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1.
毫米波大规模MIMO系统中低复杂度混合预编码方法   总被引:1,自引:0,他引:1  
针对毫米波大规模多输入多输出(MIMO)系统混合预编码方案设计的难点,提出了一种低复杂度混合预编码方法.首先基于奇异值分解,构造初始射频(RF)预编码矩阵,然后构造数字预编码矩阵.进而将残差矩阵最大左奇异矢量构造的矢量添加到RF矩阵的最后一列,以更新初始RF矩阵.经过多次迭代,从而形成最终RF预编码矩阵.最后基于最小二乘准则设计数字预编码矩阵.理论分析和仿真结果表明,相比于基于正交匹配追踪(OMP)算法的混合预编码设计方法,该方法在计算复杂度大幅下降的同时,其性能远远优于基于OMP算法的混合预编码方法,同时在数据流数相对较小时,其性能接近最优的全数字预编码设计方法.  相似文献   
2.
针对毫米波大规模MIMO系统采用全数字预编码时,系统所需射频链路数量较大而导致实现成本和能耗较高的问题,提出了一种在基站端和用户端分别采用混合预编码和模拟合并的方案.在充分考虑信道特性的基础上,根据收发两端的天线阵列响应矢量分别设计模拟预编码矩阵和模拟合并矩阵,然后根据生成的有效信道矩阵,在基带部分设计低维的数字预编码,从而消除系统中噪声和用户间干扰的影响.仿真结果表明,在有效减少系统所需射频链路数量的基础上,所提混合预编码方案能够接近传统全数字预编码方案的性能.  相似文献   
3.
This paper proposes a novel relay selection strategy based on the feedback beamforming (BF) information through designed sector sweep (SSW) report frame for millimeter-wave (mmWave) wireless personal networks (WPANs). First, an SSW report frame compatible with IEEE 802.11ad standard is designed. Second, an approach collecting instantaneous channel state information (CSI) overheard during BF is devised. Third, with the aim of minimizing the outage probability and maximizing the overall network throughput capacity, the optimal relay selection issue for non-line-of-sight (NLoS) links is formulated as a bipartite graph, and Kuhn Munkres (KM) algorithm is provided to resolve it. Both theoretical analysis and simulation results show, with CSI considering NLoS conditions and selected relays according to the overall network throughput capacity maximization principle, the improvements achieved over opportunistic relay selection strategy in terms of overall network throughput capacity and outage probability with minimal modifications to IEEE 802.1lad.  相似文献   
4.
There is an increasing interest in 60 GHz millimeter-wave (mmWave) communication technologies for multi-Gigabit wireless personal area networks (WPAN), aiming to support broadband multimedia applications. Internet Protocol TV (IPTV) is an emerging killer application which requires high data rate and stringent quality of services (QoS) in terms of delay and packet loss. In this paper, we propose a method to efficiently support high definition video flows in a mmWave-based WPAN with QoS guarantee, considering the characteristics of both the IPTV traffic and the mmWave communication technology. We first quantify the effective bandwidth of IPTV video sources using a simple, two-level Markov traffic model. Considering the overheads of the protocol stack in mmWave WPANs, we then quantify the minimum channel time needed for each IPTV flow. Since mmWave-based WPANs will deploy directional antennas to not only extend the transmission range, but also reduce the interference level to neighboring flows, we further propose an admission control scheme and scheduling algorithm to improve the network resource utilization by taking advantage of concurrent transmissions. Extensive simulations with NS-2 using real video traces have validated our analysis and demonstrated the efficiency and effectiveness of the proposed schemes, which will be an enabling technology for future mmWave-based WPANs supporting IPTV services. Part of this work was presented at 2008 Int. Conf. Heterogeneous Networking for Quality, Reliability, Security and Robustness (QShine’08), Hong Kong, July 2008. This work has been supported by research grants from the Natural Sciences and Engineering Research Council (NSERC) of Canada.  相似文献   
5.
