A Tree Attenuation Factor Model for a Low-Power Wide-Area Network in a Ruby Mango Plantation

Abstract

Ruby mangoes are a cultivar with a thick skin, firm texture, red color, no splinters, and thin seeds that is grown in eastern Thailand for export. Implementing a low-power wide-area network (LPWAN) for smart agriculture applications can help increase the crop quality or yield. In this study, empirical path loss models were developed to help plan a LPWAN, operating at 433 MHz, of a Ruby mango plantation in Sakaeo, eastern Thailand. The proposed models take advantage of the symmetric pattern of Ruby mango trees cultivated in the plantation by using tree attenuation factors (TAFs) to consider the path loss at the trunk and canopy levels. A field experiment was performed to collect received signal strength indicator (RSSI) measurements and compare the performance of the proposed models with those of conventional models. The proposed models demonstrated a high prediction accuracy for both line-of-sight and non-line-of-sight routes and performed better than the other models.

A Critical Review of the Propagation Models Employed in LoRa Systems

“…Xiao et al [ 140 ] introduced the BHF model, where represents an optimized offset value for path loss in dB, and characterizes the coefficient for path loss caused by vegetation attenuation. The Phaiboon–Phokharatkul model [ 82 ] incorporates log-distance decay with an additional tree attenuation term. In Table 8 , denotes the tree attenuation factor.…”

“…Typically, researchers formulated these models to predict excess attenuation caused by vegetation. LoRa propagation studies within vegetation considered the Weissberger model [ 79 , 80 , 81 ], the ITU-R P.833 model [ 8 , 79 , 80 , 81 , 82 ], the FITU-R model [ 8 , 79 , 80 , 81 , 82 ], the COST 235 model [ 8 , 79 , 80 , 81 , 82 ], and the LITU model [ 8 , 81 , 82 ]. Some authors employed these models by contrasting them with measurements taken within vegetation to choose the best one.…”