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为提高大规模多输入多输出(MIMO)系统复用增益,降低天线硬件成本,提出一种基于全阵列天线结构的混合预编码算法.以多用户加权最小均方误差为优化目标,综合考虑天线结构硬件限制、用户公平性和功率限制,采用数字-模拟混合式两级预编码与最优一级数字预编码最大逼近的方法求解两级混合预编码.仿真结果表明,所提算法能最大限度地减小所求混合预编码矩阵与最优一级预编码矩阵的误差,具有较好的收敛性,可获得近乎最优的混合预编码性能增益. 相似文献
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Ji-Sung Jung Won-Seok Lee Yeong-Rong Lee Jaeho Kim Hyoung-Kyu Song 《计算机、材料和连续体(英文)》2021,67(3):3057-3070
Massive multiple input multiple output (MIMO) has become essential for the increase of capacity as the millimeter-wave (mmWave) communication is considered. Also, hybrid beamforming systems have been studied since full-digital beamforming is impractical due to high cost and power consumption of the radio frequency (RF) chains. This paper proposes a hybrid beamforming scheme to improve the spectral efficiency for multi-user MIMO (MU-MIMO) systems. In a frequency selective fading environment, hybrid beamforming schemes suffer from performance degradation since the analog precoder performs the same precoding for all subcarriers. To mitigate performance degradation, this paper uses the average channel covariance matrix for all subcarriers and considers an iterative algorithm to design analog precoder using approximation techniques. The analog precoder is iteratively updated for each column until it converges. The proposed scheme can reduce errors in the approximating process of the overall spectral efficiency. This scheme can be applied to fully-connected and partially-connected structures. The simulation results show that spectral efficiency performance for the proposed scheme is better than the conventional schemes. The proposed scheme can achieve similar performance with full-digital beamforming by using a sufficiently large number of RF chains. Also, this paper shows that the proposed scheme outperforms other schemes in the frequency selective fading environment. This performance improvement can be achieved in both structures. 相似文献
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研究了MIMO系统中基于奇异值分解(SVD)、几何均值分解(GMD)与均匀信道分解(UCD)的预编码算法原理,并对三种算法做了详细的对比研究。通过在反馈噪声误差不同的情况下计算SVD,GMD与UCD的误码率,可以观察预编码矩阵的反馈误差对SVD,GMD与UCD性能的影响。 相似文献
108.
MIMO系统下行多用户线性疏散空时编码设计方案 总被引:1,自引:0,他引:1
针对使用了MIMO传输技术的单小区下行移动通信系统,在基站只能以有限个数据速率下传数据给移动台的条件下,给出了使得每个移动台接收信噪比达到最大的多用户线性疏散码所对应的组合优化问题,并给出求解该组合优化问题的低复杂度次最优算法.所给出的线性疏散码的设计方案,克服了前人连续数据传输速率的限制,更加接近实际系统.仿真结果表明,此算法性能较前人算法有所改进. 相似文献
109.
Hang Long Kan Zheng Fangxiang Wang Wenbo Wang 《International Journal of Communication Systems》2010,23(11):1334-1352
Precoding techniques can be introduced into multi‐relay systems due to the similarity between cooperative communication systems and traditional multi‐input–multi‐output (MIMO) systems. In this paper, a channel state information (CSI) feedback scheme based on the zero‐forcing (ZF) relaying protocol is proposed at first, where the information of relaying channel and noise related to each relay node can be compressed into two positive real parameters. Then, based on the proposed feedback scheme, the singular‐vector‐based local temporal precoder is presented at the source node through two continuous transmitted vectors, which is termed as distributed spatial–temporal precoding (DSTP). Moreover, various spatial data rates can be conveniently supported by DSTP. Based on the analysis on DSTP, it is better that the number of data streams is not larger than the number of antennas equipped at the source node. The unitary DSTP with the proposed feedback scheme outperforms not only the close‐loop direct transmission but also the simple ZF relaying method. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
110.
第三代移动通信系统长期演进(3G LTE)系统的下行链路传输中,基站端无法获知完全的信道状态信息(CSI),需要根据终端反馈的预编码序号从已有的码本中挑选合适的预编码矩阵进行信号处理。研究了多小区场景下基于有限信息反馈的码本选择算法,提出了一种单双流自适应的码本选择方案,分析了2×2天线情况下所提预编码算法的性能,通过计算机仿真给出了不同多天线预编码方案的性能对比。 相似文献