# Earth-to-Earth Microwave Rain Attenuation Measurements: A Survey On the Recent Literature
## 7 Discussion and Conclusions  
This paper is focused on the extensive survey and research on finding the proper recent works on rainfall measurements by using various types of communications. The goal was to present all the recent viable technologies that could even be combined in order to give the readers the capability of choosing the best possible combination for themselves. This capability could help them become acquainted, involved, or even to progress in the aforementioned area of expertise. Consequently, much information is given relevant to the theory of operation along with new evolving techniques and i.e., the physical mechanism of attenuation due to rain, the signal, and rainfall measurement parameters, specific rainfall measurements through backhaul cellular infrastructure, customized experimental setups and research challenges. Published works on rainfall measurements are summarized in Table 1 whereas the latter has been emerged during synthesis and analysis based on SALSA methodology. The works are classified by year of publication, and there are columns with location measurements, operating frequency, and path length. There is also the column with the validation method and the remarks. In addition to previous, the idea behind the aforementioned area is simple and should stay simple, and i.e., the degree of accuracy should differ for each condition. e.g., in the case of areas that are easily susceptible to floods and imminent destructions, the sampling rates, power resolution, and other measured characteristics should be of high analysis and should definitely combine cellular with costumed wireless infrastructure along with rain gauges for acquiring the best possible measurement that could act as an accurate alert. According to the literature, using microwave path attenuation for estimating rain rate is an up-and-coming and viable method. However, several crucial points need to be considered in order to achieve better accuracy for any model describing the relationship between attenuation and rain rate. Various phenomena occur between transmitter and receiver, including reflections from other objects, atmospheric parameters, causing extra signal attenuation not solely due to rain. Special care must be taken into designing the electronic devices in custom wireless link setups keeping the electronic noise as low as possible. Noise plays a significant role in signal fluctuations and consequently, in the system's inaccuracies. Transmitter power must be as constant as possible. In addition, the receiving power strength must be measured with adequate resolution and be sampled frequently enough that is several samples per minute. Additionally, zero or minimal access to signal strength data of cellular network providers is a significant research restriction. It is shown that factors such as the wet antenna effects and jitters caused by wind on antennas may lead to significant errors too. Additionally, it is worth mentioning that very few researchers are working in the lower microwave spectrum band which is the most extensively used band and with great coverage. Despite the theoretical aspects of negligible signal attenuation at this frequency range, it is not proven experimentally that these frequencies are not recommended in practice. Instead, this is an area that deserves further investigation. Finally, a future scope based on this survey and other research on this area of expertise should be the development of a global protocol that should involve the combination of an adequate number of fixed technologies for every emerged critical situation. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline
**Ref** & **Authors** & **Year** & **Location** & **\(\ell\) (K\(\ell\))** & **Fil (Rank)** & **Validation** & **Remarks** & **8** \\ \hline
[7] & [PERSON] et al.