OFDM技术在Beyond3G中的应用

目前,继3G 之后的下一代移动通信系统“Beyond 3G ”或“4G ”的技术研究和标准建议工作正在紧张展开,预计下一代移动通信系统的速率可达到20M bit/s ,最高速率可达100M bit/s,国际电信联盟已经着手有关标准的制定工作。正交频分复用(O FD M )技术因其网络结构高度可扩展,具有良好的抗噪声性能和抗干扰能力以及频谱利用率高而被普遍认为是下一代移动通信系统必不可少的技术。 一、Beyond 3G 系统的特点[1,2] Beyond 3G 将是一种全IP 的网络结构(包括各种接入网与核心网),各种针对不同业务的接入系统连接到基于IP 的核心网中,形成…     

基于MATLAB的OFDM系统仿真分析

正交频分复用（OFDM）是一种多载波宽带数字调制技术，它具有频带利用率高和抗多径干扰能力强等优点，因而适合于高速率的无线通信系统。分析了OFDM技术的实现原理，用MATLAB软件对OFDM的传输性能进行了仿真模拟并对结论进行了分析。     

OFDM仿真软件系统研究

本文将介绍一套自行开发的适用于多种传输系统（包括ＯＦＤＭ－ＤＡＢ、ＯＦＤＭ－ＨＤＴＶ和ＯＦＤＭ－ＤＶＢ等）的ＯＦＤＭ软件仿真系统，并分析载波频偏对ＯＦＤＭ－ＤＡＢ系统和ＯＦＤＭ－ＤＶＢ－Ｔ系统的影响，以及抽样时钟误差对ＯＦＤＭ－ＤＡＢ系统的影响，最后给出相应的仿真测试结果。     

浅谈OFDM技术

在无线信道环境中可靠、高速的传输数据是无线通信技术的目标和要求。OFDM技术能够大幅度的提高无线通信系统的信道容量和传输速率,并能有效地抵抗多经衰落、抑制干扰和噪声,因此,OFDM在无线通信系统中广泛应用。本论文以OFDM系统为基础,介绍了OFDM系统的基本原理,以及使用OFDM技术的优势所在,展望了今后的无线移动技术的发展前景。在简单介绍OFDM原理的同时,给出了OFDM系统模型。     

浅谈OFDM技术

在无线信道环境中可靠、高速的传输数据是无线通信技术的目标和要求。OFDM技术能够大幅度的提高无线通信系统的信道容量和传输速率,并能有效地抵抗多经衰落、抑制干扰和噪声,因此,OFDM在无线通信系统中广泛应用。本论文以OFDM系统为基础,介绍了OFDM系统的基本原理,以及使用OFDM技术的优势所在,展望了今后的无线移动技术的发展前景。在简单介绍OFDM原理的同时,给出了OFDM系统模型。     

OFDM系统仿真与性能分析

正交频分复用（OFDM）是一种特殊的多载波方案,它既是一种调制技术,也是一种复用技术。由于其具有良好的抗频率选择性衰落或窄带干扰、频谱利用率高和成本低的优点,应用越来越广泛。采用Simulink搭建的OFDM仿真系统,既能有效测试OFDM的性能指标,也能研究和理解OFDM特点和具体应用。     

OFDM技术发展综述

正交频分复用（OFDM）是一种无线环境下的高速数据传输技术,它采用相互正交的多载波传递信息,具有很强的抗干扰、抗衰落能力及较高的频谱利用率,被认为是未来无线宽带接入系统的基本实现技术之一。首先对ODFM技术的原理和发展历史加以介绍,阐述了OFDM技术的优势和劣势,然后着重阐述了OFDM技术在移动通信领域的典型应用,以及OFDM在几种主流通信体制中发挥的作用。最后,讨论了OFDM技术的发展方向。     

OFDM系统收端仿真

本文概述了正交频分复用(OFDM)系统的基本原理和数学模型,然后在具有白噪声的信道中进行了仿真,从仿真中可以看出OFDM系统有较好的系统性能。     

OFDM系统仿真与分析

正交频分复用(OFDM)是一种多载波数字调制技术,它能有效地克服传输中的多径干扰和消除码间串扰,所以在高速数据传输中得到了广泛的应用.这里将OFDM系统引入高斯白噪声信道中,实现高速数据的传输,并对误码率进行分析.     

OFDM技术应用浅析

介绍了OFDM技术的基本原理和一些实际应用,重点分析了OFDM在DTTB运用中的优势和发展变化,指出了设计和应用OFDM系统的几个关键点.     

A Simulation Study on Channel Estimation for MIMO-OFDM Based Beyond 3G Mobile Systems

1 Introduction Future wireless cellular communication networks areexpected to fully support multi-media services on a real-ti me basis ,therefore pose a challengingissue of develop-ing high-speed access and high data-rate transmissiontechnologies , which are not satisfied by current 2nd-and3rd-generation cellular mobile communications net-works[1]. Orthogonal Frequency Division Multiplexing(OFDM) has become a popular technique for high datarate wirelesstransmission duetoits many advantagesfo…     

Improved AGC method for B3G MIMO-OFDM system

Automatic gain control (AGC) has an important role in multi-input multi-output-orthogonal frequency-division multiplexing (MIMO-OFDM) system, especially, when receiving antennas are distributed.In recent years, much work has been done on efficiency and simplification of AGC, but few of them are aiming at multiple antennas.This article, on the assumption of ideal AGC for single receiving antenna, analyzes feasible AGC methods for MIMO system from a new aspect, then brings forward three applicable AGC methods separate automatic gain control, joint automatic gain control, and partly-joint automatic gain control (PJ-AGC).After simulation, when parameters are properly set, PJ-AGC has the best performance and can be applied to B3G MIMO-OFDM system.     

