IMT-2000技术发展

从国际上来说,制定第三代移动通信标准的标准化组织主要有3GPP和3GPP2.3GPP主要负责FDD（WCDMA）和TDD（HCR TDD和LCR TDD）技术的标准化.3GPP2主要负责cdma2000技术的标准化工作.     

TD-SCDMA系统在频谱利用方面的优势

作为我国对国际上第三代移动通信的贡献,我国提出的TD-SCDMA RTF建议,通过三年多的完善和融合,已经成为ITU和3GPP的国际标准.本文将对第三代移动通信中的TDD技术,特别是对TD-SCDMA的特点作简单介绍.然后,着重讨论第三代移动通信有关频谱利用的三个主要问题频谱灵活性、频谱利用率及系统间于扰,以说明TD-SCDMA系统在频谱利用方面的优势.     

IMT-2000技术发展

从国际上来说，制定第三代移动通信标准的标准化组织主要有3GPP和3GPP2。3GPP主要负责FDD（WCDMA）和TDD（HCRTDD和LCRTDD）技术的标准化。3GPP2主要负责cdma2000技术的标准化工作。     

TD-SCDMA在3GPP中的演进

1 引言 TD-SCDMA作为由中国提出的第三代移动通信系统,其国际标准化的工作主要在3GPP中进行。目前在 3GPP的框架下,对于第三代移动通信系统一共包含三种不同的空中无线接口形式,即UTRA FDD(WCDMA), HCR TDD和LCR TDD(TD-SCDMA),其中LCR TDD即为我国提出的TD-SCDMA。低码片速率、TDD的双工方     

在GSM网络中使用TD-SCDM——向第三代移动通信过渡的方案建议

中国现有世界上最大的GSM网,又在以世界上最快的速度在发展。两年之内将面临IS-95 CDMA和第三代移动通信的挑战。本分析了移动通信的发展,提出用在GSM网络基础上提供第三代移动通信业务的方案。在使用以我国建议为主融合形成的CDMA TDD模式的技术和设备的前提下,用本建议方案实现过渡,在顺利演进到IMT2000,建成包括TDD和PDD方式之内的第三代系统时,至2005年所需投人比直接佣GSM系统扩容还低。而且,还避免了背上沉重的第二代设备包袱的风险。     

走向世界的TD-SCDMA——“第一届国际TD-SCDMA高级研讨会”在京胜利召开

<正> 由于国际上第三代移动通信(3G)商用化的一再推迟,而业界对3G的实现及3G标准的选择,逐渐进入了冷静的理性思考阶段。在3G标准中,由于主流技术规范FDD遭受了挫折,这正好为TDD提供了一个崭露头角的发展机会。而基于TDD技术规范的TD-SCDMA标准,也就日益受到了业界的重视。为了适应形势的变化,在西门子、大唐电信、阿尔卡特等公司的推动下,“第一届国际TD-SCDMA高级研讨会”于2001年9月5日在北京顺利召开。 此次研讨会得到了信息产业部和科技部的批准,并由中国移动和中国联通作为     

第三代移动通信TD-SCDMA关键技术介绍

TD－SCDMA（时分同步码分多址）是关于第三代移动通信系统的ITU（国际电信联盟）IMT－2000系统家族中的一员。它将在各种无线环境下建立一个全球性系统。TD－SCDMA是中国提议,由CWTS（中国无线通信标准组织）向ITU提交并被接受的第三代无线通信标准,它同时也被3GPP（第三代协作项目组织）所接受。概述了TD－SCDMA这一标准的关键技术,以及它在对称和非对称的数据传输业务中的优势,运用时分双工（TDD）模式将获得最佳频谱效率。这些关键技术包括TDD运营模式,联合检测和智能天线。TD－SCDMA的无线方案能够在所有的移动无线应用和环境中运行。     

2G到3G演进过程中应注意的主要问题

本文首先简要分析了我国GSM移动通信的发展现状,导出了我国发展第三代移动通信的必要性。然后介绍了国际电联制定的第三代移动通信标准。最后重点阐述了我国GSM网向第三代移动通信网演进时应注意的主要问题,包括对2G网络设备的有效利用问题,3G频率分配规划与运营执照发放改革问题,FDD、TDD有机互补与健康合理发展的问题,以及关平3G标准IPR（知识产权）的问题等等。     

