# A LoRaWAN Architecture for Communications in Areas without Coverage: Design and Pilot Trials
## 5 Results
### Experimental Set-Up  
In this subsection, the hardware and software resources used in the work are detailed. Hardware resources refer to the devices used in the development of the work and the physical components that make up the proposed network. The devices used are described below and summarized in Table 2:  
* One Plus 7t [35]: a smartphone used in the testing of the TeamUp mobile application and analysis of the proposed scenarios. * Notes: the devices in charge of receiving messages through the mobile application and acting as a repeater to transmit them to the other corresponding gateway motes. Two models were used in the work: TTGO ESP32-LoRa [36] and PyCom Fipy [37]. * LoRaWAN gateway: a gateway between the motes and the servers. Three models were used in the work: TTGO ESP32-LoRa (1-channel), PyCom Fipy and IMST Gateway Lite (IMST ic880A concentrator) [38]. Software resources refer to the programs used for the implementation and analysis of the results. Throughout the work, free software was used as much as possible. In the following, the software programs used are described:  
* Arduino IDE [39]: a development environment used in the programming of the NodeM-CUv03 (ESP32-LoRa) motes. Version 1.8.12 was used. * Visual Studio Code [40]: a text editor used for programming the PyCom Fipy motes, the proprietary server programs, the databases and the web interface. In addition, the analysis of the samples taken was carried out. For this purpose, different programming languages such as PHP, HTML5 and Python were used with version 1.46 of the software. * Android Studio [41]: a development environment for Android devices used for programming the smartphone application. Version 3.6.3 was used. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Device** & **O.S.** & **Processor** & **RAM** & **Storage** \\ \hline One Plus 7t & Android 11 & Snapdragon 855 Plus & 8 GB & 128 GB \\ TTGO ESP32-LoRa & - & Xtensa LX6 & 4 MB & 4 Mb \\ PyCom Fipy & - & Xtensa LX6 & 4 MB & 8 MB \\ IMST Gateway Lite & Raspbian & ARM 6 & 1 GB & 32 GB \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Main characteristics of hardware resources. Figure 8: Sequence diagram of login messages for the TeamUp server. * Chirpstack [42]: an open source platform used for the implementation of the LoRaWAN network core privately and the authentication of the LoRaWAN network components. It also includes a web interface for device management and APIs for the integration of motes and gateways. * Matlab [43]: a programming and numeric computing platform used to analyze data. Version R2019b was used. In the first experiment, the simulated analysis of the data transmission rate was performed using Matlab. The results of this experiment are shown in Section 5.2. This simulation was performed because of the need to know the transmission capacity of the network as a function of the modulation parameters used. The number of bits that could be encoded in each symbol was given by the spreading factor (\(SF\)). Then, the information bit rate (\(R_{b}\)) was defined, as discussed in [22], as follows:  
\[R_{b}=\frac{SF*BW*CR}{2^{SF}}\ [bps] \tag{1}\]  
where \(SF\) can take integer values between 7 and 12, \(BW\) refers to the bandwidth used in transmission, LoRa supports bandwidths of 125, 250 and 500 KHz and the coding rate (\(CR\)) is the ratio of non-redundant bits for forward error correction (FEC) and can take the values 4/5, 4/6, 4/7 and 4/8 [22]. Finally, in the second experiment proposes the analysis of system coverage and performance in terms of signal strength. This analysis considers the received signal strength indication (RSSI) and signal-to-noise ratio (SNR) in real environments. The real environments were urban, rural and natural areas. These areas are described below and shown in Figure 9:  
* The urban environment (worst case) was located in the \"Avenida Andalucia\" of the city of Granada. * The rural environment was located in a little village in the province of Jaen called \"Llanos del Sotillo\".