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).
|Workshop||Sixth ACM International Workshop on Underwater Networks, WUWNet 2011|
|Period||1/12/11 → 2/12/11|
|Other||1-2 December 2011|