Research Of Polarization Channel Modeling And The Method Of Polarization And OAM Multiplexing In Wireless Communications

The traditional time domain, frequency domain and spatial domain of wireless resources are facing the shortage situation with the rapid development of wireless communication technology and the increasing of user data services of broadband and diverse needs, these problems have restricted the sustain and develop of wireless mobile communication and business application. The need to explore new ways of communicating is becoming more and more urgent. In recent years, the research and application of the polarization state of electromagnetic waves and orbital angular momentum have attracted much attention.At present, although the research on the polarization state of electromagnetic wave is more mature than that of orbit angular momentum, but there are still a lot of problems to be explored, especially with the development of the polarization signal processing technology, the modeling requirement of the polarization channel in wireless communication becomes more and more urgent. Compared to the field of radar communication and optical fiber communication, the polarization channel of the wireless channel presents complex depolarization effect, which leads to the relative difficulty of the channel modeling, which greatly affects the communication quality. The research on electromagnetic vortex wave is at the beginning stage, although the orbital angular momentum and polarization of the multiplexed beam can greatly improve the spectrum utilization and improve the communication efficiency, but in the multiplexed beam, the relationship between the polarization and the orbital angular momentum is very fuzzy, therefore to clearly know the relationship between the two state has a great influence. This paper deals with the research and proposes the corresponding solution. The main results and conclusions are as follows.(1) This paper analyzes and summarizes related characterization of polarization, polarization information of related technologies and the main method of polarization channel modeling, and points out the necessity of polarization channel modeling. At the same time, this paper discusses the necessity of the relationship between the polarization and the orbital angular momentum in multiplexed beam. This lays the theoretical foundation for the further development of the research work in this paper.(2) Aiming at the problem of channel depolarization effect, the paper proposed a new multi-antenna polarization channel model based on geometrical scattering theory. The method to establish model of the each path depolarization effect based on the known antenna configuration, spatial polarization field radiation patterns and the distribution of scatterers, thus indicates the depolarization effect of polarization channel by the values of cross polarization discrimination. It can expand the use of polarization modulation for F2M and M2M communication system, and improve the rate of information transmission. Experimental results show that the value of XPD has a threshold that influenced by the distance between distance between transmitter and receiver, and it also strongly dependent on the distributed constant values of azimuth angle of arrival when the polarized waves arrive at the receiving end. Furthermore, the value of XPD was changed to a fixed trend when the azimuth angle of arrival in different values. The channel model can reduce the complexity of the traditional channel modeling, and can be used to direct the transmission process of the signal.(3) Aiming at the problem of polarization and orbital angular momentum multiplexing beam, a new representation method of Poincare sphere is proposed. The method obtained the different polarization states corresponding to each point on the sphere of different balls by applying a different mode of orbital angular momentum for different Poincare sphere. In order to facilitate the presentation, the paper select a few special point that on the surface, and then draw the polarization state diagram of these points in different azimuth. Finally, the paper get the conclusion that there is inseparable relationship between polarization states and mode value, azimuth angle of electromagnetic vortex wave. This is of great significance to the further understanding of the multiplexed beam.