# Experimental Study on LTE Mobile Network Performance Parameters for Controlled Drone Flights
## 6 Conclusions  
As drone realization and logistics are becoming more topical with every year, in this research, an experimental study on LTE mobile network parameters for controlled drone flights was carried out. Recent and topical research trends in this topic were evaluated and therefore KPIs, such as RSRP, RSRQ, SINR, downlink, uplink, and ping, and their values were set to distinguish acceptable levels of measured parameters during experimental measurements in various configurations. The experimental setup of the DJI M30 drone and OnePlus NORD BE2029 was used at altitudes of 40, 60, 90, and 110 m.  
When investigating the RSRQ parameter, it was found that in the range below the set RSRQ threshold of \(-16\) dB (\(-16\) to \(-18\) dB) consistent network speeds and ping were still possible. However, RSRQ was rarely observed in the range of \(-18\) to \(-20\) dB and when it did, inconsistencies in other parameters appeared. Meanwhile, RSRP values still mainly reached above the set threshold of \(-100\) dBm, even when the RSRQ was below the set KPI threshold. However, SINR values were affected negatively when RSRQ was below the set KPI but when in the RSRQ range of \(-16\) to \(-18\) dBm, this drop was only by about 10 percent and these effects would not result in network parameters dropping below KPI. In our analysis of RSRP and SINR, it was rarely observed that these parameters would drop below their respective thresholds of \(-100\) dBm and \(-5\) dBm. When these drops below threshold values were visible, inconsistencies in other parameters would emerge.  
Our set KPIs, which are based on the evaluated previous research, 3 GPP recommendations, RTU and LMT from previous experience, experimental study, and data gathered and shown within this article, can be further used in the business and research industries as they proved to be realistic and optimal; if the measured values are recorded outside the reference KPI zone, connections also become unstable and unreliable as shown in the data. Vast data gathered, analyzed, and shown in this research can also be used for better preparation of drone logistics and monitoring solutions.  
Figure 14: DT model of mobile network coverage and UAV flight.  
**Author Contributions:** Conceptualization, A.L., G.J., G.V., J.B., A.O. and E.P.; methodology, A.L., J.B., G.J. and A.O.; software, I.M.; validation, A.L., J.B., I.M. and U.S.; formal analysis, G.J., A.L., J.B., E.P. and E.L.; investigation, R.R., A.O., G.J., E.P., A.L., J.B., I.M., U.S., G.V. and E.L.; resources, J.B., U.S. and A.L.; data curation, I.M., G.J. and A.O.; writing--original draft preparation, I.M., J.B., A.L., U.S. and E.P.; writing--review and editing, J.B., I.M. and U.S.; visualization, E.L. and I.M.; supervision, E.P.; project administration, G.J., G.V. and E.P.; funding acquisition, G.J., G.V. and E.P. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This research was funded by the ECSEL Joint Undertaking (JU) under project Comp4 Drones grant agreement No. 826610, the European Regional Development Fund project No. 1.1.1.3/18/A/001 (PVS 3912.6.2--Industrial PhD), National Research Program within project No. VPP-EM-FOTONIKA2022/1-0001 and Connecting Europe Facility Digital program (CEF Digital) under project 5G4 LTVES grant agreement No. 101133716.  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** The data used to support the findings of this study are available from the first correspondence author upon request.  
**Conflicts of Interest:** Authors [PERSON] and [PERSON] has received research grants (in the period from 2019 to 2022) from Company Latvijas Mobilais Telefons SIA.