MIMO信道在不同条件下的容量分析

对影响多输入多输出(MIMO)信道容量的因素进行分析研究有助于未来无线传感器网络的组建与优化。假设信道系数不变,给出了发射端不同功率分配方案对信道容量的影响并进行了对比,通过实验仿真可知,注水算法对信道容量是最优的,此结论与理论分析相吻合,但其运算复杂度较高。推导了等功率分配方案在低信噪比时信道容量的近似表达式,并通过实验仿真与理论值进行了比较,其运算量大大降低,且在低信噪比时逼近理论值。假设MIMO信道矩阵随机分布,对影响信道容量的天线相关性进行了分析与仿真;比较了在不同天线配置下,遍历容量和中断容量的变化趋势,结论有助于组网时根据相关要求选择适宜的天线数目。

Capacity analysis of MIMO channels under different conditions

The analysis and study on MIMO channels capacity is benifit to wireless sensor networks construction and optimization in the future.Under the condition of invariable coefficient of channels,different power allocation schemes’ influence on channel capacity is given and compared with them at the transmitter.Among them waterfilling algorithm is optimal from simulation experiments.The result is consistent with the theory,but it is too complex.Approximate expression of channel capacity in low SNR is deduced and compared with theoretical value by simulation when equal transmit energy scheme is adopted.It is known that its complexity significantly decreases and its value is closed to theoretical one.Antenna correlation affecting on MIMO random channel capacity is analyzed and simulated.The tendency of change on ergodic capacity and outage capacity is compared in various antenna configurations.The result is helpful to adopt acceptable number of antennas when network is constructed.