John Heidemann / Papers / Time Synchronization for High Latency Acoustic Networks

Time Synchronization for High Latency Acoustic Networks
Affan Syed and John Heidemann
USC/Information Sciences Institute


Affan Syed and John Heidemann. Time Synchronization for High Latency Acoustic Networks. Technical Report ISI-TR-2005-602. USC/Information Sciences Institute. [PDF] [alt PDF]


Distributed time synchronization is an important part of a sensor network where sensing and actuation must be coordinated across multiple nodes. Several time synchronization protocol that maximize accuracy and energy conservation have been developed, including FTSP, TPSN, and RBS. All of these assume nearly instantaneous wireless communication between sensor nodes; each of them work well in today’s RF-based sensor networks. We are just beginning to explore underwater sensor networks where communication is primarily via acoustic telemetry. With acoustic communication, where the propagation speed is nearly five orders of magnitude slower than RF, assumptions about rapid communication are incorrect and new approaches to time synchronization are required. We present Time Synchronization for High Latency (TSHL), designed assuming such high latency propagation. We show through analysis and simulation that it achieves precise time synchronization with minimal energy cost. Although at very short distances existing protocols are adequate, TSHL shows twice the accuracy at 500m, demonstrating the need to model both clock skew and propagation latency.

Bibtex Citation

  author = {Syed, Affan and Heidemann, John},
  title = {Time Synchronization for High Latency Acoustic Networks},
  institution = {USC/Information Sciences Institute},
  year = {2005},
  sortdate = {2005-04-01},
  project = {ilense, snuse, cisoft},
  jsubject = {chronological},
  number = {ISI-TR-2005-602},
  month = apr,
  note = {Superseded by [Syed06a] and [Syed05b].},
  location = {johnh: pafile xxx},
  keywords = {tshl, time synchronization, snuse},
  myorganization = {USC/Information Sciences Institute},
  copyrightholder = {authors},
  url = {},
  pdfurl = {}
Copyright © by John Heidemann