Clock Skew Estimation for Timestamp-Free Synchronization in Industrial Wireless Sensor Networks

2021 ◽  
Vol 17 (1) ◽  
pp. 90-99 ◽  
Author(s):  
Heng Wang ◽  
Fei Yu ◽  
Min Li ◽  
Yang Zhong
Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2718 ◽  
Author(s):  
Zhaowei Wang ◽  
Peng Zeng ◽  
Linghe Kong ◽  
Dong Li ◽  
Xi Jin

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.


Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3904
Author(s):  
Jose Vera-Pérez ◽  
Javier Silvestre-Blanes ◽  
Víctor Sempere-Payá

Wireless sensor networks (WSNs) play a key role in the ecosystem of the Industrial Internet of Things (IIoT) and the definition of today’s Industry 4.0. These WSNs have the ability to sensor large amounts of data, thanks to their easy scalability. WSNs allow the deployment of a large number of self-configuring nodes and the ability to automatically reorganize in case of any change in the topology. This huge sensorization capacity, together with its interoperability with IP-based networks, allows the systems of Industry 4.0 to be equipped with a powerful tool with which to digitalize a huge amount of variables in the different industrial processes. The IEEE 802.15.4e standard, together with the access mechanism to the Time Slotted Channel Hopping medium (TSCH) and the dynamic Routing Protocol for Low-Power and Lossy Networks (RPL), allow deployment of networks with the high levels of robustness and reliability necessary in industrial scenarios. However, these configurations have some disadvantages in the deployment and synchronization phases of the networks, since the time it takes to synchronize the nodes is penalized compared to other solutions in which access to the medium is done randomly and without channel hopping. This article proposes an analytical model to characterize the behavior of this type of network, based on TSCH and RPL during the phases of deployment along with synchronization and connection to the RPL network. Through this model, validated by simulation and real tests, it is possible to parameterize different configurations of a WSN network based on TSCH and RPL.


2021 ◽  
pp. 116045
Author(s):  
Carlos Augusto Ribeiro Soares ◽  
Rodrigo de Souza Couto ◽  
Alexandre Sztajnberg ◽  
Jorge Luís Machado do Amaral

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