Research On Soft-Cell Virtualization Technology For Heterogeneous Networks With Massive MIMO

The data traffic of wireless mobile communication will be expected to grow three times in the next three years,and the demand for user services will tend to be dense.The problems faced by the existing system are:frequency and time resources tend to be saturated,intra-cell and inter-cell interference is serious,and the network cost is high.In order to realize the vision of fifth generation mobile communication(5G)to improve spectrum efficiency and energy efficiency and reduce the cost,5G standardization organization put forward a number of key technologies,among which,the solutions to network capacity and spectrum efficiency are mainly cell virtualization and massive MIMO technology.This paper mainly focuses on the research of soft-cell technology for macro cell and macro-small cell heterogeneous networks(HeNet)with massive MIMO.Firstly,this paper introduced the basic concepts of cell virtualization,soft-cell and so on,and designed the soft-cell antenna with massive MIMO and analyzed its performance according to the basic characteristic parameter formula of the soft-cell antenna.Then,focusing on the problem of the dense and non-uniform distribution of traffic in macro cell massive MIMO scenario,this paper designed a macro soft-cell virtualization scheme based on massive MIMO,to improve network throughput for meeting users' demands,and reduce the deployment number of small cell for flexibly coping with changes in traffic distribution.The proposed scheme exploited directional beams in dense traffic areas to form soft-cell,and provided extra capacity for hotspots,and reduced the costs of network deployment and maintenance while improving system performance.Secondly,this paper also studies on the macro-small cell HetNet soft-cell technology.In the macro-small cell network with same frequency,there are same-layer and cross-layer hotspot's interference,and the existing solutions have not yet accurately assessed and avoided interference.In this paper,combining soft-cell with massive MIMO,a 3-dimensional interference model,a small cell subsystem model,and a macro base station subsystem model are proposed.A scheme on soft-cell technology for macro-small cell with massive MIMO was designed,which includes the beamforming scheme on macro-small cell with massive MIMO and the macro-small cell cooperative scheduling scheme with utility function.In the case of avoiding more small cell deployments,the proposed scheme can provide users with flexible coverage,reduce same-layer and cross-layer interference,and improve network utility.Finally,the future research work was prospected.It is expected to carry out further research in the following aspects:in view of user characteristics,researching on hotspots formation;in order to improve performance,the problem of utility function merit optimization can be studied;adaptive priority setting was studied to adapt to the change of traffic request and the appearance of new traffic.