.png){kind=icon}
返回
Two-Layer Large Scale Fading Precoding for Cell-Free Massive MIMO: Performance Analysis and Optimization
.png){kind=icon}
PRE
AI
DOI：10.1109/TVT.2023.3327745.png)
.png){kind=icon}
原文求助.png){kind=icon}
分享.png){kind=icon}
收藏
摘要
En 中文
In this paper, a two-layer large scale fading precoding (LSFP) method is proposed in a downlink cell-free massive multiple-input multiple-output (mMIMO) system. In the first LSFP layer, the access points are responsible for designing distributed precoding and power control coefficients for each user equipment (UE). While for the second LSFP layer, the central processing unit performs the proposed zero forcing LSFP (ZF-LSFP) for the copilot UEs in order to mitigate the interference caused by pilot contamination. To address power constraints and enhance the system's spectral efficiency (SE), we introduce the copilot power scaling factors. Specifically, we derive closed-form expressions for the lower-bound achievable SE under distributed precoding schemes. These expressions are versatile and applicable to downlink SE irrespective of the availability of ZF-LSFP. Based on the derived closed-form results, we formulate a sum SE maximization problem with respect to copilot power scaling factors. Two approaches are designed to solve this problem, i.e. the weighted minimum mean square error (W-MMSE) based approach and the geometric programming (GP) based approach. While the W-MMSE-based approach is suitable for various systems, the GP-based approach is specifically tailored for systems with high signal-to-noise ratios, offering fast running speed. Finally, we validate all theoretical analyses and assess the effectiveness of the proposed two-layer LSFP method through numerical simulations.
Keyword:
Cell-free massive multiple-input multiple-output (mMIMO)
large scale fading precoding (LSFP)
Sum-spectral efficiency (SE) maximization
pilot assignment
期刊
IF:
7.1
论文数:
1.8W
被引数:
6.6W
机构
引用论文
.png){kind=icon}
查看更多内容