Hybrid MIMO Architectures for Millimeter Wave Communications: Phase Shifters or Switches?
Hybrid MIMO Architectures for Millimeter Wave Communications: Phase Shifters or Switches?
复制标题
DOI：
10.1109/access.2015.2514261
复制
发表时间：
2016-01-01
期刊：
影响因子：
3.9
通讯作者：
Heath, Robert W., Jr.
中科院分区：
文献类型：
--
作者：
Mendez-Rial, Roi;Rusu, Cristian;Heath, Robert W., Jr.
混合模拟/数字多输入多输出架构最近被提出作为毫米波无线通信系统中的全数字预编码的替代方案。这是由RF链和模数转换器数量的可能减少所激发的。在这些架构中，模拟处理网络通常基于可变移相器。在本文中，我们提出了基于开关网络的混合架构，以降低基于移相器的结构的复杂性和功耗。我们定义了一个功耗模型，并使用它来评估这两种结构的能源效率。为了估计完整的MIMO信道，我们提出了一种开环压缩信道估计技术，该技术独立于模拟处理阶段中使用的硬件。我们分析了基于移相器和开关的混合结构的新的估计算法的性能。利用该估计，我们提出了两种基于开关的混合合路器的设计算法，并分析了所获得的频谱效率。最后，我们研究了基于相移网络和开关网络的混合架构的功耗，硬件复杂性和频谱效率之间的权衡。数值结果表明，基于开关的架构获得相等或更好的信道估计性能，获得使用移相器，同时降低硬件复杂度和功耗。对于相同的功耗，所有的混合架构提供类似的频谱效率。
Hybrid analog/digital multiple-input multiple-output architectures were recently proposed as an alternative for fully digital-precoding in millimeter wave wireless communication systems. This is motivated by the possible reduction in the number of RF chains and analog-to-digital converters. In these architectures, the analog processing network is usually based on variable phase shifters. In this paper, we propose hybrid architectures based on switching networks to reduce the complexity and the power consumption of the structures based on phase shifters. We define a power consumption model and use it to evaluate the energy efficiency of both structures. To estimate the complete MIMO channel, we propose an open-loop compressive channel estimation technique that is independent of the hardware used in the analog processing stage. We analyze the performance of the new estimation algorithm for hybrid architectures based on phase shifters and switches. Using the estimate, we develop two algorithms for the design of the hybrid combiner based on switches and analyze the achieved spectral efficiency. Finally, we study the tradeoffs between power consumption, hardware complexity, and spectral efficiency for hybrid architectures based on phase shifting networks and switching networks. Numerical results show that architectures based on switches obtain equal or better channel estimation performance to that obtained using phase shifters, while reducing hardware complexity and power consumption. For equal power consumption, all the hybrid architectures provide similar spectral efficiencies.