Optimal Design of Energy-Efficient Multi-User MIMO Systems: Is Massive MIMO the Answer?
Optimal Design of Energy-Efficient Multi-User MIMO Systems: Is Massive MIMO the Answer?
复制标题
DOI：
10.1109/twc.2015.2400437
复制
发表时间：
2015-06-01
影响因子：
10.4
通讯作者：
Debbah, Merouane
中科院分区：
文献类型：
--
作者：
Bjornson, Emil;Sanguinetti, Luca;Debbah, Merouane
假设一个多用户多输入多输出（MIMO）系统从头开始设计，均匀覆盖一个给定的区域与最大的能量效率（EE）。天线、活跃用户和发射功率的最佳数量是多少？本文的目的就是回答这个基本问题。我们共同考虑在基站的上行链路和下行链路与不同的处理方案，并提出了一个新的现实的功耗模型，揭示了上述参数如何影响EE。封闭形式的表达式EE最佳值的每个参数，当其他两个是固定的，提供迫零（ZF）处理在单小区的情况下。这些表达式证明了参数是如何相互作用的。例如，与通常的看法形成鲜明对比的是，发现发射功率随着天线的数量而增加（而不是减少）。这意味着，节能系统可以在高信噪比的制度，其中干扰抑制信号处理是强制性的。数值和分析结果表明，最大的EE是通过一个大规模的MIMO设置，其中部署了数百个天线，以服务于相对大量的用户使用ZF处理。数值结果表明，在不完美的信道状态信息和对称多小区的情况下，相同的行为。
Assume that a multi-user multiple-input multiple-output (MIMO) system is designed from scratch to uniformly cover a given area with maximal energy efficiency (EE). What are the optimal number of antennas, active users, and transmit power? The aim of this paper is to answer this fundamental question. We consider jointly the uplink and downlink with different processing schemes at the base station and propose a new realistic power consumption model that reveals how the above parameters affect the EE. Closed-form expressions for the EE-optimal value of each parameter, when the other two are fixed, are provided for zero-forcing (ZF) processing in single-cell scenarios. These expressions prove how the parameters interact. For example, in sharp contrast to common belief, the transmit power is found to increase (not to decrease) with the number of antennas. This implies that energy-efficient systems can operate in high signal-to-noise ratio regimes in which interference-suppressing signal processing is mandatory. Numerical and analytical results show that the maximal EE is achieved by a massive MIMO setup wherein hundreds of antennas are deployed to serve a relatively large number of users using ZF processing. The numerical results show the same behavior under imperfect channel state information and in symmetric multi-cell scenarios.