基于TDD的第四代移动通信技术

TDD模式在第三代移动通信中引起了高度重视，随着数据业务的增长、频率资源的紧张，TDD技术研究的深入和TDD系统的不断成熟，在第四代移动通信中TDD模式也将会占有重要的地位，届时拥有自主知识产权的基于TDD模式下的4G通信技术必将成为主流技术。     

2G到3G演进过程中应注意的主要问题

首先简要分析了我国GSM移动通信的发展现状，导出了我国发展第三代移动通信的必要性。然后介绍了国际电联制定的第三代移动通信标准。最后重点阐述了我国GSM网向第三代移动通信网演进时应注意的主要问题，包括对2G网络设备的有效利用问题，3G频率分配规划与运营执照发放改革问题，FDD、TDD有机互补与健康合理发展的问题，以及关乎3G标准IPR（知识产权）的问题等等。     

TD-LTE关键技术在水利防汛中的应用

TD-LTE通信技术采用了国际上先进的LTE通信技术体制,以TDD双工方式为特征,是我国自主创新的TD-SCDMA的演进技术,是下一代移动通信与宽带无线接入融合的典范,也是未来宽带移动通信的主流标准之一。结合水利通信业务的发展,文中分析了TD-LTE的关键技术及特点,并给出了基于TD-LTE技术的网络架构,同时重点介绍了其在水利防汛中的应用。     

未来中国4G开放移动通信终端和网络接入架构

This paper relates to an advanced open mobile communication system and method of integrating the mobile communications, wireless access systems and wired communications into one common platform architecture for China＇s 4th generation mobile communications, supporting costeffective broadband voice, data and video services in wireless, mobile and wired environment with one single integrated mobile terminal device. The paper includes new architecture in the integrated mobile device and converged network access, and minimum modification in the existing mobile telecommunication infrastructures. This paper introduces the long-term evolution strategy for China＇s TDD system platform towards China＇s future 4G mobile communications.     

A vision from the future: beyond 3G TDD

This article introduces the visions and developments of Beyond 3G mobile communications in the China TDD Special Work Group. System structure, radio transmission design, radio resource management, and demonstration system implementation are covered. In system structure, the concept of group cell and the architecture of distributed antennas are introduced. The radio link transmission design presented in this article includes the radio frame structure, multiple access scheme, and promising key techniques. Link-level simulations prove the advantages of the design. The radio resource management strategies are introduced to optimize the system performance. The B3G TDD demonstration system being built by the TDD Special Work Group is also shown finally.     

IMT—2000技术与标准化动向

１９９９年３月,在ＩＴＵ－Ｒ ＴＧ８／１第１６次会议上确定了ＩＭＴ－２０００无线接口参数;目前提交到ＩＴＵ的ＩＭＴ－２０００地面无线传输技术提案已有１０种。其中Ｗ０ＣＤＭＡ和ｃｄｍａ２０００两种主流宽带ＣＤＭＡ技术仍在努力寻求标准的统一,我国提交的ＴＤ－ＳＣＤＭＡ技术与３ＧＰＰ的ＴＤＤ方案也在积极探讨融合。标准融合尽管很困难,但仍存在着可能性。我国在考虑第三代移动通信采取的态度和策略时,应充分兼顾     

The most spectrum-efficient duplexing system: CDD

The game to play in wireless communications, when it comes to increasing spectrum efficiency, is eliminating interference. Currently, all cellular systems use frequency-division duplexing in an attempt to eliminate interference from adjacent cells. The use of many technologies has limited the effects of interference, but two types of interference remain. These are adjacent base-to-home mobile interference and adjacent mobile-to-home base interference, Time-division duplexing has not been used for mobile cellular systems because it is even more susceptible to different forms of interference. Not only is TDD subject to adjacent base-to-home mobile interference and adjacent mobile-to-home base interference; it also has to battle additional adjacent base-to-home base interference, and adjacent mobile-to-home mobile interference. Therefore, TDD can only be used for small confined area systems. Code-division duplexing (CDD) is an innovative solution that can eliminate all four kinds of interference: adjacent base-to-home mobile, adjacent mobile-to-home base, adjacent base-to-home base, and adjacent mobile-to-home mobile in cellular systems. Eliminating each of these types of interference makes CDD the most spectrum-efficient duplexing system. This article elaborates on a set of smart codes that will make an efficient CDD system a reality     

