In order to improve the spectral efficiency in wireless communications, multiple antennas are employed at both transmitter and receiver sides, where the resulting system is referred to as the Multiple-Input multiple-output (MIMO) system. In MIMO systems, it is usually requiredto detect signals jointly as multiple signals are transmitted through multiple signal paths between the transmitter and the receiver. This joint detection becomes the MIMO detection.
标签： Complexity Detection MIMO Low
上传时间： 2020-05-27
上传用户：shancjb
The family of recent wireless standards included the optional employment of Multiple-Input Multiple-Output(MIMO)techniques.This was motivatedby the observationaccordingto the classic Shannon–Hartley law that the achievable channel capacity increases logarithmically with the transmit power. In contrast, the MIMO capacity increases linearly with the number of transmit antennas, provided that the number of receive antennas is equal to the number of transmit antennas. With the further proviso that the total transmit power is increased in proportion to the number of transmit antennas, a linear capacity increase is achieved upon increasing the transmit power, which justifies the spectacular success of MIMO systems.
标签： Multi-Functional Systems MIMO
上传时间： 2020-05-31
上传用户：shancjb
This book is about multipoint cooperative communication, a key technology to overcome the long-standing problem of limited transmission rate caused by inter- point interference. However, the multipoint cooperative communication is not an isolated technology. Instead, it covers a vast range of research areas such as the Multiple-Input multiple-outputsystem, the relay network, channel state information issues, inter-point radio resource management operations, coordinated or joint transmissions, etc. We suppose that any attempt trying to thoroughly analyze the multipoint cooperative communication technology might end up working on a cyclopedia for modern communication systems and easily get lost in discussing all kinds of cooperative communication schemes as well as the associated models and their variations.
标签： Communication Multi-point Cooperative Systems
上传时间： 2020-05-31
上传用户：shancjb
The purpose of this book is to introduce the concept of the Multiple Input Multiple Output (MIMO) radio channel, which is an intelligent communication method based upon using multiple antennas. The book opens by explaining MIMO in layman’s terms to help stu- dents and people in industry working in related areas become easily familiarised with the concept. Therefore the structure of the book will be carefully arranged to allow a user to progress steadily through the chapters and understand the fundamental and mathematical principles behind MIMO through the visual and explanatory way in which they will be written. It is the intention that several references will also be provided, leading to further reading in this highly researched technology.
上传时间： 2020-05-31
上传用户：shancjb
The Multiple-Input multiple-output (MIMO) technique provides higher bit rates and better reliability in wireless systems. The efficient design of RF transceivers has a vital impact on the implementation of this technique. This first book is com- pletely devoted to RF transceiver design for MIMO communications. The book covers the most recent research in practical design and applications and can be an important resource for graduate students, wireless designers, and practical engineers.
标签： Transceiver Design RF
上传时间： 2020-06-01
上传用户：shancjb
Driven by the desire to boost the quality of service of wireless systems closer to that afforded by wireline systems, space-time processing for Multiple-Input multiple-output (MIMO) wireless communications research has drawn remarkable interest in recent years. Excit- ing theoretical advances, complemented by rapid transition of research results to industry products and services, have created a vibrant and growing area that is already established by all counts. This offers a good opportunity to reflect on key developments in the area during the past decade and also outline emerging trends.
