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In the recent years, low power computing systems have gained popularity. Networks, which use low power computer systems and transmit data by using wireless connection, are called wireless sensor networks. Nowadays, the most topical studies are aimed at grouping wireless sensor networks by the new optimisation of structure of network transmission protocol, the routing optimisation in a transmission network, optimisation of network structure, as a result of which it is possible to increase the life cycle of wireless network sensors. There are a number of methods that allow solving this problem. These include the choice of the capacity of individual battery, the deployment of the node density, the adjustment of power transmitter, the application of energy-efficient data transfer protocol, positioning of network nodes and other methods that are associated with the introduction of additional network costs. The present article discusses a new method for balancing energy through the mobility of network node intellectual agent, which provides the opportunity for reconfiguration of dynamic network or change of network topology. [ABSTRACT FROM AUTHOR]

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]

Wireless sensor networks are formed by a large number of sensor nodes which are commonly known as motes. In the past few years, several reliable, congestion controlled and energy efficient transport layer protocols in wireless sensor networks have been developed and proposed in the literature. In this paper, we have presented a hybrid and dynamic reliable transport protocol which provides the mechanism to dynamically assign the timing parameters to the nodes as well as enhance the protocol performance by using a hybrid Acknowledgement/Negative Acknowledgement scheme. The performance of proposed protocol is tested under TinyOS Simulator varying different parameters and protocol settings and found that proposed protocol is able to program all the nodes when given proper pump/fetch ratios, is able to solve the booting sensor nodes problem by being able to wait till all the nodes finished booting and solves the all-packets-lost problem by acknowledging the receipt of its first packet delivered that is the inform message. [ABSTRACT FROM AUTHOR]

Mobile ad hoc networks (MANETs) are wireless, self-organizing and infrastructure-less networks with nodes that rely on power. Hence, there is a need for an energy-aware and energy-efficient routing protocol. To enhance the lifetime of nodes and network performance, intervals such as the Hello-Interval and TC-Interval of the optimized link state routing (OLSR) protocol are tuned. Additionally, the residue forecast algorithm is incorporated with the protocol, yielding the Hello-Interval 1, TC-Interval 3 residue forecasted optimized link state routing (HTR-OLSR) protocol. In addition, the modified multipoint relay (MPR) selection plays a vital role in energy consideration. In the case of dynamic networks, a gain in throughput of approximately 10% to 15% is obtained. [ABSTRACT FROM AUTHOR]

Designing a lightweight, secure communication protocol for Wireless Sensor Networks (WSNs) remains a challenging issue since sensor networks are resource limited and are left unattended. Sensor nodes in WSNs are subjected to varying forms of attacks. An adversary may destroy or damage the communications done in multi-hop WSNs by means of packet dropping and modification. Hence it is essential to have an efficient cryptographic scheme to protect the communications done in WSNs. This study introduces a Reliable Anonymous Secure Packet forwarding (RASP) scheme that can prevent not only traffic analysis attack but also the attacks done through compromised forwarding nodes. The mechanisms followed here are effective with low computation and communication overhead. The performance of the proposed scheme is evaluated over NS2 with a series of simulation. The simulated results show that the proposed scheme performs better than other comparable schemes. [ABSTRACT FROM AUTHOR]

This paper proposes a cross-layer mobility support scheme for the IPv6 over low-power wireless personal area network (6LoWPAN) wireless sensor network (WSN). This scheme combines the handover in the network layer (L3) with the handover in the link layer (L2) so that the L3 handover and the L2 one can be performed simultaneously. During the L3 handover process, a sensor node neither needs a care-of address nor participates in the handover process. During the L2 handover process, a node uses the channel information to directly achieve the L2 handover without scanning all channels. Finally, this paper analyzes and evaluates the performance of this protocol, and the data results show that this protocol improves the mobility handover performance. [ABSTRACT FROM AUTHOR]

Our research work proposes Multi-hop Communication with Localization (MCL), a strategy to localize and route information to nodes present in such areas by determining angles and distances of consecutive nodes hop by hop towards the Base Station. Based on the application area, Subterranean Wireless Sensor Networks are specifically designed to detect underground abnormal conditions and reported to the base station. Many protocols use distance between the nodes as one of the criteria for multi-hop communication in the network. It is found to be necessary to know the location of the nodes and the distance between the nodes in many power optimization protocols. But the query of how to attain the distance or the location arises in the same. The main objective here is to design a technique to both localize and transmit data efficiently in subterranean areas. Initially there is a group of nodes deployed in the underground areas all of which bond to a sink that is further connected to the Base Station. It is possible to locate all the nodes through GPS which can be used as a reference in the worst case scenario by the Base Station. The sink node has a Node Transmission Area (NTA) within which a node can be directly recognized by the sink node otherwise it finds the target node through the intermediate nodes. Our empirical work proves the computational method on attaining the performance. [ABSTRACT FROM AUTHOR]

In energy constrained wireless sensor networks, maximizing network coverage lifetime while ensuring optimized coverage is important. The challenge is to determine an appropriate duty cycle for the nodes while maintaining sufficient count of active nodes for optimal network coverage. Most of the existing work, for coverage optimization based on duty cycle, does not consider the residual energy of the active nodes. This can result in suboptimal wake-up of sleeping nodes. RBSP considers the residual energy but ignores the active nodes’ battery discharge rate. In this paper, we propose DCBSP ( Discharge Curve Backo ff Sleep Protocol ), which considers the battery discharge curve of the active nodes to determine the duty cycle of the inactive nodes. Thus in DCBSP, inactive nodes wake-up close to death of the active nodes which leads to lesser energy consumption and increased network lifetime. NS-2 simulations show the energy consumption of DCBSP is lesser than that of PEAS by 39% and lesser by 25% and 15% as compared to RBSP and PECAS respectively. Further, the coverage ratio of DCBSP is higher than PEAS by 32% and higher by 17% and 6% as compared to RBSP, PECAS respectively. Hence, DCBSP is effective in ensuring higher coverage while extending the network lifetime. [ABSTRACT FROM AUTHOR]

