The nodes in a wireless sensor network typically need to operate on
limited energy budgets, and may therefore be switched between active
and sleep modes to conserve energy. It is clear that the performance
of the sensor network could degrade due to having sleepy sensors and
therefore any sleeping policy trades off performance with energy
savings. Such sleeping is usually effective only if the sensor is
completely turned off in the sleep mode, i.e., a sensor that is asleep
cannot be communicated with or woken up prematurely. A natural way to
implement the sleeping in this setting is to have the sensor enter and
exit the sleep mode using a fixed or random duty cycle. This
presentation will describe an alternative smart approach to sleeping
that uses all available information about the state of the network to
set the sleep times of the sensors. It is shown through the example of
tracking that the smart approach can yield significant improvements
over the duty cycle approach in the tradeoff between performance and
energy savings.
Audio (MP3 File, Podcast Ready)
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