## 4 Experimental Results  
In order to improve the efficiency of a heterogeneous network system, the paper proposes the implementation of a comprehensive method of optimization, including the following:  
* Dynamic reservation of the number of sessions, which allows to evenly distribute the load from users (proposed method 1);
* Rejection of non-priority sessions to provide guaranteed quality of service to priority users (proposed method 2). First, let us consider the operation of a homogeneous network when mobile technologies work independently (traditional method 1) as described in paper [19]. The block diagram of the operation of each technology, separately, is depicted in Figure 12.  
Based on the analysis of homogeneous networks, histograms of the distribution of the number of active and lost requests for each available service show the state of each individual network. The total number of active and lost requests in homogeneous networks is depicted in Figure 13.  
Figure 12 shows that the base station with 2G and 3G technology are overloaded, while all other base stations of other mobile technologies are idle. Thus, the use of homogeneous networks is not optimal, because in the case of overloading of some technologies, requests from users are dropped, which leads to a degradation of the quality of service as well as a decrease in the network performance. Therefore, in this thesis it is proposed to use a heterogeneous network (traditional method 2), proposed by the authors in [17], to improve the quality of service as well as to reduce the number of dissatisfied customers. With the increasing number of users and complexity of services, one communication network cannot meet all QoS requirements. Heterogeneous networks are, therefore, an effective solution. Vertical handover (VHO) is an important step in the convergence process of heterogeneous networks. An appropriate handover algorithm can improve the quality of service (QoS) of users. To solve the problem of network congestion caused by a large number of users connecting to partial networks in heterogeneous networks, a load-balanced vertical handover algorithm (Figure 9) is proposed. Among the networks that can meet the user requirements, the most load-balanced network is obtained, using the optimal algorithm. In addition, to take into account user requirements and ensure QoS of the network service, we use a process of analytical hierarchy using big data technology to weight different networks. This method allows the full use of different network resources, so that the load distribution between networks is average. We proposed an approach for the study of the processes of functioning of the heterogeneous network environment, which, unlike the known ones, uses the technique of processing large amounts of data to perform monitoring of information transfer, analysis of tasks that are formed by network users and output of statistical data on the initiation of handover in the infrastructure of mobile communications. This approach allowed us to  
Figure 12: Block diagram of the operation of each technology separately (traditional method 1). Figure 13: The total number of active and lost requests in homogeneous networks (traditional method 1). investigate the process of optimizing the operator's network by implementing an algorithm to redistribute its network resources and provide flexible load balancing. The principle of operation of a heterogeneous network with static reservation of resources is presented in Figure 14.  
Figure 14 shows the operation of a heterogeneous network; in this case, the total load coming from users is distributed between the base stations according to the type of service and reserved resource on the BS of each technology. Let us consider the operation of a heterogeneous network in the case of an incoming load, given in the previous example for the set of homogeneous networks.