Self-Interference Cancellation For Full-Duplex In Spatial-Polarized Domain

With the vigorous expansion of wireless communication,the research of the fifth generation mobile communication network(5G)is in full swing.But the shortage of spectrum resources limits the development.Therefore,the improvement of spectrum efficiency has become one of the hot-spots in 5G Full-duplex allows a node to simultaneously transmit and receive signals at the same frequency.Compared with the traditional half-duplex communication,the spectrum efficiency of the full-duplex communication can be multiplied theoretically,and the key to realize the full-duplex is to cancel the self-interference signal.Supported by Chinese National Nature Science Foundation Project"Research on Full-duplex Polarization Self-interference Elimination Based on Phase Noise Additive Gaussization(61501050)",this thesis studies the full-duplex self-interference cancellation technology in the spatial domain and the polarization domain.By combining the advantages in the spatial and polarized domains,two kinds of self-interference cancellation algorithms for full-duplex in the spatial-polarized domain are proposed.Being robust to the phase noise,the self-interference cancellation is realized and the data rate is improved.The main research and achievements are as follows:(1)This thesis summarizes the current research of full-duplex,and focused on the classification and research of full-duplex self-interference cancellation technologies.Then it introduced the relevant theories and techniques in the polarization signal processing technology as a theoretical foundation for the research.By comparing the characteristics of various self-interference cancellation technologies,the thesis pointed out that the self-interference cancellation technologies in the spatial and polarization domains have complementary advantages.(2)In the single transmit/receive antenna full-duplex system,this thesis proposes a full-duplex self-interference cancellation algorithm based on the combination of spatial isolation and polarization.Firstly,part of the self-interference is eliminated by the spatial isolation in the propagation domain.Secondly,the polarization processing is used to further cancel the self-interference at the baseband of the receiver,which is not affected by the phase noise.Finally the desired signal is recovered from polarization matching.The algorithm considers the effects of characteristics in spatial and polarized domain.The theoretical analysis and simulation of the proposed algorithm are carried out,which show that the proposed self-interference cancellation algorithm has better performance than in the traditional spatial domain or polarized domain.(3)In the MIMO full-duplex system,this thesis proposes a self-interference cancellation algorithm for full-duplex based on spatial MIMO and polarization,which makes full use of the advantages of data rate in spatial domain.Firstly,the information of polarization state is used to construct the orthogonal standard matrix to eliminate the influence of phase noise.Secondly,a precoding matrix is designed to cancel the self-interference by using channel information and polarization information.Finally the desired signal is recovered by polarization matching.Theoretical analysis and simulations show that the proposed algorithm can achieve self-interference cancellation without the effect of the phase noise compared with that in spatial domain.Compared with the self-interference cancellation in polarized domain,the data rate of the proposed algorithm is improved.This thesis utilizes the complementary advantages in the spatial and polarized domains to improve the performance of self-interference cancellation,which provides a possible way to cancel the self-interference in full-duplex communication system.