Abstract:
Palm oil is the main cash crop of tropical Asia, and the implementation of LPWAN (low-
power wide-area network) technologies for smart agriculture applications in palm oil plantations
will benefit the palm oil industry in terms of making more revenue. This research attempts to
characterize the LoRa 433 MHz frequency channels for the available spreading factors (SF7-SF12)
and bandwidths (125 kHz, 250 kHz, and 500 kHz) for wireless sensor networks. The LoRa channel
modeling in terms of path-loss calculation uses empirical measurements of RSS (received signal
strength) in a palm oil plantation located in Selangor, Malaysia. In this research, about 1500 LoS
(line-of-sight) and 300 NLoS (non-line-of-sight) propagation measurement data are collected for
path-loss prediction modeling. Using the empirical data, a prediction model is constructed. The
path-loss exponent for LoS propagation of the proposed prediction model is found to be 2.34 and 2.9
for 125–250 kHz bandwidth and 500 kHz bandwidth, respectively. Again, for the NLoS propagation
links, the attenuation per trunk is found to be 7.58 dB, 7.04 dB, 5.35 dB, 5.02 dB, 5.01 dB, and 5 dB for
SF7-SF12, and the attenuation per canopy is found to be 9.32 dB, 7.96 dB, 6.2 dB, 5.89 dB, 5.79 dB, and
5.45 dB for SF7-SF12. Moreover, the prediction model is found to be the better choice (mean RMSE
2.74 dB) in comparison to the empirical foliage loss models (Weissberger’s and ITU-R) to predict the
path loss in palm oil plantations.
