Home // International Journal On Advances in Networks and Services, volume 8, numbers 1 and 2, 2015 // View article

Evaluation of an Uncertainty Aware Hybrid Clock Synchronisation System for Wireless Sensor Networks

Authors:
Christoph Steup
Sebastian Zug
Jörg Kaiser

Keywords: Wireless Sensor Networks; Clock Synchronisation; Uncertainty

Abstract:
Wireless Sensor Networks, aiming to monitor the real world's phenomena reliably, need to combine and post-process the detected individual events. This is not possible without reliable context information for each event. One important aspect of this context is time. It enables ordering of events as well as deduction of further data like rates and durations. Consequently, an unreliable time base affects all aspects of further processing. Any uncertain time information generates uncertain values and decisions, which jeopardize the correct behaviour of the system unless the system knows them. Therefore, the synchronisation of the clocks of the individual nodes is of high importance to the reliability of the system. On the other hand, tight and reliable synchronisation typically induces a large message overhead, which is often not tolerable in WSN scenarios. This paper evaluates a new hybrid synchronisation mechanism enabling tight synchronisation in single-hop environments and looser synchronisation in multi-hop environments. The lack of a guaranteed synchronisation precision is mitigated by an explicit synchronisation uncertainty, which is passed to the application. This enables the application to react to changes in the current synchronisation precision. The new approach is evaluated using the network Simulator OMNET++ and a small scale wireless sensor network to verify the expected performance and assumptions. The new method showed excellent performance in single-hop environments and a decreasing synchronisation precision based on the topological distance in multi-hop scenarios, which are useful results for Wireless Sensor Networks.

Pages: 54 to 68

Copyright: Copyright (c) to authors, 2015. Used with permission.

Publication date: June 30, 2015

Published in: journal

ISSN: 1942-2644