Showing papers on "Key distribution in wireless sensor networks published in 2012"

Radio link quality estimation in wireless sensor networks: A survey

Abstract: Radio link quality estimation in Wireless Sensor Networks (WSNs) has a fundamental impact on the network performance and also affects the design of higher-layer protocols. Therefore, for about a decade, it has been attracting a vast array of research works. Reported works on link quality estimation are typically based on different assumptions, consider different scenarios, and provide radically different (and sometimes contradictory) results. This article provides a comprehensive survey on related literature, covering the characteristics of low-power links, the fundamental concepts of link quality estimation in WSNs, a taxonomy of existing link quality estimators, and their performance analysis. To the best of our knowledge, this is the first survey tackling in detail link quality estimation in WSNs. We believe our efforts will serve as a reference to orient researchers and system designers in this area.

Sensor OpenFlow: Enabling Software-Defined Wireless Sensor Networks

Abstract: While it has been a belief for over a decade that wireless sensor networks (WSN) are application-specific, we argue that it can lead to resource underutilization and counter-productivity. We also identify two other main problems with WSN: rigidity to policy changes and difficulty to manage. In this paper, we take a radical, yet backward and peer compatible, approach to tackle these problems inherent to WSN. We propose a Software-Defined WSN architecture and address key technical challenges for its core component, Sensor OpenFlow. This work represents the first effort that synergizes software-defined networking and WSN.

Wireless Sensor Network Applications: A Study in Environment Monitoring System

Abstract: Development in the technology of sensor such as Micro Electro Mechanical Systems (MEMS), wireless communications, embedded systems, distributed processing and wireless sensor applications have contributed a large transformation in Wireless Sensor Network (WSN) recently. It assists and improves work performance both in the field of industry and our daily life. Wireless Sensor Network has been widely used in many areas especially for surveillance and monitoring in agriculture and habitat monitoring. Environment monitoring has become an important field of control and protection, providing real-time system and control communication with the physical world. An intelligent and smart Wireless Sensor Network system can gather and process a large amount of data from the beginning of the monitoring and manage air quality, the conditions of traffic, to weather situations. In this paper, we discuss and review wireless sensor network applications for environmental monitoring. In order to implement a good monitoring system, there are several requirements to be followed. From the studies, it has been proved to be an alternative way to replace the conventional method that uses men force to monitor the environment. It is also proven that these approaches can improve the system performance, provide a convenient and efficient method and can also fulfill functional requirements.

Making sensor networks immortal: an energy-renewal approach with wireless power transfer

Abstract: Wireless sensor networks are constrained by limited battery energy. Thus, finite network lifetime is widely regarded as a fundamental performance bottleneck. Recent breakthrough in the area of wireless power transfer offers the potential of removing this performance bottleneck, i.e., allowing a sensor network to remain operational forever. In this paper, we investigate the operation of a sensor network under this new enabling energy transfer technology. We consider the scenario of a mobile charging vehicle periodically traveling inside the sensor network and charging each sensor node's battery wirelessly. We introduce the concept of renewable energy cycle and offer both necessary and sufficient conditions. We study an optimization problem, with the objective of maximizing the ratio of the wireless charging vehicle (WCV)'s vacation time over the cycle time. For this problem, we prove that the optimal traveling path for the WCV is the shortest Hamiltonian cycle and provide a number of important properties. Subsequently, we develop a near-optimal solution by a piecewise linear approximation technique and prove its performance guarantee.

Fuzzy-Logic-Based Clustering Approach for Wireless Sensor Networks Using Energy Predication

Abstract: In order to collect information more efficiently, wireless sensor networks (WSNs) are partitioned into clusters. Clustering provides an effective way to prolong the lifetime of WSNs. Current clustering approaches often use two methods: selecting cluster heads with more residual energy, and rotating cluster heads periodically, to distribute the energy consumption among nodes in each cluster and extend the network lifetime. However, most of the previous algorithms have not considered the expected residual energy, which is the predicated remaining energy for being selected as a cluster head and running a round. In this paper, a fuzzy-logic-based clustering approach with an extension to the energy predication has been proposed to prolong the lifetime of WSNs by evenly distributing the workload. The simulation results show that the proposed approach is more efficient than other distributed algorithms. It is believed that the technique presented in this paper could be further applied to large-scale wireless sensor networks.

