# Performance Assessment and Comparison of Deployment Options for 5G Millimeter Wave Systems
## 5 Conclusions  
In this work, we introduced system, propagation, and blockage models for different deployments for the 3 gpp standard [8]. We studied three different scenarios of connection between a BS and a UE, including direct connection, connection via a terrestrial re-transmitter, and connection via an aerial re-transmitter. Our numerical results demonstrate that the aerial re-transmitters enable a single BS to serve an area of 1 km\({}^{2}\). In contrast, terrestrial re-transmitters reach this efficiency only with a significantly high number of elements in the antenna array-- 64 elements for \(P_{0}=0.1\), or even higher for a lower outage probability. At the same time, we showed that the most benefits are drawn from the link BS-UAV. We also identified a drawback in using aerial relays--the fact that the link UAV-UE is vulnerable to a low outage probability, and, in order to successfully operate under strict conditions on blockage probability, the number of antenna elements on the relay should be increased as, otherwise, the relay cannot hold a connection to the UE with a given outage probability. The vulnerable part is the link UAV-UE. At the same time, it was shown that terrestrial re-transmitters do not have that drawback, since they are located much closer to the UEs; however, it is much harder to provide the same coverage using them. One possible solution is the use of a hybrid system, where terrestrial re-transmitters would help to improve the vulnerable links in aerial relays; however, further study is necessary to evaluate the benefits and drawbacks of such a system.  
Since, in the current work, we only considered data-link level with full-buffer traffic, in future work, it might be necessary to also compare these scenarios with regards to the number of users and their traffic types in relation to different architectures. Moreover, the  
Figure 6: BS density.  
scenarios might be further improved by adding some different blocker types, such as cars and greenery.  
Conceptualization, K.S.; methodology, E.M.; software, validation and formal analysis, E.M.; writing--original draft preparation, E.M.; writing--review and editing, K.S.; supervision, K.S.; project administration, K.S.; funding acquisition, E.M. All authors have read and agreed to the published version of the manuscript.  
The research was funded by the Russian Science Foundation (project No. 21-79-00157).  
Not applicable.  
The authors declare no conflict of interest.  
The following abbreviations are used in this manuscript:  
\begin{tabular}{l l}
5G & Fifth-Generation \\ NR & New Radio \\ CAPEX & Capital Expenditures \\ OPEX & Operational Expenditures \\ IMT & International Mobile Telecommunications \\ MIMO & Multiple-Input and Multiple-Output \\ IAB & Integrated Access and Backhaul \\ BS & Base Station \\ UAV & Unmanned Aerial Vehicle \\ UE & User Equipment \\ Terr & Terrestrial re-translator \\ SNR & Signal-to-Noise Ratio \\ UMa & Urban Macro Cell \\ UMi & Urban Micro Cell \\ RMa & Rural Macro Cell \\ Tx & Transmitter \\ Rx & Receiver \\ LoS & Line-of-Sight \\ NLoS & Non-Line-of-Sight \\ SCM & Shannon's Capacity Margin \\ MCS & Modulation and Coding Scheme \\ \end{tabular}