2.4 GHz RF Received Signal Strength Based Node Separation in WSN Monitoring Infrastructure for Millet and Rice Vegetation

The WSN monitoring infrastructure developed for a vegetative environment may encounter network disconnectivity due to node isolation if the node deployment strategy has not accounted for the change in vegetation density at different crop development stages. This proposal develops a path loss model by analyzing the effects of vegetation height and density on signal strength between two sensor nodes communicating under the IEEE802.15.4 Wireless standard. For this, the path loss coefficients have been analyzed for 2.4 GHz RF signals through measurement campaigns at various development stages of Rice and Millet crop. The proposed path loss model controls the separation between sensor nodes to achieve a distribution that is resistant to network disconnectivity caused by node isolation. The acquired database and formulated path loss model can be used by IoT network architects and researchers in the field of precision agriculture as a benchmark for network development and comparison with the signal strength in other crops.

I. Introduction

Agricultural production must double by 2050 in order to meet the expected food demand due to population growth. Precision agriculture technology aims to improve crop productivity and resource utilization under the diverse challenges faced by farmers due to climate changes, land degradation, land availability and labor shortage. Precision agriculture addresses these challenges by Data-mining of crop growth and health through a monitoring infrastructure developed using state-of-the-art sensing techniques. The Wireless Sensor Network (WSN) based monitoring infrastructures are scalable and economical data collection method that facilitates optimal resource utilization and high crop yield [1]. In WSN, coverage and connectivity enhancement are fundamental design challenges that are affected by node placement in the target area [2]. The -coverage strategy provides a measure of Quality of Service (QoS) by ensuring that a minimum -node covers each location in the target area.