Mobile computer configured to select wireless communication network

Abstract: A mobile computer can comprise a processor, a memory, and a wireless communication interface. The mobile computer can be configured to periodically monitor one or more network metrics of the currently connected wireless network. In order to maintain an uninterrupted data connection, the mobile computer can be further configured, responsive to determining that at least one pre-defined Quality of Service (QoS) metric of the currently connected network averaged over a pre-defined time period falls outside of an allowable range or at least one pre-defined Quality of Service (QoS) metric of the currently connected network has been outside of an allowable range for at least a pre-defined time period, to select a new wireless network of a plurality of available wireless networks based on at least one network selection criterion and connect to the new wireless network.

Multipath Routing in Wireless Sensor Networks: Survey and Research Challenges

Abstract: A wireless sensor network is a large collection of sensor nodes with limited power supply and constrained computational capability. Due to the restricted communication range and high density of sensor nodes, packet forwarding in sensor networks is usually performed through multi-hop data transmission. Therefore, routing in wireless sensor networks has been considered an important field of research over the past decade. Nowadays, multipath routing approach is widely used in wireless sensor networks to improve network performance through efficient utilization of available network resources. Accordingly, the main aim of this survey is to present the concept of the multipath routing approach and its fundamental challenges, as well as the basic motivations for utilizing this technique in wireless sensor networks. In addition, we present a comprehensive taxonomy on the existing multipath routing protocols, which are especially designed for wireless sensor networks. We highlight the primary motivation behind the development of each protocol category and explain the operation of different protocols in detail, with emphasis on their advantages and disadvantages. Furthermore, this paper compares and summarizes the state-of-the-art multipath routing techniques from the network application point of view. Finally, we identify open issues for further research in the development of multipath routing protocols for wireless sensor networks.

Advanced Optical Wireless Communication Systems

Abstract: Optical wireless communications is a dynamic area of research and development. Combining fundamental theory with a broad overview, this book is an ideal reference for anyone working in the field, as well as a valuable guide for self-study. It begins by describing important issues in optical wireless theory, including coding and modulation techniques for optical wireless, wireless optical CDMA communication systems, equalization and Markov chains in cloud channels and optical MIMO systems, as well as explaining key issues in information theory for optical wireless channels. The next section describes unique channels that could be found in optical wireless applications, such as NLOS UV atmospheric scattering channels, underwater communication links and a combination of hybrid RF/optical wireless systems. The final section describes applications of optical wireless technology, such as quantum encryption, visible light communication, IR links and sensor networks, with step-by-step guidelines to help reduce design time and cost.

Apparatus and method for transmitting wireless power

Abstract: A method and a wireless power transmitter are provided for transmitting wireless power to at least one wireless power receiver. The method includes setting, by the wireless power transmitter, a search channel to be used for communication with the at least one wireless power receiver; detecting at least one of an energy level and a Received Signal Strength Indication (RSSI) value of a signal received on the search channel; and determining whether to designate the search channel as a communication channel based on the detection results.

A cluster-based routing protocol for wireless sensor networks with nonuniform node distribution

Abstract: Due to the nonuniform node distribution, the energy consumption among nodes are more imbalanced in cluster-based wireless sensor networks. Based on this problem, in this paper, a cluster-based routing protocol for wireless sensor networks with nonuniform node distribution is proposed, which includes an energy-aware clustering algorithm EADC and a cluster-based routing algorithm. EADC uses competition range to construct clusters of even sizes. At the same time, the routing algorithm increases forwarding tasks of the nodes in scarcely covered areas by forcing cluster heads to choose nodes with higher energy and fewer member nodes as their next hops, and finally, achieves load balance among cluster heads. Theoretical analysis and simulation results show that our protocol can balance the energy consumption among nodes and increase the network lifetime significantly.

A Survey of Localization in Wireless Sensor Network

Abstract: Localization is one of the key techniques in wireless sensor network. The location estimation methods can be classified into target/source localization and node self-localization. In target localization, we mainly introduce the energy-based method. Then we investigate the node self-localization methods. Since the widespread adoption of the wireless sensor network, the localization methods are different in various applications. And there are several challenges in some special scenarios. In this paper, we present a comprehensive survey of these challenges: localization in non-line-of-sight, node selection criteria for localization in energy-constrained network, scheduling the sensor node to optimize the tradeoff between localization performance and energy consumption, cooperative node localization, and localization algorithm in heterogeneous network. Finally, we introduce the evaluation criteria for localization in wireless sensor network.

Systems and methods for detecting and protecting a wireless power communication device in a wireless power system

Abstract: Embodiments are directed to detecting and limiting power transfer to communication device, such as NFC and RFID cards. A method may include detecting one or more communication devices positioned within a wireless power transfer region of a wireless power transmitter. The method may further include limiting an amount of power transmitted by a transmitter in response to the detection.

