Pulse‐Based Clock Synchronization and Physical Layer Communication in Wireless Sensor Networks

Many researchers employ IEEE802.15.4 as communication technology for wireless sensor networks (WSNs). However, medium access control (MAC) layer requirements for communications in wireless sensor networks (WSNs) vary because the network is usually optimized for specific applications. Thus, one particular standard will hardly be suitable for every possible application. Two general categories of MAC techniques exist: contention based and schedule based. This paper explains these two main approaches and includes examples of each one. The paper concludes with a unique performance analysis and comparison of benefits and limitations of each protocol with respect to WSNs.

Problem statement: The Wireless Body Area Sensor Networks (WBASNs) is a wireless network used for communication among sensor nodes operating on or inside the human body in order to monitor vital body parameters and movements. This study surveys the state-of-the-art on Wireless Body Area Networks, discussing the major components of research in this area including physiological sensing and preprocessing, WBASNs communication techniques and data fusion for gathering data from sensors. In addition, data analysis and feedback will be presented including feature extraction, detection and classification of human related phenomena. Approach: Comparative studies of the technologies and techniques used in such systems will be provided in this study, using qualitative comparisons and use case analysis to give insight on potential uses for different techniques. Results and Conclusion: Wireless Sensor Networks (WSNs) technologies are considered as one of the key of the research areas in computer science and healthcare application industries. Sensor supply chain and communication technologies used within the system and power consumption therein, depend largely on the use case and the characteristics of the application. Authors conclude that Life-saving applications and thorough studies and tests should be conducted before WBANs can be widely applied to humans, particularly to address the challenges related to robust techniques for detection and classification to increase the accuracy and hence the confidence of applying such techniques without physician intervention.

The growing awareness of the strategic value of service along with higher product performance expectations has directed many industries to adopt service centric competitive strategies in managing their supply chains. Service innovation based on currently available advanced technologies has become critical in improving enterprises’ competitive strengths. Wireless sensor network (WSN) technology, which can provide a mobile, scalable, and reliable monitoring solution, is emerging as a tool for service innovation in supply chain management. This paper provides an overview of wireless sensor network technology and discusses how it can benefit modern industries. The fundamental theories of WSN are introduced as well as an overview of the development. The impact of information technologies on supply chain management and service innovation is then briefly discussed. Much emphasis is placed on the feasibility, procedures, and critical challenges of implementing WSN in supply chain management innovation. Current and future applications of WSN are also provided, followed by a case study demonstrating the application potentials of WSN for service innovation in the healthcare industry.

In order to tackle the problem of random communication delays in time synchronization process, this paper has mainly discussed the relationship between the global steady-state error of clock synchronization and the probability distribution of the delays of all the communication links for least square estimation based time synchronization algorithm (LSTS) in wireless sensor networks ( WSNs ). First under the general condition of communication in WSNs, it has been described that the probability distribution of bounded random communication delays has a great influence on the clock synchronization error. Then considering that all round-trip delays can be determined correctly between every pair of sensor nodes, the update rule of clock offset compensation has introduced round-trip delays so as to reduce the adjusting amplitude of the clock offset and the error of clock synchronization. Finally simulations for the improved algorithm has been given. It is shown that the error of clock skew compensation mainly depends on the variance of random communication delays rather than expectation, while the global synchronization error depends on the expectation of communication delays. The introduction of round-trip delay in LSTS algorithm can decrease both the expectation and the variance of clock synchronization error.

Wireless Sensor Network (WSN) have been attracting increasing interest for supporting a new generation of ubiquitous computing systems with great potential for many applications. However, the communication paradigms in WSNs differ from the ones associated to traditional wireless networks, triggering the need for efficient wireless communication technology. Several wireless technologies have emerged ranging from short and medium distance. Bluetooth, ZigBee and Impulse Radio Ultra Wide Band (IR-UWB) are three popular short range wireless communications. Due to its various features and advantages (especially low power consumption and low complexity), IR-UWB is a very promising wireless communication technology for WSN. In this paper, we evaluate the main features and advantages of this new technology (IR-UWB) for WSN in terms of transmission time, data coding and power consumption compared to Bluetooth and ZigBee. To analyze and evaluate the main features and advantages of IR-UWB as an efficient short range wireless communication technology for WSN, we used MiXiM platform under OMNet++ simulator.

