WirelessSensor Network (WSN) is a communication's architecture composed of several nodes with small power supply, which may be used to monitor hazardous events in inaccessible areas. Thus, on one hand, it is preferable to assure the adoption of the minimum transmission power in order to extend the WSN lifetime, as far as possible. On the other hand, it is crucial to guarantee that the nodes receive the transmitted data correctly. Therefore, trading off power optimization and quality of service has become one the most important concerns when dealing with modern systems based on WSNs. This paper proposes a new technique based on Time Division Multiple Access (TDMA) focusing on the minimization of energy consumption. The proposed technique adjusts the monitoring timeslot of the sensors according to the environmental changes. The results obtained throughout a WSN simulator show that the implemented technique provides satisfactory results, when compared with classic TDMA techniques. The analyzed scenarios demonstrated improvements regarding the WSN's energy consumption of 17%, in the worst case, and up to 52%, in the most favorable case. The proposed technique reduces the energy consumption of the network and consequently, increases its lifetime.

This paper presents an experiment using a Wireless Sensor Network (WSN) in a rural area with focus on precision agriculture. The experiment lasted 90 days and during this time several events were analyzed highlighting the quality of the communication and events of the environment that affected the normal operation of the WSN. This experiment was the starting point for the proposition of a communication architecture model applied to WSN based on Grid.