An Efficiency Degradation Model of Power Amplifier and the Impact against Transmission Power Control for Wireless Sensor Networks

Abstract

To extend an available period of wireless sensor networks, transmission power control is regarded as one of the promising schemes. In most of the previous studies on the transmission power control, it is assumed that a transmitter has power consumption of O(d <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sup> ), where d and n denote a maximum communication distance and a pass loss factor. This assumption would substantially hold under the condition that the transmission efficiency is always constant at any transmission power (efficiency-fixed model). In practice, however, the transmission efficiency degrades as the transmission power is reduced. We analytically verify that an actual power amplifier with the efficiency degradation has a power consumption of O(d <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</sup> ), where n/2.8 les r les n/2 (efficiency-degradation model). The efficiency-degradation model gives the negative impact against the transmission power control