有限状态下MIMO信道容量的研究及仿真分析

On Capacity of MIMO Fading Channel with Finite-size Constellation

研究了有限状态下MIMO衰落信道容量,建立了输入为离散调制信号的MIMO系统模型,证明了均匀分布为取得此时信道容量的最佳输入概率分布,并提出了一种基于Monte-Carlo积分的估计方法,通过该估计方法比较了输入为PSK和QAM信号时的受限信道容量。仿真结果表明,该估计方法近似程度好,复杂度低。相同阶数时输入分别为PSK和QAM信号的信道容量近似相等,均匀分布的受限信道容量可认为是QAM输入下MIMO信道容量的下界。

The capacity of the Multiple Input Multiple Output （MIMO） system with constellations was studied. It is proved that the uniform distribution is the best input probability distribution to compute the channel capacity. Based on Monte-Carlo integral, an estimation method of the discrete capacity was proposed. The proposed method was used to compare the PSK and QAM input capacities. Numerical results show that PSK input and QAM input capacities with the same modulation orders are approximately equal, and that the constrained channel capacity with uniform distribution can be considered as the lower bound of MIMO channel capacity with QAM input.