Method, apparatus, and computer program product for wireless charging detection

Abstract: Method, apparatus, and computer program product example embodiments provide wireless charging detection. According to an example embodiment of the invention, a method comprises advertising by a wireless charging device, an availability for wireless charging over a wireless communication interface; scanning, by the wireless charging device, for wireless signals from one or more other wireless devices; providing, by the wireless charging device, information usable for characterizing charging capabilities of the wireless charging device; transmitting, by the wireless charging device, one or more wireless communication packets over the wireless communication interface, including the information usable for characterizing the charging capabilities of the wireless charging device, in response to receiving one or more wireless signals from the one or more other wireless devices; and providing, by the wireless charging device, power to the one or more other wireless devices over a wireless power interface.

Method and apparatus for transmitting wireless power

Abstract: A method and apparatus are provided for transmitting wireless power in a wireless power network managed by a wireless power transmitter. The method includes transmitting first charging power to a first wireless power receiver; detecting a second wireless power receiver; and transmitting second charging power to the second wireless power receiver.

Wireless power transmitter and wireless power transfer method thereof in many-to-one communication

Abstract: A wireless power transmitter for transmitting power in a wireless manner by forming a wireless power signal and a wireless power transfer method thereof are capable of optimizing transmission efficiency for a plurality of wireless power receivers, by deciding an optimal transmission parameter (especially, a frequency corresponding to the wireless power signal or a resonant frequency) for the plurality of wireless power receivers based on control errors received from the plurality of wireless power receivers, respectively, via respective time slots allocated to the plurality of wireless power receivers.

System and Method for Providing Wireless Power Feedback in a Wireless Power Delivery System

Abstract: A wireless power delivery system includes a wireless power source and a control module. The wireless power source provides power to an information handling system. The control module is in communication with the wireless power source, and is configured to detect a presence signal from the information handling system, to set an output power level for the information handling system based on the presence signal, to receive a signal from the information handling system, and to adjust the output power level based on the signal.

CitySee: Urban CO 2 monitoring with sensors

Abstract: Motivated by the needs of precise carbon emission measurement and real-time surveillance for CO 2 management in cities, we present CitySee, a real-time CO 2 -monitoring system using sensor networks for an urban area (around 100 square kilometers). In order to conduct environment monitoring in a real-time and long-term manner, CitySee has to address the following challenges, including sensor deployment, data collection, data processing, and network management. In this discussion, we mainly focus on the sensor deployment problem so that necessary requirements like connectivity, coverage, data representability are satisfied. We also briefly go through the solutions for the remaining challenges. In CitySee, the sensor deployment problem can be abstracted as a relay node placement problem under hole-constraint. By carefully taking all constraints and real deployment situations into account, we propose efficient and effective approaches and prove that our scheme uses additional relay nodes at most twice of the minimum. We evaluate the performance of our approach through extensive simulations resembling realistic deployment. The results show that our approach outperforms previous strategies. We successfully apply this design into CitySee, a large-scale wireless sensor network consisting of 1096 relay nodes and 100 sensor nodes in Wuxi City, China.

Apparatus and method for sharing energy in wireless device

Abstract: A method and apparatus to share energy in a wireless device are provided. A power sharing method between a wireless device and at least one neighboring wireless device, includes scanning, by the wireless device, the at least one neighboring wireless device. The power sharing method further includes determining to share power with the at least one neighboring wireless device. The power sharing method further includes sharing power with the at least one neighboring wireless device.

An intelligent self-adjusting sensor for smart home services based on ZigBee communications

Abstract: Wireless sensor networks (WSNs) have been becoming increasingly essential in recent years because of their ability to manage real-time situational information for various novel services. Recently, the scope of WSN technologies has been expanded to places such as the home, in order to provide the residents with various intelligent services, such as home automation services or home energy management services. However, due to their architectural constraints, such as the trade-off between the performance and cost, WSNs are not effectively implemented in home environments. Therefore, this paper proposes a ZigBee-based intelligent self-adjusting sensor (ZiSAS) in order to address these concerns. This paper presents a situation-based selfadjusting scheme, an event-based self-adjusting sensor network, and hardware and middleware implementation. We also introduce some smart home services using the proposed system. We implemented our system in real test bed and conducted an experiment. Our experiment shows that we reduce the system's energy consumption.