This paper mainly introduces the application of multichannel communication technology in wireless sensor network. The corresponding solutions are proposed based on the analysis of the structure and characteristics of wireless sensor, and the multi-channel MAC protocol in wireless sensor network. In this paper, multi-channel communication technology in wireless sensor network (WSN) is studied, the existing problems and reasons are analysed, and some solutions to further promote the further development of the technology are put forward. With the wide application of WSN, the security of WSN has been paid more and more attention. In this paper, the existing time synchronization protocol, from the security point of view, and the fault tolerance design of the fits protocol. The protocol has an intrusion detection mechanism, which can detect the attack of malicious nodes in time synchronization. Aiming at the small deviation of slow attack and the problem of time synchronization error, information fusion is based on the quality principle, and according to the time synchronization information of different nodes, we make random weighted average correction for local time nodes. The simulation results show that the fits time synchronization protocol has good intrusion detection and fault tolerance capability.

Time consistency of each node and each core is one of the kernel problems that must be addressed to promote the development of many-core cluster system that keeps the distributed system in step, and it is the basis of performance evaluation. In this study, a new model of hybrid time synchronization architecture was established to improve the precision of internal clock synchronization of a many-core cluster and the accuracy of time. First, some clock synchronization method was compared for clock synchronization model decision. Second, a high precision time acquire method based on was explored. Third, a hybrid clock synchronization and time acquire architecture on cluster system was designed to enhance the time precision and internal clock consistency. Finally, the architecture was implemented on a Zynq SoC and Epiphany many-core processor combined platform. An experiment was conducted to evaluate the precision and accuracy of this architecture. The result shows that the hybrid architecture achieved a higher level time precision and internal clock consistency than common clock synchronization method like NTP. And result demonstrates the promising application of the proposed architecture in study many-core cluster system and in supplying reliable time reference for the evaluation of distributed system performance.

There is a plethora of recent research on high performance wireless communications using a cross‐layer approach in that adaptive modulation and coding (AMC) schemes at wireless physical layer are used for combating time varying channel fading and enhance link throughput. However, in a wireless sensor network, transmitting packets over deep fading channel can incur excessive energy consumption due to the usage of stronger forwarding error code (FEC) or more robust modulation mode. To avoid such energy inefficient transmission, a straightforward approach is to temporarily buffer packets when the channel is in deep fading, until the channel quality recovers. Unfortunately, packet buffering may lead to communication latency and buffer overflow, which, in turn, can result in severe degradation in communication performance. Specifically, to improve the buffering approach, we need to address two challenging issues: (1) how long should we buffer the packets? and (2) how to choose the optimum channel transmission threshold above which to transmit the buffered packets? In this paper, by using discrete‐time queuing model, we analyze the effects of Rayleigh fading over AMC‐based communications in a wireless sensor network. We then analytically derive the packet delivery rate and average delay. Guided by these numerical results, we can determine the most energy‐efficient operation modes under different transmission environments. Extensive simulation results have validated the analytical results, and indicates that under these modes, we can achieve as much as 40% reduction in energy dissipation. Copyright © 2008 John Wiley & Sons, Ltd.

This work presents a solar power based water quality monitoring wireless sensor network (WSN) technology, to screen water quality over various destinations as an ongoing application, an astounding framework engineering comprised by disseminated sensor nodes and a base station is proposed. The model and base station are associated utilizing WSN innovation like Zig-Bee. Modeling and implementation of a proposed model using one node powered by solar cell and WSN technology is the challenging work. Data collection by different sensing element at the node side like pH, turbidity conductivity, saltiness and temperature is sent by means of WSN to the base station. Information gathered from the distant site can be shown in visual organization too as it very well may be examined utilizing diverse reproduction apparatuses at base station. This original framework has benefits like no fossil fuel byproduct, low power utilization, more adaptable to send data at far off site, etc.

