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With the development of IoT technology and the improvement of people's living standards, smart locks have become prevalent in ordinary households. However, for enterprises and institutions requiring unified management and control capabilities for networked smart locks, the technology has been relatively lagging, and there is a lack of established brands. Existing products are mostly based on wireless low-power network protocols, leading to common issues of low stability, limited network scalability, and high maintenance efforts. This paper addresses the problems existing in current networked lock systems and leverages the centralized office characteristics of enterprises and institutions. By integrating IoT technology and Power over Ethernet- (PoE-) centralized power supply, we have developed a networked smart lock system with unified management and control capabilities. This system is primarily designed for applications in offices, collective dormitories, and hotels of enterprises, institutions, and schools. The test results demonstrate that even with a scale of over tens of thousands of networked locks under unified control, the system maintains fast response times and low packet loss rates. It also incorporates energy-saving and environmentally friendly features, as well as easy automatic updates, facilitating convenient postdeployment maintenance. Thus, it effectively meets the requirements for centralized management and control in different application scenarios with centralized use of rooms. In conclusion, this research has led to the development of a unified management and control networked smart lock system, which is well suited for enterprises, institutions, and schools. Its scalability, speed, energy efficiency, and ease of maintenance make it an excellent solution for various application scenarios requiring centralized management and control of access. [ABSTRACT FROM AUTHOR]

Bluetooth low energy is an almost ubiquitous technology currently embedded in billions of power-constrained Internet of Things devices around the world. The Bluetooth mesh profile, released by the Bluetooth Special Interest Group in July 2017, allows Bluetooth low energy devices to form a mesh network, further enabling smart home and building applications where long-range connectivity is required. However, the current release of Bluetooth mesh profile still has power and deployment constraints that limit its applicability. To explore the viability of Bluetooth mesh profile in home/building automation applications, we built the Smart Doorbell: a proof-of-concept Bluetooth mesh profile–based visitor notification system for office spaces. The Smart Doorbell was implemented using a mesh network topology with nodes distributed across office building floors, serving as a real Internet of Things deployment and as a testbed for mesh network protocols. Similar Bluetooth mesh profile evaluations found in literature use mostly development kits and/or synthetic traffic in artificial settings; we contribute by using the Smart Doorbell, a system as close as possible to a minimum viable product, to evaluate power consumption and responsiveness as a proxy for product viability. This article presents the architecture of the Smart Doorbell, the viability evaluation results, and a direct comparison with FruityMesh, a competing Bluetooth low energy mesh network protocol. Overall, the fact that Bluetooth mesh profile devices can directly communicate with a user's mobile phone (using Bluetooth low energy) considerably eases deployment and provisioning. However, the use of flooding to forward messages across the mesh network increases power consumption, precluding the use of battery-powered nodes on the network's backbone and severely limiting the applicability of Bluetooth mesh profile in building automation. [ABSTRACT FROM AUTHOR]

The development of wireless sensor and actuator network is leading to high complexity networks and subsequently, new challenges in task assignment for effective sensor–actuator coordination. This article proposes an adaptive auction protocol for task assignment in multi-hop wireless actuator networks, considering a scenario where all actuators are immobile and each of them can obtain the target information from sensors. Unlike existing methods that neglect the adaptive auction area required by dynamic networks, the proposed method uses an adaptive factor k o (reflects the adaptive auction area) that is deduced based on the relation between network characteristics and protocol performance. Simulation results show that the adaptive protocol can dynamically change the auction area during the network operation. In addition, comparison with existing methods, such as simple auction protocol, 1 hop simple auction aggregation protocol, and 1 hop simple auction aggregation protocol greedy extension, shows that the adaptive auction protocol can choose the optimal solution at a low communication cost with a high probability, irrespective of the changes in the network. [ABSTRACT FROM AUTHOR]

