# A Multi-Gateway Behaviour Study for Traffic-Oriented LoRaWAN Deployment
## 5 Conclusions  
In this paper, we conduct a behaviour study of multi-gateway usage in LoRaWAN under high-traffic conditions. For this, we simulate several scenarios to show how the  
Figure 8: Number of lost packets at the gateway since it was in the transmitting phase while varying the number of gateways (**a,b**) and the payload length (**c,d**) with a frequency of 1 packet/min—confirmed traffic.  
payload length impacts the PDR of the whole network and how it interacts when varying the sending packet frequency, the packet payload, the number of gateways, and the number of nodes, with and without confirmed traffic. As the main results, we can say that for a low number of deployed GWs, it is more appropriate to use a high payload length to achieve a high A-PDR. On the contrary, it is more appropriate to use a low payload length when the number of GWs increases. In addition, using several gateways can improve the network QoS; however, the right number of gateways to use must be based not only on the number of EDs deployed but also on the data flow to be generated. This flow can be determined by the sending data periodicity or by the packet's payload length. In addition, we have seen through our work that adopting a multi-gateway strategy increases the number of nodes using lower spreading factors (_SF_7). This behaviour makes the multi-gateway network fail in the case of high traffic, mainly when the packet payload increases. Therefore, a multi-gateway network is not a guarantee of optimization in all circumstances. Thus, we can have better results in terms of traffic by focusing on the proper settings. For future work, we plan to make a more extensive study by considering other metrics such as energy and latency.  
Conceptualization, K.S.A. and I.B.; methodology, K.S.A., I.B., A.A. and P.L.; validation, K.S.A., I.B., A.A. and P.L.; formal analysis, K.S.A., I.B., A.A. and P.L.; investigation, K.S.A. and I.B.; data curation, K.S.A. and I.B.; writing--original draft preparation, K.S.A. and I.B.; writing--review and editing, K.S.A., I.B., A.A. and P.L.; supervision, A.A. and P.L. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
The authors declare no conflict of interest.  
The following abbreviations are used in this manuscript:  
\begin{tabular}{l l} ACK & Acknowledgement \\ ADR & Adaptive Data Rate \\ AFA & Adaptive Frequency Agility \\ A-PDR & the Aggregated Packet Delivery Ratio \\ BW & bandwidth \\ CAPEX & Capital expenditure \\ CF & Central Frequency \\ CR & Coding Rate \\ CSS & Chirp Spread Spectrum \\ CSMA & Carrier Sense Multiple Access \\ DC & Duty Cycle \\ GW & Gateway \\ IoT & Internet of Things \\ ISM & Industrial, Scientific and Medical \\ LBT & Listen Before Talk \\ LPWAN & Low Power Wide Area Network \\ LoRAWAN & Long Range Wide Area Network \\ LPI & Lost Packets at the gateway due to Interference \\ LPTX & Lost Packet at the gateway since it is in the transmitting phase (TX) \\ MAC & Media Access Control \\ OPEX & operational expenditure \\ Pkt-Sent & Packets sent by all ED in the network \\ QoS & Quality of Service \\ SF & Spreading Factor \\ TP & Transmission Power \\ \end{tabular}