The Sapienza University Networking framework for underwater Simulation Emulation and real-life Testing (SUNSET) is a toolkit for the implementation and testing of protocols for underwater sensor networks. SUNSET enables a radical new way of performing experimental research on underwater communications. It allows protocol designers and implementors to easily realize their solutions and to evaluate their performance through simulation, in-lab emulation and trials at sea in a direct and transparent way, and independently of specific underwater hardware platforms. SUNSET provides a complete toolchain of pre-deployment and deployment time tools able to identify risks, malfunctioning and under-performing solutions before incurring the expense of going to sea. Novel underwater systems can therefore be rapidly and easily investigated. Heterogeneous underwater communication technologies from different vendors can be used, allowing the evaluation of the impact of different combinations of hardware and software on the overall system performance. Using SUNSET, underwater devices can be reconfigured and controlled remotely in real time, using acoustic links. This allows the performance investigation of underwater systems under different settings and configurations and significantly reduces the cost and complexity of at-sea trials. This paper describes the architectural concept of SUNSET and presents some exemplary results of its use in the field. The SUNSET framework has been extensively validated during more than fifteen at-sea experimental campaigns in the past four years. Several of these have been conducted jointly with the NATO STO Centre for Maritime Research and Experimentation (CMRE) under a collaboration between the University of Rome and CMRE. [ABSTRACT FROM AUTHOR]

Underwater Acoustic Sensor Networks (UWSN) is challenging research area due to limited bandwidth, low data rate, severe multipath, and high variability in the channel conditions. These complicated and non-linear channel characteristics render incorrect most simplifying assumptions used in simulations. We believe that, while researchers have proposed several novel protocols, their use of models and simulations as the only form of validation and intra-protocol comparison remains removed from reality. We argue that research experimentation is hindered by two fundamental constraints: high cost of underwater networking experiments, and lack of a single, easily-replicable platform for evaluation. We present here Underwater Platform to Promote Experimental Research (UPPER): a low-cost and flexible underwater platform designed to enable cost-effective and repeatable experimentation. We utilize commercial off-the-shelf (COTS) components to provide a HW/SW integrated solution that interfaces to two version of our custom hydrophones, from laptops that act as an Software-Defined Radio (SDR)-based physical layer, while allowing higher layer protocols to interact via a flexible API. With a total cost of $25 and $65 for each version of our underwater communication platform, we evaluate the platforms to demonstrate their data rates (50–600 bps) and range (5–10 m for v1, 30–50 m for v2), thus indicating a cost-range tradeoff. We believe our platform removes the barrier to validating simulation results in underwater environments while also allowing a fair comparison between protocols. [ABSTRACT FROM AUTHOR]

This paper proposes receiver-initiated X-MAC with tree topology (TRIX-MAC), an improved energy-efficient MAC protocol based on an asynchronous duty cycling for wireless sensor networks with tree topology. TRIX-MAC improves energy efficiency through utilizing short preambles and adopting the receiver-initiated approach that minimizes sender nodes’ energy consumption by enabling transmitters to predict receiver nodes’ wake-up times and reduces receiver nodes’ energy consumption by decreasing the number of control frames. In many sensor network applications, the data flow from source nodes to a sink forms a unidirectional tree. A property of tree topology, the parent-child relation, is also exploited to reduce the likelihood of collisions between frames sent by children nodes. We use the network simulator, ns-2, to evaluate TRIX-MAC’s performance. Compared to the prior asynchronous duty cycling approaches of X-MAC, RIX-MAC, and PW-MAC, the proposed protocol shows better performance in terms of throughput, energy efficiency, and end-to-end delay. [ABSTRACT FROM AUTHOR]

Secure key distribution is one of the most important building blocks to ensure confidentiality in wireless sensor and actor networks (WSANs). However, the key distribution becomes a challenging task when keys have to be relayed by compromised nodes in order to establish secure communication between distant nodes. To deal with this issue, we propose in this paper a key distribution scheme, named key distribution using fragmentation and assimilation (KDFA). In this scheme, the sender node splits the actual key into fragments and sends them through intermediate actor nodes towards the receiver node. The latter assimilates these key fragments using XOR operation to reconstruct the actual key. In this case, attacker cannot retrieve the actual key and only gets the key fragment. KDFA is composed of two parts: (a) key distribution protocol (KDP) to distribute the key using intra-actor and interactor communication scenarios and (b) key fragmentation algorithm (KFA) to slice the key using binary calculations. KDFA execution has been specified and formally verified using Rubin logic. Moreover, the performance and the resilience of the proposed protocol are further analyzed through extensive simulations using ns-2.35. Results show that KDFA is resilient against actor node compromise and key exposure. [ABSTRACT FROM AUTHOR]

