## 3 Research Methodology and Procedures
### Technical Specifications and Core Concepts of LoRa Technology
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Parameters** & **Values** & **Description** \\ \hline Transmission Power (TP) & 4 dBm to 20 dBm & Power levels greater than 17 dBm \\  & & Can only be used at 0.1 duty cycle \\  & & due to hardware restrictions. \\ \hline Carrier Frequency (CF) & 137 MHz to 1020 MHz & Relays the messages received from \\  & & LoRa sensor nodes to the central server. \\ \hline Spreading Factor (SF) & [SF6..SF12] & lengthens the airtime of the packet. \\  & & Enhancing sensitivity and range by \\  & & increasing the SNR. \\ \hline  & & Is the transmission band’s frequency \\ Bandwidth (BW) & 7.8 kHz to 500 kHz & width. \\  & & A lower BW provides higher sensitivity \\  & & but a lesser data rate. \\ \hline Coding Rate (CR) & 4/5, 4/6, 4/7, or 4/8 & Protects against interference bursts. \\ \hline \hline \end{tabular}
\end{table} 
Table 2: LoRa parameters description. where \(-174\) accounts for receiver thermal noise at 1 Hz bandwidth, NF represents additional receiver noise, and SNR is the signal-to-noise ratio required for modulation. A LoRa packet structure is commonly used and includes an 8-base up-chirp preamble, a 2-base up-chirp synchronization word, a 2.25-base down-chirp start of frame delimiter (SFD), and payload data, followed by a Cyclic Redundancy Check (CRC). In LoRa modulation, the frequency of the chirps continuously varies linearly with time within the limited bandwidth available. A base up-chirp is specifically defined as a signal that sweeps linearly from its initial frequency of BW/2 to BW/2, written as [33]:  
\[c(t)=e^{i2\pi(k^{2}t-\frac{BW^{2}}{T})} \tag{5}\]  
Each bit of the payload is represented by several chirps with a shifted start frequency during the LoRa modulation process, and the signal of a symbol is described in Equation (6). \[S(t,f_{sym})=C(t)\times e^{i2\pi f_{sym}t} \tag{6}\]  
When it comes to demodulation, the receiver executes the \"de-chirp\" operation, which multiplies each received symbol by the conjugate of a base up-chirp, or as in Equation (7), resulting in a tone of a single frequency. \[S(t,f_{sym})\times C^{-1}(t)=e^{i2\pi f_{sym}t} \tag{7}\]  
The receiver then applies a Fast Fourier Transform (FFT) to the multiplication result, with the resulting peak representing the original frequency \(f_{sym}\). In this section, the importance of using the GNU Radio in the experiments is highlighted. In addition, the software aspect of our methodology is introduced. Moreover, some insights about the interaction with the GNU Radio, the used modules and their configuration as well as the software interface help us to check and test LoRa communication protocols. The first step of the proposed process is to optimize the LoRa research environment by considering the GNU Radio software interface. The second step consists of Hardware Setup (SDR), including the SDR devices, antennas, and specialized hardware. This setup is considered the main key of our research, which ensures accurate data acquisition and transmission, and provides a comprehensive view to explore the LoRa technology.