Low-Complexity Hybrid Linear/Tomlinson-Harashima Precoding for Downlink Large-Scale MU-MIMO Systems
Low-Complexity Hybrid Linear/Tomlinson-Harashima Precoding for Downlink Large-Scale MU-MIMO Systems
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DOI：
10.1109/glocomw.2016.7848954
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发表时间：
2016-04
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影响因子：
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通讯作者：
S. Zarei;W. Gerstacker;R. Schober
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文献类型：
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作者：
S. Zarei;W. Gerstacker;R. Schober
在本文中，我们提出了一种用于下行链路大规模多用户多输入多输出（MU-MIMO）系统的新型低复杂度混合线性/Tomlinson-Harashima预编码器（HL-THP）。所提出的预编码器包括仅基于信道状态信息(CSI)的二阶统计设计的内部线性预编码器和利用实际信道和内部预编码器级联的瞬时总体CSI的外部THP。由此，用户终端（UT）被分成组，其中对于每个组，THP连续地减轻组内干扰，而组间干扰被内部线性预编码器消除。我们的分析和仿真结果表明，与线性正则化迫零 (RZF) 预编码器相比，所提出的 HL-THP 实现了显着更高的每个 UT 平均速率和显着更低的误码率 (BER)。此外，所提出的 HL-THP 的每个 UT 的平均可实现速率和 BER 都接近于传统的 THP。此外，我们还根据所需的浮点运算数量分析了所提出的 HL-THP 的计算复杂度。这些结果表明，所提出的 HL-THP 的计算复杂度分别比传统的 THP 和 RZF 预编码器低得多。这一特性及其高性能使 HL-THP 成为实用系统的绝佳候选者。
In this paper, we propose a novel low-complexity hybrid linear/Tomlinson-Harashima precoder (HL-THP) for downlink large-scale multiuser multiple-input multiple-output (MU-MIMO) systems. The proposed precoder comprises an inner linear precoder which is designed based on only the second order statistics of the channel state information (CSI) and outer THPs which exploit the instantaneous overall CSI of the cascade of the actual channel and the inner precoder. Thereby, the user terminals (UTs) are divided into groups, where for each group a THP successively mitigates the intra-group interference, whereas the inter-group interference is canceled by the inner linear precoder. Our analytical and simulation results show that the proposed HL-THP achieves a substantially higher average rate per UT and a considerably lower bit error rate (BER) than the linear regularized zero-forcing (RZF) precoder. Moreover, both the average achievable rate per UT and the BER of the proposed HL-THP are close to those of the conventional THP. In addition, we analyze the computational complexity of the proposed HL-THP in terms of the required number of floating-point operations. These results reveal that the proposed HL-THP has a much lower computational complexity than the conventional THP and RZF precoders, respectively. This and its high performance make the HL-THP an excellent candidate for practical systems.