Nodes in a wireless sensor network are normally constrained by hardware and environmental conditions and face challenges of reduced computing capabilities and system security vulnerabilities. This fact calls for special requirements for network protocol design, security assessment models, and energy-efficient algorithms. Data aggregation is an effective energy conservation technique, which removes redundant information from the data aggregated from neighbor sensor nodes. How to further improve the effectiveness of data aggregation plays an important role in improving data collection accuracy and reducing the overall network energy consumption. Unfortunately, sensor nodes are normally deployed in an open environment and thus are subject to various attacks conducted by adversaries. Consequently, data aggregation brings new challenges to wireless sensor network security. In this article, we propose a novel secure data aggregation solution based on autoregressive integrated moving average model, a time series analysis technique, to prevent private data from being learned by adversaries. We leverage the autoregressive integrated moving average model to predict the data volume in sensor nodes, and update and synchronize the model as needed. The experimental results demonstrate that our model provides accurate predictions and that, compared with competing methods, our solution achieves better security, lower computation and communication costs, and better flexibility. [ABSTRACT FROM AUTHOR]

This article presents an Internet of Things architecture for Smart Homes that specifically targets service composition and reconfiguration as enablers for the actuation and smart behavior capabilities. To this end, the main challenge that has to be addressed is the support to a seamless integration, composition, and reconfiguration of Internet of Things objects. Two enabling technologies are proposed here: a planning strategy based on a common-sense reasoning approach for service composition and a virtual-network protocol for Inter-Domain Messaging. The planner will identify the services that, properly connected, will cater for arisen, and therefore, unexpected needs. The virtual-network protocol will provide the support for this interconnection to take place in a transparent and orthogonal manner. This is particularly important to enable autonomous systems to instantiate composite services. To demonstrate the capabilities of the resulting framework, two use cases are presented, which under real circumstances demonstrate the potential of the proposed approach. [ABSTRACT FROM AUTHOR]

In this article, we propose a time division multiple access scheduling algorithm for end-to-end on-time packet delivery in multi-hop wireless sensor networks. Our proposed algorithm establishes a new communication path to substitute the old path including the link failed and schedules communication links on the new path by allocating timeslots satisfying end-to-end delay bound. Max-min optimization is employed to maximize the number of dedicated timeslots to establish the substitute path in the event of the next link failure. We evaluate the performance of the proposed algorithm using QualNet network simulator and compare it with the performance of the algorithm that minimizes the end-to-end delay. Our numerical results show that the path survival ratio of the proposed algorithm is approximately two times higher when large number of communication links fails. In addition, we apply the global recovery and local recovery schemes to observe the increase in the overhead message exchanges. Compared to the global recovery scheme, local recovery scheme requires six times less control messages to establish the substitute path when a small number of link failures occur, whereas more than 90% communication paths survive. [ABSTRACT FROM AUTHOR]

Various protocols have been proposed in the area of wireless sensor networks in order to achieve network-wide time synchronization. A large number of proposed protocols in the literature employ a message passing mechanism to make sensor node clocks tick in unison. In this paper, we first classify Message Passing based Time Synchronization (MPTS) protocols and then analyze them based on different metrics. The classification is based on the following three criteria: structure formation of the network affected by the synchronization protocol, frequency of synchronization process (synchronization interval), and synchronization message overhead. Proposed protocols are analyzed and evaluated from different perspectives based on available data. A comparison table of the reviewed protocols is presented according to the evaluation metrics. Finally, some potential methods will be proposed to improve the synchronization process. [ABSTRACT FROM AUTHOR]

Internet of Things (IoT) technologies allow everyday objects to be capable of connecting to the Internet, thereby making smart and convenient daily life. Although users’ daily lives can be convenient due to various smart services utilizing IoT, it can also be a target of attack through the Internet. Thus, security has now been recognized as mandatory technology to activate IoT based smart service. Several standard organizations related to IoT technologies recommend using the CoAP over DTLS protocol stacks for enabling secure communications between resource constrained things. In general DTLS, a cipher suite required to support specific security service should be negotiated between the CoAP client and server in the process of performing the DTLS handshake protocol. However, the handshake requires too much processing and transmission overhead in constrained IoT environment. To improve such an issue, this paper proposes a secure but efficient scheme for resource constrained things. The proposed scheme can selectively apply application data encryption or integrity to the DTLS record layer during an on-going secure session, thereby reducing the burden of DTLS handshake in resource constrained Internet of Things. [ABSTRACT FROM AUTHOR]