Given the limited resources and computational power of current embedded sensor devices, memory protection is difficult to achieve and generally unavailable. Hence, the software run-time buffer overflow that is used by the worm attacks in the Internet could be easily exploited to inject malicious codes into wireless sensor networks (WSNs). As a result, the remote attestation on the application codes installed in WSNs is the first important step to detect any unauthorized changes through the buffer overflow attack. Previous software-based remote code verification approaches such as SoftWare-based ATTestation and Secure Code Update By Attestation have been shown difficult to deploy in recent work. In this paper, we propose and implement a remote attestation protocol for detecting unauthorized tampering in the application codes running on sensor nodes with the assistance of Trusted Platform Modules (TPMs), a tiny, cost-effective and tamper-proof cryptographic micro-controller. In our design, each sensor node is equipped with a TPM, and the firmware running on the node could be verified by the other sensor nodes in a WSN, including the sink. Specifically, we present a hardware-based remote attestation protocol, discuss the potential attacks an adversary could launch against the protocol and provide comprehensive system performance results of the protocol in a multi-hop sensor network testbed. The experimental results demonstrated that our scheme is able to attest the application codes running in sensor node with small delay (less than 25 s for single-hop), considerable network lifetime and reasonable communication and energy overhead. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Neighbor discovery and the power of sensors play an important role in the formation of Wireless Sensor Networks (WSNs) and mobile networks. Many asynchronous protocols based on wake-up time scheduling have been proposed to enable neighbor discovery among neighboring nodes for the energy saving, especially in the difficulty of clock synchronization. However, existing researches are divided two parts with the neighbor-discovery methods, one is the quorum-based protocols and the other is co-primality based protocols. Their distinction is on the arrangements of time slots, the former uses the quorums in the matrix, the latter adopts the numerical analysis. In our study, we propose the weighted heuristic quorum system (WQS), which is based on the quorum algorithm to eliminate redundant paths of active slots. We demonstrate the specification of our system: fewer active slots are required, the referring rate is balanced, and remaining power is considered particularly when a device maintains rendezvous with discovered neighbors. The evaluation results showed that our proposed method can effectively reschedule the active slots and save the computing time of the network system. [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]

The advent of the Internet of Things where billions of devices are able to exchange their data to give a better control to users on their environment has led to the expansion of Wireless Sensor Networks (WSN). To address the specificities of WSN, standards on networking protocols for low power sensors such as 6LoWPAN have been developed. While 6LoWPAN is well suited to fixed- sensor WSN, it must be extended to better address mobile sensors. However, so far little effort has been devoted to the handling of mobile sensor node peculiarities. In this article, generic mobility scenarios are highlighted, existing mobility solutions based in Mobile IPv6 are reviewed and remaining challenges to handle mobile sensors properly are identified. [ABSTRACT FROM AUTHOR]

Cooperative routing is a hybrid approach utilizing routing techniques and cooperative communication to improve the communication quality of single-antenna sensor nodes. It exploits the broadcast nature of wireless medium and transmits cooperatively using nearby sensor nodes as relays. In this research, a cooperative transmission scheme is proposed for UnderWater Sensor Networks (UWSNs) to improve the network performance called ARCUN. The protocol is an energy-efficient and high-throughput routing scheme for UWSN. Potential relays are selected from a group of neighbor nodes that utilize signal-to-noise ratio and distance computation of the underwater channel. Optimal role of cooperation provides load balancing in the network and gives profound improvement in network stability period and packet delivery ratio. [ABSTRACT FROM AUTHOR]

Efficient medium access control (MAC) algorithms are needed for nodes to share a transmission medium and achieve a high throughput. A MAC algorithm schedules packet transmissions so as to that minimize the time taken to send the packets without collisions. In wireless ad hoc and sensor networks, a MAC algorithm must conserve energy as well as provide good throughput. Most existing MAC algorithms for wireless networks are designed to work well under low traffic rates. In this paper we propose a new distributed algorithm Ad-ATMA for wireless ad hoc and sensor networks under relatively high traffic rates. We demonstrate using simulations that Ad-ATMA outperforms the best existing algorithms designed for higher traffic rates in terms of packet delivery ratio and latency while consuming almost identical energy as them. [ABSTRACT FROM AUTHOR]

In this paper, we present an investigation of MAC protocols for linear wireless sensor networks (LWSNs). Recently, there have been a number of applications like roads, bridges and pipeline monitoring, in which the transmission of data over very long lines of consecutive nodes is required. Due to the additional restrictions imposed by the linear topology, such applications present new challenges regarding the provision of low latency and low energy consumption. In order to address these issues researches have proposed a number of protocols tailored specifically for linear topologies. Two different operational mechanisms stand out: the first is based on explicit book and burst transmission, while the second is based on low power listening (LPL) and adaptive sleep cycle. The paper covers the details of the operation of these two types of protocols and provides simulation results for their performance comparison in terms of latency, energy consumption and throughput. The results clearly show the limitations of burst transmission and the advantages of LPL and adaptive sleep cycle as realized in LINE_MAC. [ABSTRACT FROM AUTHOR]

The Internet of Things or “IoT” defines a highly interconnected network of heterogeneous devices where all kinds of communications seem to be possible, even unauthorized ones. As a result, the security requirement for such network becomes critical whilst common standard Internet security protocols are recognized as unusable in this type of networks, particularly due to some classes of IoT devices with constrained resources. The document discusses the applicability and limitations of existing IP-based Internet security protocols and other security protocols used in wireless sensor networks, which are potentially suitable in the context of IoT. The analysis of these protocols is discussed based on a taxonomy focusing on the key distribution mechanism. [ABSTRACT FROM AUTHOR]

Due to the imbalanced energy consumption among nodes in wireless sensor networks, some nodes die prematurely, which decreases the network lifetime. To solve this problem, existing clustering protocols usually construct unequal clusters by exploiting uneven competition radius. Taking their imperfection on designing the uneven competition radius and intercluster communication into consideration, this paper proposes an improved distributed unequal clustering protocol (IDUC) for wireless sensor networks, where nodes are energy heterogeneous and scattered unevenly. The cores of IDUC are the formation of unequal cluster topology and the construction of intercluster communication routing tree. Compared with previous protocols, IDUC is suitable for various network scenarios, and it can balance the energy consumption more efficiently and extend the lifetime of networks significantly. [ABSTRACT FROM AUTHOR]

