Energy Efficiency Optimization for MIMO Broadcast Channels
Energy Efficiency Optimization for MIMO Broadcast Channels
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DOI：
10.1109/twc.2012.122212.120086
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发表时间：
2012-02
影响因子：
10.4
通讯作者：
Jie Xu;Ling Qiu
中科院分区：
文献类型：
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作者：
Jie Xu;Ling Qiu
研究MIMO广播信道的基本能量效率极限对绿色无线通信的发展具有重要意义。在本文中，我们解决了MIMO-BC的EE优化问题，并考虑了一个实际的功率模型，即，考虑与活动发射天线的数量相关的发射独立功率。在此基础上，提出了一种新的优化方法，在固定的发射天线组下优化发射协方差，然后利用主动发射天线选择（ATAS）。在发送协方差优化过程中，通过求解一系列基于块坐标上升算法的凹凸分式规划，提出了一种全局最优的能量有效的迭代注水方案。在此之后，ATAS被用来确定活动的发射天线集。由于激活更多的发射天线可以实现更高的和速率，但是以更大的发射独立功耗为代价，因此在和速率增益与功耗之间存在折衷。在这里，ATAS可以探索最佳的折衷曲线，从而进一步提高EE。最佳穷举搜索和低复杂度的范数为基础的ATAS计划的发展。通过仿真，我们讨论了不同参数对MIMO-BC的EE的影响。
Characterizing the fundamental energy efficiency (EE) limits of MIMO broadcast channels (BC) is significant for the development of green wireless communications. We address the EE optimization problem for MIMO-BC in this paper and consider a practical power model, i.e., taking into account a transmit independent power which is related to the number of active transmit antennas. Under this setup, we propose a new optimization approach, in which the transmit covariance is optimized under fixed active transmit antenna sets, and then active transmit antenna selection (ATAS) is utilized. During the transmit covariance optimization, we propose a globally optimal energy efficient iterative water-filling scheme through solving a series of concave-convex fractional programs based on the block-coordinate ascent algorithm. After that, ATAS is employed to determine the active transmit antenna set. Since activating more transmit antennas can achieve higher sum-rate but at the cost of larger transmit independent power consumption, there exists a tradeoff between the sum-rate gain and the power consumption. Here ATAS can explore the optimal tradeoff curve and thus further improve the EE. Optimal exhaustive search and low-complexity norm based ATAS schemes are developed. Through simulations, we discuss the effect of different parameters on the EE of the MIMO-BC.