We propose an underwater CSMA/CA protocol with multi-RTS and multi-DATA receptions using the long underwater propagation delay. We analyze the throughput and delay of the proposed underwater CSMA/CA protocol through a ring-based underwater network modeling. The proposed protocol does not need to maintain the information of internode propagation delay for each pair of underwater nodes. In the proposed protocol, when there are simultaneous transmissions of RTS frames from different underwater sensors to an underwater sink as their back-off counters reach zero, the sink can recover some RTS frames which are not overlapped at the sink in the time domain due to the long underwater propagation delay. Then, the sink transmits CTS frame containing the DATA transmission order and the IDs of the sensors which transmitted the recovered RTS frames. Sensors which correspond to the IDs contained by the CTS frame can transmit DATA frame to the sink according to the DATA transmission order. We evaluate the throughput and delay performance of the proposed protocol with varying the number of sensors and the contention window size compared to the conventional protocols. The analytical results agree with the simulation results well for the proposed protocol with various numbers of sensors and contention window sizes. The analytical and simulation results show that the proposed protocol outperforms the conventional protocols. [ABSTRACT FROM AUTHOR]

Internet of Things (IoT) is expected to become a driver in an emerging era of interconnected world through the advanced connectivity of smart devices, systems, and services. IoT goes beyond a broad range of Machine-to-Machine (M2M) communication technologies and covers a wide variety of networking protocols. There exist solutions like MQTT or SIP collecting data from sensors, CoAP for constrained devices and networks, or XMPP for interconnecting devices and people. Also there is a plethora of standards and frameworks (OSGi, AllJoyn) bringing closer the paradigm of IoT vision. However, the main constraint of most existing platforms is their limited mutual interoperability. To this end, we provide a comprehensive description of protocols suitable to support the IoT vision. Further, we advocate an alternative approach to already known principles and employ the SIP protocol as a container for M2M data. We provide description of data structures and practical implementation principles of the proposed structures (JSON and Protocol Buffers are discussed in detail) transmitted by SIP as a promising enabler for efficient M2M communication in the IoT world. Our reported findings are based on extensive hands-on experience collected after the development of advanced M2M smart home gateway in cooperation with the operator Telekom Austria Group. [ABSTRACT FROM AUTHOR]

Link duration between two vehicles is considered an important quality of service metric in designing a network protocol for vehicular networks. There exist many works that study the probability density functions of link duration in a vehicular network given various vehicle mobility models, for example, the random waypoint model. None of them, however, provides a practical solution to estimating the link duration between two vehicles on the road. This is in part because link duration between vehicles is affected by many factors including the distance between vehicles, their turning directions at intersections, and the impact of traffic lights. Considering these factors, we propose the extended link duration prediction (ELDP) model which allows a vehicle to accurately estimate how long it will be connected to another vehicle. The ELDP model does not assume that vehicles follow certain mobility models; instead, it assumes that a vehicle’s velocity follows the Normal distribution. We validate the ELDP model in both highway and city scenarios in simulations. Our detailed simulations illustrate that relative speed between vehicles plays a vital role in accurately predicting link duration in a vehicular network. On the other hand, we find that the turning directions of a vehicle at intersections have subtle impact on the prediction results. [ABSTRACT FROM AUTHOR]

Software Defined Network (SDN) architecture has been widely used in various application domains. Aiming at the authentication and security issues of SDN architecture in autonomous decentralized system (ADS) applications, securing the mutual trust among the autonomous controllers, we combine trusted technology and SDN architecture, and we introduce an authentication protocol based on SDN architecture without any trusted third party between trusted domains in autonomous systems. By applying BAN predicate logic and AVISPA security analysis tool of network interaction protocol, we can guarantee protocol security and provide complete safety tests. Our work fills the gap of mutual trust between different trusted domains and provides security foundation for interaction between different trusted domains. [ABSTRACT FROM AUTHOR]

