基于坐标下降算法的5G广播波束权值智能优化方法研究

随着5G建设步伐的加快,无线通信网络的复杂程度不断更迭,网络优化需求增多,且精细化要求不断提高,传统的Massive MIMO广播波束权值优化仅依靠人工配置,已无法满足当前网络变化的需要。本文创新性地提出了一种基于坐标下降算法的5G广播波束权值智能优化方法,可自适应灵活调整天线波束权值配置,实现多场景下波束权值智能优化,极大提升优化效率,减少人工成本投入。     

楼宇场景下的5G广播波束研究

5G由于采用了Massive MIMO和波束赋形(Beamforming BF)等技术有效的解决城区不同场景下的覆盖问题,进而覆盖效果更加完善.5G天线数量可达16/32/64/128阵列,因此被称为大规模的MIMO.本文研究高、中、低层楼宇场景下广播波束权值规划最佳方案,给出配置建议,供规划优化参考.     

典型场景下5G天线波束权值研究

5G NR系统采用波束赋形技术。不同权值赋形的广播波束,增强不同组网场景下广播信道、同步信号的覆盖范围,更好地匹配小区覆盖范围和用户分布。根据不同场景选择适合自身覆盖需求的波束配置方案,能够解决当前小区覆盖能力有限以及受周围环境干扰等问题,适用于不同组网场景。基于此,结合实际场景问题,深入探究基站的下倾角、高度以及距离与需要覆盖区域的高度和宽度之间的关系,匹配出适配的波束覆盖方案,并给出典型场景下5G权值建议。     

密集城区5G广播波束配置策略研究

5G移动通信关键技术在于波束赋形,以及波束多样性带来的垂直角度覆盖增益,配置不同的波束赋形权值,小区水平和垂直覆盖增益各不相同。5G TDD 3.5G频段分配17种波束配置模式,开网默认S0模式垂直波宽小、电子下倾调整范围小、电子方位角不能调整、覆盖局限性大。通过结合城区地域特色结合理论模型搭建、仿真支撑、路测数据验证、室内CQT验证、系统指标同步评估、验证结果合理性整体评估的方法,给出适合城区的5G小区广播波束配置组合模式,提升室内外整体覆盖能力。     

5G大规模天线阵列波束权值自优化系统

大规模天线波束赋形技术是5G的重要技术之一,本文基于用户最小化路测数据,采用大数据分析算法,真实模拟出用户三维分布,拟合出天线最佳波束权值,增强了无线网络的覆盖能力,激发了5G流量增长.     

基于AI算法的Massive MIMO波束权值优化研究与应用

针对Massive MIMO波束权值优化的难点,提出了一种基于GBDT机器学习的回归预测算法,通过实测及仿真,研究该算法在不同场景下各种波束权值的覆盖能力,基于机器学习模型,利用研究结果结合三维地图、建筑物数据、MR数据、仿真/测试数据等进行机器学习建模,输出Massive MIMO波束自适应覆盖优化算法。在现网的应用结果表明,该算法能够有效地提升5G网络覆盖质量。     

利用智能天线广播波束赋形实现小区覆盖优化

本文提出了一种针对采用智能天线的无线网络覆盖优化的方法,充分利用了智能天线这种多天线系统的优势,通过调整广播波束赋形进行覆盖区域的优化,大幅度改善了TD网络系统指标,大大减少了人工上天面调整工程参数的难度和危险性.该方法有利于网络优化向集中化、信息化、标准化和智能化方向发展.     

