Integração de uma rede de sensores sem fio com um RTOS tickless

Abstract

This work aims to reduce the energy consumption of the elements of a sensor networks based on real-time operating systems (RTOS), by implementation a tickless timer for the RTOS and using a media access protocol with duty cycle control. The use of a RTOS is fundamental to manage the existing concurrence and time constraints in a WSN software. Such operating systems usually have a better implementation of network resources, such as time management, semaphores, task synchronization, among others. However, the use of an RTOS has a computational cost, as well as the inherent increase in power consumption due to its operating modes. Thus, among the existing techniques in the literature for the reduction of energy consumption of a real-time system, it was chosen to implement a tickless timer for the real-time operating system time management, as well as the use of a low power consumption mode available in the ARM processors architecture. Another major source of energy consumption in WSN, the radio, also had its consumption reduced in the router device by using a media access protocol with duty cycle control. For data analysis, a minimum structure was used to represent a WSN, i.e., a coordinator and a router were configured to maintain communication using a star topology and the obtained reduction in average power consumption of the system was 54.74%.