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

Sink location protection is critical to the viability of sensor networks as the central point of failure. Most existing work related to sink location protection focuses on local traffic analysis attack. In this paper, we study the sink location protection problem under a more powerful type of attack, the global traffic analysis attack. In order to hide the sink location, a protocol based on packet sending rate adjustment (SRA) is proposed. By controlling the packet sending rate of each node according to the current number of source nodes, SRA conceals the real traffic volume generated by source nodes and hence disguises the location of the sink. For further reducing the communication cost, we propose a light weight SRA protocol (L-SRA), which protects the sink location while significantly decreasing the communication cost. Performance of both SRA and L-SRA has been validated by theoretical analysis and simulation results. [ABSTRACT FROM AUTHOR]

This thesis presents a mural broadcast authentication protocol (MBAP) for wireless sensor networks based on Fourier series according to the issues of the main broadcast authentication protocol µTESLA being limited in authentication delay, more initial parameters, limited time, large key chain, and network congestion. Firstly, achieving the forward authentication work for common sensor nodes to base station is based on the characteristic of continuous-integrability function f(x) in [-π,π] which could be expanded into Fourier series, including entity authentication and source attestation. Secondly, assume that f(x) is the quadratic form function, and achieve the reverse authentication work for base station to common sensor nodes by detecting the security of f(x). The analysis results of safety performance in MBAP show that the captured nodes in WSN will not affect the security of broadcast authentication protocol and have low computation and communication cost, the base station can make broadcast randomly, and common sensor nodes can authenticate messages instantly, which solves the problem of network congestion well. The most important thing of MBAP is the mutual broadcast authentication method which ensures the security of the network greatly. [ABSTRACT FROM AUTHOR]

Most research done on the channel polling mechanisms for WSN MAC protocols has focused on achieving efficiency in terms of optimizing either delay or energy performance. This study introduces the mechanism of altering the polling interval distribution for the MAC protocol, based on the application’s optimization objective (delay or energy). Two options have been considered for both packet interarrival and polling interval distributions: deterministic and exponential, and their impact on performance analysis has been studied. The packet aggregation and block acknowledgements transmission schemes have also been incorporated in the performance analysis. Simulations for energy consumption and delay have been performed using MATLAB, for various combinations of interarrival and polling interval distributions. Results show that the energy consumption improves for the exponentially distributed polling intervals, while deterministic polling intervals provide better delay performance. Changing values of traffic load and packet aggregation demonstrate the trade-off between delay and energy consumption. The impact of aggregation on the error probability and subsequently on delay and energy has also been illustrated in simulations. Finally, optimal operating parameters have been studied in order to combine delay and energy consumption as optimization criteria. [ABSTRACT FROM AUTHOR]

This paper addresses the energy-efficient transmission for the scenario of cooperative wireless sensor networks with partial energy harvesting (EH) nodes. A new EH decoding-recoding policy is proposed by regarding the EH constraints and the characteristics of random network coding. We develop an energy efficiency model to investigate the tradeoff mechanism between the saved energy and the waiting time of the EH node, through which the corresponding parameters in the policy are also optimized. Moreover, we propose a novel transmission protocol by embedding the considered policy in the opportunistic reception algorithm. The decoding failure probability is then derived to examine its transmission reliability. The obtained theoretical and simulation results indicate that the proposed protocol achieves superiority in energy efficiency; meanwhile, it can also provide similar transmission reliability under specific conditions, as compared to the conventional algorithms in the two-hop model. [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]

With the rapid growth of internet technologies, there have been many recent innovations in printing methods and mobile printing service has become important part of our daily life. In this paper, we design and implement a secure mobile printing service using NFC tag to protect our personal information from the technical vulnerability and physical accident such as a robbery. To protect the personal information, the user has to scan the NFC information at the NFC reader using recognition robot to confirm the authentication. In addition, we propose a secure NFC-based authentication protocol that provides printer authorization method and document access control in accordance with user’s authority. Lastly, to prove validity and efficiency of the proposed system, the experimental test was confirmed and provided the results. [ABSTRACT FROM AUTHOR]

