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Highlights

The prediction model of LoRa signal reception strength in tea gardens was established and verified.

Abstract. The influence of the tea plantation environment on wireless signal path loss is not considered when aiming for node deployment in the traditional tea plantation wireless sensor network, resulting in a waste of node energy consumption and an increase in wireless sensor network equipment maintenance costs. The transmission characteristics of LoRa wireless signals in tea plantations were investigated in this paper using 433 MHz as the operating frequency. The RSSI values of LoRa signal reception strength were collected at various antenna heights and communication distances in the experimental tea tree area. The data was used for model comparison, regression analysis, and modeling. A prediction model of LoRa signal reception intensity in hilly tea plantations was established and verified. The results show that the logarithmic distance model was superior to the free-space model and the ground reflection (two-line) model for modeling the LoRa signal path loss in tea plantations. The revised model can correct the differences between different tea trees and has better universality. The model fitting coefficient of determination was between 0.840 and 0.881. When the antenna height was 0 m (placed on the ground), the environmental propagation factor n was the largest, which was 3.0045. When the antenna height was 0.7 m, the environmental propagation factor n was the smallest, which was 2.6417. Therefore, the best location for deploying antennas in tea gardens was near the top of the tea tree. The established prediction model can effectively predict the signal reception strength of LoRa signals at different antenna heights and distances in tea plantations, and the results can provide a theoretical basis for the planning and deployment of tea garden wireless sensor networks.