Time Synchronization in Wireless Sensor Networks: A Survey

Abstract

___ Time synchronization is a critical piece of infrastructure for any distributed system. Wireless sensor networks have emerged as an important and promising research area in the recent years. Time synchronization is important for many sensor network applications that require very precise mapping of gathered sensor data with the time of the events, for example, in tracking and vehicular surveillance. It also plays an important role in energy conservation in MAC layer protocols. The paper studies different existing methods, protocols, significant time parameters (clock drift, clock speed, synchronization errors, and topologies) to achieve accurate synchronization in a sensor network. The studied Synchronization protocols include conventional time sync protocols (RBS, Timing-sync Protocol for Sensor Networks-TPSN, FTSP), and other application specific approaches such as all node-based approach, a diffusion-based method and group sync approaches aiming at providing network-wide time. The goal for writing this paper is to study most common existing time synchronization approaches and stress the need of a new class of secure-time synchronization protocol that is scalable, topology independent, fast convergent, energy efficient, less latent and less application dependent in a heterogeneous hostile environment. Our survey provides a valuable framework by which protocol designers can compare new and existing synchronization protocols from various metric discussed in the paper. So, we are hopeful that this paper will serve a complete one-stop investigation to study the characteristics of existing time synchronization protocols and its implementation mechanism in a Sensor network environment.

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“…If the measurements were to provide give satisfactory results, the time synchronizations of different channels would be implemented [30]. Moreover, the platform would firstly be tested using controlling actuators and later for closed loop control.…”

Message Passing Based Time Synchronization in Wireless Sensor Networks: A Survey

“…Therefore, it is a concern for researchers in this area [21,26,29]. Some works attempt to measure energy consumption based on awake and sleep time of the nodes [18] while others try to measure it based on the frequency of message exchange or the number of messages exchanged [28,30].…”

“…(i) Complexity is another concern of researchers [25][26][27]29] as computation load is the second most energy consuming activity that a sensor node can have. Statistical methods normally have high computation load.…”

“…(ii) Robustness against node failure describes the behavior of the protocol on node failure [19,25,[27][28][29]. In many protocols, there is one or various special node(s) that other nodes get synced with.…”

A Survey of Time Synchronization Techniques in Underwater Acoustic Networks

“…되어 제안되고 있다 [1][2][3] . 육상 센서네트워크의 대표적 인 동기화 프로토콜로는 RBS (reference broadcast synchronization) [4] , TPSN (timing-sync protocol for sensor networks) [5] , FTSP (flooding time synchronization protocol) [6] , 트리 기반 동기화 알고리 즘 [7] 등이 있다.…”