Efficient pilot contamination mitigation approach with a hybrid method in 5G and beyond systems

As a result of wireless communication advancements, efforts have been made to improve the technology by completing the developing technology and the shortcomings it has brought, and by means of developing new techniques, many studies have been carried out in order to achieve high data transmission speed, uninterrupted communication and best performance. The negative effects of interferences (as an air medium) in wireless communication is due to some reasons. One of those challenges is pilot contamination. Pilot contamination occurs between two terminals using the same pilot sequence known as the reference signal. In addition, reuse of pilot sequences of several co-channel cells also causes pilot contamination. Therefore, the performance of the system is reduced and sometimes even in effective communication. Techniques for reducing this effect, include having a large number of pilot sequences and random switching between them. Another method that may be improved is the use of Blind or Semi-Blind techniques. The realization of the pre-coding design and the development of appropriate algorithms can also be effective in trying to eliminate pilot contamination. It is also possible to prevent interference caused by coordinated permission for the use of pilots. In addition, methods for optimizing the permitted pilot sequences will help to reduce this impact. In general, in this thesis, the research is being carried out on techniques to eliminate the effect of pilot contamination, which limits the performance of the systems. In this study, a new pilot assignment method is used for the users who cause high interference in the cell by the hybrid method proposed. Reference cell users are divided into the edge and the center users. Thus, the problem of pilot contamination is reduced. In order to determine whether these requirements can be implemented in real time or not, simulations will be conducted through the simulation program, according to which performance evaluation will be made.