Enhanced multimodal switching mechanisms for node scheduling and data gathering in wireless sensor networks

Several monitoring oriented applications in Wireless Sensor Networks (WSNs) are characterized by the necessity of two data-reporting modes: time-driven and event-driven. The former is used mainly for constantly supervising an area and the latter for event detection and target tracking. By switching between both modes a WSN can improve its energy-efficiency and accuracy of measurement processes, compared to single data-reporting schemes. This type of switching mechanism we called multimodal switching mechanism. This paper presents an implementation and evaluation of two multimodal switching mechanisms: Enhanced hybrid node scheduling (eHNS) and Enhanced hybrid data gathering (eHDG), in ContikiOS-Cooja. The experimental results showed that by adopting a duty-cycling technique, such as ContikiMAC, the energy savings of the whole WSN is further improved.