MMSE precoding for multiuser MISO downlink transmission with non-homogeneous user SNR conditions
MMSE precoding for multiuser MISO downlink transmission with non-homogeneous user SNR conditions
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DOI：
10.1186/1687-6180-2014-85
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发表时间：
2014-06-06
影响因子：
1.9
通讯作者：
Tho Le-Ngoc
中科院分区：
文献类型：
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作者：
Nguyen, Duy H. N.;Tho Le-Ngoc
本文关注多用户下行链路传输的线性预编码设计。我们考虑具有多个单天线用户设备（UE）的多输入单输出（MISO）系统，其经历非均匀平均信噪比（SNR）条件。这项工作的第一部分研究了具有完美信道状态信息 (CSI) 和基站 (eNB) 平均 SNR 的不同预编码方案。然后，我们提出了一种加权最小均方误差（WMMSE）预编码器，它利用了非均匀 SNR 条件。在封闭式解决方案中，所提出的 WMMSE 预编码器优于其他众所周知的线性预编码器，例如迫零（ZF）、正则化 ZF（RZF），同时在可实现的网络和速率方面实现了与局部最优迭代 WMMSE（IWMMSE）预编码器接近的性能。在这项工作的第二部分中，我们考虑具有有限和量化的信道质量指示符（CQI）和信道方向指示符（CDI）反馈的非同质多用户系统。基于为长期演进高级标准提出的 CQI 和 CDI 反馈模型，我们在考虑量化误差的封闭式解决方案中提出了鲁棒的 WMMSE 预编码器。仿真表明，与非鲁棒线性预编码器设计相比，所提出的鲁棒 WMMSE 预编码器在可实现的网络和速率方面有显着改进。
This paper is concerned with linear precoding designs for multiuser downlink transmissions. We consider a multiple-input single-output (MISO) system with multiple single-antenna user equipment (UE) experiencing non-homogeneous average signal-to-noise ratio (SNR) conditions. The first part of this work examines different precoding schemes with perfect channel state information (CSI) and average SNR at the base-station (eNB). We then propose a weighted minimum mean squared error (WMMSE) precoder, which takes advantage of the non-homogeneous SNR conditions. Given in a closed-form solution, the proposed WMMSE precoder outperforms other well-known linear precoders, such as zero-forcing (ZF), regularized ZF (RZF), while achieving a close performance to the locally optimal iterative WMMSE (IWMMSE) precoder, in terms of the achievable network sum-rate. In the second part of this work, we consider the non-homogeneous multiuser system with limited and quantized channel quality indicator (CQI) and channel direction indicator (CDI) feedbacks. Based on the CQI and CDI feedback models proposed for the Long-Term Evolution Advanced standard, we then propose a robust WMMSE precoder in a closed-form solution which takes into account the quantization errors. Simulation shows a significant improvement in the achievable network sum-rate by the proposed robust WMMSE precoder, compared to non-robust linear precoder designs.