标签： Space-Time Processing
上传时间： 2020-06-01
上传用户：shancjb
5G通信系统中massive-MIMO-FBMC技术的结合概述摘要为了应对第五代移动通信（5G）中更高数据率和更低时延的需求，大规模MIMO （massive Multiple-Input multiple-output）技术已经被提出并被广泛研究。大规模 MIMO技术能大幅度地提升多用户网络的容量。而在5G中的带宽研究方面，特别 是针对碎片频谱和频谱灵活性问题，现有的正交频分多址（Orthogonal Frequency Division Multiplexing, OFDM）技术不可能应对未来的挑战，新的波形方案需要 被设计出来。基于此，FBMC（filter bank multicarrier）技术由于具有比OFDM低 得多的带外频谱泄露而被受到重视，并已被标准推进组IMT-2020列为5G物理层 的主要备选方案之一。 本文首先回顾了5G中波形设计方案（主要是FBMC调制）和大规模多天线系 统（即massive MIMO）的现有工作和主要挑战。然后，简要介绍了基于Massive MIMO的FBMC系统中的自均衡性质，该性质可以用于减少系统所需的子载波数 目。同时，FBMC中的盲信道跟踪性质可以用于消除massive MIMO系统中的导频 污染问题。尽管如此，如何将FBMC技术应用于massive MIMO系统中的误码率、 计算复杂度、线性需求等方面仍然不明确，未来更多的研究工作需要在massive MIMO-FBMC方面展开来。 关键词：大规模MIMO；FBMC；自均衡；导频污染；盲均衡
上传时间： 2022-02-25
上传用户：
When a system designer specifies a nonisolated dc/dc powermodule, considering the needed input voltage range isequally as important as considering the required performanceattributes and features. Generally, nonisolated moduleshave either a narrow or a wide input voltage range. Narrowinputmodules typically have a nominal input voltage of3.3, 5, or 12 V. For systems that operate from a tightlyregulated input bus—such as those that do not use batterybackup—a narrow-input module is often adequate sincethe input remains fairly stable.Offering greater flexibility, wide-input modules operatewithin a range of 7 to 36 V, which includes the popular12- or 24-V industrial bus. This enables a single module tobe used for generating multiple voltages. These modulesare ideal for industrial controls, HVAC systems, vehicles,medical instrumentation, and other applications that usea loosely regulated distribution bus. In addition, systemspowered by a rectifier/battery charger with lead-acidbattery backup almost always require wide-input modules.System designers who choose power supplies may wantto take a close look at the latest generation of wide-inputdc/dc modules.
标签： Wide-input modules offer dc
上传时间： 2014-12-24
上传用户：dragonhaixm
All inputs of the C16x family have Schmitt-Trigger input characteristics. These Schmitt-Triggers are intended to always provide proper internal low and high levels, even if anundefined voltage level (between TTL-VIL and TTL-VIH) is externally applied to the pin.The hysteresis of these inputs, however, is very small, and can not be properly used in anapplication to suppress signal noise, and to shape slow rising/falling input transitions.Thus, it must be taken care that rising/falling input signals pass the undefined area of theTTL-specification between VIL and VIH with a sufficient rise/fall time, as generally usualand specified for TTL components (e.g. 74LS series: gates 1V/us, clock inputs 20V/us).The effect of the implemented Schmitt-Trigger is that even if the input signal remains inthe undefined area, well defined low/high levels are generated internally. Note that allinput signals are evaluated at specific sample points (depending on the input and theperipheral function connected to it), at that signal transitions are detected if twoconsecutive samples show different levels. Thus, only the current level of an input signalat these sample points is relevant, that means, the necessary rise/fall times of the inputsignal is only dependant on the sample rate, that is the distance in time between twoconsecutive evaluation time points. If an input signal, for instance, is sampled throughsoftware every 10us, it is irrelevant, which input level would be seen between thesamples. Thus, it would be allowable for the signal to take 10us to pass through theundefined area. Due to the sample rate of 10us, it is assured that only one sample canoccur while the signal is within the undefined area, and no incorrect transition will bedetected. For inputs which are connected to a peripheral function, e.g. capture inputs, thesample rate is determined by the clock cycle of the peripheral unit. In the case of theCAPCOM unit this means a sample rate of 400ns @ 20MHz CPU clock. This requiresinput signals to pass through the undefined area within these 400ns in order to avoidmultiple capture events.For input signals, which do not provide the required rise/fall times, external circuitry mustbe used to shape the signal transitions.In the attached diagram, the effect of the sample rate is shown. The numbers 1 to 5 in thediagram represent possible sample points. Waveform a) shows the result if the inputsignal transition time through the undefined TTL-level area is less than the time distancebetween the sample points (sampling at 1, 2, 3, and 4). Waveform b) can be the result ifthe sampling is performed more than once within the undefined area (sampling at 1, 2, 5,3, and 4).Sample points:1. Evaluation of the signal clearly results in a low level2. Either a low or a high level can be sampled here. If low is sampled, no transition willbe detected. If the sample results in a high level, a transition is detected, and anappropriate action (e.g. capture) might take place.3. Evaluation here clearly results in a high level. If the previous sample 2) had alreadydetected a high, there is no change. If the previous sample 2) showed a low, atransition from low to high is detected now.
上传时间： 2013-10-23
上传用户：copu
DirectFB is a thin library that provides hardware graphics acceleration, input device handling and abstraction, integrated windowing system with support for translucent windows and multiple display layers on top of the Linux Framebuffer Device.
标签： acceleration DirectFB hardware graphics
上传时间： 2014-06-30
上传用户：wangchong
