Time synchronization is an important requirement for many services provided by distributed networks. A lot of time synchronization protocols have been proposed for terrestrial Wireless Sensor Networks (WSNs). However, none of them can be directly applied to Underwater Sensor Networks (UWSNs). A synchronization algorithm for UWSNs must consider additional factors such as long propagation delays from the use of acoustic communication and sensor node mobility. These unique challenges make the accuracy of synchronization procedures for UWSNs even more critical. Time synchronization solutions specifically designed for UWSNs are needed to satisfy these new requirements.
This paper proposes Mobi-Sync, a novel time synchronization scheme for mobile underwater sensor networks. Mobi-Sync distinguishes itself from previous approaches for terrestrial WSN by considering spatial correlation among the mobility patterns of neighboring UWSNs nodes. This enables Mobi-Sync to accurately estimate the long dynamic propagation delays. Simulation results show that Mobi-Sync outperforms existing schemes in both accuracy and energy efficiency. Mobi-Sync Efficient Time Synchronization for Mobile Underwater Sensor Networks
In Existing addresses the time synchronization problem, a critical service in any sensor network. Nearly all UWSN applications depend on time synchronization service. For example, data mining requires global time information, TDMA, one of the most commonly used Medium Access Control (MAC) protocols, often requires nodes to be synchronized.
Furthermore, most of the localization algorithms for underwater and terrestrial sensor networks assume the availability of time synchronization service. Numerous time synchronization protocols for terrestrial Wireless Sensor Networks (WSNs) have been proposed in the literature. Their synchronization accuracy and energy efficiency for land-based applications is cogent.
This lack of serviceability imposes even more stringent requirements. The UWSN will need to be energy efficient. These sets of distinguishing characteristics introduce new challenges into the design of time synchronization schemes for UWSNs.
To overcome the limitations of existing approaches, this paper proposes Mobi-Sync, a high energy efficient time synchronization scheme specifically designed for mobile UWSNs. The distinguishing attribute of Mobi-Sync is how it utilizes information about the spatial correlation of mobile sensor nodes to estimate the long dynamic propagation delays among nodes.
The time synchronization procedure consists of three phases: