Electromagnetic Lens-Focusing Antenna Enabled Massive MIMO: Performance Improvement and Cost Reduction
Electromagnetic Lens-Focusing Antenna Enabled Massive MIMO: Performance Improvement and Cost Reduction
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DOI：
10.1109/jsac.2014.2328151
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发表时间：
2013-12
影响因子：
16.4
通讯作者：
Yong Zeng;Rui Zhang;Zhi Ning Chen
中科院分区：
文献类型：
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作者：
Yong Zeng;Rui Zhang;Zhi Ning Chen
近年来，大规模多输入多输出（MIMO）技术的发展极大地提高了无线通信网络的性能。然而，在基站上使用超大天线阵列带来了新的问题，如硬件和信号处理成本的显著增加。为了获得大规模MIMO的性能提升并降低其成本，本文提出了一种将电磁透镜与大型天线阵列集成在一起的新型系统设计，称为EM透镜使能MIMO。EM透镜具有将入射波的功率聚焦到天线阵列的小区域的能力，而焦点区域的位置随波的到达角（AoA）而变化。因此，在来自地理位置分开的用户的到达信号具有不同aoa的情况下，em透镜启用的接收器提供了两个新的优势，即能量聚焦和空间干扰抑制。通过考虑导频辅助训练的不完全信道估计的影响，本文分析表明，em透镜使能系统可以提高单用户和多用户上行传输的平均接收信噪比。此外，我们证明了所提出的设计可以大大降低硬件和信号处理成本，而性能仅略有下降。为此，提出了两种降低复杂度/成本的方案，即在天线子组上应用并行接收机滤波的小型mimo处理以降低计算复杂度，以及基于信道协方差的天线选择以减少所需的射频链数。数值结果证实了我们的分析，并显示了我们提出的em透镜支持的MIMO系统在下一代蜂窝网络中的巨大潜在优势。
Massive multiple-input-multiple-output (MIMO) techniques have been recently advanced to tremendously improve the performance of wireless communication networks. However, the use of very large antenna arrays at the base stations brings new issues, such as the significantly increased hardware and signal processing costs. In order to reap the performance gains of massive MIMO and yet reduce its cost, this paper proposes a novel system design by integrating an electromagnetic (EM) lens with the large antenna array, termed the EM-lens enabled MIMO. The EM lens has the capability of focusing the power of an incident wave to a small area of the antenna array, whereas the location of the focal area varies with the angle of arrival (AoA) of the wave. Hence, in scenarios where the arriving signals from geographically separated users have different AoAs, the EM-lens enabled receiver provides two new benefits, namely, energy focusing and spatial interference rejection. By taking into account the effects of imperfect channel estimation via pilot-assisted training, in this paper, we analytically show that the average received signal-to-noise ratio in both the single-user and multiuser uplink transmissions can be improved by the EM-lens enabled system. Furthermore, we demonstrate that the proposed design makes it possible to considerably reduce the hardware and signal processing costs with only slight degradations in performance. To this end, two complexity/cost reduction schemes are proposed, which are small-MIMO processing with parallel receiver filtering applied over subgroups of antennas to reduce the computational complexity, and channel covariance based antenna selection to reduce the required number of radio frequency chains. Numerical results are provided to corroborate our analysis and show the great potential advantages of our proposed EM-lens enabled MIMO system for next generation cellular networks.