Time synchronization accuracy in real-time wireless sensor networks

Wireless Sensor Networks (WSNs) have received considerable attention in recent years because of its broad area of applications. In the same breadth, it also faces many challenges. Time synchronization is one of those fundamental challenges faced by WSN being a distributed system. Several approaches have been proposed in the last decade for time synchronization in WSNs. Recently, Consensus Time Synchronization (CTS) approaches are gaining popularity due its computational lightness, robustness and distributed nature. Though a rich set of CTS algorithms are proposed, their energy consumption has so far not been studied. Apart from synchronization precision, energy consumption should also be considered meticulously for time synchronization algorithms in energy-constraint WSNs. In this paper, a thorough energy consumption analysis is presented for some recent state-of-the-art CTS algorithms for WSN and tested by simulation. The simulation results will help in selecting an appropriate CTS algorithm that meets the requirements of synchronization accuracy and energy consumption for a specific WSN application.

Download Full-text

Research on a Real-Time Fault Tolerant Time Synchronization Algorithm for GSM-R Wireless Sensor Networks Based on Network Materials

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.63-64.905 ◽

2011 ◽

Vol 63-64 ◽

pp. 905-910

Author(s):

Xiao Wu Huang ◽

Gui Tang Wang ◽

Wen Juan Liu ◽

Feng Wang

Keyword(s):

Wireless Sensor Networks ◽

Fault Tolerance ◽

Sensor Networks ◽

Real Time ◽

High Speed ◽

Time Synchronization ◽

Fault Tolerant ◽

Wireless Sensor ◽

Synchronization Algorithm ◽

Network Time

Time synchronization is a key technology in wireless sensor networks. In this paper, aim at high-speed railway GSM-R network require higher real time, fault tolerance and band coverage way, presents a real-time fault-tolerant wireless sensor network time synchronization algorithm, using direct forwarding strategy, regression analysis and abnormal data filtering methods to meet the requirements of GSM-R network. Analysis and simulation show that the algorithm has good real-time and fault tolerance to meet the requirements of GSM-R network applications.

Download Full-text

Robust time synchronization in wireless sensor networks using real time clock

Proceedings of the 12th ACM Conference on Embedded Network Sensor Systems - SenSys '14 ◽

10.1145/2668332.2668365 ◽

2014 ◽

Author(s):

Hessam Mohammadmoradi ◽

Omprakash Gnawali ◽

Nir Rattner ◽

Andreas Terzis ◽

Alex Szalay

Keyword(s):

Wireless Sensor Networks ◽

Sensor Networks ◽

Real Time ◽

Time Synchronization ◽

Wireless Sensor ◽

Real Time Clock

Download Full-text

Time Synchronization Algorithm for Wireless Sensor Networks Based on Frequency Offset Estimation

International Journal of Online Engineering (iJOE) ◽

10.3991/ijoe.v14i06.8699 ◽

2018 ◽

Vol 14 (06) ◽

pp. 71

Author(s):

Shaojun Yu ◽

Li Lin ◽

Yujian Wang ◽

Xingyuan Chen

Keyword(s):

Wireless Sensor Networks ◽

Sensor Networks ◽

Time Synchronization ◽

Estimation Method ◽

Frequency Offset ◽

Wireless Sensor ◽

Frequency Offset Estimation ◽

Dynamic Adjustment ◽

Synchronization Algorithm ◽

Synchronization Accuracy

Aiming at solving the poor the classical synchronous algorithm stability in wireless sensor network and high overhead of clock phase offset and frequency offset, a synchronization algorithm (CSMS algorithm) was designed for wireless sensor networks based on frequency offset estimation. The CSMS algorithm used the low overhead phase bias and frequency offset estimation method to improve the synchronization accuracy and stability of the pair nodes. At the same time, a synchronization strategy was built based on layering and broadcast monitoring, which ensured the stability and synchronization accuracy of the algorithm, realized the synchronization with neighbor nodes and root nodes, and optimized the total synchronization cost. Among them, the CSMS algorithm was mainly divided into two stages: level discovery phase, which was used for generating a layered structure of network; synchronization phase, used to estimate clock offset and frequency offset between pairs of nodes. The experimental results showed that the CSMS algorithm can effectively balance the synchronization energy consumption, synchronization accuracy and synchronization stability. As a result, it is summed up that dynamic adjustment of the nodes clock deviation is realized, the long-term stability of synchronization is ensured, and the precision of synchronization is improved.

