Bak R. Increasing the availability of telecommunication services in mobile networks.

The thesis is devoted to solving the relevant scientific task of development the methods, models and algorithms for increasing the telecommunication services availability by using the load balancing during rush-hour in particular segments of mobile communication network. The current state and trends of cellular network development has been analysed in details. It was determined that process of seamless and continious service provision in mobile network is significantly affected by mobility management and load balancing mechanisms. A new iterative method of load balancing for mobile communication network has been introduced first time. The novelty of the proposed method is that it takes into account resource availability in both neighbour and more distant cells, cells load, user’s velocity and traffic demand and efficiency of spectrum utilization. All these factors in total provide effective load distribution among the cells without interruption of service provision process. The topological model of cellular network has been further developed based on the graph, which takes into account the set of resources occupied by users, connections among the radio network elements, and state of users’ connection within target cells neigborhoud to improve the efficiency of load balancing. For the description of cells structures, that are divided into sectors, for the mapping of the basic and more complete interconnection between the components of the radio network, the graph is proposed without taking into account the overlap of non-related sectors and with taking into account this overlap. The method of channel utilization efficiency estimation has been further developed by generalized criterion of spectral and energy efficiency, by using the distance to the Shannon limit for each user radio link that allows finding the optimal strategy for radio access network planning. The efficiency of mobile network operation in conditions of peak load on the particular cells has been tested by the developed simulation model. This system allows to reduce the number of the iterations of the proposed load balancing algorithm. Also, the base stations allocation for 5G mobile network has been proposed to reduce the number of active macro- and micro-BSs in the network by successively excluding base stations and the assignment of serving BSs to individual users based on calculation of the weighted distance between the selected user and all the BSs in the network.