A dynamic heterogeneous and multihop (DHMH) wireless health monitoring system (WHMS) as a three-tier semi-self-organizing health monitoring network was presented. From bottom to top, the first tire of the network is the mobile data acquisition layer (DAL), the second tire of the network is the data transporting layer (DTL), and the third tire of the network is the data collection layer (DCL). A RF power control based topology management mechanism is proposed to balance the network load and to improve the network throughput. A lightweight hierarchical routing protocol (LHRP) was designed to reduce the transmission delay and improve the network throughput. For the mobile DAL nodes, the seamless mobile access mechanism (SMAM) was designed to ensure the low packet loss ratio. To evaluate the network performance, the end-to-end delay, the averaged reception ratio, and the network throughput of the DHMH were tested and the results proved that the network performance of the DHMH was improved. [ABSTRACT FROM AUTHOR]

Wireless network is a major research domain in the past few decades. Wireless network evolves in many forms like cellular communication, ad hoc network, vehicular network, mesh network and sensor network. Next generation network is a recent cellular communication which provides heterogeneous connectivity on cellular communication. The routing in next generation wireless networks is an important research issue which requires many constraints than wired networks. Hence, Ant Colony Optimization (ACO) is applied in this paper for routing in heterogeneous next generation wireless network. The ACO is a swarm intelligence technique which applied for many engineering applications. ACO is an optimal technique for routing and travelling salesman problem. This paper proposed Restructured ACO which contains additional data structures for reducing packet loss and latency. Therefore, the proposed RACO provides higher throughput. [ABSTRACT FROM AUTHOR]

Energy harvesting (EH) technology in the field of wireless sensor networks (WSNs) is gaining increasing popularity through removing the burden of having to replace/recharge depleted energy sources by energy harvester devices. EH provides an alternative source of energy from the surrounding environment; therefore, by exploiting the EH process, WSNs can achieve a perpetual lifetime. In view of this, emphasis is being placed on the design of new medium access control (MAC) protocols that aim to maximize the lifetime of WSNs by using the maximum possible amount of harvested energy instead of saving any residual energy, given that the rate of energy harvested is greater than that which is consumed. Various MAC protocols with the objective of exploiting ambient energy have been proposed for energy-harvesting WSNs (EH-WSNs). In this paper, first, the fundamental properties of EH-WSN architecture are outlined. Then, several MAC protocols proposed for EH-WSNs are presented, describing their operating principles and underlying features. To give an insight into future research directions, open research issues (key ideas) with respect to design trade-offs are discussed at the end of this paper. [ABSTRACT FROM AUTHOR]

Wireless sensor networks (WSNs) are a family of wireless networks that usually operate with irreplaceable batteries. The energy sources limitation raises the need for designing specific protocols to prolong the operational lifetime of such networks. These protocols are responsible for messages exchanging through the wireless communications medium from the sensors to the base station (sink node). Therefore, the determination of the optimal location of the sink node becomes crucial to assure both the prolongation of the network’s operation and the quality of the provided services. This paper proposes a novel algorithm based on a Particle Swarm Optimization (PSO) approach for designing an energy-aware topology control protocol. The deliverable of the algorithm is the optimal sink node location within a deployment area. The proposed objective function is based on a number of topology control protocol’s characteristics such as numbers of neighbors per node, the nodes’ residual energy, and how they are far from the center of the deployment area. The simulation results show that the proposed algorithm reveals significant effectiveness to both topology construction and maintenance phases of a topology control protocol in terms of the number of active nodes, the topology construction time, the number of topology reconstructions, and the operational network’s lifetime. [ABSTRACT FROM AUTHOR]

Recently, there has been a clear trend towards the application of ad hoc networking technology in civil aviation communication systems, giving birth to a new research field, namely, aeronautical ad hoc networks (AANETs). An AANET is a special type of ad hoc wireless network with a significantly larger scale and distinct characteristics of its mobile nodes. Thus, there is an urgent need to develop a simulator to facilitate the research in these networks. In this paper, we present a network simulator, Aero-Sim, for AANETs. Aero-Sim, which is based on the freely distributed NS-2 simulator, enables detailed packet-level simulations of protocols at the MAC, link, network, transport, and application layers by composing simulations with existing modules and protocols in NS-2. Moreover, Aero-Sim supports three-dimensional network deployment. Through several case studies using realistic China domestic air traffic, we show that the proposed simulator can be used to simulate AANETs and can reproduce the real world with high fidelity. [ABSTRACT FROM AUTHOR]

Constructive interference (CI) is a synchronous transmission technique for multiple senders transmitting the same packet simultaneously in wireless sensor networks (WSNs). CI enables fast and reliable network flooding in order to reduce the scheduling overhead of MAC protocols, to achieve accurate time synchronization, to improve link quality of lossy links, and to realize efficient data collection. By achieving microsecond level time synchronization, Glossy realizes millisecond level CI-based flooding and 99% reliability. However, Glossy produces substantial unnecessary data forwarding, which significantly reduces the network lifetime. This is a very critical problem, especially in energy-limited large-scale wireless sensor networks for agriculture and forestry (WSN-AF) system. In this paper, we present an energy adaptive CI-based flooding protocol (EACIF) by exploiting CI in WSN-AF. EACIF proposes a distributed active nodes selection algorithm (ANSA) to reduce redundant transmissions, thereby significantly reducing energy consumption and flooding latency. We estimate the performance of EACIF both with real data traces and with uniformly distributed topology. Simulation results show that EACIF achieves almost the same packet reception ratio (PRR) as Glossy (e.g., 99%), while reducing 63.96% energy consumption. EACIF also reduces 25% flooding latency. When the packet interval is 30 seconds, EACIF achieves 0.11% duty cycle. [ABSTRACT FROM AUTHOR]

