In this article we introduce a MAC protocol designed for underwater localization and time-synchronisation. The MAC protocol assumes a network of static reference nodes and allows blind nodes to be localized by listening-only to the beacon messages. Such a system is known to be very scalable. We show localization and time-synchronization algorithms can be designed for listen-only blind nodes by adapting the equations from GPS. We extend the set of GPS equations with angular information to reduce the number of beacons a blind node has to receive before it can determine its position. We evaluate scheduled and unscheduled communication for sending reference-beacon message using simulation mechanisms. Our experimental results show that when energy-consumption of the beacons is of concern or when the modulation rate is low (≤ 1kbps), scheduled communication is preferred. For systems which are not concerned with the energy-consumption of the beacons, unscheduled communication delivers more messages to the blind-nodes and localization and time-synchronization are performed faster in case of high modulation rates (5kbps and 10kbps).
|Title of host publication||The Sixth ACM International Workshop on Underwater Networks (WUWNet)|
|Place of Publication||New York|
|Publisher||Association for Computing Machinery (ACM)|
|Number of pages||5|
|Publication status||Published - 1 Dec 2011|
van Kleunen, W. A. P., Meratnia, N., & Havinga, P. J. M. (2011). Scheduled MAC in Beacon Overlay Networks for Underwater Localization and Time-Synchronization. In The Sixth ACM International Workshop on Underwater Networks (WUWNet) (pp. 6:1-6:5). New York: Association for Computing Machinery (ACM). https://doi.org/10.1145/2076569.2076575