scholarly journals Clocks, power and synchronization in duty-cycled wireless sensor nodes

2011 ◽  
Vol 24 (2) ◽  
pp. 183-208 ◽  
Author(s):  
Mile Stojcev ◽  
Ljubisa Golubovic ◽  
Tatjana Nikolic
Keyword(s):  
Time Scale ◽  
Large Scale ◽  
Time Synchronization ◽  
Clock Synchronization ◽  
Low Cost ◽  
Limited Resource ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Reference Source ◽  
Common Time

Recent advances in CMOS VLSI ICs and micro-electromechanical technology have led to development of small, low-cost, and low-power multifunctional sensors. Wireless sensor networks (WSNs) are large-scale networks of such sensors, dedicated to observing and monitoring various aspects of the physical world. Some intrinsic properties of WSNs including limited resource of energy, storage, computation, and bandwidth, make traditional synchronization methods unsuitable for WSNs. Time synchronization as an important issue consists of giving all sensor nodes (SNs) of the WSN a common time scale to operate. The common time scale is usually achieved by periodically synchronizing the clock of each SN to a reference source. In this manner the local time seen by each SN of the network is approximately the same, and time synchronization allows the entire system to cooperate. This paper gives a brief look to the time synchronization problem and the need for synchronization in WSNs. Then it points out that clock systems become a bottle-neck, after that it presents the available current clock technologies, next it examines the influence of these clock technologies, and finally provides guidelines for WSN developers who must choose among the different clock synchronization techniques.

scholarly journals Current research on Internet of Things (IoT) in Agriculture

2020 ◽  
Vol 9 (8) ◽  
pp. 882-886
Keyword(s):  
Power Supply ◽  
Precision Agriculture ◽  
Large Scale ◽  
Low Cost ◽  
Low Energy ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Energy Usage ◽  
Major Application ◽  
Sensing Time

IoT, a sensation in modern-day technology, has a major impact on the rapidly growing technological aspects. It’s making people’s life easier and also enabling us to do things that were previously seen as miracles. It helps in solving many complex real-time problems. One such major application in the field of agriculture can turn out to be productive and profitable. This paper explains a variety of techniques infusing IoT in agriculture, that helps in productive and predictive results in that field, thereby leading towards precision agriculture. A low-cost power supply and unambiguous farming can be possible with using IoT system. Wireless Sensor Networks (WSN) in which sensor nodes learn and adopt over the sensing time, gives simplicity, low energy usage. This is aimed to be deployed on a large scale by predicting using big data techniques from centralized data analysis.

scholarly journals Proposing a novel method for clock synchronization in WSN

2015 ◽  
Vol 4 (2) ◽  
pp. 95-106
Author(s):  
Seyed Kazem Kazeminezhad ◽  
Shahram Babaie ◽  
Amir Shiri
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Time Synchronization ◽  
Clock Synchronization ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Crystal Oscillator ◽  
Error Factor ◽  
Spatially Distributed ◽  
Two Factors

Wireless sensor networks (WSNs) of spatially distributed autonomous sensors are used to monitor physical or environmental conditions such as temperature, sound, pressure, etc. They are also used to cooperatively pass the collected data through the network to a main location. Due to the application of wireless sensor networks as a monitoring device in the real world, the physical time of the occurrence of events is important. Since WSNs have particular constraints and limitations, synchronizing the physical times for these networks is considered to be a complex task. Although many algorithms have been proposed for synchronizing time in the network, there are two main error factors in all the proposed algorithms. The first factor is the clock drift which might be caused by the influence of different environmental factors such as temperature, ambient temperature, humidity, it might be generated on crystal oscillator which is inevitable The second error factor is indeterminacy which is attributed to the existence of non-deterministic delays in sending and receiving messages between sensor nodes. These two factors together reduce the precision of synchronization algorithms. In this paper, the researchers proposed a new approach for dealing with the above-mentioned two problems and achieving better synchronization. The proposed approach is a combination of flooding time synchronization protocol (FTSP) and reference broadcast synchronization (RBS).This approach is intended to increase synchronization accuracy and network lifetime by reducing the number of synchronization messages sent between nodes and eliminating the most of non-deterministic errors in sending messages. The results of simulations conducted in the study indicated that the proposed approach is significantly more efficient than the FTSP and RBS methods in terms of parameters such as accurate synchronization, amount of sent packets and power consumption.