Achieving same notion of time remains an important task for most distributed systems. Time synchronization requires a unique combination of high accuracy ( $$\upmu $$ s level) and energy efficiency. Several application layer protocols have been developed to meet these requirements. This article proposes that the physical layer clock recovery process can provide application layer clock drift estimate, and the application layer clock can be corrected with the help of this estimate. This eliminates the need of application layer time synchronization protocol i.e. the cross-layer approach reduces the number of message exchanges required by application layer for time synchronization that leads to energy conservation. It argues that such a cross-layer approach can provide a more accurate frequency offset estimation, or can achieve greater energy savings, for a given accuracy, by reducing the message exchanges. Analysis of the proposed method provides concrete bounds on achieved improvement. Experimental evaluation showed that physical layer clock drift can be used to correct application layer clock drift as they are identical. [ABSTRACT FROM AUTHOR]

Due to the lack of dependency on beacon messages for location exchange, the beaconless geographic routing protocol has attracted considerable attention from the research community. However, existing beaconless geographic routing protocols are likely to generate duplicated data packets when multiple winners in the greedy area are selected. Furthermore, these protocols are designed for a uniform sensor field, so they cannot be directly applied to practical irregular sensor fields with partial voids. To prevent the failure of finding a forwarding node and to remove unnecessary duplication, in this paper, we propose a region-based collision avoidance beaconless geographic routing protocol to increase forwarding opportunities for randomly-deployed sensor networks. By employing different contention priorities into the mutually-communicable nodes and the rest of the nodes in the greedy area, every neighbor node in the greedy area can be used for data forwarding without any packet duplication. Moreover, simulation results are given to demonstrate the increased packet delivery ratio and shorten end-to-end delay, rather than well-referred comparative protocols. [ABSTRACT FROM AUTHOR]

Wireless networks adapt easily to changes and offers flexibility in the configuration of the network. In MANET, each node will change its location dynamically and configure itself according to the environment. An effective mechanism for route discovery in such networks is broadcasting, but routing overhead associated with broadcasting can be large in high dynamic networks. To reduce this routing overhead in MANETs, a neighbor coverage based probabilistic rebroadcast protocol is used. To determine the rebroadcast order, a novel rebroadcast delay is used and it obtains the more accurate additional coverage ratio by sensing neighbor coverage knowledge. The rebroadcast probability is calculated by merging the additional coverage ratio and connectivity factor. In the proposed method Energy Efficient Neighbor Coverage Protocol(EENCP) is introduced. In this, the node does not forward RREQ unless there is sufficient energy (battery lifetime), and until the node density in its surrounding exceeds a particular threshold. These two parameters are defined taking into consideration various statistics. EENCP analyzes these two parameters, when implementing routing discovery, and avoiding the unnecessary information sending efficiently and avoid unnecessary information transfer. [ABSTRACT FROM AUTHOR]

Range extension is a promising feature offered by cooperative transmission (CT), also known as virtual multiple-input–single-output (VMISO). Many authors have considered how the diversity and array gains from CT may benefit a wireless multi-hop network, when the gains are used for increasing link reliability and reducing transmit power. However, relatively less attention has been given to the benefits of CT range extension and few testbed implementations of CT have been demonstrated. In this paper, we focus on how CT range extension can impact the lower three layers, especially medium access control (MAC) and routing for ad hoc and sensor multi-hop networks (AHSMNs). We assume cooperators decode and forward the packets. Various analytical models, performance analyses, and experimental results using software-defined radios in an indoor office environment are discussed. For wireless sensor networks (WSNs), we review CT range extension at the network layer, to eliminate the energy hole that forms around sink nodes in non-CT networks, and we review cooperator selection and duty cycle scheduling algorithms at Layer 2, to maximize the lifetime of a multi-hop WSN. For ad hoc networks, we emphasize a family of lightweight broadcasting and unicasting protocols based on a simple form of CT called the opportunistic large array (OLA). Experimental results, including OLA-based unicast routing and diversity order effects in two-hop CT networks, are discussed. [ABSTRACT FROM AUTHOR]

A 2.45 GHz active integrated ZigBee RFID system embedded with GPS is developed with an automated switching protocol algorithm utilizing wireless sensor network (WSN) platform to track the physical belongings or people in indoor and outdoor environments within a control area. In addition, to make the system contactless when the tag is not joining the network, the function of global system for mobile (GSM) communication is added to the integration. The communication between RFID reader and RFID tags is via WSN platform that supports mesh network and self-healing mechanism. Energy efficiency, robustness, and reliability are key factors in the design algorithm of the system. Comparisons are made between the existing active RFID system and the proposed active RFID system to study the performance of the proposed RFID system with an automated switching algorithm implemented on it. Based on the experimental study and statistical analysis done for all situations, a conclusion has been made where the proposed embedded RFID tag provided better signal propagation compared to the existing RFID tag and the battery lifetime for embedded RFID tag with switching mechanism is better than without switching mechanism. [ABSTRACT FROM AUTHOR]

Packet corruption caused by collision is a critical problem that damages the performance of wireless networks. Traditional medium access control (MAC) protocols resort to collision avoidance to improve the efficiency of channel utilization. According to our investigation, however, collision avoidance causes time delay, which also hurts channel utilization, especially in the dense networks or intensive traffic. Discovering the ability to tolerate collisions with the correlatable preamble at the physical layer implementations of wireless networks, we propose CWM in this paper, a MAC protocol that advocates simultaneous accesses from multiple senders to a shared channel, allowing collisions instead of avoiding them. With the correlatable sequences, CWM addresses the challenges in achieving collision tolerance, such as precise sender alignment and control of the transmission concurrency. We implement the experiments on USRP verifying the feasibility of our protocol and implement CWM in 802.15.4 networks and evaluate its performance with 100 nodes on MATLAB. The results demonstrate that our protocol significantly improves the spatial reuse of the wireless channel by at least 23% compared with the state-of-the-art protocols. [ABSTRACT FROM AUTHOR]

