# A LoRaWAN Architecture for Communications in Areas without Coverage: Design and Pilot Trials
## 6 Conclusions  
This article proposes an innovative and low-cost network based on LoRaWAN technology, whose functionality consists of establishing the team in areas without coverage. It is specially designed to interconnect members of emergency teams in areas without coverage. This network established a connection between a smartphone and the base station or central node using different communication technologies between devices. The network design proposes alternatives in terms of mobility, information transmission capacity and coverage range. LoRaWAN technology is not intended for real-time applications and is mainly used for monitoring. Therefore, the emergency communications service adapts to the established time constraints in exchange for providing a wide coverage range. The network was tested by a civil protection team with good results in terms of functionality, and an amount of feedback has been obtained for the improvement of the network.  
Our solution was established with specific parameters for LoRa modulation (\(SF=7\), \(CR=4/5\) and \(BW=125\) KHz) in order to offer the maximum data transfer rate (\(R_{b}=5.4688\) Kbps) using the lowest possible bandwidth. This data rate was higher than the minimum required in the design objectives and was sufficient for sending the information. In addition, the possibilities in terms of coverage range were taken into account. In addition, the possibilities  
Figure 14: Empirical CDF of SNR measurements.  
Figure 13: Empirical CDF of RSSI measurements.  
in terms of coverage range were taken into account, such as the possibility of increasing the coverage range by increasing the signal's robustness, albeit with a decrease in the data rate.  
On the other hand, a series of experiments was realized in real areas (urban, rural and natural). These experiments showed that the performance of the TeamUp network was acceptable in all areas for a distance of approximately 500 m. Furthermore, in rural and natural areas, the bidirectional connection distance increased up to 1000 m. It is noteworthy that the best network performance was provided in the natural scenario. This scenario was relevant to the research, given that areas without coverage are often found in similar areas.  
Future work includes the addition of gateways using a mesh architecture. These gateways will be tested to see if they can improve the coverage offered in the different environments. In addition, the impairments and attenuations caused by the different environments will be observed when conducting a new measurement campaign. It is also proposed to add retry mechanisms for automatic message forwarding. Finally, although it is a non-significant improvement, group tracking functionality will be added to detect emergencies before they are reported by the user.  
Conceptualization, F.D.-F., J.N.-O. and J.J.R.-M.; methodology, J.J.R.-M.; software, F.D.-F. and J.N.-O.; validation, F.D.-F., J.N.-O. and N.C.-R.; formal analysis, F.D.-F.; investigation, F.D.-F. and J.N.-O.; resources, F.D.-F., J.N.-O. and N.C.-R.; writing--review and editing, F.D.-F. and J.N.-O. All authors have read and agreed to the published version of the manuscript.  
This research was partially funded by the Andalusian Knowledge Agency (projects A-TIC-241-UGR18 and B-TIC-568-UGR20), the Spanish Ministry of Science and Innovation (project PID2019-108713 RB-C53), the Spanish Ministry of Economic Affairs and Digital Transformation (project TSI-063000-2021-28) and the Spanish Ministry of Universities (FPU Grant Number: 20/02621).  
Not applicable.  
The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.