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1.
当前小体积远端射频单元(Remote Radio Unit,RRU)主要是皮站级别的Pico-RRU,其重量和体积仍然难以满足掌上型的要求。为此,采用高集成度的AD9361芯片来实现长期演进(Long Term Evolution,LTE)宽带收发信机功能,配合时钟同步模块、放大器模块和控制接口电路等一起构建低成本的掌上型RRU。主要解决了基于AD9516的时钟同步、低相位噪声设计和高灵敏度接收机设计三个技术难点,成功实现了掌上型、高性能、低成本的设计目标。整个RRU样机尺寸为18 cm×10 cm×2 cm,质量约500 g,量产成本千元以内。测试表明,该RRU下行误差向量幅度(Error Vector Magnitude,EVM)小于3%,优于3GPP要求的8%;10 MHz带宽时上行接收机灵敏度优于3GPP要求的-93.5 dBm。 相似文献
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介绍了未来高速移动通信新标准IEEE802.20的总体概况,具体分析了IEEE802.20的技术特性、系统参考结构以及系统的组成模型,并对IEEE802.20标准前景分析与展望进行了详细描述。 相似文献
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LEI Hong-zhen CHEN Hao XU Yi-ping LI Yun 《中国经济评论(英文版)》2007,6(3):41-48
The concept and the characteristic of spread spectrum technology of knowledge network based on information integration environment are given at first. And the basic principle of the wireless network of knowledge and information is recommended. Then a project alternatives using the spread spectrum technology and wireless network is given to build a across-the abroad knowledge network system. 相似文献
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Nisrine Mouhrim Ahmed El Hilali Alaoui Jaouad Boukachour 《International Journal of Sustainable Transportation》2019,13(6):419-432
Electric vehicles (EV) use an eco-friendly technology that limits the greenhouse gas emissions of the transport sector, but the limited battery capacity and the density of the battery are the major barriers to the widespread adoption of EV. To mitigate this, a good method seems to be the innovative wireless charging technology called ‘On-Line EV (OLEV)’, which is a contactless electric power transfer technology. This EV technology has the potential to charge the vehicle’s battery dynamically while the vehicle is in motion. This system helps to reduce not only the size of the battery but also its cost, and it also contributes to extending the driving range before the EV has to stop. The high cost of this technology requires an optimal location of the infrastructure along the route. For this reason, the objective of this paper is to study the problem of the location of the wireless charging infrastructure in a transport network composed of multiple routes between the origin and the destination. To find a strategic solution to this problem, we first and foremost propose a nonlinear integer programming solution to reach a compromise between the cost of the battery, which is related to its capacity, and the cost of installing the power transmitters, while maintaining the quality of the vehicle’s routing. Second, we adapt the multi-objective particle swarm optimization (MPSO) approach to our problem, as the particles were robust in solving nonlinear optimization problems. Since we have a multi-objective problem with two binary variables, we combine the binary and discrete versions of the particle swarm optimization approach with the multi-objective one. The port of Le Havre is presented as a case study to illustrate the proposed methodology. The results are analyzed and discussed in order to point out the efficiency of our resolution method. 相似文献
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针对无线传感器网络分簇算法中能量分布不均衡导致的"热区"和簇头负载过重问题,提出了一种基于PSO算法优化簇头选举的非均匀分簇算法。在候选簇头选举和竞争半径计算过程中综合考虑节点动态能量、节点密度和节点距基站距离,将网络进行非均匀分簇,并引入PSO算法进行最终簇头选举。根据节点能量、节点密度和距基站距离确定簇间单跳多跳结合的路由规则,选取代价函数小的节点作为下一跳节点。基于节点信息熵确定融合阈值,进行簇内数据融合剔除冗余数据。仿真结果表明,改进算法的数据传输量比EEUC算法和UCRA算法分别提高了20%和10%,提升了数据的融合效率,有效延长了网络生命周期,簇头能量消耗得到均衡,减少了网络能量消耗,网络的整体性能显著优于其他对比算法。 相似文献
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在国家大力推进产业结构调整、信息化的压力下,物联网技术和O2O商业模式作为信息时代的新型生产力,在国内的普及率并不高。本文运用案例分析的方法通过研究大学生创业项目引入O2O商业模式的概念,并与物联网技术有机结合,把握两者之间优势互补的关系,提出两者创新应用,同时从商业模式构成要素的角度对该模式进行系统、深入分析,为中国现代农业信息化建设和结构调整提供了新思路。 相似文献
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Francesco Schiavone Salvatore Esposito De Falco 《Technology Analysis & Strategic Management》2016,28(1):60-75
Drawing on the structurationist notion of ‘technologies-in-practice’, this article analyses the different types of technological actions that users perform, after technological change, in order to keep a declining technology alive over time. The research question of the article is: How do technologies-in-practice based on the application of new technology hamper the creative destruction of old technology? The case study of ham radio technology and amateur radio operators is explored. The results of the investigation support the development of a technology-in-practice ‘experimentation’ and four inductive research propositions. 相似文献
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