Robust MSE-Balancing Hierarchical Linear/Tomlinson-Harashima Precoding for Downlink Massive MU-MIMO Systems
Robust MSE-Balancing Hierarchical Linear/Tomlinson-Harashima Precoding for Downlink Massive MU-MIMO Systems
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DOI：
10.1109/twc.2018.2866112
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发表时间：
2018-08
影响因子：
10.4
通讯作者：
S. Zarei;W. Gerstacker;R. Weigel;M. Vossiek;R. Schober
中科院分区：
文献类型：
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作者：
S. Zarei;W. Gerstacker;R. Weigel;M. Vossiek;R. Schober
针对发射端信道状态信息（CSI）不理想的下行大规模多用户多输入多输出（MU-MIMO）系统，提出了一种鲁棒的最小最大均方误差Tomlinson-Harashima预编码（Min-Max-MSE THP）方案和一种低复杂度的鲁棒Min-Max-MSE分层线性/THP（HL-THP）方案.所提出的鲁棒Min-Max-MSE HL-THP方案包括基于二阶CSI统计数据设计的内部线性波束形成器（BF）和利用实际信道和内部BF级联的瞬时总体CSI的外部THP模块。由此，用户终端被划分成组，其中对于每个组，THP模块连续地减轻组内干扰，而组间干扰由内部BF消除。为了确保公平性，我们采用最大化的渐近信号泄漏加噪声比在大系统的限制和最小最大均方误差作为优化标准，分别设计内部BF和每组THP模块。我们的分析和仿真结果表明，所提出的鲁棒的Min-Max-MSE HL-THP方案实现了显着改善的性能相比，线性正则化迫零预编码的Max-MSE，最大误比特率，和最小速率。此外，所提出的鲁棒Min-Max-MSE HL-THP方案相比于鲁棒Min-Max-MSE THP方案的性能损失较小。此外，我们的复杂性分析表明，所提出的鲁棒的Min-Max-MSE HL-THP方案具有比Min-Max-MSE THP方案低得多的计算复杂度。因此，鲁棒的Min-Max-MSE HL-THP方案提供了复杂度和性能之间的有利折衷。
In this paper, we propose a robust minimum maximum mean square error Tomlinson-Harashima precoding (Min-Max-MSE THP) scheme and a low-complexity robust Min-Max-MSE hierarchical linear/THP (HL-THP) scheme for downlink massive multiuser multiple-input-multiple-output (MU-MIMO) systems with imperfect channel state information (CSI) at the transmitter. The proposed robust Min-Max-MSE HL-THP scheme comprises an inner linear beamformer (BF), which is designed based on second-order CSI statistics, and outer THP modules, which exploit the instantaneous overall CSI of the cascade of the actual channel and the inner BF. Thereby, the user terminals are divided into groups, where for each group a THP module successively mitigates the intra-group interference, whereas the inter-group interference is canceled by the inner BF. To ensure fairness, we adopt the maximization of the asymptotic signal-to-leakage-plus-noise ratio in the large system limit and the Min-Max-MSE as an optimization criterion for designing the inner BF and the per-group THP modules, respectively. Our analytical and simulation results show that the proposed robust Min-Max-MSE HL-THP scheme achieves a substantially improved performance in terms of the Max-MSE, maximum bit error rate, and minimum rate compared to linear regularized zero-forcing precoding. Moreover, the performance loss of the proposed robust Min-Max-MSE HL-THP scheme compared to the robust Min-Max-MSE THP scheme is small. In addition, our complexity analysis reveals that the proposed robust Min-Max-MSE HL-THP scheme has a much lower computational complexity than the Min-Max-MSE THP scheme. Hence, the robust Min-Max-MSE HL-THP scheme provides a favorable tradeoff between complexity and performance.