CDMA IS-95系统的特点及演进策略

结合中国联通现有的CDMA IS－95网络，介绍了CDMA IS－95系统的网络结构，技术特点及可提供的业务，介绍了DCMA技术的是及各阶段的技术特点，CDMA系统的演进策略，介绍了cdma2000 lx系统在我国的实验情况。     

CDMA IS-95的安全识别技术

介绍了CDMA IS－95系统的安全和识别技术     

浅述IS-95 CDMA网络的射频规划与设计(下)

介绍了IS－95CDMA的特点和无线网络的设计目标；提出了在规划和设计IS－95CDMA网络时，进行射频设计（如链路设计、基站设置和计算机仿真）的基本理论和方案流程。     

浅述IS-95CDMA网络的射频规划与设计(上)

介绍IS－95CDMA的特点和无线网络的设计目标；提出了在规划和设计IS－95CDMA网络时，进行射频设计（如链路设计、基站设置和计算机仿真）的基本理论和方案流程。     

关于CDMA制式的第三代移动通信展望

移动通信从第一代模拟网络发展到第二代的数字网络,各种制式群雄并起,最终GSM和CDMA两大系统在世界各地得到大规模应用。本文主要对CDMA 2000的发展进行分析和展望。第二代GSM、IS95 CDMA系统提供传统的话音业务和低速率的数据业务,在向第三代移动通信演进的过程中,出现了称之为二代半的GPRS、PDSN系统,它们以ATM/IP网络为基础,通过在传统的电路设备上叠加分组数据网络,提供高速数据业务来实现。IS95 CDMA系统属于第二代移动通信技术,它采用CDMA制式作为空中多址接入技术,分为IS95A和IS95B两个阶段。从核心技…     

北美IS—95双模标准中CDMA系统的关键技术

本文介绍了IS－95标准中关于CDMA部分的关键技术，包括：功率控制、地址码选择、软切换、分集技术、反向CDMA信道调制等。     

智能天线对CDMA系统上行链路的影响

智能天线技术将信号处理由空域、时域、码域扩展到了空域，它已成为第3代移动通信系统的关键技术之一。本文结合IS－95和cdma2000系统的特点，仿真并分析智能天线对CDMA系统上行链路性能的影响。     

CDMA数字蜂窝系统中几个值得注意的问题

一、CDMA蜂窝移动通信发展概要众所周知，CDMA的基础在于扩频技术。扩频技术自50年代中期开始研究，至今已有叙多年历史。70年代中期已在军事抗干扰通信中得到应用，以后逐渐转向民用。在SO年代木叨年代初，数字蜂窝通信中的多址技术一直是人们争论的焦点，这就推动了CDMA技术的高速发展。90年代初，美国提出了CDMA数字蜂窝移动通信系统，其发展速度令人震惊。美国TIA于1993年7月17日通过了CDMA公共空中接口标准IS－95，使CDMA成为与TDMA并驾齐驱的移动通信系统，促进其走向商业化。IS－95公共空间接口俗称QCDMA，其接口标…     

自动路测系统在浙江移动的应用

目前，浙江移动正在使用的自动路测系统是一种自动化程度高，客观性好，采样的时间，范围，样本数量能满足海量数据要求，操作省时省力的采集测试系统。该系统是专门应用于对GSM900／1800的自动路测系统，同时经过扩充可以针对CDMA IS95A／B和CDMA IS2000 1x无线网络实现远程自动测试，可以同时测试最多32个测试终端；每个测试终端支持多个GSM，GPRS、CDMA测试手机，利用无线Modem(GSM／CDMA IS95／CDMA IS2000 1X)讲行测试数据的自动传输；把     

扩频技术在IS-95 CDMA系统中的应用

首先简要介绍了IS－95CDMA系统的结构，在此基础上，以该系统中的前向信道为例，讨论了扩频技术在其中的应用。     

Evolution of wireless data services: IS-95 to cdma2000

Existing IS-95-based CDMA systems support circuit-mode and packet-mode data services at a data rate limited to 9.6-14.4 kb/s. Fueled by the explosive growth of the Internet, applications and market opportunities are demanding that higher capacity, higher data rates, and advanced multimedia services be supported in the near future. The evolution of the IS-95 CDMA standard to higher data rates and more advanced services occurs in two steps. The first step, IS-95-B, is an enhancement to the IS-95-A standard and offers the highest possible performance without breaking current IS-95-A air interface design characteristics, thereby maintaining strict compatibility with existing base station hardware. The proposed standard will support a high data rate (64 kb/s) in both directions, to and from the mobile device. A new burst mode packet data service is defined to allow better interference management and capacity utilization. The second evolution step, cdma2000, provides next-generation capacity, data rates, and services. The cdma2000 system includes a greatly enhanced air interface supporting CDMA over wider bandwidths for improved capacity and higher data rates while also maintaining backward compatibility with existing IS-95 CDMA end-user devices. The cdma2000 system also includes a sophisticated MAC feature to effectively support very-high-data-rate services (up to 2 Mb/s) and multiple concurrent data and voice services. This article describes the design and performance of the high-data-rate service provided by second- and third-generation CDMA systems     