An Intelligent Monitoring and Controlling of Greenhouse: Deployment of Wireless Sensor Networks and Internet-of-Things

2018 ◽  
Author(s):  
Jehangir Arshad ◽  
Saqib Saleem ◽  
Muhammad Sana Ullah Badar ◽  
Samreen Khalid ◽  
Zain Mumtaz ◽  
...  
Keyword(s):  
Embedded System ◽  
Large Scale ◽  
Low Cost ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Agricultural System ◽  
Agricultural Field ◽  
Climate Data ◽  
Specific Criterion ◽  
Climate Parameters

Typically, the farmers are using the traditional ways of farming that cannot provide the proper amount of fertilizers and no specific criterion can be set the proper amount of climate parameters. Henceforth, the agricultural field demands up-to-date technology to enhance the desired outputs by deploying automated crop techniques for the better production of crops and plants. In the prescribed context, we have devised an architecture consisting of an embedded system and a wireless sensor network that could be employed to monitor the climatic parameters such as humidity, temperature, carbon dioxide, acidity, soil moisture, and light intensity etc. in a greenhouse. This work is accomplished by manually positioning the different sensor nodes in the greenhouse for collection of climate data which is subsequently forwarded to gateway nodes. Gateway nodes are responsible to send this information to the intended user or an agriculture professional via an internet web browser. The received data trigger the proposed embedded system to automatically proceed a decision by executing suitable actions to adjust an agriculture field with climate parameters. For instance, the climate of a greenhouse is controlled by turning on certain devices including fan, water sprinkler, lights etc. The proposed fruitful system is constructed at lab-scale prototype as a witness to proof the reliability, low-cost and efficiency of the proposed design. We consider that the proposed design can be easily implemented at large-scale in future, and will be beneficial for escalation of the profitability, sustainability, and productivity of the agricultural system.

scholarly journals A Mobility-Assisted Localization Algorithm for Three-Dimensional Large-Scale UWSNs

Sensors ◽  
2020 ◽  
Vol 20 (15) ◽  
pp. 4293
Author(s):  
Junhai Luo ◽  
Yang Yang ◽  
Zhiyan Wang ◽  
Yanping Chen ◽  
Man Wu
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Sensor Node ◽  
Large Scale ◽  
Time Synchronization ◽  
Three Dimensional ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Underwater Environment ◽  
Localization Scheme

As one of the important facilities for marine exploration, as well as environment monitoring, access control, and security, underwater wireless sensor networks (UWSNs) are widely used in related military and civil fields, since the sensor node localization is the basis of UWSNs’ application in various related fields. Therefore, the research of localization algorithms based on UWSNs has gradually become one of the research hotspots today. However, unlike terrestrial wireless sensor networks (WSNs), many terrestrial monitoring and localization technologies cannot be directly applied to the underwater environment. Moreover, due to the complexity and particularity of the underwater environment, the localization of underwater sensor nodes still faces challenges, such as the localization ratio of sensor nodes, time synchronization, localization accuracy, and the mobility of nodes. In this paper, we propose a mobility-assisted localization scheme with time synchronization-free feature (MALS-TSF) for three-dimensional (3D) large-scale UWSNs. In addition, the underwater drift of the sensor node is considered in this scheme. The localization scheme can be divided into two phases. In Phase I, anchor nodes are distributed in the monitoring area, reducing the monitoring cost. Then, we address a time-synchronization-free localization scheme, to obtain the coordinates of the unknown sensor nodes. In Phase II, we use the method of two-way TOA to locate the remaining ordinary sensor nodes. The simulation results show that MALS-TSF can achieve a relatively high localization ratio without time synchronization.

scholarly journals Wireless Sensor Networks for Smart Cities: Network Design, Implementation and Performance Evaluation

Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 218
Author(s):  
Ala’ Khalifeh ◽  
Khalid A. Darabkh ◽  
Ahmad M. Khasawneh ◽  
Issa Alqaisieh ◽  
Mohammad Salameh ◽  
...  
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Experimental Evaluation ◽  
Large Scale ◽  
Performance Metrics ◽  
Smart Cities ◽  
Field Tests ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Real Field

The advent of various wireless technologies has paved the way for the realization of new infrastructures and applications for smart cities. Wireless Sensor Networks (WSNs) are one of the most important among these technologies. WSNs are widely used in various applications in our daily lives. Due to their cost effectiveness and rapid deployment, WSNs can be used for securing smart cities by providing remote monitoring and sensing for many critical scenarios including hostile environments, battlefields, or areas subject to natural disasters such as earthquakes, volcano eruptions, and floods or to large-scale accidents such as nuclear plants explosions or chemical plumes. The purpose of this paper is to propose a new framework where WSNs are adopted for remote sensing and monitoring in smart city applications. We propose using Unmanned Aerial Vehicles to act as a data mule to offload the sensor nodes and transfer the monitoring data securely to the remote control center for further analysis and decision making. Furthermore, the paper provides insight about implementation challenges in the realization of the proposed framework. In addition, the paper provides an experimental evaluation of the proposed design in outdoor environments, in the presence of different types of obstacles, common to typical outdoor fields. The experimental evaluation revealed several inconsistencies between the performance metrics advertised in the hardware-specific data-sheets. In particular, we found mismatches between the advertised coverage distance and signal strength with our experimental measurements. Therefore, it is crucial that network designers and developers conduct field tests and device performance assessment before designing and implementing the WSN for application in a real field setting.

