Clock Drift Management Using Nature Inspired Algorithms

2012 ◽  
Vol 5 (4) ◽  
pp. 48-62
Author(s):  
Prakash Tekchandani ◽  
Aditya Trivedi
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Time Synchronization ◽  
Synchronization Error ◽  
Wireless Sensor ◽  
Clock Skew ◽  
Clock Drift ◽  
Distributed Sensor ◽  
Network Applications ◽  
Nature Inspired Algorithms

Time Synchronization is common requirement for most network applications. It is particularly essential in a Wireless Sensor Networks (WSNs) to allow collective signal processing, proper correlation of diverse measurements taken from a set of distributed sensor elements and for an efficient sharing of the communication channel. The Flooding Time Synchronization Protocol (FTSP) was developed explicitly for time synchronization of wireless sensor networks. In this paper, we optimized FTSP for clock drift management using Particle Swarm Optimization (PSO), Variant of PSO and Differential Evolution (DE). The paper estimates the clock offset, clock skew, generates linear line and optimizes the value of average time synchronization error using PSO, Variant of PSO and DE. In this paper we present implementation and experimental results that produces reduced average time synchronization error using PSO, Variant of PSO and DE, compared to that of linear regression used in FTSP.

scholarly journals Node-Identification-Based Secure Time Synchronization in Industrial Wireless Sensor Networks

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2718 ◽  
Author(s):  
Zhaowei Wang ◽  
Peng Zeng ◽  
Linghe Kong ◽  
Dong Li ◽  
Xi Jin
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Time Synchronization ◽  
Information Filtering ◽  
Algorithm Design ◽  
Main Idea ◽  
Wireless Sensor ◽  
Clock Skew ◽  
Industrial Wireless Sensor Networks ◽  
Sybil Attacks

Time synchronization is critical for wireless sensors networks in industrial automation, e.g., event detection and process control of industrial plants and equipment need a common time reference. However, cyber-physical attacks are enormous threats causing synchronization protocols to fail. This paper studies the algorithm design and analysis in secure time synchronization for resource-constrained industrial wireless sensor networks under Sybil attacks, which cannot be well addressed by existing methods. A node-identification-based secure time synchronization (NiSTS) protocol is proposed. The main idea of this protocol is to utilize the timestamp correlation among different nodes and the uniqueness of a node’s clock skew to detect invalid information rather than isolating suspicious nodes. In the detection process, each node takes the relative skew with respect to its public neighbor as the basis to determine whether the information is reliable and to filter invalid information. The information filtering mechanism renders NiSTS resistant to Sybil attacks and message manipulation attacks. As a completely distributed protocol, NiSTS is not sensitive to the number of Sybil attackers. Extensive simulations were conducted to demonstrate the efficiency of NiSTS and compare it with existing protocols.

scholarly journals Pair Nodes Clock Synchronization Algorithm Based on Kalman Filter for Underwater Wireless Sensor Networks

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4426
Author(s):  
Xiaomeng Ni ◽  
Ting Lu ◽  
Sijia Ye ◽  
Yunsi Zheng ◽  
Pengfei Chen ◽  
...  
Keyword(s):  
Wireless Sensor Networks ◽  
Kalman Filter ◽  
Sensor Networks ◽  
Time Synchronization ◽  
Clock Synchronization ◽  
Wireless Sensor ◽  
Underwater Wireless Sensor Networks ◽  
Clock Skew ◽  
Time Stamps ◽  
Clock Offset

Time synchronization is the basis of many applications. Aiming at the limitations of the existing clock synchronization algorithms in underwater wireless sensor networks, we propose a pairwise synchronization algorithm called K-Sync, which is based on the Kalman filter. The algorithm does not need the assistance of the position sensor or the speed sensor, and the high time synchronization accuracy can be realized only by utilizing the time-stamps information in the process of message exchange. The K-Sync uses the general constraints of the motion characteristics of the sensor nodes to establish the recursive equations of the clock skew, clock offset, relative mobility velocity, and relative distance. At the same time, the time-stamps are viewed as the observation variables and the system observation equation is obtained. The K-Sync estimates the normalized clock skew and offset of the node via the Kalman filter to achieve high-precision clock synchronization between the two nodes. The simulation shows that the K-Sync has obvious advantages in the key indicators such as the estimated accuracy of clock skew and clock offset, convergence speed, etc. In addition, the K-Sync is more robust to a variety of underwater motion scenes.

Simulation Study on Time Synchronization Based on RBS in Wireless Sensor Networks

2013 ◽  
Vol 321-324 ◽  
pp. 630-634
Author(s):  
Wan Xu ◽  
Guang You Yang ◽  
Jing Jing Zhou
Keyword(s):  
Wireless Sensor Networks ◽  
Sensor Networks ◽  
Simulation Study ◽  
Routing Protocol ◽  
Time Synchronization ◽  
Synchronization Error ◽  
Wireless Sensor ◽  
Synchronization Algorithm

Time synchronization is important for wireless sensor networks. In this paper RBS time synchronization algorithm principle and EECH routing protocol are introduced, and the simulation of RBS on the basis of EECH routing protocol is realized using the Synsinc software. The average synchronization error of the simulation is 25.86 us.This value is basically same with other types of simulation, which confirmed the simulation is credible.

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