Download Full-text

Optimal Message Bundling with Delay and Synchronization Constraints in Wireless Sensor Networks

Sensors ◽

10.3390/s19184027 ◽

2019 ◽

Vol 19 (18) ◽

pp. 4027 ◽

Cited By ~ 1

Author(s):

Xintao Huan ◽

Kyeong Soo Kim ◽

Sanghyuk Lee ◽

Moon Keun Kim

Keyword(s):

Energy Efficiency ◽

Wireless Sensor Networks ◽

Sensor Networks ◽

Time Synchronization ◽

Sensor Nodes ◽

Wireless Sensor ◽

End To End Delay ◽

End To End ◽

Optimal Approach ◽

Synchronization Accuracy

Energy efficiency and end-to-end delay are two of the major requirements for the monitoring and detection applications based on resource-constrained wireless sensor networks (WSNs). As new advanced technologies for accurate monitoring and detection—such as device-free wireless sensing schemes for human activity and gesture recognition—have been developed, time synchronization accuracy becomes an important requirement for those WSN applications too. Message bundling is considered one of the effective methods to reduce the energy consumption for message transmissions in WSNs, but bundling more messages increases the transmission interval of bundled messages and thereby their end-to-end delays; the end-to-end delays need to be maintained within a certain value for time-sensitive applications like factory monitoring and disaster prevention, while the message transmission interval affects time synchronization accuracy when the bundling includes synchronization messages as well. Taking as an example a novel WSN time synchronization scheme recently proposed for energy efficiency, we investigate an optimal approach for message bundling to reduce the number of message transmissions while maintaining the user-defined requirements on end-to-end delay and time synchronization accuracy. Formulating the optimal message bundling problem as integer linear programming, we compute a set of optimal bundling numbers for the sensor nodes to constrain their link-level delays, thereby achieving and maintaining the required end-to-end delay and synchronization accuracy. Extensive experimental results based on a real WSN testbed using TelosB sensor nodes demonstrate that the proposed optimal bundling could reduce the number of message transmissions about 70% while simultaneously maintaining the required end-to-end delay and time synchronization accuracy.

Download Full-text

A study on the optimal time synchronization accuracy in wireless sensor networks

Computer Networks ◽

10.1016/j.comnet.2004.10.018 ◽

2005 ◽

Vol 48 (4) ◽

pp. 549-566 ◽

Cited By ~ 18

Author(s):

Qing Ye ◽

Yuecheng Zhang ◽

Liang Cheng

Keyword(s):

Wireless Sensor Networks ◽

Sensor Networks ◽

Time Synchronization ◽

Wireless Sensor ◽

Optimal Time ◽

Synchronization Accuracy

Download Full-text

Time synchronization for long-chain-type wireless sensor networks

International Journal of Distributed Sensor Networks ◽

10.1177/1550147718797824 ◽

2018 ◽

Vol 14 (9) ◽

pp. 155014771879782

Author(s):

Zhenping Chen ◽

Yourui Huang ◽

Zheng Wang ◽

Feng Tao

Keyword(s):

Wireless Sensor Networks ◽

Sensor Networks ◽

Time Synchronization ◽

Least Squares Method ◽

Three Dimensional ◽

Wireless Sensor ◽

Clock Skew ◽

Synchronization Accuracy ◽

Long Chain ◽

Chain Type

In view of the requirement on time synchronization for a kind of typical wireless sensor networks with long-chain-type topologies, taking into account the three-dimensional network model currently used by the localization algorithms, one feasible time synchronization algorithm is proposed in this article. Under the three-dimensional topology, nodes in the wireless sensor networks are divided into three kinds: the sensing nodes, the relay nodes, and the measured nodes. By analyzing the distribution characteristics of these three kinds of nodes, with the introduction of the pairwise broadcast synchronization and the series multi-hop synchronization protocol, the estimation of the clock offset and the clock skew of all the nodes in the wireless sensor networks are performed by virtue of the joint maximum likelihood and the least-squares method, thus the time synchronization of the wireless sensor networks with long-chain-type topology is solved. Moreover, the sink node evaluates the network periodically and adjusts the synchronizing cycle based on the difference between the network synchronization error and the given synchronization accuracy. The feasibility and effectiveness of this scheme are analyzed by simulations from the synchronization accuracy, the number of synchronization message, and the synchronizing cycle points of view.

Download Full-text