scholarly journals Sensor System: A Survey of Sensor Type, Ad Hoc Network Topology and Energy Harvesting Techniques

Electronics ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 219
Author(s):  
Phuoc Duc Nguyen ◽  
Lok-won Kim
Keyword(s):  
Energy Harvesting ◽  
Large Scale ◽  
Ad Hoc ◽  
Sensor Nodes ◽  
Sensor System ◽  
Wireless Sensor ◽  
The Internet ◽  
Original Research ◽  
Energy Scavenging ◽  
Term Operation

People nowadays are entering an era of rapid evolution due to the generation of massive amounts of data. Such information is produced with an enormous contribution from the use of billions of sensing devices equipped with in situ signal processing and communication capabilities which form wireless sensor networks (WSNs). As the number of small devices connected to the Internet is higher than 50 billion, the Internet of Things (IoT) devices focus on sensing accuracy, communication efficiency, and low power consumption because IoT device deployment is mainly for correct information acquisition, remote node accessing, and longer-term operation with lower battery changing requirements. Thus, recently, there have been rich activities for original research in these domains. Various sensors used by processing devices can be heterogeneous or homogeneous. Since the devices are primarily expected to operate independently in an autonomous manner, the abilities of connection, communication, and ambient energy scavenging play significant roles, especially in a large-scale deployment. This paper classifies wireless sensor nodes into two major categories based the types of the sensor array (heterogeneous/homogeneous). It also emphasizes on the utilization of ad hoc networking and energy harvesting mechanisms as a fundamental cornerstone to building a self-governing, sustainable, and perpetually-operated sensor system. We review systems representative of each category and depict trends in system development.

scholarly journals A Distributed Collision-Free Data Aggregation Scheme for wireless sensor network

2018 ◽  
Vol 14 (8) ◽  
pp. 155014771879584 ◽  
Author(s):  
Danyang Qin ◽  
Yan Zhang ◽  
Jingya Ma ◽  
Ping Ji ◽  
Pan Feng
Keyword(s):  
Wireless Sensor Network ◽  
Sensor Network ◽  
Data Aggregation ◽  
Large Scale ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Network Delay ◽  
Free Data ◽  
Aggregation Scheme ◽  
Aggregation Technology

Due to the advantages of large-scale, data-centric and wide application, wireless sensor networks have been widely used in nowadays society. From the physical layer to the application layer, the multiply increasing information makes the data aggregation technology particularly important for wireless sensor network. Data aggregation technology can extract useful information from the network and reduce the network load, but will increase the network delay. The non-exchangeable feature of the battery of sensor nodes makes the researches on the battery power saving and lifetime extension be carried out extensively. Aiming at the delay problem caused by sleeping mechanism used for energy saving, a Distributed Collision-Free Data Aggregation Scheme is proposed in this article to make the network aggregate data without conflicts during the working states periodically changing so as to save the limited energy and reduce the network delay at the same time. Simulation results verify the better aggregating performance of Distributed Collision-Free Data Aggregation Scheme than other traditional data aggregation mechanisms.

scholarly journals DOS Attacks on TCP/IP Layers in WSN

2013 ◽  
Vol 1 (2013) ◽  
pp. 40-45
Keyword(s):  
Wireless Sensor Network ◽  
Sensor Networks ◽  
Sensor Network ◽  
Low Cost ◽  
Denial Of Service ◽  
Sensor Nodes ◽  
Wireless Sensor ◽  
Renewable Energy Resources ◽  
Dos Attack ◽  
Dos Attacks

The emergence of sensor networks as one of the dominant technology trends in the coming decades has posed numerous unique challenges on their security to researchers. These networks are likely to be composed of thousands of tiny sensor nodes, which are low-cost devices equipped with limited memory, processing, radio, and in many cases, without access to renewable energy resources. While the set of challenges in sensor networks are diverse, we focus on security of Wireless Sensor Network in this paper. First, we propose some of the security goal for Wireless Sensor Network. To perform any task in WSN, the goal is to ensure the best possible utilization of sensor resources so that the network could be kept functional as long as possible. In contrast to this crucial objective of sensor network management, a Denial of Service (DoS) attack targets to degrade the efficient use of network resources and disrupts the essential services in the network. DoS attack could be considered as one of th

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