Analysis of 433 MHz LoRa Communication Quality Based on RSSI and SNR Parameters in A Solar-Powered IoT Chili Irrigation System in Hilly Forest Farmland

Abstract

Agricultural areas in tropical hilly regions generally face challenges due to dense vegetation and uneven topography, which can cause signal attenuation and unstable communication performance. Therefore, this study analyzed the communication quality of a 433 MHz LoRa network based on the parameters of Received Signal Strength Indicator (RSSI), Signal-to-Noise Ratio (SNR), and Packet Delivery Ratio (PDR) in an Internet of Things (IoT)-based chili irrigation system implemented in a tropical hilly agricultural area at an altitude of 210 meters above sea level. This study employed a quantitative experimental method through direct field measurements and descriptive analysis to evaluate wireless communication performance under Non-Line-of-Sight (NLOS) conditions. The system utilized an ESP32 microcontroller and a LoRa SX1278 module operating at 433 MHz to evaluate the reliability and effectiveness of wireless data transmission. Over a continuous monitoring period of approximately 2 hours and 27 minutes, 303 LoRa packets were transmitted, of which 186 were successfully received, yielding a Packet Delivery Ratio of 61.4% and a packet loss rate of 38.6%. RSSI values fluctuated between −92 dBm and −97 dBm, with an average of approximately −93 to −94 dBm, while SNR values ranged from 6.7 dB to 10.8 dB, with most communication sessions maintaining values of approximately 8 dB. Two distinct communication gaps, lasting approximately 8.5 and 33 minutes, respectively, were observed during the monitoring period. The results demonstrate that the 433 MHz LoRa network was able to maintain wireless communication under the tested tropical hilly NLOS conditions, although the relatively low PDR indicates that communication reliability remains a challenge. Further optimization of antenna placement, network configuration, and error-correction mechanisms is recommended to improve communication reliability for more demanding IoT irrigation applications.