Research progress in wireless sensor network for agricultural environment monitoring

Wireless sensor network (WSN) technology is a major solution for networking remote monitoring for multi-faceted variable of agricultural environment. The researches of WSN applications are focused on radio path-loss caused by distance between transmitter and receiver, as well as influences of the height of transmitters or receivers, plant canopy height and shape, so as to choose the reasonable parameters for system based on the research. The researches of wireless underground sensor network (WUSN) are focused on path-loss, error rate, the maximum transmission distance, the water content test error of multi-path transmission of electromagnetic waves, which are affected by meteorological environment, soil type, soil moisture content, soil structure and composition, burial depth of the node, node distance, frequency and power range, the network topology, routing algorithms, networking. According to the research, frequency of 300 MHz to 500 MHz, the maximum transmission distance of which can reach 5 m, is more appropriate for WUSN. Transmission distance is the main limiting factor for system in large scale. Transmission characteristics, channel models and path-loss of 433MHz electromagnetic waves in different soils and air multi-media will be the focus of future researches. Based on that, we can choose the reasonable position of network nodes and optimal network topology under different agriculture environment.