Traditional wireless sensor networks (WSNs) work over the unlicensed spectrum, and as the spectrum becomes increasingly crowded, they suffer from uncontrolled interference. Recently, cognitive radio based sensor networks (CRSNs) have been envisioned as a promising type of implementation that provides quality-of-service (QoS) features for data transmissions. However, key challenges remain in designing energy-efficient medium access control techniques that can achieve QoS. In this paper, we have developed a multiconstrained QoS aware MAC protocol, MQ-MAC, for a cluster based CRSN. In MQ-MAC, a data channel and a backup channel are assigned to a secondary user by the respective cluster head by using dynamic channel priorities. The user device can switch to the backup channel when a primary user appears to be operating over the data channel. Member nodes of a cluster are also prioritized with respect to the urgency of their generated data packets. Performance evaluations, carried out in NS-3 simulator, show that the proposed MQ-MAC protocol offers better performance than existing MAC protocols for CRSN. [ABSTRACT FROM AUTHOR]

Wireless Sensor Networks are a key element of the Internet of Things since they are one of the most interesting pervasive systems. However, they are battery-powered, so energy efficiency represents one of the primary design challenges to address. This goal can be primarily achieved through an optimization of the communication procedure, which is the most power-consuming component of a WSN node. Nevertheless, the poor resources of the embedded devices usually limit the complexity of protocol solutions, which thus are not sufficient to reach satisfactory results. For this reason, the current trend aims at integrating both hardware and software solutions. In this work, a cross-layer solution, based on the combined use of a duty-cycling MAC protocol and a reconfigurable beam-steering antenna, is presented and validated. It significantly reduces the nodes’ power consumption by exploiting scheduling techniques and directional communications. Specifically, a MAC scheduler manages the activation of the antenna sectors based on information coming from both MAC and network layers. This way, node awakenings occur only when an actual communication has to take place and only the interested antenna sector is activated. The effectiveness of the proposed cross-layer approach has been evaluated through OMNeT++ simulation tool. [ABSTRACT FROM AUTHOR]

Owning to the proliferation of cost-effective sensors, there has been an increased growth in a number of applications of wireless sensor networks (WSNs). In addition, the skyline operator as well as its variants such as the dynamic skyline and reverse skyline operator has attracted increasing attention since those are useful for multicriteria decision making applications. Since the energy efficiency is utmost important issue to prolong the network lifetime, in this paper, we proposed efficient algorithms to process a reverse skyline query over a sliding window in WSN environments. We first devise our algorithm for the data stream environments and extend it to WSN environments. To compute the reverse skyline, we partition the data space into several orthants with respect to a query point. And, in each orthant, we compute the reverse skyline independently using two buffers. In our experiment study, we demonstrate that our algorithm is much better than other algorithms. [ABSTRACT FROM AUTHOR]

Wireless sensor network (WSN) is built of many sensor nodes. The sensors can sense a phenomenon, which will be represented in a form of data and sent to an aggregator for further processing. WSN is used in many applications, such as object tracking and security monitoring. The objects in many situations need physical and location protection. In addition to the source location privacy, sink location privacy should be provided. Providing an efficient location privacy solution would be challenging due to the open nature of the WSN. Anonymity is a key solution for location privacy. We present a network model that is protected against local, multilocal, and global adversaries that can launch sophisticated passive and active attacks against the WSN. [ABSTRACT FROM AUTHOR]

Technological advances within the area of wireless sensor technology allow WSNs to be used in a increasing number of measurement scenarios. As new application areas are emerging, such as infrastructure monitoring and smart cities, the need for sensor mobility handling requires efficient and secure authentication protocols. This paper presents EAP-Swift, a novel EAP based authentication protocol with a focus on lightweight processing and faster response. It supports end-to-end session encryption key generation and mutual authentication. By utilizing lightweight hashing algorithms, the challenge-response authentication mechanism uses only two round trips to the AAA server for the complete authentication procedure leading to the reduction of latency by 33% compared to the baseline protocols. Further, using extensive experimentation, we validate that the authentication time can be kept below 250 ms and the power consumption can be kept below 15 mJ. Furthermore, we show that a battery lifetime of more than four years can be achieved when running the system on a regular button cell battery. Finally, the protocol was verified in terms of security using the AVISPA tool. [ABSTRACT FROM AUTHOR]

A data discovery and dissemination protocol for wireless sensor networks (WSNs) is responsible for updating configuration parameters of, and distributing management commands to, the sensor nodes. All existing data discovery and dissemination protocols suffer from two drawbacks. First, they are based on the centralized approach; only the base station can distribute data items. Such an approach is not suitable for emergent multi-owner-multi-user WSNs. Second, those protocols were not designed with security in mind and hence adversaries can easily launch attacks to harm the network. This paper proposes the first secure and distributed data discovery and dissemination protocol named DiDrip. It allows the network owners to authorize multiple network users with different privileges to simultaneously and directly disseminate data items to the sensor nodes. Moreover, as demonstrated by our theoretical analysis, it addresses a number of possible security vulnerabilities that we have identified. Extensive security analysis show DiDrip is provably secure. We also implement DiDrip in an experimental network of resource-limited sensor nodes to show its high efficiency in practice. [ABSTRACT FROM AUTHOR]

Radio link quality estimation is essential for protocols and mechanisms such as routing, mobility management and localization, particularly for low-power wireless networks such as wireless sensor networks. Commodity Link Quality Estimators (LQEs), e.g. PRR, RNP, ETX, four-bit and RSSI, can only provide a partial characterization of links as they ignore several link properties such as channel quality and stability. In this paper, we propose F-LQE (Fuzzy Link Quality Estimator, a holistic metric that estimates link quality on the basis of four link quality properties—packet delivery, asymmetry, stability, and channel quality—that are expressed and combined using Fuzzy Logic. We demonstrate through an extensive experimental analysis that F-LQE is more reliable than existing estimators (e.g., PRR, WMEWMA, ETX, RNP, and four-bit) as it provides a finer grain link classification. It is also more stable as it has lower coefficient of variation of link estimates. Importantly, we evaluate the impact of F-LQE on the performance of tree routing, specifically the CTP (Collection Tree Protocol). For this purpose, we adapted F-LQE to build a new routing metric for CTP, which we dubbed as F-LQE/RM. Extensive experimental results obtained with state-of-the-art widely used test-beds show that F-LQE/RM improves significantly CTP routing performance over four-bit (the default LQE of CTP) and ETX (another popular LQE). F-LQE/RM improves the end-to-end packet delivery by up to 16%, reduces the number of packet retransmissions by up to 32%, reduces the Hop count by up to 4%, and improves the topology stability by up to 47%. [ABSTRACT FROM AUTHOR]

