An algorithm for WSN clock synchronization: Uncertainty and convergence rate trade off
06 Jul 2009-pp 74-79
TL;DR: A synchronization algorithm based on a linear controller is used to dynamically compensate both mutual offsets and drifts of the clock associated with the nodes of a WSN, which explicitly takes into account the inter-node communication latencies.
Abstract: -Achieving tight time synchronization between wireless sensor network (WSN) nodes is essential to coordinate the activities of different devices. In this paper, a synchronization algorithm based on a linear controller is used to dynamically compensate both mutual offsets and drifts of the clock associated with the nodes of a WSN. This approach, compared with other existing solutions based on control theory, explicitly takes into account the inter-node communication latencies. Furthermore, it presents on optimal (fastest convergence) controller in the case of full visibility among nodes. In the case of noise in both the clock measurements and the clock drifts, a controller that reduces the noise effect on the synchronization accuracy is also proposed and compared to the optimal one. In all cases, the correct operation of the algorithm has been proved through simulations.
Citations
More filters
TL;DR: The node availability and WSN availability are formulated with the assumption that the information arrival is a Poisson process and the age-based replacement model is applied to obtain the optimal reallocation interval with lowest long run expected cost rate.
Abstract: A wireless sensor network is applied for detecting information, by nodes, then generates and transfers the packets to the clustering head for further transmission. In practice, due to the influence of environmental factors, traffic loads of nodes and barrier, a node may fail to detect the information which occurs within its sensing area. Thus, the redundant deployment is often conducted. There are some frequent questions need to be considered when deploying the WSN: (1) how many nodes are required for obtaining a confident coverage of the area; (2) how well does the WSN perform as time goes by, because it is an energy consumption technique; (3) when is the best opportunity to reallocate the nodes. To answer the above questions, we conduct this research. We use $$k$$
-out-of-
$$n$$
model to calculate the $$k$$
-coverage probability, which determines the minimal number of nodes that are needed to be deployed in the monitored area. We formulate the node availability and WSN availability with the assumption that the information arrival is a Poisson process. By applying the age-based replacement model, we obtain the optimal reallocation interval with lowest long run expected cost rate.
35 citations
17 Dec 2010
TL;DR: This paper considers a group as being a set of nodes sensing the same type of data and proposes an efficient secure group communication scheme that enables group management and secure group key distribution based on a logical ring architecture.
Abstract: It is worth noting that securing group communication in Wireless Sensor Networks (WSNs) has recently been extensively investigated. Although many works have addressed this problem, they have considered the concept of grouping differently. In this paper, we consider a group as being a set of nodes sensing the same type of data and we alternatively propose an efficient secure group communication scheme that enables group management and secure group key distribution. The proposed scheme is based on a logical ring architecture, which permits to alleviate the task of the group controller in maintaining the group key. The proposed scheme also provides backward and forward secrecy, addresses the node compromise attack and gives solution to detect and eliminate the compromised nodes. Finally, our implementation shows that the proposed scheme is highly efficient and secure.
12 citations
TL;DR: This paper aims to study the reliability of a data flow in event-driven wireless sensor networks with multiple sending transmission approach without acknowledgments, and analyzes the network reliability, the wireless link reliability and the node energy availability.
Abstract: Reliability analysis is an important issue in wireless sensor networks (WSNs). This paper aims to study the reliability of a data flow in event-driven wireless sensor networks with multiple sending transmission approach without acknowledgments. Initially, an event-driven wireless sensor network model is described in terms of limited node battery energy and shadowed fading channels. Then, in order to analyze the network reliability, the wireless link reliability and the node energy availability are investigated, respectively. Furthermore, the analytical expressions of the instantaneous network reliability and the mean time to failure (MTTF) are derived. Finally, the simulation results validate the correctness and accuracy of the analytical results.
6 citations
Cites background from "An algorithm for WSN clock synchron..."
...cn 1National Mobile Communications Research Laboratory, Southeast University, Nanjing 211111, China Full list of author information is available at the end of the article In the past few years, intensive researches for WSNs have been conducted in many aspects, such as localization [5], synchronization [6,7], deployment [8], and communication protocol [9]....
[...]
12 Dec 2011
TL;DR: The design, implementation and evaluation of a trustful infrastructure for the Internet of Things (IoT) based on EPOS Mote is described, which features an ARM processor and an IEEE 802.15.4 radio transceiver.
Abstract: This article describes the design, implementation and evaluation of a trustful infrastructure for the Internet of Things (IoT) based on EPOS Mote The infrastructure was built around EPOS' second generation of motes, which features an ARM processor and an IEEE 802154 radio transceiver It is presented to end users through a trustful communication protocol stack compatible with TCP/IP Trustfulness was tackled at MAC level by extending C-MAC, EPOS native MAC protocol, with Advanced Encryption Standard (AES) capabilities that were subsequently used to encrypt and authenticate packets containing IP data grams Our authentication mechanism encompasses temporal information to protect the network against replay attacks The infrastructure was designed bearing in mind the severe resource limitation typical of IoT devices The prototype implementation was assessed for processing, memory, and energy consumption and strongly confirmed our assumptions
5 citations
Cites background from "An algorithm for WSN clock synchron..."
...When an activity is removed, its inputs are forwarded to the activity targeted by its outputs, still maintaining the original flow semantics....
[...]