一种通过优化天线权值来改善LTE覆盖的研究

文章根据LTE特点,在不增加投资的情况下,通过分析计算,修改天线权值,来达到增加覆盖、抑止干扰的效果,提高用户感知。     

基于数据挖掘的5G Massive MIMO天线权值优化方法研究

本文基于4G/5G数据挖掘分析给出了一种NSA组网下5G Massive MIMO天线权值智能优化方法。该方法结合4G MDT和5G MR数据,采用聚类和成形算法分析得到待优化小区理想权值集合,可以在海量权值因子中快速寻优得到最优权值组合,采用基于风险控制的调整算法实现Massive MIMO天线权值智能自动化迭代寻优。     

5G 功放DPD 的FPGA 宽带实现及自动优化

5G 宽带功放数字预失真器(DPD)的FPGA 实现过程中,常遇到数字处理带宽不够和资源有限问题,对 此,文中提出一种基于双路并行数据流的数字预失真带宽扩展方法和基于Zynq Ultrascale+ MPSoC 的自动化模型优化 验证方法,可快速实现对5G 宽带功放线性化方案的优化。使用该并行处理结构的数字预失真器,克服了数字电路最 大时钟频率造成的对FPGA 线性化带宽的限制,使得数字预失真电路在每个时钟周期内可以处理更多的数据,不仅有 效地增加了数字处理带宽,而且降低了DPD 的功耗。然而,这种带宽增加以消耗更多硬件资源为代价,对此,文中同时 提出了对预失真非线性模型的在线自动优化方法,以简化非线性模型、降低DPD 的硬件资源开销。最后,在Zynq Ultrascale+ FPGA 实验平台上实现了具有两路并行数据处理的I-MSA 自优化数字预失真电路,采用100 MHz 的5G 新无 线电(NR)信号在2. 6 GHz 功率放大器上进行线性化实验验证,获得了满意的预失真性能,验证了所提方法的有效性。     

Throughput enhancement of cognitive M2M networks based on NOMA for 5G communication systems

One of the promising technologies for 5G cellular networks is machine‐to‐machine (M2M) communications. We propose a cognitive radio network (CR) that includes a primary cellular system and a secondary cognitive system. The primary cellular system has a primary client (PC) and the secondary cognitive system has M2M clients which are called secondary clients (SCs). In a conventional system of CR network based on orthogonal frequency division multiple access (CR‐OFDMA), when the primary client (PC) is absent, only one SC can obtain the idle spectrum. But, the SC must leave the spectrum when detecting the existence of the PC. So, the spectrum usage of this system is very low. This paper proposes a cooperative CR network based on nonorthogonal multiple access (CCR‐NOMA) for spectrum sensing using energy detection (ED) to allow multiple SCs to share the same frequency at the same time, but are differentiated according to the power domain or code domain, to improve spectrum efficiency of 5G communications and the transmission performance of CR network at the absence and presence of the PC. To evaluate the channel sensing performance of the ED technique in CCR‐NOMA, we derived a closed‐form expression between the achievable throughput and sensing time for the CCR‐NOMA system. The same analysis for the case of CR‐OFDMA is reproduced for the sake of comparison. The analysis showed that the CR‐NOMA system for M2M communication outperforms the CR‐OFDMA system for M2M communication for the same noncooperative and cooperative spectrum sensing and physical layer parameters.     

基于权重不可知神经网络的旋翼无人机检测

针对传统无人机检测方法缺乏智能性和泛化性的问题,提出了一种基于权重不可知神经网络(Weight Agnostic Neural Network,WANN)的无人机微动特征检测方法,以实现探测无人机的目的.推导了旋翼无人机微动模型,详细说明了WANN模型的构建过程.以回波信号的循环谱等高图作为训练、测试数据集进行了仿真,...     

