基于多点协作联合传输的超密集组网性能分析

超密集组网的基站高密度特性会带来严重的小区间干扰，多点协作联合传输应用于超密集组网进行干扰管理是目前的研究热点，该文对多点协作联合传输时基站密度对网络性能的影响进行了分析。首先采用随机几何方法推导了3维空间基站与用户距离的概率密度函数，为选取距离用户最近的多个基站联合传输的协作机制提供了基础；然后结合有界双斜率路径损耗模型，进行用户下行链路的干扰建模，进一步推导出用户下行链路覆盖率和网络区域频谱效率的表达式，并分析了协作基站数、基站密度等参数对网络性能的影响。数值仿真表明:协作基站数为2时就可使下行链路覆盖率增加10%，且实现2到3倍的频谱效率的增益，当协作基站数为3时，费效比更优，同时可得到多点协作下的基站密度极限使区域频谱效率最高。该文工作可为下一代移动通信网络的基站部署提供理论支持。

Performance Analysis of Ultra-dense Networks Based on Coordinated Multiple-points Joint Transmission

The high-density characteristic of base stations in Ultra-Dense Networks (UDN) brings serious inter-cell interference. It is the current research hotspot that Coordinated Multiple-Points Joint Transmission (CoMP-JT) is applied to UDN for interference management. The impact of base station density on network performance with CoMP-JT is analyzed. Firstly, the probability density function of the distance between the base station and the user in 3D space is derived using the stochastic geometric method. It provides the cooperation mechanism’s basis for CoMP-JT that selecting the multiple base stations closest to the user to joint transmission. Then, the downlink interference model is carried out based on the bounded dual-slope path loss model, and the downlink coverage probability and network area spectrum efficiency are further derived. Thereafter, the impact of the parameters such as the number of cooperating base stations and the base station density on the performance of the system is investigated. Numerical simulations show that when the number of cooperative base stations is 2, the downlink coverage probability increases by 10%, and the network area spectral efficiency achieves a gain of 2 to 3 times. When the number of cooperating base stations is 3, the cost-effectiveness ratio is better, and the density of base stations that maximizes the network area spectral efficiency under CoMP-JT can be obtained. This paper provides theoretical support for the deployment of base stations in next-generation mobile communication networks.