NESL Technical Report #: 2009-5-5
Authors:
Abstract:
Time synchronization in embedded sensor networks is an important service for
correlating data between nodes and communication scheduling. While many
different approaches to the problem are possible, one major effect of clock
frequency difference between nodes, environmental temperature changes, has
often been left out of the solution. The common assumption that the
temperature is static over a certain period of time is often used as an excuse
to assume constant frequency errors in a clock. This assumption
forces synchronization protocols to resynchronize too often. While there
exists hardware solutions to this problem, their prohibitive high cost and
power consumption make them unsuitable for some applications, such as wireless
sensor networks.
Temperature Compensated Time Synchronization (TCTS) exploits the on-board temperature
sensor existing in many sensor network platforms. It uses this
temperature sensor to autonomously calibrate the local oscillator and removes
effects of environmental temperature changes. This allows a time
synchronization protocol to increase its resynchronization period, without
loosing synchronization accuracy, and thus saves energy and communication
overhead. In addition, TCTS provides a stable clock source when
radio communication is impaired. We present the theory behind TCTS,
and provide initial results of a simulated comparison of TCTS and the Flooding
Time Synchronization Protocol.
Publication Forum: IEEE Embedded Systems Letters
Volume: 1
Number: 2
Page (Start): 37
Page (End): 41
Page (Count): 5
Date: 2009-08-01
Public Document?: Yes
NESL Document?: Yes
Document category: Journal Paper
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