A method for synchronizing low cost energy aware sensors used in industrial process monitoring

Time synchronization is needed in distributed industrial systems. When wireless low cost energy aware sensors are used for monitoring industrial processes a new concept for time and synchronization must be developed. These sensor systems are much more heterogeneous and energy aware than traditional systems, making standard time synchronization methods inadequate. Implementation differences, energy resources and environmental conditions may greatly vary even inside one cell of sensors. This must be considered in the design. The authors propose a new time synchronization method that scales to the real synchronization requirements of the cell application. The method has been designed to be energy efficient, flexible and robust. It is based on three steps that respectively learn the system and its behavior, make coarse synchronization and perform precise synchronization according to the desired synchronization level and the energy available in each sensor. They show some early simulation results that indicate the potential of the method discussed in the paper.

[1]  Mineo Takai,et al.  Parssec: A Parallel Simulation Environment for Complex Systems , 1998, Computer.

[2]  Deborah Estrin,et al.  Time synchronization for wireless sensor networks , 2001, Proceedings 15th International Parallel and Distributed Processing Symposium. IPDPS 2001.

[3]  Leslie Lamport,et al.  Time, clocks, and the ordering of events in a distributed system , 1978, CACM.

[4]  T. O'Shaughnessy A CMOS, self calibrating, 100 MHz RC-oscillator for ASIC applications , 1995, Proceedings of Eighth International Application Specific Integrated Circuits Conference.

[5]  David L. Mills Algorithms for synchronizing network clocks , 1985, RFC.

[6]  Anantha Chandrakasan,et al.  Operating System and Algorithmic Techniques for Energy Scalable Wireless Sensor Networks , 2001, Mobile Data Management.

[7]  Timo Rahkonen,et al.  A micropower RC oscillator chip for consumer ASIC applications , 1991, [1991 Proceedings] 6th Mediterranean Electrotechnical Conference.

[8]  Wojciech E. Kozlowski,et al.  Synchronizing low-cost energy aware sensors in a short-range wireless cell , 2001, Proceedings Euromicro Symposium on Digital Systems Design.