-2 specifications, is resistant to replay attacks, and can efficiently find validation information. The proposed scheme is applied to mobile devices as a proof of concept for use in wireless/mobile RFID systems. [ABSTRACT FROM AUTHOR]

Summary: Opportunistic networks (OppNets) are networks that can be used in situations of sparse network connectivity. Strategies for implementing secure transmission of messages in OppNets offer complex and distinctive problems that are wholly different from traditional networks using TCP/IP protocols for data transmission. In this paper, a security protocol named FuzzyPT is proposed which combats black hole attacks in OppNets. The defense mechanism is based on the information extracted from messages in the buffer, potential threat (PT) messages, and fuzzy logic. Fuzziness aids the system in being adaptive by modeling the character of nodes as either benign or malicious. It provides the network with the ability to judge the character of nodes based on relationships between different parameters instead of basing this decision on fixed conditions. FuzzyPT is observed to reduce erroneous decision‐making and decrease the number of false positives and false negatives in the system. An evolutionary game theoretic model is applied, which analyzes the decision‐making ability of relays in choosing varied strategies while forwarding messages. The evolutionary stable state is computed for the protocol, which verifies the proposition that a majority of the relays will cooperate by forwarding messages. The efficiency of the protocol is judged on various grounds such as delivery probability, network overhead ratio, packets dropped, and transmission latency. It is observed that the proposed game theoretic protocol outperforms an existing acknowledge and evolutionary game theory–based security protocol in terms of all the aforementioned performance characteristics. [ABSTRACT FROM AUTHOR]

Over the next few years, the Industrial Wireless Sensor Network (IWSN), which is a major part of the Industrial Object Internet (IIoT), will play a crucial role in transforming the industrial world by opening a new era of economic and competitive growth in the Industrial Revolution known as "Industry 4.0". IIoT is able to help organizations achieve better benefits in industrial manufacturing markets by increasing productivity, reducing costs and developing new services and products. In this paper we present a wireless industrial communication system based on Node-RED platform using Modbus protocol for smart factories. [ABSTRACT FROM AUTHOR]

Vehicular ad hoc network (VANET) is a dedicated network to connect vehicles without any centralized administration or infrastructure. The wireless access in vehicular environments (WAVE) protocol leveraging IEEE 1609/802.11p is widely implemented for VANETs. However, in congested traffic situation, the performance of the WAVE system degrades significantly due to serious collision, especially for safety related broadcast services on the control channel (CCH) interval due to the inherent drawback of its collision avoidance mechanisms called carrier sense multiple access with collision avoidance (CSMA/CA). In this paper, we propose a method that can decrease the number of frame collisions in CCH with a few modifications to the IEEE 802.11p protocol. In the paper, vehicles still employ CSMA/CA to compete for the channel access opportunity. However, by taking advantage of periodicity of synchronization interval, a two-state switching scheme introducing two new inter frame space (IFS) is proposed to reduce the number of competing vehicles substantially and as a result, the collision probability is significantly decreased. The simulation results demonstrate the superiority of the proposed method in packet collision rate. [ABSTRACT FROM AUTHOR]

The interest shown by some community of researchers to autonomous drones or UAVs (unmanned aerial vehicles) has increased with the advent of wireless communication networks. These networks allow UAVs to cooperate more efficiently in an ad hoc manner in order to achieve specific tasks in specific environments. To do so, each drone navigates autonomously while staying connected with other nodes in its group via radio links. This connectivity can deliberately be maintained for a while constraining the mobility of the drones. This will be suitable for the drones involved in a given path of a given transmission between a source and a destination. This constraint could be removed at the end of the transmission process and the mobility of each concerned drone becomes again independent from the others. In this work, we proposed a flocking-based routing protocol for UAVs called BR-AODV. The protocol takes advantage of a well known ad hoc routing protocol for on-demand route computation, and the Boids of Reynolds mechanism for connectivity and route maintaining while data is being transmitted. Moreover, an automatic ground base stations discovery mechanism has been introduced for a proactive drones and ground networks association needed for the context of real-time applications. The performance of BR-AODV was evaluated and compared with that of classical AODV routing protocol and the results show that BR-AODV outperforms AODV in terms of delay, throughput and packet loss. [ABSTRACT FROM AUTHOR]

The Internet of Things is a concept that is increasingly present in our lives. The emergence of intelligent devices has led to a paradigm shift in the way technology interacts with the environment, leading society to a smarter planet. Consequently, new advanced telemetry approaches appear to connect all kinds of devices with each other, with companies, or with other networks, such as the Internet. On the road to an increasingly interconnected world, where critical devices rely on communication networks to provide an essential service, there arises the need to ensure the security and reliability of these protocols and applications. In this paper, we discuss a security-based approach for MQTT (Message Queue Telemetry Transport), which stands out as a very lightweight and widely used messaging and information exchange protocol for IoT (Internet of Things) devices throughout the world. To that end, we propose the creation of a framework that allows for performing a novel, template-based fuzzing technique on the MQTT protocol. The first experimental results showed that performance of the fuzzing technique presented here makes it a good candidate for use in network architectures with low processing power sensors, such as Smart Cities. In addition, the use of this fuzzer in widely used applications that implement MQTT has led to the discovery of several new security flaws not hitherto reported, demonstrating its usefulness as a tool for finding security vulnerabilities. [ABSTRACT FROM AUTHOR]

Aiming at the problems of the WPKI certificate verification schemes based on online certificate status protocol (OCSP), this paper proposes a WPKI certificate verification scheme based on the certificate digest signature-online certificate status protocol (CDS_OCSP). Compared with the existing schemes, the proposed scheme optimizes the number of communication connections between the communication entities and the network, reduces the consumption of the wireless network bandwidth in the certificate verification process, and uses the elliptic curves cipher- (ECC-) based encrypting/decrypting functions to sign and verify the certificate digest, which ensures the consistency of the verified certificates among the communication entities. The proposed scheme makes the certificate verification process more efficient and secure. The experimental results show that the proposed scheme effectively reduces the communication consumption of the wireless network and saves the storage space of the wireless entities. [ABSTRACT FROM AUTHOR]

In this article, we propose a novel networking paradigm called Small-world SSDNet, servicing applications such as public safety, proximity based services, and fog computing based on device-todevice multi-hop wireless communications. The "small-world" feature is determined by the service area, whose size is usually within a community level, and the well known small-world properties existing in SSDNets; the "super-dense" feature comes from the fact that the increased direct communication range and the popularity of 5G and IoT devices jointly result in a large number of devices within a single-hop communication range. This article first formally defines SSDNet. Then the challenges and the opportunities brought by the design and the implementation of the SSDNet protocols and applications are addressed. Finally, the broader discussions on issues relevant to modeling, engineering, and dissemination are provided. [ABSTRACT FROM AUTHOR]

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]