Emergingmarketshaveseenanunprecedentedgrowthinthelastfewyears.Theoperatorfocus has been on giving complete coverage to all regions (urban to rural) and to subscription to all – people from the highest to the lowest income groups. When the idea is taking coverage for the remotest of the regions and getting the ‘unconnected–connected’, technology and business modelling are two important focus areas.
标签： Technologies Cellular Emerging Markets for
上传时间： 2020-05-26
上传用户：shancjb
In this paper we revisit hybrid analog-digital precoding systems with emphasis on their modelling and radio-frequency (RF) losses, to realistically evaluate their benefits in 5G system implementations. For this, we decompose the analog beamforming networks (ABFN) as a bank of commonly used RF components and formulate realistic model constraints based on their S-parameters. Specifically, we concentrate on fully-connected ABFN (FC-ABFN) and Butler networks for implementing the discrete Fourier transform (DFT) in the RF domain. The results presented in this paper reveal that the performance and energy efficiency of hybrid precoding systems are severely affected, once practical factors are considered in the overall design. In this context, we also show that Butler RF networks are capable of providing better performances than FC-ABFN for systems with a large number of RF chains.
标签： Analog-Digital Precoding Hybrid
上传时间： 2020-05-27
上传用户：shancjb
With this book at your fingertips, you, the reader, and I have something in common. We share the same interest in mobile radio channels. This area attracted my interest first in autumn 1992 whenImovedfromindustrytoacademiatofindachallengeinmylifeandtopursueascientific career. Since then, I consider myself as a student of the mobile radio channel who lives for modelling, analyzing, and simulating them. While the first edition of this book resulted from my teaching and research activities at the Technical University of Hamburg-Harburg (TUHH), Germany, the present second edition is entirely an outcome of my work at the University of Agder, Norway.
上传时间： 2020-05-30
上传用户：shancjb
Radio propagation measurements and channel modelling continue to be of fundamental importance to radio system design. As new technology enables dynamic spectrum access and higher data rates, radio propagation effects such as shadowing, the presence of multipath and frequency dispersion are the limiting factors in the design of wireless communication systems. While there are several books covering the topic of radio propagation in various frequency bands, there appears to be no books on radio propagation measurements, which this book addresses at length.
标签： Propagation Measurement Radio
上传时间： 2020-06-01
上传用户：shancjb
Modern day large power systems are essentially dynamic systems with stringent requirements of high reliability for the continuous availability of electricity. Reliability is contingent on the power system retaining stable operation during steady-state operation and also following disturbances. The subject of power sys- tem stability has been studied for many decades. With new developments, and there have been many over the past couple of decades, new concerns and problems arise that need to be studied and analysed. The objective of this book is a step in that direction though not ignoring the conventional and well-established approaches.
标签： modelling Stability System Power
上传时间： 2020-06-07
上传用户：shancjb
This introductory chapter is devoted to reviewing the fundamental ideas of control from a multivariable point of view. In some cases, the mathematics and operations on systems (modelling, pole placement, etc.), as previously treated in introductory courses and textbooks, convey to the readers an un- realistic image of systems engineering. The simplifying assumptions, simple examples and “perfect” model set-up usually used in these scenarios present the control problem as a pure mathematical problem, sometimes losing the physical meaning of the involved concepts and operations. We try to empha- sise the engineering implication of some of these concepts and, before entering into a detailed treatment of the different topics, a general qualitative overview is provided in this chapter.
标签： MultivariableControlSystems
上传时间： 2020-06-10
上传用户：shancjb
国外大牛写的电源控制仿真模型，讲解很详细。
标签： 电源控制仿真模型
上传时间： 2021-11-03
上传用户：kent
