CDMA技术标准和系统规划

本文论述了ＣＤＭＡ技术有其优越性，并详细介绍了ＣＤＭＡ系统接口标准，网络同步形式，ＣＤＭＡ系统规划等。     

DS—CDMA系统容量的分析

ＣＤＭＡ技术的开发应用是为了增加系统的通信容量，而ＣＤＭＡ系统的系统容量与系统的信噪比密切相关。本文主要根据信息理论对ＤＳ－ＣＤＭＡ系统的容量作了简要分析，得到了系统总容量的边界，并说明了系统信噪比与容量的关系。     

基于CDMA的第三代移动通信系统

为引起通信界人士对ＣＤＭＡ技术的的关注，对利用ＣＯＤＩＴ试验平台所建立的ＣＤＭＡ第三代移动通信系统进行了简单的介绍。     

CADM数字蜂窝通信技术（一）

无线频谱是最宝贵而有限的资源，为了充分利用这一资源，出现了ＣＤＭＡ技术，本文将主要介绍和分析ＣＤＭＡ的技术基础、ＣＤＭＡ蜂窝系统的构成、工作方式、系统容量、关键技术及其主要特点。     

多载波CDMA系统

介绍了一种基于ＣＤＭＡ技术和ＯＦＤＭ的多载波ＣＤＭＡ系统,并对其三种类型进行了比较。     

码分多址蜂窝移动通信（1）

本文首先介绍ＣＤＭＡ、ＴＤＭＡ和ＦＤＭＡ这三种移动通信多址方式的差异，并介绍目前在数字蜂窝移动通信中，使用直接序列扩谱（ＤＳ－ＳＳ）ＣＤＭＡ的基本原理，在上述基础上简单介绍目前市场推出的窄带ＣＤＭＡ蜂窝移动电话系统，并探讨其容量、分析功率控制对容量的关系，最后，介绍ＣＤＭＡ蜂窝移动电话的自然属性，它对增加容量，提高通信服务质量等方面的一些好处。     

CDMA蜂窝系统反向链的话务容量分析

随着通信技术的发展，ＣＤＭＡ通信体制的潜在技术优势正在得到发掘。本文首先介绍了在ＣＤＭＡ蜂窝系统中呼叫“软阻塞”问题，然后通过严密的数学推导，对功率受控的ＣＤＭＡ蜂窝系统单个扇区反向链的话务容量作了详细分析，其结果具有一定的参考价值．     

模拟系统同DS—CDMA蜂房系统在同一区域内共存分析

本文从蜂房系统的特性出发，在分析模拟系统同ＣＤＭＡ系统相互干扰的基础上，讨论了模拟系统和ＣＤＭＡ系统在同一区域共存时，满足一定质量条件下，ＣＤＭＡ系统的带宽、容量及其模拟系统的频率配置应具有哪些限制。     

CDMA—发展移动通信的领先技术

本文介绍了ＣＤＭＡ数字蜂窝系统的优点，概述了ＣＤＭＡ在北美，欧洲和亚太等地区的商用化情况，以及郎讯科技，摩托罗拉等著名企业ＣＤＭＡ技术的发展趋势。     

CDMA与TDMA数字蜂窝系统频谱效率的比较

在数字蜂窝系统中频谱效率与频谱利用率有着直接的关系。ＣＤＭＡ与ＴＤＭＡ系统的频谱效率可以由系统的无线电容量所体现。本文将在可比条件下对ＣＤＭＡ与ＴＤＭＡ系统的频谱效率进行比较，从而也必然地导致对频率复用系数Ｋ的比较及共信道干扰减少因子ｑ的计算。作者在对蜂窝概念、系统的频谱效率及ＣＤＭＡ系统无线电容量计算方法进行了研究后，较为系统地归纳并提出了ＣＤＭＡ与ＴＤＭＡ频谱效率的具体比较方法，并对一些关键公式来源进行了推导、分析，最后得出了ＣＤＭＡ与ＴＤＭＡ系统频谱效率比较的结果。     

多载波CDMA及其技术简介

多载波CDMA具有更高的灵活性 ,更高的频谱效率 ,简单的检测技术 ,窄带干扰抑制能力等一系列优点 ,引起了研究者的广泛兴趣。文中介绍了三种多载波CDMA技术 ,即MC CDMA (多载波CDMA) ,多载波DS CD MA (直接序列CDMA)和多音CDMA并简单介绍了它们的发射和接收技术。最后还指出多载波CDMA技术所固有的缺陷。     

Performance comparison of asynchronous and synchronouscode-division multiple-access techniques for fiber-optic local areanetworks