Clock synchronization in wireless sensor networks (WSNs) assures that sensor nodes have the same reference clock time. This is necessary not only for various WSN applications but also for many system level protocols for WSNs such as MAC protocols, and protocols for sleep scheduling of sensor nodes. Clock value of a node at a particular instant of time depends on its initial value and the frequency of the crystal oscillator used in the sensor node. The frequency of the crystal oscillator varies from node to node, and may also change over time depending upon many factors like temperature, humidity, etc. As a result, clock values of different sensor nodes diverge from each other and also from the real time clock, and hence, there is a requirement for clock synchronization in WSNs. Consequently, many clock synchronization protocols for WSNs have been proposed in the recent past. These protocols differ from each other considerably, and so, there is a need to understand them using a common platform. Towards this goal, this survey paper categorizes the features of clock synchronization protocols for WSNs into three types, viz. structural features, technical features, and global objective features. Each of these categories has different options to further segregate the features for better understanding. The features of clock synchronization protocols that have been used in this survey include all the features which have been used in existing surveys as well as new features such as how the clock value is propagated, when the clock value is propagated, and when the physical clock is updated, which are required for better understanding of the clock synchronization protocols in WSNs in a systematic way. This paper also gives a brief description of a few basic clock synchronization protocols for WSNs, and shows how these protocols fit into the above classification criteria. In addition, the recent clock synchronization protocols for WSNs, which are based on the above basic clock synchronization protocols, are also given alongside the corresponding basic clock synchronization protocols. Indeed, the proposed model for characterizing the clock synchronization protocols in WSNs can be used not only for analyzing the existing protocols but also for designing new clock synchronization protocols. [ABSTRACT FROM AUTHOR]

Applications based on video and image in wireless sensor network are highly attractive due to their wealth of information. In this context, application for object recognition and tracking using image and video information is one the attractive approaches that can be applied for event detection and localization, security processes, following of the rare animal species and control of road traffic, and so forth. However, the implementation of such approach with WMSN requires a specific image processing scheme and efficient transmission protocol. In fact, because of the limited energy of the batteries embedded in motes, the power consumption is the major constraint facing network life time and reliability in WMSN. The efficiency and the validity of these multimedia applications over wireless sensor networks are then dependent on the capabilities of the designer to provide low-power scheme for data processing and energy-aware transmission protocols. This paper presents a contribution to the design of low complexity scheme based on object identification for efficient sensing of multimedia information in wireless multimedia sensor networks. It proposes a new solution and explores the associated performances of this scheme. The presented results in this paper attest the high efficiency to achieve low-power objects identification when implemented in wireless motes. [ABSTRACT FROM AUTHOR]

Research on wireless sensor networks has progressed rapidly over the last decade, and these technologies have been widely adopted for both industrial and domestic uses. Several operating systems have been developed, along with a multitude of network protocols for all layers of the communication stack. Industrial Wireless Sensor Network (WSN) systems must satisfy strict criteria and are typically more complex and larger in scale than domestic systems. Together with the non-deterministic behavior of network hardware in real settings, this greatly complicates the debugging and testing of WSN functionality. To facilitate the testing, validation, and debugging of large-scale WSN systems, we have developed a simulation framework that accurately reproduces the processes that occur inside real equipment, including both hardware- and software-induced delays. The core of the framework consists of a virtualized operating system and an emulated hardware platform that is integrated with the general purpose network simulator ns-3. Our framework enables the user to adjust the real code base as would be done in real deployments and also to test the boundary effects of different hardware components on the performance of distributed applications and protocols. Additionally we have developed a clock emulator with several different skew models and a component that handles sensory data feeds. The new framework should substantially shorten WSN application development cycles. [ABSTRACT FROM AUTHOR]

Multicast is a process used to transfer same message to multiple receivers at the same time. This paper presents the simulation and analysis of the performance of six different multicast routing protocols for Wireless Sensor Network (WSN). They are On Demand Multicast Routing Protocol (ODMRP), Protocol for Unified Multicasting through Announcement (PUMA), Multicast Adhoc On demand Distance Vector Protocol (MAODV), Overlay Boruvka-based Adhoc Multicast Protocol (OBAMP), Application Layer Multicast Algorithm (ALMA) and enhanced version of ALMA (ALMA-H) for WSN. Among them, ODMRP, MAODV and PUMA are reactive protocols while OBAMP, ALMA and ALMA-H are proactive protocols. This paper compares the performance of these protocols with common parameters such as Throughput, Reliability, End-to- End delay and Packet Delivery Ratio (PDR) with increasing the numbers of nodes and increasing the speed of the nodes. The main objective of this work is to select the efficient multicast routing protocol for WSN among six multicast routing protocol based on relative strength and weakness of each protocol. The summary of above six multicast routing protocols is presented with a table of different performance characteristics. Experimental result shows that ODMRP attains higher throughput, reliability and higher packet delivery ratio than other multicast routing protocol, while incurring far less end-to-end delay. [ABSTRACT FROM AUTHOR]

