# Data Traffic Modeling in RPAS/UAV Networks with Different Architectures
###### Abstract  
Deploying of Fifth Generation and Beyond Fifth Generation (5G/B5G) wireless networks will require wider coverage, flexible connectivity, low latency, support for a large number of user devices, and more bandwidth. This article explores the paradigm that Remotely Piloted Air Systems (RPASs) or Unmanned Aerial Vehicles (UAVs) are integrated as a communication platform with cellular networks using radio access. It is important to know the possibilities and ways of such integration for effective interaction with RPASs. This paper studies the issues of ensuring the required Quality of Service (QoS) during heavy traffic and the choice of necessary data transmission modes for this. Models of RPAS communication channels with different architectures were created. The relationships between models' performance and traffic parameters were obtained using the NetCracker Professional 4.1 software. The dependencies of the Average Utilization (AU) on the Transaction Size (TS) were analyzed. The effects of different bandwidths and the Bit Error Rate (BER) were studied. The traffic characteristics in all models were compared.  
remotely piloted air systems (RPAS); unmanned aerial vehicles (UAVs); 5G/B5G; data traffic; transaction size; average utilization; BER; bandwidth +
Footnote †: journal: 28 March 2021  
In this article, we study a RPAS/UAV-enabled Radio Access Networks (RAN) where the RPAS/UAV is used as an airborne platform supporting communications for terrestrial users, including relaying data from the base station to other RPASs/UAVs and terrestrial users, downlink data transmission to terrestrial users, and collecting uplink data. This multi-mode aerial communication platform is most attractive for a practical RAN with different user requirements for the received data. For the RANs under consideration, four models with different architectures are used, which are of practical interest. In the first model, the base station controls the RPAS within the line of sight and communicates through it with the users of the cellular network. In the second model, the base station communicates with the cellular network via two RPASs to investigate the problem of increasing coverage. The third model is used to study the traffic ramification and operation with a large number of users. The fourth model is the closest to real conditions and contains a complex architecture with the largest number of drones and ground users. The main contributions of this paper are summarized as follows.  
First, we offer original models as communication platforms for RPASs/UAVs with cellular networks in various operating conditions, for which the characteristics of data traffic in communication channels have been calculated for the first time.  
Secondly, due to the complexity of the research problem for the designed models, we propose an effective approach based on simulation modeling. The term \"simulation\" means the calculation of the characteristics of a model, changing over time, by reproducing the flow of this process on a computer using the equations of its mathematical model.  
Third, for various architectures of communication channels, the results were obtained and compared data transmission quality. From this point of view, the work can be considered as the development of theoretical methods for predicting the behavior of RPAS communication channels in critical conditions.  
Fourth, the practical value of the results is that using the obtained dependencies, you can predict the channel's behavior when the transaction size, channel bandwidth and bit error rate change.  
The rest of this article is organized as follows. Section 3 presents a research method and algorithms for calculating traffic parameters. Section 4 describes the proposed models and parameters of communication channels. Numerical results are presented in Section 5. At the end of the article, the results are discussed in Section 6 and conclusions are given in Section 7.