Power-receiving device, wireless power-feeding system including power-receiving device, and wireless communication system including power-receiving device

Abstract: When a portable electronic appliance is provided with two systems, a wireless power-feeding system and a wireless communication system, each system requires two power-receiving devices, a coil and an antenna, leading to a problem of increased electronic appliance size and cost. Wireless power feeding employs the resonance method and uses a resonance coil using the resonance method and a power-receiving coil that receives power from the resonance coil. At least one of the resonance coil and the power-receiving coil can also be used as an antenna for wireless communication. Thus, a power-receiving device that can be used for two systems, wireless power feeding and wireless communication, can be provided.

Evaluation of the reliability of RSSI for indoor localization

Abstract: In wireless sensor networks, nodes can be static or mobile, depending on the application requirements Dealing with mobility can pose some formidable challenges in protocol design, particularly, at the link and network layers These difficulties require mobility adaption algorithms to efficiently localize mobile nodes and predict the quality of link that can be established with these nodes An off the shelf development platform that uses Radio Signal Strength Indication (RSSI) is mostly selected as the sensor localization method, especially in the indoor environment Despite this, not much research work has been done to practically demonstrate the reliability of RSSI for indoor localization Therefore, in this paper, we aim to calibrate and map RSSI to distance by doing a series of experiments The result shows that the RSSI technology gives an unacceptable high error and thus is not reliable for the indoor sensor localization

A novel energy-aware cluster head selection based on particle swarm optimization for wireless sensor networks

Abstract: The wireless sensor networks have long been an attractive field to the researchers and scientists for its ease in deployment and maintenance. In this research, we focus on the maximization of network lifetime which has become a critical issue in sensor networks. Clustered organization of nodes with aggregation of data at the cluster head becomes one of the significant means to extend life expectancy of the network. This paper proposes Particle Swarm Optimization (PSO) approach for generating energy-aware clusters by optimal selection of cluster heads. The PSO eventually reduces the cost of locating optimal position for the head nodes in a cluster. In addition, we have implemented the PSO-based approach within the cluster rather than base station, which makes it a semi-distributed method. The selection criteria of the objective function are based on the residual energy, intra-cluster distance, node degree and head count of the probable cluster heads. Furthermore, influence of the expected number of packet retransmissions along the estimated path towards the cluster head is also reflected in our proposed energy consumption model. The performance evaluation of our proposed technique is carried out with respect to the well-known cluster-based sensor network protocols, LEACH-C and PSO-C respectively. Finally, the simulation clarifies the effectiveness of our proposed work over its comparatives in terms of network lifetime, average packet transmissions, cluster head selection rounds supported by PSO and average energy consumption.

Reliability and Availability Evaluation of Wireless Sensor Networks for Industrial Applications

Abstract: Wireless Sensor Networks (WSN) currently represent the best candidate to be adopted as the communication solution for the last mile connection in process control and monitoring applications in industrial environments. Most of these applications have stringent dependability (reliability and availability) requirements, as a system failure may result in economic losses, put people in danger or lead to environmental damages. Among the different type of faults that can lead to a system failure, permanent faults on network devices have a major impact. They can hamper communications over long periods of time and consequently disturb, or even disable, control algorithms. The lack of a structured approach enabling the evaluation of permanent faults, prevents system designers to optimize decisions that minimize these occurrences. In this work we propose a methodology based on an automatic generation of a fault tree to evaluate the reliability and availability of Wireless Sensor Networks, when permanent faults occur on network devices. The proposal supports any topology, different levels of redundancy, network reconfigurations, criticality of devices and arbitrary failure conditions. The proposed methodology is particularly suitable for the design and validation of Wireless Sensor Networks when trying to optimize its reliability and availability requirements.

Improvement of LEACH protocol for WSN

Abstract: In wireless sensor networks, sensor nodes always have a limited power resource. The energy consumed by transferring data from the sensor node to its destination raises as a critical issue in designing reasonable wireless sensor network routing protocols. In this paper we propose a revised cluster routing algorithm named E-LEACH to enhance the hierarchical routing protocol LEACH. In the E-LEACH algorithm, the original way of the selection of the cluster heads is random and the round time for the selection is fixed. In the E-LEACH algorithm, we consider the remnant power of the sensor nodes in order to balance network loads and changes the round time depends on the optimal cluster size. The simulation results show that our proposed protocol increases network lifetime at least by 40% when compared with the LEACH algorithm.

Mobile wifi arrangement

Abstract: A system for enabling wireless near-field hot-spot communication between a wide variety of wireless ground-position-indicating personal communication devices being utilized within a zone and a further communication network outside of the zone.