Investigation Of Wireless Communication With 3D MIMO Channel

MIMO(Multiple Input Multiple Output)is a key technology to improve the system throughput and system capacity for wireless communication.MIMO technology has been specified in 3GPP(The 3rd Generation Partnership Project)Rel-8.In order to further improve the performance,multiple stream beamforming and higher order MIMO are introduced in later evolved Rel-9 and Rel-10.Before Rel-12,MIMO technique only considered the azimuth 2 dimension property of wireless channel.The realization of AAS(Active Antenna System)makes it practical to use the three dimension property of channel.With 3D MIMO technology,we can take good advantage of channel characterstics,which will make beamforming more freely.3D MIMO has been decided as one of key techniques in future 5G technologies and draws high attention of 3GPP.Firstly,through the 3D MIMO modeling,the impact of different factors on 3D MIMO channel performance is studied in this paper.Our research includes impact of antenna port number,impact of antenna vertical distance and impact of different polarization.Based on the constructed communication simulator,beamforming and virtual sectorization with different precoding method are investigated with 3D MIMO channel.Simulation results showed that virtual sectorization can improve the system performance more than 10%when compared with vertical beamforming and the improvement for edge UE(User Equipment)is more obvious.The related simulation results has been used for 3GPP Rel-12 discussion.Secondly,by CSI-RS(Channel State Information Reference Signal)configurations in Rel-12,the influence of CSI-RS on legacy UEs' performance is studied via link-level simulator,and the influence of CSI-RS on system performance is investigated with system-level simulator by the link-level results.Based on the study results,different adaptive methods are proposed to reduce the impact of introduced CSI-RS,with the results are simulated.These methods can be referenced for the future study of impact of newly introduced CSI-RS by 3D MIMO on 2D MIMO UEs.