基于OFDM的码分多址技术及其性能仿真

给出了多载波CDMA系统构架。目前提出有3种方案,分别是:频域扩频(MC CDMA)、时域扩频(MC DSCDMA)和多音CDMA(MT CDMA)。以MC CDMA,MC DS CDMA为例,对两种模型在AWGN和Rayleigh信道的性能进行了仿真。仿真数据表明:多载波频率分集CDMA系统(MC CDMA)在无线宽带数据传输中性能大大优于时域扩频CDMA系统,具有良好的应用前景。     

Opportunities for IP in Communications Beyond 3G

Future communication will be based on TCP/IP as common network and transport layers to provide global connectivity to users and applications. IP is used to provide ubiquitous access across different access networks and exploits the benefits of a common connectivity layer while reducing the cost of operation and maintenance of the network. This paper discusses the opportunities for IP in the evolution towards a future broadband, all-IP mobile communication network. In particular, we argue for three opportunities for the future: Interworking access technologies over IP, IP layer transparency, and the ability to manage complexity.Thomas Toftegaard Nielsen was born on September 26th 1970 in Århus, Denmark. He holds a M.Sc.E.E. (‘95) and a Ph.D. (‘99) degree in mobile radio communications from Aalborg University, Center for PersonKommunikation, Denmark. In 1996, he joined the Danish mobile operator Sonofon, where he was involved in capacity and performance evaluations and enhancements of the frequency hopping GSM BSS system as well as advanced wireless network planning. In 1999 he was appointed senior radio project manager, where he became technically responsible for the GPRS mobile data dimensioning/planning. In 2000 he joined Ericsson Telebit A/S as wireless IP software development manager. Currently he is responsible for Ericsson’s IPv6/IPv4 termination dual-stack used in the Ericsson 2G, 2.5G and 3G terminal platforms, in parts of the Ericsson 2G and 3G access network as well as in the Ericsson MSC and MGW of the 3G core network.Rune Hylsberg Jacobsen was born in Copenhagen, Denmark, on October 12th, 1970. He holds a M.Sc. degree in physics and chemistry (1995) and a Ph.D. degree in physics (1997) from University of Aarhus. In 1996 he guested Bell Laboratories, Lucent Technologies, USA. During this period he conducted research in optoelectronic, terahertz-bandwidth radiation applied to material characterization. In 1997 he joined the R&D unit of the Danish telecommunication operator TDC where he worked on fixed broadband access, with emphasis on ADSL deployment and the characterization of transmission properties of the local loop. In 1999 he joined Ericsson Telebit A/S and started to work on European research projects in the 4th and 5th EU framework programs. He was appointed department manager for a software development unit in year 2000. In this position he was in charge of an IP router development for the radio access network and has since worked with aspects of using IP for wireless communication systems.     

B3G TDD系统的基带链路架构与时序设计

本文通过参与“863”FuTURE项目中B3G TDD系统的设计与实现过程,探讨B3G系统中基带时序设计和系统中存在的问题,并给出解决方法。     

超100G技术发展浅析

100G技术已启动规模商用前奏,业界关注焦点已转向超100Gbit/s速率。本文分析了超100G技术及产业涉及的一些关键问题,并对超100G未来发展及应用提出了相应观点。     

Adaptive Modulation with Channel Estimation in High-Speed Packet-Based OFDM Communication Systems

1　Introduction　TherapidgrowthofInternetandmobilecommu nicationssuggestthatwirelesshigh speeddataser viceswillbeingreatdemand .Beyond 3Gsystemsaimingatdataratesupto 2 0Mbpsorevenhigherareunderintensivestudy[1～ 3] .Butprovidinghighdataratesinadversewirelesschannelsischalleng ing .OFDMhasbeenconsideredthemostpromisingsolutionforbeyond 3GbecauseofitsrobustnesstoInter SymbolInterference (ISI)andhighspectrumefficiency[4] .　OFDMhasanumberofapplications,includingAsymmetricDigitalSubscriber…     

100G产业化及超100G发展分析

100G高速传输技术日趋成熟,而超100G面临技术抉择。本文分别从100G标准化现状,100G产业化进展,超100G技术路线等方面分别对100G产业化面临的挑战、超100技术的选择等方面进行了较深入的分析。     

3G组网技术研究

作为未来3G的三大主流技术标准,TD-SCDMA．cdma2000和WCDMA已经得到业界的广泛认可。在技术创新和市场驱动的双重作用下,3G技术开始加快从概念向产业化的进程,全球主要设备稍造商都在积极跟黥和研发基于3G技术的阙络产品。对TD-SCDMA,cdma2000和WCDMA的组网能力分别进行了分析,并给出了相应的组网结构和组网模式。     

3G时代位置服务技术研究

由于具备动态3D地图、POI实时更新、实时交通导航等2G时代不具备的特点,3G时代的位置服务必将获得广阔的应用前景。首先介绍了当前三大类主流定位技术——基于网络的定位技术、基于移动终端的定位技术和混合定位技术,并简要分析了COO、AFLT、AGPS、GPSOne等技术的优缺点;然后按被定位单元、位置服务核心子系统、位置服务业务子系统、监控和管理端四个子系统讲解了国内运营商所采纳的主流位置服务平台的体系结构,描述了PDE、MPC、LCSClient等主要网元的功能,最后以一个移动台发起的定位过程为例说明了3G时代位置服务的实现过程。