With the popularity of IEEE 802.11 based wireless fidelity (Wi-Fi) portable devices, it becomes increasingly significant to support the mobile users carrying Wi-Fi devices to access the Internet of Things (IoT) so that the communications between the mobile users and the smart objects deployed in the IoT stay uninterrupted when the mobile users are in movement. A scheme using Extended Service Set- (ESS-) based architecture is presented to implement the proxy mobile IPv6 protocol, that is, PMIPv6, for IEEE 802.11 infrastructure Wireless Local Area Networks (WLANs). The key signaling packets together with their time sequences for the mobility management in the proposed scheme are proposed. Moreover, the handoff delay in the proposed scheme is derived, through which the performance of the proposed scheme is analyzed. Numerical analysis indicates that the proposed scheme considerably outperforms the existing scheme that uses the Basic Service Set (BSS) based architecture in terms of handoff delay in the case when the delay between Mobile Access Gateway (MAG) and local mobile anchor (LMA) is relatively large. [ABSTRACT FROM AUTHOR]

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

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]

Periodical broadcasts of individual vehicle’s safety information such as velocity and acceleration are critical in vehicular ad hoc networks (VANETs). However, current contention-based media access control (MAC) protocols cannot guarantee high performance in high density VANETs. In this paper, we propose a MAC protocol based on s-disjunct code to achieve reliable and real-time broadcasts via assigning a channel to each vehicle as the vehicle enters the network. Our protocol is adaptive as vehicles are required to adjust their communication ranges according to the network density in order to avert the interference among them. We conduct an extensive simulation study, and our results indicate that the proposed scheme can successfully achieve the requirements of the dedicated short range communication (DSRC) standard, that is, to broadcast safety information 10 times per second. Even at a high vehicle density, our scheme still guarantees that the success rates of both transmission and reception are greater than 95%, and the collision rates of access collision and merging collision are lower than 10 collisions/period. [ABSTRACT FROM AUTHOR]

In VANETs, a clustering algorithm can be used to partition the network into smaller segments. Therefore, the clustering algorithms provide not only limited channel contention but also fair channel access within the cluster. In addition, they also increase spatial reuse in VANETs and efficient control for the network topology. The main concern in the clustering algorithm is the cluster stability. The major challenge is to elect a cluster head and to maintain the membership of member nodes in a highly dynamic and a fast-changing topology. Therefore, the major criterion for cluster formation is to form a stable cluster. In this paper, a clustering algorithm to affect organization and cooperative ADHOC MAC for cluster-based TDMA system in VANETs (ECCT) is proposed. The cooperation is used to help a cluster head update each neighbor cluster’s information which helps each cluster head to avoid collision when two clusters move into each other’s cluster’s transmission range. This efficiently utilizes a time slot. We use the lowest-ID algorithm to achieve organization. The analytical and simulated results show that not only the average number of time slots for electing a cluster head but also total number of time slots before data can be successfully transmitted is less than the existing cluster-based TDMA system and IEEE 802.11p. [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 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]

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]

With a rapid progress of numerous applications in wireless sensor networks (WSNs), performance evaluation and analysis techniques face new challenges in energy efficiency area in WSN applications. One of the key issues is to perform the security trade-off and energy efficiency analysis. In this paper, the energy analysis module for the QoP-ML (quality of protection modeling language) is proposed by means of which one can analyze the influence of various security levels on the energy consumption of a protocol. Moreover, an advanced communication module is proposed as an extension of the QoP-ML language, which enhances the abilities to analyze complex wireless sensor networks. The case study of WSN deployed on the Jindo Bridge in South Korea was carried out and the lifetime of protocols with various security levels was simulated. The results show that the introduction of various security levels can entail large differences in performance and energy consumption, and hence result in different lifetime. Therefore, the designers of WSN protocols should search for balance between the required lifetime and security level. The introduced QoP-ML extension, along with the AQoPA (automated quality of protection analysis) tool, has been developed to meet the above requirements. [ABSTRACT FROM AUTHOR]

