Near-optimal power allocation for MIMO channels with mean or covariance feedback
Near-optimal power allocation for MIMO channels with mean or covariance feedback
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DOI：
10.1109/tcomm.2010.01.070377
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发表时间：
2010
影响因子：
8.3
通讯作者：
Xiao Li;Shi Jin;Xiqi Gao;Kai‐Kit Wong
中科院分区：
文献类型：
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作者：
Xiao Li;Shi Jin;Xiqi Gao;Kai‐Kit Wong
通过平均或协方差频道反馈，可以设计输入协方差矩阵，以实现MIMO褪色通道的千古能力。众所周知，最佳输入协方差矩阵的特征向量与通道平均值或协方差矩阵的特征向量相同。但是，在本征载体之间的最佳功率分配知之甚少。在本文中，研究了两种情况：（1）带有平均通道反馈的里克里亚二莫通道，以及（2）具有协方差频道反馈的瑞利MIMO通道。我们首先根据空间结构域中的一种次优功率分配算法，以最大程度地获得两个发射天线系统的预期相互信息，这是基于发射机上具有通道平均值或协调信息的MIMO通道的上端界限。然后，我们将结果扩展到发射器和接收器端具有多个天线的系统。提出的功率分配解决方案允许封闭形式的表达，并具有填充水解释。仿真结果表明，所提出的方法的性能与最佳解决方案（需要在随机过程上进行高度复杂的优化程序）几乎相同，并且具有不合适的差异。
With mean or covariance channel feedback, the input covariance matrix can be designed to achieve the ergodic capacity of a MIMO fading channel. It is known that the eigenvectors of the optimal input covariance matrix are the same as the eigen-vectors of the channel mean or covariance matrix. However, the optimal power allocation across the eigen-vectors is much less understood. In this paper, two scenarios are investigated: (1) Rician MIMO channels with mean channel feedback, and (2) Rayleigh MIMO channels with covariance channel feedback. We first derive a suboptimal power allocation algorithms in the spatial domain for expected mutual information maximization for two transmit antennas systems, based on an upper bound for the ergodic capacity of a MIMO channel with either channel mean or covariance information at the transmitter. Then, we extend heuristically the results to systems with multiple antennas at both the transmitter and receiver side. The proposed power allocation solution permits a closed-form expression and has a water-filling interpretation. Simulation results reveal that the proposed method performs nearly the same as the optimal solution (which requires highly complex optimization routines over random processes) with inappreciable difference.