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multiplexing

数据通信系统或计算机网络系统中,传输媒体的带宽或容量往往会大于传输单一信号的需求,为了有效地利用通信线路,希望一个信道同时传输多路信号,这就是所谓的多路复用技术(multiplexing)。采用多路复用技术能把多个信号组合起来在一条物理信道上进行传输,在远距离传输时可大大节省电缆的安装和维护费用。频分多路复用FDM(FrequencyDivisionmultiplexing)和时分多路复用TDM(TimeDivisionmultiplexing)是两种最常用的多路复用技术。
  • Broadband Wireless Networks

    Emerging technologies such as WiFi and WiMAX are profoundly changing the landscape of wireless broadband.  As  we evolve into future generation wireless networks, a primary challenge is the support of high data rate, integrated multi- media type traffic over a unified platform. Due to its inherent advantages in high-speed communication, orthogonal frequency division multiplexing (OFDM) has become the modem  of  choice for a number of high profile wireless systems (e.g., DVB-T, WiFi, WiMAX, Ultra-wideband).

    标签: Broadband Wireless Networks

    上传时间: 2020-05-26

    上传用户:shancjb

  • Coding+for+MIMO+Communication+Systems

    Employing multiple transmit and receive antennas, namely using multi-input multi-output (MIMO) systems, has proven to be a major breakthrough in providing reliable wireless communication links. Since their invention in the mid-1990s, transmit diversity, achieved through space-time coding, and spatial multiplexing schemes have been the focus of much research in the area of wireless communications. 

    标签: Communication Systems Coding MIMO for

    上传时间: 2020-05-26

    上传用户:shancjb

  • Large-scale+Antenna+Systems

    To meet the future demand for huge traffic volume of wireless data service, the research on the fifth generation (5G) mobile communication systems has been undertaken in recent years. It is expected that the spectral and energy efficiencies in 5G mobile communication systems should be ten-fold higher than the ones in the fourth generation (4G) mobile communication systems. Therefore, it is important to further exploit the potential of spatial multiplexing of multiple antennas. In the last twenty years, multiple-input multiple-output (MIMO) antenna techniques have been considered as the key techniques to increase the capacity of wireless communication systems. When a large-scale antenna array (which is also called massive MIMO) is equipped in a base-station, or a large number of distributed antennas (which is also called large-scale distributed MIMO) are deployed, the spectral and energy efficiencies can be further improved by using spatial domain multiple access. This paper provides an overview of massive MIMO and large-scale distributed MIMO systems, including spectral efficiency analysis, channel state information (CSI) acquisition, wireless transmission technology, and resource allocation.

    标签: Large-scale Antenna Systems

    上传时间: 2020-05-27

    上传用户:shancjb

  • Multicarrier+Techniques+for+4G

    At recent major international conferences on wireless communications, there have been several sessions on beyond third generation (3G) or fourth generation(4G)mobilecommunicationssystems,wheremodulation/demod- ulation and multiplexing/multiple access schemes related to multicarrier techniques have drawn a lot of attention. We often met at the conference venuesandrealizedthatnobookcoveredthebasicsofmulticarriertechniques to recent applications aiming at the 4G systems. Therefore, we decided to write a book on multicarrier techniques for 4G mobile communications systems.

    标签: Communications Multicarrier Techniques Mobile for 4G

    上传时间: 2020-05-30

    上传用户:shancjb

  • OFDM+Baseband+Receiver+Design

    All wireless communication standards, existing and under development, adopt or consider adopting orthogonal frequency-division multiplexing (OFDM) as the modulation technique. It is clear that OFDM has become the definitive modulation scheme in current and future wireless communication systems.

    标签: Baseband Receiver Design OFDM

    上传时间: 2020-05-31

    上传用户:shancjb

  • OFDM+Wireless+LANS

    Before delving into the details of orthogonal frequency division multiplexing (OFDM), relevant background material must be presented first. The purpose of this chapter is to provide the necessary building blocks for the development of OFDM principles. Included in this chapter are reviews of stochastic and random process, discrete-time signals and systems, and the Discrete Fourier Transform (DFT). Tooled with the necessary mathematical foundation, we proceed with an overview of digital communication systems and OFDM communication systems. We conclude the chapter with summaries of the OFDM wireless LAN standards currently in existence and a high-level comparison of single carrier systems versus OFDM.

    标签: Wireless OFDM LANS

    上传时间: 2020-05-31

    上传用户:shancjb

  • OFDM-Based Broadband Wireless Networks

    Emerging technologies such as WiFi and WiMAX are profoundly changing the landscape of wireless broadband.  As  we evolve into future generation wireless networks, a primary challenge is the support of high data rate, integrated multi- media type traffic over a unified platform. Due to its inherent advantages in high-speed communication, orthogonal frequency division multiplexing (OFDM) has become the modem  of  choice for a number of high profile wireless systems (e.g., DVB-T, WiFi, WiMAX, Ultra-wideband).

    标签: OFDM-Based Broadband Networks Wireless

    上传时间: 2020-05-31

    上传用户:shancjb

  • Optical+Communication+Theory+and+Techniques

    Since the advent of optical communications, a great technological effort has been devoted to the exploitation of the huge bandwidth of optical fibers. Start- ing from a few Mb/s single channel systems, a fast and constant technological development has led to the actual 10 Gb/s per channel dense wavelength di- vision multiplexing (DWDM) systems, with dozens of channels on a single fiber. Transmitters and receivers are now ready for 40 Gb/s, whereas hundreds of channels can be simultaneously amplified by optical amplifiers.

    标签: Communication Techniques Optical Theory and

    上传时间: 2020-05-31

    上传用户:shancjb

  • 论文-面向5G的新型多载波传输技术比较

    面向 5G 的新型多载波传输技术比较 摘 要: 介绍了几种面向 5G 的新型多载波传输技术: 滤波器组多载波( FBMC,Filter Bank Multicarri- er) 、通用滤波多载波( UFMC,Universal Filtered Multicarrier) 和广义频分复用( GFDM,Generalized Fre- quency Division multiplexing) 的基本原理,并从第五代移动通信系统( 5G) 支持的应用场景和技术需求的 角度对三种多载波传输技术的优缺点进行比较。研究表明三种多载波传输技术的带外泄露较低,FBMC 系统 不使用 CP( CP,Cyclic Prefix) ,因此具有很高的时频效率,但 FBMC 系统帧的长度比较长,不适合短 包类业务; UFMC 对一组连续的子载波滤波,可以支持较短的帧结构,但 UFMC 不使用 CP,复杂度较高; GFDM 基于独立的块调制,具有灵活的帧结构,鲁棒性好,复杂度比前两者 低,便于实际应用。 关键词: 多载波; 第五代移动通信系统; 滤波器组多载波; 通用滤波多载波; 广义频分复用

    标签: 5G

    上传时间: 2022-02-24

    上传用户:kingwide

  • 5G通信系统中massive-MIMO-FBMC技术的结合概述

    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

    标签: 5G 通信系统

    上传时间: 2022-02-25

    上传用户:tigerwxf1