Performance Evaluation of Wireless Sensor Network Channel in Agricultural Application

Problem statement: In this study, the behavior of small scale fading channel due to a moving sink node of a Wireless Sensor Network (WSN) or moving of surrounding objects is presented. Approach: Specifically, this research introduces the effects of multipath and scattering on the transmitted signal due to mobile sink node within forest or closed field filled of reflectors and scatters. Signal propagation above the cross canopy suffer attenuation and variance in the strength of the received signal. Results: The density of leaves in the crop changes over time thus results in more signal obstacles and attenuation at receiver node. The sink node is considered to be in stationary status or it moves with speed not more than 1 m sec^-1, while the sensor nodes of the WSN is preplanned in a fixed position. Conclusion/Recommendations: The modeling of pass band transmitted signal fused in Rayleigh fading channel of stationary and moving status of a receiver are derived. The fluctuation of RF signal, average received signal level, outage probability and the Doppler shift effects are simulated and a detailed analysis is present. The appropriate spatial distribution of the network nodes and the exist of a LOS component will highly necessary between sensor nodes and the sink node in agricultural applications. Indeed power consumption must well maintain so packet loss due to less power level can be overcome. Best position found is center of the application field of the greenhouse for the sink node in stationary situation, while for movement situation the best height of the sink node is to be little above line level of the sensor nodes.