Air pollution is one of environmental issues that have been often discussed. The fast-growing population and urbanization result in the population concentrated in certain areas. Heavy transportation may lead to poor air quality, and inhaling pollutants for a long time also causes damages in human health. A traditional air quality monitoring method is to build air quality monitoring stations, but this method is expensive and provides low resolution sensing data. In addition, monitoring stations are generally less densely deployed. This paper proposed an urban air quality monitoring system based on the wireless sensor network (WSN) technology and integrated with the global system for mobile communications. The system consists of sensor node, a gateway, and a back-end platform controlled by the LabVIEW program through which sensing data can be stored in a database. This system is deployed to the main roads in the Taipei city to monitor the carbon monoxide (CO) concentration caused by vehicle emissions. The experimental results show that the proposed system can provide micro-scale air quality monitoring in real-time through the WSN technology.

In recent years, secure, reliable and high speed data transmission have become key elements for cooperative based communication systems. Conventional communication methods are no longer sufficiently fulfilling the demands of next generation communication systems. In this paper, in order to establish communication between sensor nodes with the 3GPP LTE standard and achieve better communication values in terms of low Signal to Noise Ratio (SNR) regimes, four different Multi-Carrier modulation scenarios were investigated for relay network configuration of Wireless Sensor Networks' (WSNs) Physical Layer (PHY). Orthogonal Frequency Division Multiple Access (OFDMA) and Single Carrier Frequency Division Multiple Access (SC-FDMA) modulation techniques were selected due to their wide usage areas in broadband wireless communication as LTE. Optimal simulation results were achieved when the SC-FDMA was employed for all relay network configurations.

Wireless Sensor Networks (WSN) is of ubiquitous importance in the present day wireless communication. While disseminated architecture delights a more security and fault-tolerant WSN, such architecture also places a number of security challenges particularly when employed in vital applications such as health care, environment monitoring and battlefield. In this paper, we propose Trust Awaken Routing for Improving the Reliable Communication in WSN. The main objective of this paper is to develop trust management for WSNs, and this technique is used to improve the reliability of data transmission in the network. In this scheme, the trust Awaken Factor is used to select the reliable path from source to destination in the system. trust Awaken Factor computed by node interaction, node recommendation, quick response and node selfishness. The simulation results show the better improvement in throughput and reduce the network delay in the network.

The growing awareness of the strategic value of service along with higher product performance expectations has directed many industries to adopt service centric competitive strategies in managing their supply chains. Service innovation based on currently available advanced technologies has become critical in improving enterprises’ competitive strengths. Wireless sensor network (WSN) technology, which can provide a mobile, scalable, and reliable monitoring solution, is emerging as a tool for service innovation in supply chain management. This paper provides an overview of wireless sensor network technology and discusses how it can benefit modern industries. The fundamental theories of WSN are introduced as well as an overview of the development. The impact of information technologies on supply chain management and service innovation is then briefly discussed. Much emphasis is placed on the feasibility, procedures, and critical challenges of implementing WSN in supply chain management innovation. Current and future applications of WSN are also provided, followed by a case study demonstrating the application potentials of WSN for service innovation in the healthcare industry.

The Multi-Wireless-Agent-Communication (MWAC) model uses a multiagent self-organization process through to manage communications in wireless sensor networks. This paper presents a first improvement of the MWAC model using an ant colony optimization. We introduce the use of ant colony optimization in the context of multiagent systems and wireless sensor networks. Ants are not simply deployed on the multiagent society. Each ant interacts with agents to obtain the best compromise on the routes choice to enable a reliable communication.

The quality of wireless communication makes a great impact on the performance of wireless sensor networks, but wireless communication has the notorious reputation of being unpredictable. The paper discusses reliable communication in wireless sensor networks at the data link layer. We provide reliable many-to-one and point-to-point communication ability by dynamically adjusting the power settings of the radio transceivers. Our results might be helpful for those who are puzzled by the packet loss problem in wireless sensor networks.