ETSP: An Energy-Efficient Time Synchronization Protocol for Wireless Sensor Networks

Abstract

Wireless Sensor Networks (WSN) have specific constraints and stringent requirements in contrast to traditional wired and wireless computer networks. Among these specific requirements, energy-efficiency is the most prominent. Sensor motes have finite amount of energy supply. In most WSN applications, hundreds or thousands of motes are deployed in an area (e.g., behind enemy lines or foliage) and there is no provision for battery recharging. Therefore, a fundamental constraint on WSN applications and services is to extend the network's lifetime by making the batteries run longer. In this paper we propose an energy-efficient Time Synchronization Protocol, referred as ETSP, which gives significant improvement in energy consumption over existing time synchronization schemes. We first evaluate the existing Reference Broadcast Synchronization (RBS) and Timesync Protocol for Sensor Networks (TPSN), which are two prominent examples of receiver-receiver and sender-receiver synchronization methods. This performance analysis demonstrates that combination of RBS and TPSN can work better than using these techniques separately. In the proposed ETSP protocol, we identify conditions to toggle between RBS and TPSN based on a threshold value. We experimentally and mathematically derive an optimal value of the switching threshold for different sensor motes. In this way we effectively reduce the number of transmissions which results in saving energy. Moreover, we assess the performance of our protocol on the bit error traces collected over a real WSN test bed to cater for retransmissions overload for the time synchronization protocols under consideration.

AEF: Adaptive En-Route Filtering to Extend Network Lifetime in Wireless Sensor Networks

“…We also assumed that the underlying sensor platform for our simulation experiments is a MICA2 sensor mote [22]. Each sensor node’s system clocks are synchronized using a time synchronization mechanism [23]. Sensor nodes can determine their location using some localization components [45].…”

“…Simulation experiments are supposed to have Mica2 [22] as experimental platforms in this work. Sensor clocks are synchronised using the synchronization component presented in the energy-efficient time synchronization protocol (ETSP) [23]. Sensor nodes could determine their location using some localization component.…”

“…MICA2 [22] sensor motes sensing platform was used in the experiments. Sensor clocks are synchronised using the energy-efficient time synchronization protocol (ETSP) [23]. Recent work [20,24,25,26,27] also highlighted countermeasures against attacks in en-route filtering with an emphasis on network lifetime.…”

Universal Synchronization Algorithm for Wireless Sensor Networks—``FUSA algorithm''

“…Other class of synchronization algorithms that use master node for synchronization or the group of master nodes contains Time Diffusion Synchronization (TDP) [28] and ETSP [29], which use both TPSN and RBS methodology. They switch between the TPSN and RBS based on the threshold value.…”

An Investigational Analysis of Different Approaches and Techniques for Time Synchronization in Wireless Sensor Network

“…An effective time synchronization algorithm also calls for energy efficiency requirements as the sensors are basically resource constraint. Consideration of energy efficiency in time synchronization can be seen in the study of [24] and [25].…”