## Materials and Methods
### Acquisition System  
The coverage of the territory by the network of the telephone operator Telecel Faso is dense. The level of density of network coverage is distributed according to the cities. It is therefore very appropriate to implement the above technology throughout the territory. The first experiment was conducted on a single link, the Korsimoro-Kaya microwave link, in 2012. It was a CML link of 29 km long, with a transmission/reception frequency of 7 GHz, and whose antennas have horizontal polarization. As of 2018, thanks to the support  
Figure 1: Schematic of Telecel Faso’s CML power data acquisition system. of Fonds National de la Recherche et de l'Innovation pour le Developpement (FONRID), the experimental zone was extended to the central region, i.e., the city of Ouagadougou and its region. On the one hand, from 2019 to 2021, the challenge was to achieve greater coverage of the national territory, and, on the other hand, TOP-RainCell wanted to record the CML data, with a time step of one minute, and automatically process these data to derive the rainfall amounts. Note that all the Telecel Faso's base stations might be \"queried\" directly and automatically by our data acquisition system. For this purpose, a metadata file was built with the help of Telecel Faso since 2019 and regularly updated. This metadata file contained the identifiers, lengths, frequencies, and polarizations of the different links, as well as the latitudes and longitudes of the pylons. The experimental setup was installed at the LA.M.E (Laboratoire de Materiaux et d'Environnement) of the Joseph KI-ZERBO University, in Ouagadougou in Burkina Faso. Two antennas of 0.3 m diameter with a minimum gain of 36.6 dBi were installed for the interconnection of the experimental setup installed at LA.M.E with the transmission center of Telecel Faso, as shown in Figure 1.  
The installed device includes an indoor unit (IDU), which has the role of modulator/demodulator of the signals, and an outdoor unit (ODU), which transmits and receives the microwave signals. The link design was performed using pathloss 5.0 [25] and ITU-R rain Zone K, 66.26 mm/h inputs [26]. The inputs are provided below:  
* calculation method: ITU-R P.530,
* ITU-R raine Zone K, (66.26 mm/h UIT-R P.837-7),
* average temperature \({}^{\circ}\)C: 27,
* water vapor density (g/m\({}^{3}\)): 3.2,
* atmospheric pressure (Pa): 1013,
* frequency band: 23 GHz,
* channel spacing: 28 MHz (23 GHz-ITU-RF_737 Ann3-CEPT13-02),
* modulation: ACM (mask of modulation 128 QAM, max 1024 QAM),
* antenna size: 1 Ft/0.3 m,
* radio type: ODU600v2,
* availability objective (%): 99.999. The fading margin was 52.83 dB. The link throughput was 200 Mbps/128 QAM. A firewall was used to secure the system. Figure 2 and Table 1 provide, respectively, the microwave link in line of sight and the link budget details which were produced by Aviat Networks, Inc., Austin, TX, USA. The implementation of this link required the signing of a partnership between LA.ME and Telecel Faso, and the assignation of a license by the \"Autorite de Regulation des Communications Electroniques et des Poste (ARCEP)\" of Burkina Faso, in order to use radio frequencies, as well as the transmitting and receiving devices. Figure 2: Microwave link in line of sight (Aviat Network, Inc. (July 2017)). Figure 3 shows the acquisition system installed. It has been operational since July 2019 and allows access to more than 1000 CMLs of the Telecel Faso's network throughout Burkina Faso. These CMLs are transmitting in the 6 GHz and 15 GHz frequency bands. The latter is used only in urban regions. One may note that attenuation increased with frequency [27]. However, this aspect will not be investigated in detail in this article. The acquisition system comprises CMLs located in seven of the thirteen regions of Burkina Faso: << Le Nord>>, << Le Centre Nord>>, << Le Centre>>, << Le Centre Ouest>>, << La Boucle du Mouhoun>>, << Les Hauts Bassing>>, and << Les Cascades>> (Figure 3).