无线MIMO系统的容量分析及其在3G中的应用

在无线MIMO(MultipleInputMultipleOutput)系统信号模型的基础上,分析了无线MIMO系统的容量,讨论了无线MIMO系统提高频谱利用率的基本原理,并且给出收发天线数量和信噪比对系统容量影响的试验结果。最后,对无线MIMO系统的应用,尤其在第三代移动通信中的应用做出了比较详细的说明。     

Applications of thermodynamical modeling in molecular beam epitaxy of CdxHg1-xTe

It is well known that the crystalline quality of Cd_xHg_1-xTe grown by molecular beam epitaxy is critically dependent on the substrate temperature. The optimal growth temperature has been identified immediately below the crossing of the Te-rich phase boundary, that is just below the temperature range where Te precipitation occurs in the layer. It is potentially very useful to be able to predict the optimal temperature and its variation with other growth parameters, but no general guidelines for this can be found in the literature. We have studied experimentally the variation of the optimal growth temperature with Hg flux, Cd mole fraction and growth rate. These results are compared with a thermodynamical model published previously by Gailliard. We find that the modeled position of the phase boundary coincides well with the observed variations in optimal growth temperature for growth on Te-terminated surfaces, within the uncertainties of available thermodynamical constants. We show that the optimal substrate temperature depends mainly on the Hg flux and Cd mole fraction, while the dependence on growth rate can be neglected in practical molecular beam epitaxy conditions. The experimental observation of optimal layer quality at the phase boundary could suggest the existence of an adsorbed layer of Te, acting as a reservoir for Te atoms and reducing the supersaturation of the growth reaction. Simultaneous growth on the (211)B and (100) orientations reveals a clear, although not very large, difference in optimal growth temperature and Cd incorporation, indicating a difference in growth kinetics. This can be accounted for in the thermodynamical model by condensation and evaporation coefficients.     

光谱宽度对偏振度与差分群延时关系影响的研究

理论推导出准单色光波情况下、输入信号为高斯脉冲时偏振度(DOP)与差分群延时(DGD)关系的简明解析表达式.通过对偏振度公式的理论分析,得出了DOP随DGD变化的关系由分光比以及光源的光谱宽度决定的结论.用不同光谱宽度的10 Gbit/s归零(RZ)伪随机码光源实验研究了DOP与DGD的关系,实验结果表明了理论推导和分析的正确性.理论分析表明 ,除了分光比参数外,只有能够影响光谱宽度的参数才会对DOP-DGD关系式产生影响,如调制码型、调制啁啾和脉冲变换极限宽度等,而其它因素则与DOP-DGD关系式无关,如色散、线路啁啾以及脉冲实际宽度等.     

Design of a wideband Y-shaped antenna for the application in IoT and 5G communication

A small wideband Y-shaped antenna is presented in this paper. A monopole of Y-shaped with two rectangular-shape frequency shifting strip is used to produce a compact dimension of 10 mm × 12 mm on a 1-mm-thick FR4 substrate. The antenna has an impedance bandwidth (measured below ?10 dB from 39.57 to 44.63 GHz), a gain more than 4.9 dB, radiation efficiency of 81%, and voltage standing wave ratio (VSWR) < 2, within the bandwidth of interest, making it a viable option for 5G applications. The use of a (01.7850 × 2.6775 × 00.02) mm³ metallic strip located above the feed line is also shown to efficiently increase the antenna bandwidth to values greater than 5 GHz without affecting the other antenna parameters. Additionally, the measured results in comparison with the simulated results reveal negligible changes, confirming that the proposed antenna is also suitable for the applications of 5G with Internet of Things.     

基于量子粒子群优化的短波相控阵天线的激励优化研究

为加强短波装备远距离通信和电子对抗的干扰能力,须提高近地架设的宽带短波相控阵天线的性能,该文首先利用矩量法建立分析天线阵列的基本框架,然后再结合空域格林函数将天线剖分子模的辐射场分解成自由空间部分和含索末菲积分的部分,前者可以直接得到闭式表达,后者采用二级离散复镜像方法得到近似解,经过处理,阻抗矩阵填充速度极大提高。然后基于阻抗矩阵,结合网络理论并利用量子粒子群优化方法(QPSO)对阵列的激励相位进行优化,以控制波束指向和提高增益,能够在电离层参数随时空变化情况下,灵活地完成点对点天波传播,有较高的实际应用价值。