LoRa Communications as an Enabler for Internet of Drones towards Large-Scale Livestock Monitoring in Rural Farms

Figure 10. 

Measurement route at the UKM campus area (Bangi, Malaysia) and the heatmap of Lo-

RaWAN

®

 coverage throughout the measurement route. 

To further illustrate losses in the propagated signal due to factors such as shadowing, 

PL was calculated and compared with other reference empirical PL models. These models 

included a free space PL (FSPL) model as a baseline and two popular PL models based on 

Cloud-RF

®

. The latter models include the Longley–Rice irregular terrain model (ITM) and 

ECC-33. PL was first calculated from the measured received power (

𝑃

), equivalent to 

the measured RSSI in dBm, using Equation (8) [70]: 

𝑃𝐿(𝑑𝐵) = 𝑃 − 𝑃 + 𝐺 + 𝐺 − 𝐿,

 

(8) 

where, 

𝑃

, 

𝐺

, 

𝐺

, and 

𝐿

  are the transmitted power in dBm, transmitter antenna gain, 

receiver antenna gain, and other losses on both the transmitter and receiver’s side, respec-

tively. 

𝐿

  is neglected in the calculation and assumed to be zero. FSPL was then calculated 

using Equation (9) [70]: 

𝑃𝐿

= 20𝑙𝑜𝑔 (𝑓) + 20𝑙𝑜𝑔 (𝑑) + 32.44

,

 

(9) 

where 

𝑓

  is the frequency in MHz and 

𝑑

 

is the separation distance between the transmit-

ter and the receiver in km.