With the rapid development of the mobile internet and the internet of things (IoT), the fifth generation (5G) mobile communication system is seeing explosive growth in data traffic. In addition, low-frequency spectrum resources are becoming increasingly scarce and there is now an urgent need to switch to higher frequency bands. Millimeter wave (mmWave) technology has several outstanding features—it is one of the most well-known 5G technologies and has the capacity to fulfil many of the requirements of future wireless networks. Importantly, it has an abundant resource spectrum, which can significantly increase the communication rate of a mobile communication system. As such, it is now considered a key technology for future mobile communications. MmWave communication technology also has a more open network architecture; it can deliver varied services and be applied in many scenarios. By contrast, traditional, all-digital precoding systems have the drawbacks of high computational complexity and higher power consumption. This paper examines the implementation of a new hybrid precoding system that significantly reduces both calculational complexity and energy consumption. The primary idea is to generate several sub-channels with equal gain by dividing the channel by the geometric mean decomposition (GMD). In this process, the objective function of the spectral efficiency is derived, then the basic tracking principle and least square (LS) techniques are deployed to design the proposed hybrid precoding. Simulation results show that the proposed algorithm significantly improves system performance and reduces computational complexity by more than 45% compared to traditional algorithms.  相似文献   
6.
In this article, a tapered slot antenna (TSA) operating from 27 to 29.8 GHz with an endfire gain of 9 dBi and high pattern integrity is presented. The gain specifications for path loss compensation on ground for a ceiling mounted millimeter wave base station is computed and the gain of the antenna elements with beam angled at ±45° was found to be 12 dBi. To enhance gain with minimal physical footprint, a combination of dielectric loading and electrical resonator metamaterial unit cells were integrated to the proposed TSA to achieve the expected gain enhancement of 3 dB across the band, operating in the same frequency band with aperture efficiency greater than 73% and a 1 dB gain bandwidth of 20.7%. A compact stacking topology for pattern diversity of all three antenna elements for path loss compensation is also investigated. The base station has a coverage of ±60° with uniform illumination and mutual coupling lesser than 35 dB. The detailed simulated and measured results are presented.  相似文献   
7.
由于丰富的频谱资源,毫米波通信已成为未来无线网络的重要研究方向。毫米波通信在短距离无线接入虽已取得明显进展,但如何实现超高速广域覆盖还存在巨大的挑战。本文回顾分析了毫米波信道模型、毫米波多天线传输和毫米波通信网络构架等关键技术的国内外研究现状和发展趋势,提出将毫米波无线通信与新兴的大规模多天线和大规模协作无线传输技术紧密结合,并引入云计算和分布式存储处理等新方法,形成密集分布毫米波大规模多天线无线通信新型网络构架,解决毫米波移动通信的广域大容量无线覆盖和支持终端中高速移动等关键性技术的瓶颈。  相似文献   
8.
为了减少毫米波大规模多输入多输出(Multiple-Input Multiple-Output, MIMO)系统在数据传输过程中所使用的射频链数目,解决高硬件成本和高功耗的问题,可以将透镜天线阵列作为一个实际有效的解决方案部署在毫米波MIMO系统的基站端。利用透镜天线阵列具有基于方向的能量聚焦特性,对透镜阵列进行天线选择,并为用户分配合适的天线进行数据传输,能够在维持一定的系统性能的同时减少射频链的使用。结合机器学习在数据处理及分类方面的优势,提出了一种基于全连接神经网络(Fully Connected Neural Network, FNN)的天线选择算法。仿真结果表明,所提方案能够达到和穷搜法基本一致的系统容量,且比逻辑回归、k-近邻算法的准确率分别高了7%、2%。  相似文献   
9.
为改善智能反射表面(Intelligent reflective surface,IRS)辅助的毫米波多输入多输出(Multiple-input multiple-output,MIMO)级联信道的估计精度和收敛速度,基于平行因子(Parallel factor,PARAFAC)分解模型,把常规的双线性交替最小二乘(Bilinear alternating least squares,BALS)算法改进为带松弛因子的ω-BALS算法和正则化的T-BALS,加快了收敛速度和算法稳定性。当基站、IRS元件或用户侧的阵列天线数目较大时,提出改进的奇异值(Singular value decomposition,svd)-BALS算法。该算法通过奇异值分解压缩张量,再利用低维度的核心张量来重构模式n矩阵。仿真结果表明,该算法的归一化均方误差性能有所提高,并且加快了收敛速度。  相似文献   
10.
信道估计是大规模多输入多输出(Multiple-Input Multiple-Output,MIMO)毫米波(Millimeter Wave,mmWave)系统关键技术之一。梳理了近几年大规模MIMO毫米波的信道估计策略,重点从压缩感知(Compressive Sensing,CS)、参数估计和深度学习三个方面进行了描述与分析。通过算法性能的对比,总结了毫米波信道估计目前存在的问题以及未来发展的趋势。  相似文献   
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