Research On Transmission Performance Of Large Scale Antenna Heterogeneous Networks

The transmission rates of the fifth generation(5G)mobile communication system can increase thousands of times,and the transmission delay is less than 5 milliseconds.Heterogeneous network technology and large scale antenna technology are the key technologies for increasing the transmission rate and reducing the transmission delay.Large scale antennas can utilize channel state information(CSI)and use beamforming to eliminate inter-cell interferences in heterogeneous networks.Meanwhile,the deployment of heterogeneous networks can also increase the coverage of the network and increases the transmission rates of users at the ed ge of cells.However,with increasing of the density of small cell base stations,the analysis model based on planar distribution of small cell base stations has been unable to accurately analyze the performance of large scale antenna heterogeneous network.In order to solve this problem,this paper uses the theory of 3D stochastic geometry to model the base stations and user distribution in large scale antenna heterogeneous networks.we deduce the coverage probability,system capacity and interrupt probability,the specific contents are as follows:First of all,in large scale antenna planar heterogeneous network,considering the existence of quantization error in the limited feedback mechanism used by the frequency division duplex(FDD)system to obtain CSI,the system capacity and interrupt probability index of downlink transmission link in multi-point cooperative transmission mode are studied.Through the analysis of the statistical characteristics of the quantization error and the distribution of small cell base stations in heterogeneous networks,the large-scale antenna employs the zero-forcing beamforming method to obtain the closed-form expression of system capacity,interrupt probability and the throughput.The simulation results verify the correctness of the closed expressions and obtain the relationship between the number of large scale antennas deployed,the feedback overhead,and the deployment density of small cell base stations,with the system capacity,interrupt probability and the throughput.Secondly,in the large scale three-dimensional heterogeneous networks,considering the distribution of users and base stations in three-dimensional space,using the statistical characteristics of random distribution of space and the statistical characteristics of large scale antenna channels,the coverage probability of large-scale three-dimensional heterogeneous networks was analyzed,and the closed expression of the coverage probability is obtained,and the factors that affect the coverage probability of the large scale antenna heterogeneous network is obtained by the performance analysis.The simulation results verify the correctness of the conclusion,which provides theoretical references for the deployment of ultra-density heterogeneous networks.