# Data Traffic Modeling in RPAS/UAV Networks with Different Architectures
## 6 Discussion  
The RPAS in practical use often requires communication that goes beyond visual line of sight. Mobile networks offer the opportunity to use the RPAS outside of visual LoS with wide area, high speed, and secure wireless connections. This work is devoted to the development of theoretical methods for predicting the behavior of RPAS communication channels when integrating with cellular networks. In our previous works ([30; 31; 32; 33; 34] and references therein), we studied the transmission of messages using RPASs/UAVs in direct and indirect visibility, through terrestrial networks without and with the use of satellites. The research was based on the simulation of communication channels using Matlab and NetCracker software. IEEE 802.11a, 802.11b, and 802.16 [30; 31] and LTE Standards [32; 33] have been used in the various models. The main purpose of these studies was to obtain quantitative characteristics of RPAS communication channels and to develop methods for calculating the parameters of communication channels. The articles considered in the introduction demonstrate the achievements in the field of RPASs/UAVs communications. However, we could not find quantitative information on the influence of traffic parameters on the exchange of data between the base station and users of cellular networks through the RPAS/UAV. How does the transactions size affect channel loading? How does the bandwidth affect the channel utilization for the given traffic parameters? What and how affects the quality of service, namely the increase in the number of bit errors? There are no answers to such questions in the literature, so this article considers three main aspects: The different architecture of channel models, an  
Figure 5: Dependencies of AU on AU1 link BER (Tactical Data—FTP, TS = 1 Kbits, TBT = 1 s, Const law; Common Data—inter LAN, TS = 10 Kbits, TBT = 1 s, Const law; and BER = 0%). algorithm for calculating the parameters of communication channels, and the application of the results to assess the quality of data transmission. From data of Figure 3 (dependencies on the transaction size) it follows that in a wide range of the TS parameter (from 10 bits to 10 Kbits), the AU values practically do not change for all models. At the same time, the complexity of the network architecture leads to an increase in the network load by more than three times. Figure 4 (dependencies on the bandwidth) shows that for reliable data transmission you should use a bandwidth not lower than T3 (44.736 Mbps) for all models. In this case the network load will not exceed \(\approx\) 10%. In complex networks, efficient data transmission is practically impossible at bandwidths below 10 Mbps due to a significant increase in network utilization. At BER = 0% (Figure 5), the AU values for Models 1 and 2 coincide (\(\approx\)2.7%), for Model 3 is of the order of \(\approx\)5.4%, and for Model 4 it reaches \(\approx\)7.2%. As the BER increases, the differences between the models increase, and the situation is most unfavorable for Model 4. Figure 5 is relevant for understanding the conditions for achieving the required level of QoS in the network. In addition to the above models, we considered Model 1 (Figure 2), containing N users of the cellular network. It was important to analyze this in order to understand what to expect from a significant increase in users' number and how this increases the load in the RPAS communication channel. Model 1 was considered for the cases of N = 1, 3, 5, 7, and 10 users, for which values similar to those shown in the Figures 3-5 have been calculated. At the same time, all links bandwidth, in contrast to the data of Table 1, were taken to be equal to 10 Mbps (which is almost 5 times less), and the FTP traffic in the Control and Command channel was 10 Kbits (which is 10 times more than discussed above). This choice of parameters was interesting for analyzing the behavior of \"insufficiently fast\" networks with significant traffic volumes. For brevity, these data are not presented in full here.