波束成形下DMIMO系统下行小区平均遍历容量分析

摘要

主要对波束成形下分布式MIMO系统下行小区平均遍历容量展开分析。首先建立了包含快衰落、阴影衰落和路径损耗的复合衰落信道模型。然后，在分布式基站功率受限条件下，推导各基站权重向量即最优波束；并基于ST⁃MRT传输策略，推导特定移动台位置条件下，小区下行点对点遍历容量表达式。最后，考虑移动台在小区内任意分布的特征，进一步推导出波束成形下小区平均遍历容量理论近似表达式。结果表明所推导的理论近似表达式可很好地反应系统的实际性能。%This paper analyzes average ergodic capacity of distributed MIMO system downward district in beamforming. The composite fading channel model is established,including fast fading,shadow fading and path loss.Under the condition that the power of distributed base station is limited,the weight vector of each base station,namely the optimal beam,is derived.Based on ST⁃MRT transfer strategy, the expression of downward district point⁃to⁃point traversal capacity is derived under the condition of specific mobile station. Finally, considering the characteristics of arbitrary distribution of mobile station in the district,the approximate expression of average ergodic capacity of a district in beamforming is further derived.The simulation results show that the derived theory approximate expression can indicate the actual performance of the system.