We propose and analyse a medium access control (MAC) protocol for low energy critical infrastructure monitoring (LECIM) networks. As the packet drop probability plays crucial role in LECIM applications, we propose framed slotted aloha based MAC for LECIM using linearly increased contention window size to reduce the packet drop probability. We present a mathematical model of our proposed MAC under both saturated and nonsaturated traffic scenarios. We use probabilistic approach to find the performance metrics such as collision probability, packet drop probability, throughput, and energy consumption. Also, we obtain the probability-generating function of the head-of-line (HoL) delay of packet. The analytical results match with simulations. Our results can be used in the design of a system by providing the optimum system parameters for endpoints satisfying the given quality of service requirements on packet drop probability, energy consumption, and delay. [ABSTRACT FROM AUTHOR]

As the need for tracking objects in our daily life is increasing, how to take advantage of widely used technologies and devices to meet everyone’s need is becoming a burning issue. To achieve this aim, a tracking system supporting large-scale users based on GPS and G-sensors (TSSLSU) is designed to track items by obtaining various pieces information of the item’s states and analyzing various conditions. In this system, a microprocessor with Global Positioning System (GPS) modules embedded in target sends data in real-time through General Packet Radio Service (GPRS) and Global System for Mobile Communication (GSM), and an inner G-sensor can fetch real-time state information, such as acceleration and vibration signals. The system designed a message protocol to encapsulate and send these data to servers and also adopted distributed architecture, including backend server cluster, cache queue cluster, database cluster, and web server cluster. This specific architecture provides a better performance when large-scale users visit concurrently. In particular, there are alarm mechanisms to inform the user of any illegal cases through smart phone application and power-saving mechanism for embedded terminal by changing the frequency of sending messages. At any time, user can locate it and query the carrier’s previous path by web page or phone application. [ABSTRACT FROM AUTHOR]

With the rapid development in wireless communications and cloud computing technologies, clients (users) often use handheld mobile devices to access remote servers via open network channels. To provide authentication and confidentiality between clients and servers, a large number of ID-based authentication and key exchange (ID-AKE) protocols have been proposed for mobile client-server environments. However, most of the existing ID-AKE protocols adopt the precomputation technique so that they become vulnerable to the ephemeral-secret-leakage (ESL) attacks, in the sense that an adversary could use the ephemeral secrets to reveal the private keys of clients from the corresponding exchange messages. In the paper, we propose a new ESL-secure ID-AKE protocol for mobile client-server environments. We formally prove that the proposed protocol satisfies the security requirements of both mutual authentication and key exchange while resisting the ESL attacks. When compared with previously proposed ID-AKE protocols, our protocol has higher security and retains computational performance, since it requires no bilinear pairing operation for mobile clients. Finally, we mention the possibility of adopting our protocol as an authentication method of the extensible authentication protocol (EAP) for wireless networks. [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]

The way to distribute a wide range of services on Vehicular Ad Hoc Networks is going to be a very interesting research topic, due to the willingness of the investors and the standardization institutions. In fact, the higher the number of available services is, the higher the impact and the market penetration of the considered technology will be. Also governance institutions appreciate the benefits of VANETs, having the possibility to increase safety level along the roads, saving lots of human lives, and reducing the severity of the collisions among vehicles. In this work we propose a multicast protocol, called partitioned multicast tree (PAMTree), which is suitable for spreading several kinds of services, increasing the reliability of the network, and giving the possibility to a higher number of users of having access to those services. The proposed protocol aims to exploit the characteristics of the VANET architecture in order to distribute services along the nodes of the network; owing to the high nodes mobility, several issues have to be faced to supply an optimal distribution, having a look at the quality of service (QoS) satisfaction. [ABSTRACT FROM AUTHOR]

