Enhanced Energy-Saving Mechanisms in TSCH Networks for the IIoT: the
PRIL Approach
Abstract
Lifetime of motes in wireless sensor networks can be enlarged by
decreasing the energy spent for communication. Approaches like time
slotted channel hopping pursue this goal by performing frame exchanges
according to a predefined schedule, which helps reducing the duty cycle.
Unfortunately, whenever the receiving radio interface is active but
nobody in the network is transmitting, idle listening occurs. If the
traffic pattern is known in advance, as in the relevant case of periodic
sensing, proactive reduction of idle listening (PRIL) noticeably lowers
energy waste by disabling receivers when no frames are expected for
them. Optimal PRIL operation demands that, at any time, the transmitter
and receiver sides of a link have a coherent view of its state (either
enabled or disabled). However, this is not ensured in the presence of
acknowledgment frame losses.
This paper presents and analyzes some strategies to cope with such
events. An extensive experimental campaign has been carried out through
discrete event simulation to determine what consequences above errors
may have from both a functional and performance viewpoint. Results show
that, although no strategy is optimal in all circumstances, different
solutions can be profitably adopted depending on the specific operating
conditions.