On Energy Level Performance of Adaptive Power Based WSN in Shadowed Channel

Sensing range is an important measure of the performance in Wireless Sensor Networks (WSNs). The sensing range which is determined by detection probability depends on the nature of the propagation path, transmit power etc. The detection probability degrades with decreafixed transmit power scheme detection probabilityse in node spatial density and increase in level of shadowing. In fixed transmit power scheme detection probability degrades with decrease in node spatial density. However it is important to keep the detection probability at a particular level considering the sensing range. Further poor detection probability results degradation in performance of the system. In this paper we propose an adaptive power scheme for WSN where transmit power is adapted as node density and level of shadowing changes so as to keep the detection probability at a given level as demanded by sensing range. The impact of shadowing on detection probability and Bit Error Rate (BER) are investigated. Energy consumption of fixed and adaptive transmit power scheme is analyzed for a given packet size. Further energy consumption for an optimal packet length which yields highest energy efficiency is evaluated for both fixed and adaptive power based schemes.