## 7 Conclusions and Future Work  
In this article, we proposed an energy-efficient and reliable solution for data collection from WuR-enabled SNs deployed in remote areas using UAVs. Our proposed protocol, EEUCH, incorporates essential features such as WuR-enabled SNs, clear channel assignment, CSMA-CA, and TDMA slots, to ensure energy-efficient and reliable data collection. Additionally, EEUCH mitigates the issue of cluster overlapping. The use of WuR-enabled SNs facilitates energy-efficiency, while the incorporation of CSMA-CA and TDMA improves the reliability and efficiency of data transmission between SNs and UAVs. Overall, EEUCH is a promising solution for energy-efficient and reliable data collection in WSN-based IoT applications.  
In our proposed model, randomly deployed SNs are equipped with MR and WuRx. The EEUCH routing protocol operates in rounds, where each round commences upon the arrival of UAVs at the FoI. The arrived UAVs trigger the MRs of SNs by broadcasting WuCs, make clusters of SNs, and reliably collect data from the cluster-member SNs using a novel data collection model, and the collected data are then forwarded to the BS. Thus, a single round of EEUCH is completed. Each cluster operates independently in every round of EEUCH once the SNs have received the WuCs.  
In this study, we conducted a performance evaluation of our proposed EEUCH routing protocol and compared it with well-known benchmark routing protocols, such as LEACH, LEACH-C, SEP, TEEN, IEE-LEACH, and EEECA-THWSN, which are designed for homogeneous, two-tier, and three-tier heterogeneous WSNs. Our comparison results demonstrate that the EEECA-THWSN protocol performs better among the benchmark protocols. Therefore, we focus our comparison on EEUCH and EEECA-THWSN in this conclusion. The results show that the initial network energy consumption of EEECA-THWSN is 1.7 times higher than that of the proposed EEUCH protocol. By implementing EEUCH, SNs in the FoI can remain active for 4.72 times more rounds, collect 5.06 times more data packets, each containing 4000 bits, and achieve 7.956 times greater stability compared to the EEECA-THWSN routing protocol.  
Considering the noteworthy enhancements in all the considered nine network parameters that were evaluated, the proposed model still faces certain challenges such as the efficient deployment of UAVs, determining the optimal number of UAVs to be used, determining the maximum number of SNs that can be covered by a single UAV, and addressing the energy constraints on UAVs during a single round. Moving forward, our future research will encompass a comprehensive analysis of the EEUCH protocol and six benchmark protocols, with a specific emphasis on evaluating control overhead and information coverage ratio. These areas will be the primary focus of our forthcoming research endeavors.  
Methodology, S.L.S., Z.H.A. and F.M.; conceptualization, S.L.S. and Z.H.A.; data curation, S.L.S., Z.H.A. and G.A.; formal analysis, Z.H.A., A.H. and T.B.; supervision, Z.H.A. and G.A.; investigation, Z.H.A., G.A. and F.M.; software, S.L.S., Z.H.A. and G.A.; resources, A.H. and T.B.; writing--review and editing, S.L.S., Z.H.A., G.A., A.H. and T.B. All authors have read and agreed to the published version of the manuscript.  
This research received no external funding.  
Not applicable.  
Not applicable, as all the results are based on simulation data.  
The authors declare no conflicts of interest.