Synchronous code-division multiple access (S/CDMA) is investigated for fiber-optic local area networks. It is shown that the large bandwidth expansion required by spread-spectrum techniques, such as CDMA, can be accommodated by using a fiber-optic channel for transmission and incoherent optical signal processing for code generation and correlation. Prime sequence codes, previously developed for a fiber-optic network using (asynchronous) CDMA, are modified to fit a synchronous transmission format. A performance comparison of CDMA and S/CDMA systems reveals that S/CDMA can accommodate a larger number of subscribers and more simultaneous users than CDMA. An environment for which S/CDMA would be suited is discussed     

Spectral overlay of multicarrier CDMA on existing CDMA mobilesystems

A spectral overlay of a narrow-band code division multiple access (CDMA) system and a wide-band multicarrier CDMA system is considered as a means for existing CDMA mobile networks to evolve into a future CDMA network. The achievable joint capacity of the overlaid system is provided and compared with that of another network evolution strategy of spectrally overlaying wide-band single-carrier CDMA to the existing CDMA systems     

广义多载波CDMA技术研究

本文描述了几种不同的多载波CDMA技术 ,并将这几种技术统一成一种格式 ,这被称为广义多载波CD MA ,并给出了仿真结果     

通用多载波CDMA无线传输体制及其研究进展

为实现高速率无线多媒体信息传输,近年来提出了一种新的无线传输体制通用多载波码分多址(GMC CDMA)。在GMC CDMA中,通过把信息符号流转换成符号块后,在符号块级冗余扩频,消除了多用户间干扰和符号间干扰,从而具有对信道衰落不敏感、频谱效率高等优点,提高了系统误比特率性能和容量,是新一代无线通信系统中极具发展前景的技术体制。该文综述了GMC CDMA的原理、设计、性能特点以及研究进展等,并讨论了几个热点研究问题。     

Effect of fading,diversity and interference on the performance of multitone CDMA systems

The performance of a multitone Code Division Multiple Access (CDMA) system is investigated in this paper by considering the effect of multipath fading, diversity and narrowband interference. The performance is evaluated in terms of the average bit error rate when both multiple access and partial band interference are present. Results are obtained by deriving the statistics of the receiver output parameters and then tested by numerical evaluation. The bit error rate performance is analyzed as a function of bit rate, bandwidth, delay range and different diversity techniques, while considering issues relevant to system implementation. Comparisons were made between conventional single‐tone CDMA systems and multitone CDMA systems. The effectiveness of multitone CDMA in suppressing interference compared to conventional CDMA system is analyzed. Results reveal considerable performance improvement of multitone CDMA system over conventional CDMA system. Copyright © 2002 John Wiley & Sons, Ltd.     

CDMA随机多址接入技术研究

CDMA作为一种多址接入技术在无线网络中已广为应用,在多码CDMA和单码CDMA研究的基础上,构造了多码CDMA和单码CDMA在无线分组数据网络中的随机多址接入模型,并且分析了两种系统的吞吐率特性和归一化时延特性。结果证明单码CDMA和多码CDMA具有相同的多址接入性能。     

The necessity for and use of CDMA transmitter filtering in overlaysystems

The concept of code division multiple access (CDMA) overlay has been proposed as a way to take advantage of the unused bandwidth available in sparsely populated narrowband systems. Most research up to this point has focused on the effects of the narrowband system on the CDMA system. However, because the CDMA system is likely to be overlaid on a narrowband system that is already established, it is of equal or greater importance to examine how the CDMA overlay would affect the narrowband system's performance. It is shown that even a lightly loaded CDMA system can have a detrimental effect on a narrowband system to the point where the possibility of overlay may be precluded. To solve this problem, the idea of notch filtering the CDMA signals in an effort to avoid those bands already occupied by narrowband users is examined. For certain filtering methods the effects of CDMA interference on the narrowband system are shown to be greatly reduced, thus making overlay feasible from the perspective of the narrowband system. For the CDMA system, the performance of the minimum mean-squared error (MMSE) receiver was evaluated and it was found to work quite well with CDMA signals that have been notched. With CDMA transmitter filtering, the prospects for overlay become very encouraging     

移动IPv6实施的关键问题及在CDMA网络中的应用

IPv4的NAT缺陷、缺乏固定地址限制了CDMA网络中移动IP业务的发展,CDMA移动网络向IPv6承载过渡是必然趋势。本文探讨了移动IPv6在CDMA网络中的应用,着重分析了CDMA网络中应用移动IPv6所面临的服务质量、安全、认证、DNS自动发现、演进等问题,并对现有CDMA网络实体的改动加以阐述。