Abstract: Intended for the combination of BeamForming (BF) and Multiple Input Multiple Output (MIMO), a generalized wireless transmission scheme named BF-MIMO was presented with a view to bring both advantages into full play and enhance the channel capacity and system performance. According to a series of transformations of the signals in the transmitter and receiver antenna pairs, a combined flat fading channel matrix was analyzed and formulated. Besides, based on the steering vector of transmitter sub-arrays, the closed-form expression of the channel capacity was also given. Finally, the capacity enhancement of the proposed scheme over traditional MIMO systems was demonstrated and verified by simulation results.

Key words: BeamFoming (BF), Multiple Input Multiple Output (MIMO), Space Multiplexing (SM), Space Diversity (SD), flat fading, Channel State Information (CSI)

摘要： 针对波束赋形（BF）和多输入多输出(MIMO)这两种多天线技术的结合问题，提出一种通用的波束赋形—多输入多输出(BF-MIMO)下行链路系统方案，以期有效发挥二者优势，进一步提升信道容量和系统性能。分析了该系统的信号变换形式和处理过程，给出了平坦衰落环境下该系统的组合信道矩阵形式，得到了赋形加权后的系统信道容量闭合表达式。理论分析和仿真结果表明，在相同衰落条件下，BF-MIMO系统能够比常规MIMO系统获得更高的信道容量。

关键词: 波束赋形, 多入多出, 空间复用, 空间分集, 平坦衰落, 信道状态信息