共查询到18条相似文献,搜索用时 78 毫秒
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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。 相似文献
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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。 相似文献
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瞿轶莫建忠王颖恒应瑛樊忠文 《中国新通信》2021,(14):42-44
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。 相似文献
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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。 相似文献
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Eslam Samy EL‐Mokadem Ahmed Mahmoud El‐Kassas Talaat A. Elgarf Hadia El‐Hennawy 《International Journal of Communication Systems》2020,33(12)
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. 相似文献
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It is well known that the crystalline quality of CdxHg1-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. 相似文献
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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. 相似文献
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Kaushal Mukherjee Subhadeep Mukhopadhyay Sahadev Roy 《International Journal of Communication Systems》2022,35(1):e5021
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. 相似文献
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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。 相似文献