To build scalable and lightweight wireless sensor networks with energy saving devices, 6LoWPAN-based protocols become emergent technologies that successfully constructed ubiquitous networks and seamlessly connected the traditional Internet with WSNs. However, the existing researches cannot effectively maintain the routing and the network topology for the problems of low cost sensors’ malfunctions. In this paper, we improved the HiLow protocol in aspects of interconnection between the Internet and 6LoWPAN and designed a network routing path recovery approach. In addition, we designed and modified the address mapping table in gateway to store and map nodes’ EUI-64 address and 16-bit short address. Nodes from the Internet can access the 6LoWPAN nodes by an IPv6 address, which is generated by the EUI-64 address and IPv6 prefix. Due to the benefits of additional data structure and our designs, the simulation results manifested that our protocol improves the routing efficiency and can effectively reduce the cost for network reorganization caused by node failures and mobiles. [ABSTRACT FROM AUTHOR]

The unique characteristics of high bit error rate, low bandwidth, and long propagation delay in underwater environments pose significant challenges to the design of the medium access control (MAC) protocol for underwater wireless sensor networks (UWSNs). Clustering is an effective and practical way to enhance the performance of UWSNs. In this paper, we propose a secure MAC protocol for cluster-based UWSNs, called SC-MAC, which aims to ensure the security of data transmission. In SC-MAC, the clusters are formed and updated dynamically and securely. We leverage MAC layer information by considering the link quality as well as residual energy of the modem’s battery. After the successful mutual authentication, all sensor nodes from different clusters can protect the data transmission in the continuous communication. As the states of sensor nodes may not be observed accurately in a harsh underwater environment, we formulate the channel scheduling process as a stochastic partially observed Markov decision process (POMDP) multiarmed bandit problem and derive the optimal channel scheduling rules hereby. Simulation results show that SC-MAC can perform better than existing state-of-the-art MAC protocols in terms of network throughput, successful delivery ratio, and energy consumption in various circumstances. [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]

Energy Harvesting Wireless Sensor Networks (EH-WSNs) represent an interesting new paradigm where individual nodes forming a network are powered by energy sources scavenged from the surrounding environment. This technique provides numerous advantages, but also new design challenges. Securing the communications under energy constraints represents one of these key challenges. The amount of energy available is theoretically infinite in the long run but highly variable over short periods of time, and managing it is a crucial aspect. In this paper we present an adaptive approach for security in multihop EH-WSNs which allows different nodes to dynamically choose the most appropriate energy-affecting parameters such as encryption algorithm and key size, providing in this way energy savings. In order to provide evidence of the approach’s feasibility in a real-world network, we have designed and implemented it as extension of on-demand medium access control (ODMAC), a receiver-initiated (RI) MAC protocol specifically designed and developed to address the foundational energy-related needs of Energy Harvesting Wireless Sensor Networks. [ABSTRACT FROM AUTHOR]

Sensor networks feature low-cost sensor devices with wireless network capability, limited transmit power, resource constraints, and limited battery energy. Cooperative routing exploits the broadcast nature of wireless medium and transmits cooperatively using nearby sensor nodes as relays. It is a promising technique that utilizes cooperative communication to improve the communication quality of single-antenna sensor nodes. In this paper, we propose a cooperative transmission scheme for underwater sensor networks (UWSNs) to enhance the network performance. Cooperative diversity has been introduced to combat fading. Cooperative UWSN (Co-UWSN) is proposed, which is a reliable, energy-efficient, and high throughput routing protocol for UWSN. Destination and potential relays are selected that utilize distance and signal-to-noise ratio computation of the channel conditions as cost functions. This contributes to sufficient decrease in path losses occurring in the links and transferring of data with much reduced path loss. Simulation results show that Co-UWSN protocol performs better in terms of end-to-end delay, energy consumption, and network lifetime. Selected protocols for comparison are energy-efficient depth-based routing (EEDBR), improved adaptive mobility of courier nodes in threshold-optimized depth-based routing (iAMCTD), cooperative routing protocol for UWSN, and cooperative partner node selection criteria for cooperative routing Coop (Re and dth). [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]