The 6loWPAN (the light version of IPv6) and RPL (routing protocol for low-power and lossy links) protocols have become de facto standards for the Internet of Things (IoT). In this paper, we show that the two native algorithms that handle changes in network topology – the Trickle and Neighbor Discovery algorithms – behave in a reactive fashion and thus are not prepared for the dynamics inherent to nodes mobility. Many emerging and upcoming IoT application scenarios are expected to impose real-time and reliable mobile data collection, which are not compatible with the long message latency, high packet loss and high overhead exhibited by the native RPL/6loWPAN protocols. To solve this problem, we integrate a proactive hand-off mechanism (dubbed smart-HOP) within RPL, which is very simple, effective and backward compatible with the standard protocol. We show that this add-on halves the packet loss and reduces the hand-off delay dramatically to one tenth of a second, upon nodes’ mobility, with a sub-percent overhead. The smart-HOP algorithm has been implemented and integrated in the Contiki 6LoWPAN/RPL stack (source-code available on-line mrpl: smart-hop within rpl, 2014) and validated through extensive simulation and experimentation. [ABSTRACT FROM AUTHOR]

In this study, the authors focus on utilising receiver-based MAC protocol (RB-MAC) and adaptive RB-MAC in routing protocol for low power and lossy wireless sensor networks routing protocol in low-power and lossy wireless channel. This results in a cross-layer approach in which routing decisions can be made based on MAC-layer functionalities. The authors study the effects of multiple receiver nodes, size of preamble and variable duty-cycle in number of retransmissions. Retransmissions increase energy consumptions and delay. Analytical and numerical results confirm that the RB-MAC and adaptive RB-MAC outperform the existing state-of-the art sender-based MAC protocols in terms of end-to-end energy-efficiency, reliability and delay. Simulation result demonstrates that using receiver-based MAC protocols in RPL-based lossy channel imply less retransmissions than sender-based MAC. [ABSTRACT FROM AUTHOR]

In this paper, we present the design of a Constrained Application Protocol (CoAP) proxy able to interconnect Web applications based on Hypertext Transfer Protocol (HTTP) and WebSocket with CoAP based Wireless Sensor Networks. Sensor networks are commonly used to monitor and control physical objects or environments. Smart Cities represent applications of such a nature. Wireless Sensor Networks gather data from their surroundings and send them to a remote application. This data flow may be short or long lived. The traditional HTTP long-polling used by Web applications may not be adequate in long-term communications. To overcome this problem, we include the WebSocket protocol in the design of the CoAP proxy. We evaluate the performance of the CoAP proxy in terms of latency and memory consumption. The tests consider long and short-lived communications. In both cases, we evaluate the performance obtained by the CoAP proxy according to the use of WebSocket and HTTP long-polling. [ABSTRACT FROM AUTHOR]

Key management is required for basic security services of confidentiality, integrity, and data source authentication. Wireless sensor networks (WSNs) are a challenging environment to provide such services due to the resource constraints and the increased likelihood of nodes to be captured. Various key management techniques were proposed that trade off resilience to node capture and overhead in terms of communication and memory. We identify the main factors influencing the design space of key management protocols for sensor networks and describe representative protocols that trade off the number of links established, communication overhead, and resilience to node capture. These trade-offs are due to using direct, pathbased, or multipath-based communication to establish secure links. We propose a new multipath protocol relying on an encoding scheme tailored for WSNs and analyze the effects of key pre-distribution on multipath key establishment. We provide extensive simulations to understand the trade-offs between resilience to node compromise and communication overhead under numerous network scenarios. This comparison highlights the tradeoffs between these vastly different key management schemes. For the newer class of key management schemes--multipath based--we quantify experimentally the additional communication overhead required for extra paths and the improvement in resilience from using these paths. [ABSTRACT FROM AUTHOR]

Time synchronization is one of the most fundamental services for wireless sensor networks. Prior studies have investigated the clock stability due to environmental dynamics. In this paper, we demonstrate by experiment that in spite of the surrounding environment, time synchronization is unavoidably impacted by in-network energy heterogeneity, which may incur up to 30-40 ppm clock uncertainty. We mathematically analyze the root cause of such clock uncertainty and propose a protocol called EATS. Sensor nodes with EATS can intelligently select the best synchronization parents that minimize the negative impact of the energy heterogeneity. The selection is robust to multiple impacting factors in the network and provides fine-grained synchronization accuracy. In addition, nodes can make use of local energy information and further calibrate the clocks. In light of this, the logic time maintained among different nodes is more consistent and the synchronization can be performed with a longer re-synchronization interval and less energy consumption. We implement EATS with TelosB motes and evaluate the effectiveness and efficiency of our design through extensive experiments and simulations. [ABSTRACT FROM PUBLISHER]

As a key approach to achieve energy efficiency in sensor networks, sensing coverage has been studied extensively in the literature. Researchers have designed many coverage protocols to provide various kinds of service guarantees on the network lifetime, coverage ratio and detection delay. While these protocols are effective, they are not flexible enough to meet multiple design goals simultaneously. In this paper, we propose a unified sensing coverage architecture for duty cycled wireless sensor networks, called uSense, which features three novel ideas: Asymmetric Architecture, Generic Switching and Global Scheduling. We propose asymmetric architecture based on the conceptual separation of switching from scheduling. Switching is efficiently supported in sensor nodes, while scheduling is done in a separated computational entity, where multiple scheduling algorithms are supported. As an instance, we propose a two-level global coverage algorithm, called uScan. At the first level, coverage is scheduled to activate different portions of an area. We propose an optimal scheduling algorithm to minimize area breach. At the second level, sets of nodes are selected to cover active portions. Importantly, we show the feasibility to obtain optimal set-cover results in linear time if the layout of areas satisfies certain conditions. Through extensive testbed and simulation evaluations, we demonstrate that uSense is a promising architecture to support flexible and efficient coverage in sensor networks. [ABSTRACT FROM AUTHOR]