Research On 3D CoMP Scheme Based On Double-codebook Precoding In 3D MIMO System

Multi-Input Multi-Output(MIMO) technology has played a key role in the Fourth generation communication system,which provides substantial improvement in system throughput and spectrum efficiency,and it has also became the most welcome area in wireless research.Three Dimensional Multi-Input Multi-Output(3D-MIMO)technology deploys Active antenna array(AAS) at base station,thus brings the vertical dimension in the existing channel model.It makes a breakthrough in regular MIMO system which downtilt is fixed, makes an great improvement in coefficient of utilization of space resource,so the system throughput achieves a further gain,especially the spectrum efficiency of cell edge users.In existing LTE system,the interference from other cells is still high.Coordinated Multiple Point(CoMP) technology is able to solve the problem efficiently,by Joint Process(JP) or Coordinated Beamforming(CB).These technologies restrain the interference in a low level,so the user experience is improved heavily.And all these technology has become the key technology in LTE system.In the fourth generation communication system and its follow-up systems,base stations are connected through the X2 interface,which provides a great convenient in the coordination of base stations.With the AAS deployed wider and wider,the application of a new CoMP technology in 3D-MIMO system is becoming more and more important.In this article,we mainly do research on double-codebook precoding technology and 3D MIMO CoMP technology.Firstly,we describe the formation and development of 3D MIMO and CoMP,including the Modeling of 3D MIMO and the existing CoMP technology,which laid the foundation of the following research.Secondly,we describe the precoding strategy of 3D MIMO, points out its pros and cons,meanwhile,this article analyzes the characteristics of CB and JP. For the reason that CoMP-ZF have an strict requirements on the number of antennas,so we chosen the CoMP-SLNR as the CoMP strategy in the article.Furthermore,we analyzed the feasibility of combine 3D MIMO and CoMP.And then,we proposed a doublecodebook precoding strategy which is suitable for 3D MIMO system.This strategy takes the characteristic of 3D channel into consideration,we uses the matching codebook in different direction.Meanwhile,two precoding operation reduces the dimension of 3D channel,which reduces the complexity of our algorithm.Finally,we proposed a 3D CoMP strategy which is based on double-codebook precoding algorithm.Based on the simulation result of different distribution of bits in two directions,we made an conclusion that the coordination in vertical direction lead to low performance-to-price ratio.So we chosen a strategy which takes a precoding operation in vertical direction and a coordination operation in horizontal direction.Simulation result shows that this strategy make a full use of space resource,and reduces the interference.