Comprehensive evaluation of energy efficiency of protocols under certain cost conditions is a relatively new and ill-defined concept for collaborative wireless sensor networks (CWSN). In this paper, multicriteria decision making (MCDM) theory is introduced into comprehensive evaluation of energy efficiency of clustering protocols, which is the predecessor of collaborative protocols. Parameters about energy efficiency of total network, including cost and benefit parameters, are selected to construct a metrics system for the comprehensive evaluation. Technique for order preference by similarity to ideal solution (TOPSIS) without criterion weight is proposed as the method of MCDM, and it can be used to select most efficient scheme among many schemes. The experimental results show that the proposed method is effective and can be used in CWSN protocol selection and deployment of nodes. [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]

Real-time applications are time and event critical, therefore they have strict constraint on delay, packet loss, and energy consumption in many wireless sensor networks (WSNs) scenarios, which demands the network to continue QoS operations for a preconfigured lifetime. Due to the scarce energy constraint sensor nodes in WSNs, guaranteed network lifetime is more desirable than unpredictable and uncertain prolonged lifetime. However, in spite of its importance and necessity in WSNs real-time deployment, no research work has been proposed to solve this complex problem. In this paper, we present a new centralized energy and coverage aware node scheduling scheme for WSNs to analyze energy usage as well as balancing energy consumption among nodes to survive for the reconfigured lifetime. Furthermore, the scheduling algorithm is extended to provide real-time routing by adjusting dynamic transmission range according to current energy state of a sensor node. Thus, the energy and coverage aware scheduling with dynamic range forwarding enables the unreliable WSNs to accomplish real-time routing for a guaranteed network lifetime. Simulation results show that the proposed scheme can achieve a 10% increase in real-time packets meeting their deadline and a significantly longer guaranteed network lifetime than protocols reported in the literature. [ABSTRACT FROM AUTHOR]

Owing to complementary characteristics of wireless networks, it is deserved to achieve automatic handoff on the modern smartphone for taking full exploitation of these accessible technologies. In this paper, we have proposed the closed loop model on smartphone switching heterogeneous wireless networks, which is full-client based without requiring additional support from the access points or gateways and modification of the network protocols. It only intuitively takes advantage of user scheme as the feedback adjustment approach to handoff policy. Furthermore, we have analyzed the closed loop handoff model to illustrate and evaluate how the user feedback of the policy acts on adapting to change context. In the experiment, we have evaluated four metrics on the closed loop handoff policy in real smartphone device: performance, energy saving, data offloading, and user experience. [ABSTRACT FROM AUTHOR]

The railway is one of the most important facilities for freight logistics. This paper suggests the use of the container security devices (CSDs), which has been adopted for the marine transportation so far, to enhance the security of railway freight transportation. The proposed protocol, CSD Chain Network Protocol (CCNP), was designed for a chain-form network of CSDs, each of which is attached to a container. In CCNP, unauthorized access to freight is reliably reported to the reader deployed at the locomotive. CCNP also cares about the fairness in energy consumption. In a usual chain network, a tag closer to the reader consumes more energy since it ought to forward packets coming from rear tags as well. However, in CCNP, the tag energy consumption for packet forwarding is always the same regardless of the position in a chain owing to an efficient data fusion scheme. In our simulation using QualNet, CCNP reduces the number of disconnections between tags by 59.5% as compared to general chain networks. The energy consumption also decreases by 91.3% of other networks not using an aggregation method. [ABSTRACT FROM AUTHOR]

With the rapid development of vehicular ad hoc networks (VANETs), security issues are concerned. Among various security measures, secure group key agreement for VANETs attracts more and more attention. Researchers have studied generic group key agreement schemes for a long while; however, most of them are not designed for VANETs. Considering energy-constrained and fast moving features in vehicular ad hoc network, we propose a new location-based distributed group key agreement LDGKA scheme for VANETs. We adopt a hybrid approach in which members in the vehicular ad hoc network form various logic groups in the same region. Within each group, virtual key tree model is employed so that the rekeying operation can be efficiently carried out when members leave or join. It only requires to rebuild O(log(n)) keys when one node leaves or joins. Moreover, we adopt one-way key derivation to rebuild keys in order to reduce communication overhead of distributing new keys. We also design a protocol for establishing the secure temporary channel dynamically for the nodes that are located in different regions. [ABSTRACT FROM AUTHOR]