Hybrid Beamforming With a Reduced Number of Phase Shifters for Massive MIMO Systems
Hybrid Beamforming With a Reduced Number of Phase Shifters for Massive MIMO Systems
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DOI：
10.1109/tvt.2018.2807921
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发表时间：
2018-06-01
影响因子：
6.8
通讯作者：
Sellathurai, Mathini
中科院分区：
文献类型：
--
作者：
Payami, Sohail;Ghoraishi, Mir;Sellathurai, Mathini
本文提出了两种新的混合波束形成方法，以降低大规模多输入多输出系统中亚连接移相器网络结构的混合波束形成器的成本和功耗。这是通过用开关替换一些移相器来实现的，一般来说，与移相器相比，开关更便宜，功耗更低。根据信道矩阵奇异向量元素的性质，给出了所提出的方法及其性能的闭合表达式。在第一种方法中，通过将次连接移相器网络与全连接开关结构相结合，可以在保持频谱效率的同时将移相器的数量减少多达50%。然后，为了简化交换网络的结构，将全连接的开关替换为次连接的交换网络，例如二进制开关。分析和仿真结果表明，只要使用25%的移相器，就可以获得90%的频谱效率。最后，仿真结果表明，当无线信道被认为是稀疏的或相关的时，也观察到了类似的行为。
In this paper, two novel hybrid beamforming methods are proposed to reduce the cost and power consumption of hybrid beamformers with a subconnected phase shifter network structure in massive multiple-input multiple-output systems. This is achieved by replacing some of the phase shifters with switches, which, in general, are cheaper and have lower power consumption compared to phase shifters. The proposed methods and the closed-form expressions of their performance are derived according to the properties of the elements of the singular vectors of the channel matrix. In the first approach, it is shown that by combining the subconnected phase shifter network with a fully connected switch architecture, the number of the phase shifters can be reduced up to 50%, while the spectral efficiency is preserved. Then, in order to simplify the structure of the switch network, the fully connected switches are replaced by a subconnected switch network, e.g., binary switches. The analytical and simulation results indicate that just by using 25% of phase shifters, 90% spectral efficiency can be achieved. Finally, simulation results indicate that a similar behavior is observed when the wireless channel is considered to be sparse or correlated.