Robustness and Optimization of PRIL Techniques for Energy Saving in TSCH Networks

Saving motes energy as much as possible is a main requirement in wireless sensor networks. Time Slotted Channel Hopping (TSCH) is an effective solution, as the radio module of receivers is enabled only when a frame reception is scheduled. Unfortunately, this often leads to non-negligible idle listening, i.e., the receiving interface is switched on but no incoming frame is detected. In cases where the traffic pattern can be somehow predicted, Proactive Reduction of Idle Listening (PRIL) techniques can reduce energy wastes significantly by temporarily switching receivers off. In this paper two specific strategies are proposed, which are aimed at improving PRIL robustness in the case acknowledgment frames are lost, hence causing the transmitter and receiver to have different perceptions of the link state. They were encoded by means of a discrete event simulator and their behavior analyzed. Results obtained through an extensive experimental campaign show that there is no clear winner. Instead, each proposed strategy is suitable for specific application contexts.