Intelligent Algorithms for Dynamic Spectrum Access a Secondary User in Cognitive Radio Systems

Recently, there have been problems in the development of new technologies and communication services in the field of telecommunications. The main problem is the deficit of a radio frequency spectrum. Research by measuring companies has shown that licensed users do not use the radio frequency resource efficiently enough. Therefore, the development of cognitive radio systems is currently one of the most intensively studied areas. Cognitive radio systems use dynamic spectrum access technology to solve the problem from a radio deficit spectrum. In previous works, the authors analyzed methods for implementing dynamic access technology for cognitive radio systems. The analysis allowed the authors to propose an algorithm for dynamic spectrum access based on spectrum occupancy models. Also in subsequent works, the first stage of the proposed algorithm was described in detail and the issues of practical implementation of the algorithm were considered. This work is a continuation of the cycle of works of the authors and is aimed at developing an effective algorithm for providing a frequency resource at the request of a secondary user. In the work, two algorithms have been developed and described for providing a free part of the spectrum to a secondary user. The difference between the developed algorithms lies in the approaches to representing and interacting with the original matrix of the spectrum occupancy state. To compare the performance of the algorithms, two types of experiments were carried out. The results of the experiments made it possible to choose the more effective of the two proposed algorithms for providing a frequency resource to a secondary user. The results of the experiments showed that the user needs to send a request to search for a free part of the spectrum at least 6.54ms before the start of the session. Thus, this work contributes to the task of developing a technology for dynamic spectrum access in cognitive radio systems, to solve the problem deficit of the radio frequency spectrum. The developed algorithm will be introduced into the software modules for the intelligent tuning of operating frequencies in cognitive radio systems already developed by the authors. Also, after the implementation of the developed algorithm, a full-scale experiment with SDR devices will be continued.