Flexible and energy-efficient duty cycling in wireless networks with MacZ

In wireless networks formed of battery-powered nodes, energy consumption is a major concern. On the communication side, energy can be saved by switching transceivers to idle or power-down mode when not needed. To this end, duty cycling protocols located at MAC level have been devised. These protocols have in common that they define modified CSMA/CA schemes, and that they assume the availability of some time synchronization mechanism. This strongly limits their potential to reduce energy consumption, as well as their flexibility regarding activity phases. In this paper, we propose a more flexible and energy-efficient solution for duty cycling, which is based on our experimental wireless MAC protocol MacZ. Flexibility is strengthened by the possibility to define weakly periodic activity periods. Energy-efficiency is improved by the possibility to reserve and use exclusive transmission slots, thereby switching transceivers to active mode only when needed. Both measures are supported by an underlying protocol for accurate, deterministic tick and time synchronization. We assess our solution and compare it to a well-known duty cycling protocol based on real-life scenarios.