On Space-time-polarization Coding And Transmission Performance Under Composite Rician Channel

With the rapid progress in internet of things,mobile internet,artificial intelligence,big data,Cloud and Fog Computing,various information interaction across industries,regions and fields prompt the exponential growth of digital information and wireless terminal devices.The amazing increase would keep going because of the rapid development of some technologies including Virtual Reality,Augmented Reality,High-definition video,3-dimensional video,and that can have a huge effect on human life.Besides,it would pose many new challenges to wireless communication.Multiple-input multiple-output(MIMO),as a significant technology on increasing transmission rate and/or improving reliability,has received extensive attention.And massive MIMO has been recognized as one of key technologies in fifth generation mobile communications.Compared with space-time coding scheme in conventional MIMO,space-time-polarization coding scheme based on dual-polarized MIMO,theoretically can improve the system capacity and spectrum efficiency in a more effective way for utilizing three dimensions including time,space and polarization.In order to meet the need to improve the capacity and spectrum efficiency,this thesis develops a space-time-polarization coding scheme based on dual-polarized MIMO.In such a system,a composite Rician channel model is presented,which incorporates both depolarization effect of wireless channel and Rician fading characteristics.Under this composite Rician channel,the coding scheme on how to effectively utilize the three dimensions including space,time and polarization is investigated.Aiming to suppress the cross-polarization interference introduced in transmission,a precoding design based on oblique projection is proposed.Based on the coding scheme considered above,two scenarios including perfect channel state information(CSI)and imperfect CSI which can be available at the transmitter are investigated.Based on theoretical derivation and simulation results of symbol error rate from Matlab,the performance of dual-polarized MIMO using the space-time-polarization coding scheme is investigated under different factors including Rician factor,antenna number,cross-polarization interference when considering the perfect CSI at the transmitter.Compared with uni-polarized MIMO,the proposed scheme can obtain twice the multiplexing gain of uni-polarized MIMO while maintain the same diversity order.When imperfect CSI is considered at the transmitter,a space-polarization model is proposed to evaluate the estimation errors.Also,theoretical derivation and simulation results of symbol error rate from Matlab are both conducted under different estimation errors and Rician factors.The simulation results show that dual-polarized MIMO can perform better than uni-polarized MIMO for the high signal-to-noise ratio when there is a huge error in estimation of CSI.Besides,the increase of the number of antennas can also help improve the capability of error tolerance.