Abstract
Nowadays, Low Rate Wireless Personal Area Networks (LR-WPAN) are used in a wide variety of embedded applications, especially in medical area and patient monitoring. The use of a wireless network system for the sensor data results provides greater flexibility for both the patient and the medical staff. Power consumption is measured while doing data transmission. Depending on the estimated distance calculated from the averaged Received Signal Strength Indicator (RSSI), the transmission power needed were computed and used for each packet transmission. Hence, instead of transmitting in full power regardless of the location of the receiving node, the transmission power is carefully controlled depending on the estimated distance. In this paper, A simple transmit power management scheme is introduced and evaluated by simulation. The scheme is easy to implement yet it provides excellent performance. The study highlights that, node localization and ranging techniques aside, even the use of available RSSI readings at the sensor node can be used to reduce energy consumption levels tremendously prolonging the network/battery lifetime and with tolerant reliable delivery. Results indicate payload size has a considerable effect as up to 80% improvement can be achieved when transmitting ECG signals, while only a minimal improvement can be achieved when the temperature information is transmitted.