Towards a perpetual wireless sensor node

We report our experimental findings on a perpetual wireless sensor node. Our perpetual node is based on the integration of a wireless sensor node that runs IEEE 802.15.4e technology on TI´s MSP430 with a solar energy harvesting module that is based on TI´s bq25504 modules. We show that by default running the time synchronized channel hopping (TSCH) MAC layer draws more power than the harvester is able to provide. To close that gap, enhancements that improve the power efficiency of TSCH protocol are described and results are presented. The enhancements proposed consist of shared slot suppression, slotframe skipping, and connection setup time reduction. It is shown that even with these enhancements consumed power is still greater than harvested power. We provide future directions on how to further reduce consumed power at the node.