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The Trustful Space-Time Protocol (TSTP) allows for time synchronization to be performed upon receiving any message from another node in a sensor network, removing the need for explicit synchronization messages. Previous work has shown that TSTP performs well under controlled experimental environments. In this work, we analyze how the quality of synchronization in TSTP is affected when nodes are communicating...
This paper discusses the time synchronization issue in wireless sensor networks. An event-triggered average consensus time synchronization algorithm is proposed. This algorithm uses the average time message from one node's one-hop neighbors to update the clock parameters of the node. And it achieved acceptable synchronization accuracy. We also proposed an event-trigger mechanism to reduce the communication...
Time synchronization over a distributed BLE wireless network poses several challenging problems which may affect the accuracy of time stamping of events recorded by BLE devices. In this paper, we study the accuracy of a time synchronization scheme based on generation of an event in the application program at the time of BLE connection establishment. We discuss the background of the problem, explain...
In industrial applications synchronized sensor nodes are vital for many tasks like multi parameter sampling of complex machinery behavior. The wirelessly connected nodes are usually synchronized to a base station. Therefore, frequency or period estimation of the reference clock is a key issue for all connected tasks like sampling, localization or applying energy optimized communication protocols....
Localization of wireless networks has remained an active research topic for more than a decade, as it finds more and more applications in numerous scenarios, including environment surveillance, asset tracking, and healthcare monitoring, etc. In this paper, we consider the maximum likelihood localization of a network where some of the nodes are GPS-capable while the others attempt to achieve self localization...
The clock synchronization technologies applied to controlling layer and primary equipment like intelligent switchgear of processing layer in intelligent substation are analyzed in this paper. IEEE1588 message timing mode, which can be accurate to nanosecond, is used as the mode of substation system, in order to fulfill the real-time and accuracy requirements of intelligent switchgears and remote control...
Emerging protocols for low-power wireless networks increasingly exploit constructive interference and the capture effect. The basic idea is that the synchronous transmission of identical packets by neighboring nodes leads to constructive interference - or at least do not cause destructive interference. This requires that the temporal displacement of packets at receiving nodes is lower than 0.5 μs...
In this paper, we simulate the tri-message time synchronization protocol within the cluster sub net for the MAC layer of underwater acoustic network. Distinguished with the traditional TDMA protocols, all sub nodes are time consistent with the cluster node and the sub nodes can be quickly netted in the improved TDMA protocol. We established a network simulation with a bunch of 6 nodes in OPNET software...
This paper proposes a filter-based distributed protocol to realize time synchronization under time-varying clock parameters. The proposed protocol is derived from a first-order controller and is fully distributed, meaning that by relying merely on its local clock readings and reading announcements from its neighbouring sensor nodes, each node in WSNs can dynamically update its virtual clock and bound...
In both wired and wireless networks, time synchronization is an important service for a wide range of applications in distributed systems. This includes radio interferometry. However, literature researches show that many distributed protocols cannot satisfy sub-ns time synchronization accuracy due to asymmetric delay errors, accumulated jitters and because of the strategy used to compute and adjust...
Vehicular Ad Hoc Networks (VANET) are the fastchanging networks for connected vehicles, in which Vehicle- to-Vehicle and Vehicle-to-Infrastructure communication are the basis for technologies aiming at reducing accidents and improving operation. DSRC Safety Applications, designed to assist drivers in order to avoid accidents, might be subjected to malicious attacks, such as GPS time spoofing attacks,...
Many data center applications are latency-sensitive. Monitoring continuously the network latency and reacting to congestion on a network path is important to ensure that the applications performance does not suffer penalties. We show how to use the Precision Time Protocol (PTP) to infer network latency and packet loss in data centers, and we conduct network latency and packet loss measurements in...
Distributed cyber-physical systems cover a wide range of applications such as automotive, avionic or industrial automation. These applications require a global notion of time to fullfill their timing requirements. Multi-processor system on chips (MPSOCs) are an attractive implementation option since they offer several benefits such as parallelism and power efficiency. However, MPSOCs have a Globally...
The Smart Cities concept implies the integration of vertical application pillars, such as mobility, smart grid and public illumination, and more, for an optimal management of the resources and a reduction of the energy footprint of large cities. This approach requires the use of existing heterogeneous communication infrastructures to allow a peer to peer interconnection of services exposed by sensors...
High accurate time synchronization is very important for many applications and industrial environments. In a computer network, synchronization of time for connected devices is provided by the Precision Time Protocol (PTP), which in principal allows for device time synchronization down to microsecond level. However, PTP and network infrastructures are vulnerable to cyber-attacks, which can de-synchronize...
As wireless sensor networks become more ubiquitous in the world, the need for lightweight, resilient time synchronization protocols is apparent. Wireless nodes' internal clocks are subject to drift over time due to manufacturing imperfections and environmental changes. While various protocols have been introduced that attempt to correct for this drift, they each have their own peculiarities and issues...
Time synchronization is an essential infrastructure of various applications in sensor networks. In this paper, a time-stamping approach using field-programmable gate array (FPGA) is introduced which is applied to Reference broadcast synchronization (RBS). Then, Dynamic Adjusting Time Synchronization (DATS) protocol is proposed which enables the clock compensation to approach the optimal compensation...
In this paper, we propose a fast predictive resynchronization scheme that allows nodes to rejoin a 802.15.4e TSCH network with which they were previously synchronized. The idea of the scheme comes from the investigation of the internal and external root causes of the clock drift between two nodes--we have identified the causes and proposed a means for its estimation. Based on the prediction of the...
The continuous fluctuation of electric network frequency (ENF) presents a fingerprint indicative of time, which we call natural timestamp. This live demo demonstrates the accuracy of the natural timestamps obtained by four wired voltage sensors and four wireless electromagnetic radiation (EMR) sensors that are geographically distributed in Singapore. The voltage sensors and the EMR sensors capture...
We present Timestamp Order Preserving (TOP), a replicated state machine (RSM) protocol that exploits the synchrony of networks to provide high performance. TOP uses physical timestamp of synchronized clock as a consistent total order to achieve consensus. It keeps estimating the bounds of network latency and offset of synchronized clock to deduce the commit time for each operation. It adopts speculative...
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