03 May 2010
TL;DR: A new synchronization procedure based on a distributed Proportional Integral (PI) consensus controller is described, designed to avoid the election of any fixed time reference node, thus potentially improving the robustness of the whole synchronization procedure.
Abstract: Time synchronization of Wireless Sensor Network (WSN) nodes is essential in those applications requiring distributed task scheduling or data aggregation and fusion. In this paper, a new synchronization procedure based on a distributed Proportional Integral (PI) consensus controller is described. Compared to other similar solutions, the proposed approach keeps into account the effect of random communication and processing delays and it is expected to have lower communication overhead. Also, it is designed to avoid the election of any fixed time reference node, thus potentially improving the robustness of the whole synchronization procedure. Some simulation results show that the procedure works correctly even in different network traffic conditions.
5 citations
Cites background from "An algorithm for WSN clock synchron..."
..., 1] , a variety of solutions exists which trade convergence speed for noise robustness [14]....
[...]
References
More filters
05 Dec 2002
TL;DR: This paper discusses the major features and design objectives of the IEEE-1588 standard, designed to serve the clock synchronization needs of industrial systems, and recent performance results of prototype implementations of this standard in an Ethernet environment are presented.
Abstract: This paper discusses the major features and design objectives of the IEEE-1588 standard. Recent performance results of prototype implementations of this standard in an Ethernet environment are presented. Potential areas of application of this standard are outlined.
1,112 citations
Book•
08 Dec 2008TL;DR: Noise in delay-line oscillators and lasers, phase noise and frequency stability, and Oscillator hacking A Laplace transform.
Abstract: Foreword Lute Maleki Foreword David B. Leeson Preface List of symbols 1. Phase noise and frequency stability 2. Phase noise in semiconductors and amplifiers 3. Heuristic approach to the Leeson effect 4. Phase noise and linear feedback theory 5. Noise in delay-line oscillators and lasers 6. Oscillator hacking A Laplace transform Bibliography.
406 citations
"An algorithm for WSN clock synchron..." refers methods in this paper
...Since for quartz oscillators the phase noise is of the order of some tens of ppm of the clock frequency f0 [13], we choose for the noise standard deviation a value of σξ = 10−4....
[...]
11 Jun 2007
TL;DR: A novel consensus-based protocol for synchronizing a wireless sensor based on a class of popular distributed algorithms known as consensus, agreement, gossip or rendezvous, which compensates for clock skew differences among nodes, thus maintaining the network synchronized for longer periods than using simple clock offset compensation.
Abstract: This paper describes a novel consensus-based protocol, referred as Average TimeSync (ATS), for synchronizing a wireless sensor. This algorithm is based on a class of popular distributed algorithms known as consensus, agreement, gossip or rendezvous whose main idea is averaging local information. The proposed algorithm has three main features. Firstly, it is fully distributed and therefore robust to node failure and to new node appearance. Secondly, it compensates for clock skew differences among nodes, thus maintaining the network synchronized for longer periods than using simple clock offset compensation. Finally, it is computationally lite as it involves only simple sum/product operations. The algorithm has been implemented and preliminary experimental results are provided.
242 citations
"An algorithm for WSN clock synchron..." refers background in this paper
...A notable solution in which time information flow without any elected time reference node has been proposed by [7] using an effective nonlinear solution....
[...]
TL;DR: A proposed time synchronization method relevant for wireless sensor networks features minimal complexity in network bandwidth, storage as well as processing, and can achieve good accuracy.
Abstract: Time synchronization is a fundamental middleware service for any distributed system. Wireless sensor networks make extensive use of synchronized time in many contexts (e.g., data fusion, TDMA schedules, synchronized sleep periods, etc.). We propose a time synchronization method relevant for wireless sensor networks. The solution features minimal complexity in network bandwidth, storage as well as processing, and can achieve good accuracy. Especially relevant for sensor networks, it also provides tight, deterministic bounds on offset and clock drift. A method for synchronizing the entire network is presented. The performance of the algorithm is analyzed theoretically and validated on a realistic testbed. The results show that the proposed algorithm outperforms existing algorithms in terms of precision and resource requirements.
135 citations
"An algorithm for WSN clock synchron..." refers background in this paper
...Since WSN–specific synchronization protocols are mostly focused on the reduction of both computational burden and network traffic, at a reasonable price in terms of maximum achievable accuracy [3], general time protocols for measurement and control systems, as the well-known Precision Time Protocol (PTP) [4], are not very suitable for WSNs....
[...]
TL;DR: Experimental results are presented that show that potential accuracy limitations introduced by the physical layer of the IEEE 802.11b wireless local area network do not preclude clock-synchronization accuracy of several hundred nanoseconds.
Abstract: IEEE 1588 is a new standard to synchronize independent clocks running on separate nodes of a distributed measurement and control system. It is intended for high-accuracy implementations on compact systems such as a single subnet. This paper examines potential accuracy limitations introduced by the physical layer of the IEEE 802.11b wireless local area network. Experimental results are presented that show that these limitations do not preclude clock-synchronization accuracy of several hundred nanoseconds.
133 citations
"An algorithm for WSN clock synchron..." refers background or methods in this paper
...Furthermore, synchronization protocols are also needed to coordinate the tasks running on different nodes of the network (for example, see [1])....
[...]
...This way P [1,1] i (+∞) can also be used to evaluate the trade off between uncertainty minimization and fastest rate of convergence ((8) allows us to evaluate also the steady state uncertainty for the dead beat controller)....
[...]