Experimental Path Loss Models for Wireless Sensor Networks

Energy conservation is critical in Wireless Sensor Networks. Replacing or recharging batteries is not an option for sensors deployed in hostile environments. Generally communication electronics in the sensor utilizes most energy. This paper studies the effect of changing the transmission power and baud rate on transmission distance. Using Shannon channel capacity formula and Log - Distance Path Loss Model, transmission distance is shown to be related to transmit power and baud rate. Extensive empirical readings are taken to confirm the above relation. The path loss exponent got as a result of data fitting is within the acceptable range for wireless environment. Using the equation derived in this paper, the distance between neighboring motes and traffic density it will be possible for sensors to adjust their transmit power and baud rate so as to use only the required amount of energy to maintain the wireless link to the neighbor and conserve power.