Massive MIMO Systems With Non-Ideal Hardware: Energy Efficiency, Estimation, and Capacity Limits
Massive MIMO Systems With Non-Ideal Hardware: Energy Efficiency, Estimation, and Capacity Limits
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DOI：
10.1109/tit.2014.2354403
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发表时间：
2014-11-01
影响因子：
2.5
通讯作者：
Debbah, Merouane
中科院分区：
文献类型：
--
作者：
Bjornson, Emil;Hoydis, Jakob;Debbah, Merouane
由于空间分辨率和阵列增益的极大提高，大规模天线阵列的使用可以为无线系统带来能量和/或频谱效率的实质性改善。大规模多输入多输出（MIMO）领域的最新研究表明，当基站（BS）处的天线数量增加时，用户信道解相关，因此可以在用户间干扰很小的情况下实现强信号增益。由于这些结果依赖于渐近性，重要的是要调查是否传统的系统模型是合理的，在这个渐近制度。本文考虑了一种新的系统模型，它结合了一般的收发器硬件损伤在BS（配备大型天线阵列）和单天线用户设备（UE）。相对于传统的理想硬件的情况下，我们表明，硬件损伤创建有限的天花板上的信道估计精度和每个UE的下行链路/上行链路容量。令人惊讶的是，容量主要受UE处的硬件限制，而大规模阵列中的损伤的影响渐近消失，并且用户间干扰（特别是导频污染）变得可以忽略不计。此外，我们证明了大规模MIMO提供的巨大自由度可以用来降低发射功率和/或容忍更大的硬件损伤，这允许使用廉价和节能的天线元件。
The use of large-scale antenna arrays can bring substantial improvements in energy and/or spectral efficiency to wireless systems due to the greatly improved spatial resolution and array gain. Recent works in the field of massive multiple-input multiple-output (MIMO) show that the user channels decorrelate when the number of antennas at the base stations (BSs) increases, thus strong signal gains are achievable with little interuser interference. Since these results rely on asymptotics, it is important to investigate whether the conventional system models are reasonable in this asymptotic regime. This paper considers a new system model that incorporates general transceiver hardware impairments at both the BSs (equipped with large antenna arrays) and the single-antenna user equipments (UEs). As opposed to the conventional case of ideal hardware, we show that hardware impairments create finite ceilings on the channel estimation accuracy and on the downlink/uplink capacity of each UE. Surprisingly, the capacity is mainly limited by the hardware at the UE, while the impact of impairments in the large-scale arrays vanishes asymptotically and interuser interference (in particular, pilot contamination) becomes negligible. Furthermore, we prove that the huge degrees of freedom offered by massive MIMO can be used to reduce the transmit power and/or to tolerate larger hardware impairments, which allows for the use of inexpensive and energy-efficient antenna elements.