Multiuser MIMO OFDM Based TDD/TDMA for Next Generation Wireless Communication Systems

Multiple-input multiple-output (MIMO) wireless technology in combination with orthogonal frequency division multiplexing (MIMO OFDM) is an attractive air-interface solution for next-generation wireless local area networks (WLANs), wireless metropolitan area networks (WMANs), and fourth-generation mobile cellular wireless systems. In this paper, one multiuser MIMO OFDM systems with TDD/TDMA was proposed for next-generation wireless mobile communications, i.e., TDD/TDMA 4G, which can avoid or alleviate the specific limitations of existing techniques designed for multiuser MIMO OFDM systems in broadband wireless mobile channel scenarios, i.e., bad performance and extreme complexity of multiuser detectors for rank-deficient multiuser MIMO OFDM systems with CDMA as access modes, extreme challenges of spatial MIMO channel estimators in rank-deficient MIMO OFDM systems, and exponential growth complexity of optimal sub-carrier allocations for OFDMA-based MIMO OFDM systems. Furthermore, inspired from the Steiner channel estimation method in multi-user CDMA uplink wireless channels, we proposed a new design scheme of training sequence in time domain to conduct channel estimation. Training sequences of different transmit antennas can be simply obtained by truncating the circular extension of one basic training sequence, and the pilot matrix assembled by these training sequences is one circular matrix with good reversibility. A novel eigenmode transmission was also given in this paper, and data symbols encoded by space–time codes can be steered to these eigenmodes similar to MIMO wireless communication systems with single-carrier transmission. At the same time,, an improved water-filling scheme was also described for determining the optimal transmit powers for orthogonal eigenmodes. The classical water-filling strategy is firstly adopted to determine the optimal power allocation and correspondent bit numbers for every eigenmode, followed by a residual power reallocation to further determine the additional bit numbers carried by every eigenmode. Compared with classical water-filling schemes, it can also obtain larger throughputs via residual power allocation. At last, three typical implementation schemes of multiuser MIMO OFDM with TDMA, CDMA and OFDMA, i.e., TDD/TDMA 4G, VSF-OFCDM and FuTURE B3G TDD, were tested by numerical simulations. Results indicated that the proposed multiuser MIMO OFDM system schemes with TDD/TDMA, i.e., TDD/TDMA 4G, can achieve comparable system performance and throughputs with low complexity and radio resource overhead to that of DoCoMo MIMO VSF-OFCDM and FuTURE B3G TDD.     

TDD的关键技术及其应用前景

本文从时分双工(TDD)方式的相关关键技术、优缺点以及在未来移动通信系统中的地位等方面,对采用TDD方式的移动通信系统的特点与发展趋势进行了深入分析,并给出了一些发展建议.     

时分双工蜂窝系统的智能天线研究和性能评估

智能天线是移动多媒体通信亟待解决的关键技术,本文研究了一种适用于时分双工蜂窝系统,基于非线性判决反馈空间均衡器和递归最小平方算法的智能天线。提出了双向链路信号对干扰加噪声功率比的算法以及阵列波束方向增益和信干比累积分布函数两种性能评估方法。仿真结果表明：该智能可以抵消同波道干扰,改善信干比,减小频率复用系数。     

TDD-TDM多路复用终端设备的研制

介绍TDD-TDM多路复用终端设备的原理、数据格式和电路框图.该设备适合于无线通信的场合.还着重介绍系统的构成、帧结构和有关电路的设计(以8路为例).     

作为第三代移动通信主流技术之一的TD-SCDMA及其演进策略

首先概要介绍了第三代移动通信标准;讨论了在IMT－2000中时分双工（TDD）无线传输技术的主要优点和不足之处;之后较详细地介绍了TD－SCDMA的主工技术特点,包括TD－SCDMA多址技术的选择,基带数字信号处理技术和智能天线;最后讨论了TD－SCDMA的演进策略。