## 3 Architecture of the Platform and Related Software and Hardware Aspects
### Implementation Aspects and Associated Configuration and Monitoring Processes
#### 3.2.3 Hardware Details  
The software implementing the functions of each node in the platform runs on Raspberry Pi3 model B (RPi) [41] hardware. The RPi is a low-cost, credit card-sized unit that provides functionality comparable to that of a conventional computer and a computational power exceeding the platform's requirements. The board uses the BCM2837 chip, a quad-core Cortex-A53 (ARMv8) cluster running at 1.2 GHz, has 1 GB of RAM, and can host up to 32 GB of microSD storage. Moreover, it provides a wide range of connectivity options (USB, serial, GPIO, HDMI, Ethernet, Wi-Fi, Bluetooth, etc.). Due to these features and the existence of an active support community, RPi has been widely adopted in many prototyping projects. \begin{table}
\begin{tabular}{l l l l} \hline \hline \multicolumn{1}{c}{**Group of Parameters**} & \multicolumn{1}{c}{**Parameter**} & \multicolumn{1}{c}{**Example**} & \multicolumn{1}{c}{**Types of Nodes Using the Parameter**} \\ \hline Ad hoc network & Network specific & 192.168.167.0/24 & All \\  & Port specific & 10,000 & All \\ Monitoring Network & Monitoring IP & 192.168.168.100 & All \\  & Monitoring Port & 11,000 & All \\  & ID (host part of ad hoc net address) & 100 & All \\  & Transmission range threshold (m) & 20 & Mobile, Source \\ Node Characteristics & Period for message table checks (s) & 2 & Mobile, Source \\  & Beacon period (s) & 2 & Mobile, Destination \\  & Beacon table entry timeout threshold (s) & 4 & Mobile, Source \\  & Reference Latitude & zz.zzzz & All \\  & Reference Longitude & rr.rrrr & All \\  & Rotation Angle (Degrees) & 0 & All \\  & Buffer size for least squares smoothing & 5 & Mobile \\ Localization Characteristics & Location update period (s) & 2 & Mobile \\  & Source Latitude & yy,yyyy & Source \\  & Source Longitude & qq-qqn & Source \\  & Destination Latitude & xx.xxx & Destination \\  & Destination Longitude & www.www & Destination \\  & \# Routing Protocols & 4 & All \\  & \# Messages per protocol & 10 & Source \\  & Message generation period (s) & 100 & Source \\  & Destination IP Address & 192.168.167.103 & Source \\  & Destination ID (host part of the address) & 103 & Source \\  & Destination Latitude & xx.xxx & Source \\  & Destination Longitude & www.wwwwww & Source \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Parameters in the configuration files of individual nodes, according to their type. The RPi unit has a built-in Wi-Fi radio and can host additional USB-attached Wi-Fi adapters. In the platform, the built-in Wi-Fi unit implements the ad hoc radio link, while an additional USB-attached Wi-Fi radio, specifically a TP-Link TL-WN722N [42] unit equipped with an external omnidirectional antenna, is setup in infrastructure mode and provides connectivity to the auxiliary network used for monitoring. Concerning the GPS modules, typical units of medium accuracy have been selected for all the mobile nodes. As a first choice, the nodes were equipped with easy to install VK-162 USB GPS receiver modules (based on the Ublux 7 hardware setup [43]). This system has a positioning accuracy of 3 m and 0.5 degrees in direction and a timing accuracy of 30 ns. An alternative configuration has also been tested, in which the nodes were equipped with a more precise NEO-M8N GPS unit [44], having a positioning accuracy of 2.5 m and 0.3 degrees in direction and a timing accuracy of 30 ns. In both cases, the Gpsd Linux package has been used for reading the data provided by the GPS module. Regarding power-related issues, each RPi-based network node in the MANET platform can be powered by a 5 V power supply or by a power bank through a micro-USB plug. The exact input current requirements vary, depending mainly on the kind of equipment attached to the main RPi board, but typically remain below 0.5 A. In more detail, an active RPi model B board consumes about 250 mA, and an additional amount of 100 mA is needed for the external Wi-Fi adapter, while the GPS module takes another 70 mA.