One of the most important requirements for wireless sensor networks (WSNs) is the
energy efficiency, since sensors are usually fed by a battery that cannot be replaced
or recharged. Radio wake-up - the technology that lets a sensor completely turn
off and be reactivated by converting the electromagnetic field of radio waves into
energy - is now one of the most emergent strategies in the design of wireless sensor
networks. This work presents Scheduled on Demand Radio WakeUp (SORW), a
flexible scheduler designed for a wireless sensor network where duty cycling strategy
and radio wake-up technology are combined in order to optimize the network
lifetime. In particular, it tries to keep sensors sleeping as much as possible, still
guaranteeing a minimum number of detections per unit of time. Performances
of SORW are provided through the use of OMNet++ simulator and compared
to results obtained by other basic approaches. Results show that with SORW it
is possible to reach a theoretical lifetime of several years, compared to simpler
schedulers that only reach days of activity of the network