cdma2000反向信道的分析

根据给出的cdma2000系统的反向信道基本构成和技术特点,将RC1(即IS-95CDMA)和RC3两种最为常用的无线配置方法进行了对比,并阐述了cdma2000在扩频调制、功率控制、变速率传输、差错控制以及随机接入方法等方面的改进,而这些改进明显提高了cdma2000的通信性.     

无线分组数据自适应技术

对于分组数据业务来说 ,如果用户有一个良好的连接 ,则蜂窝的频谱效率和数据速率都会得到长足的提高 ,全世界所有的蜂窝标准都利用了这一点来进行数据速率自适应 ,文中就以下几种系统描述数据速率自适应过程 :CDMA (IS - 95 ) ,宽带CDMA (CDMA2 0 0 0和UMTSCDMA) ,TDMA (IS - 136 )和GSM (GPRS和EDGE) ,并探讨一些尚待解决的问题     

从A接口看IS-95到cdma2000 1x的演进

文章主要从A接口的角度,阐述CDMA从IS-95到cdma20001x的演进过程,着重从协议体系结构和业务功能两方面,分别对IS-95系统和cdma20001x系统的A接口进行详细描述,最后简要介绍CDMAA接口的发展趋势。     

Modeling and Performance Evaluation of 3G CDMA Networks with Beamforming

The second generation (2G) code-division multiple access (CDMA) IS-95A cellular network has been deployed for almost ten years. Although the system design rules and operating procedures for voice services are well established and understood, these rules and procedures need to be re-examined in light of several technology innovations. These innovations include the launch of third generation (3G) cdma2000 1× high-rate data services and the new research results in interference cancellation, antenna array and multiple-input multiple-output (MIMO) technologies.We have built a 3G cdma2000 1× cellular simulator, which simulates the physical layer using MATLAB and networking layers using OPNET Modeler, to investigate various design issues of cdma2000 1× networks. This paper explores the use of a simple beamforming model and investigates the effectiveness of deploying antenna array techniques in cdma2000 1× networks. The capacity improvement for CDMA networks using antenna array techniques is evaluated under different deployment scenarios (voice versus data services and various number of antenna elements). Based on the performance evaluation results it is proposed to utilize beamforming as one of the elements in quality of service (QOS) provisioning for data services and to couple antenna arrays with dynamic soft handoff threshold adjustment for further improvement in the system capacity.This paper was presented in part at IEEE 60th Vehicular Technology Conference (VTC), Los Angeles, CA, USA, Sep. 26–29, 2004.     

cdma2000接入技术

IS-95中的接入技术已无法满足分组数据业务和多媒体应用的需求,在IS-95的基础上,cdma2000系统制定了自己的接入方案。介绍了cdma2000的接入技术,并对其性能进行了分析。     

cdma2000 1x无线网络规划方法

由于无线频带资源有限,因此在无线网络规划中应着重考虑如何提高频谱效率。描述了cdma20001x无线网络规划过程,cdma20001x的基本特点,并比较了cdma20001x系统与IS-95系统在无线网络规划上的差异。     

A new base station receiver for increasing diversity order in a CDMA cellular system

A new base station receiver is proposed and analyzed for a code-division multiple-access (CDMA) cellular system. The proposed receiver can achieve remarkable diversity gain by increasing diversity order with reasonable cost and complexity. From the numerical results, it is confirmed that the proposed receiver structure can be a practical solution for enhancing reverse-link capacity and improving performance in CDMA cellular system operations. The result in the letter can find its applications to legacy IS-95/cdma2000 1x base stations with simple modifications.     

Adaptation techniques in wireless packet data services

Today's cellular systems are designed to achieve 90-95 percent coverage for voice users (i.e., the ratio of signal to interference plus noise must be above a design target over 90 to 95 percent of the cell area). This ensures that the desired data rate which achieves good voice quality can be provided “everywhere”. As a result, SINRs that are much larger than the target are achieved over a large portion of the cellular coverage area. For a packet data service, the larger SINR can be used to provide higher data rates by reducing coding or spreading and/or increasing the constellation density. It is straight-forward to see that cellular spectral efficiency (in terms of b/s/Hz/sector) can be increased by a factor of two or more if users with better links are served at higher data rates. Procedures that exploit this are already in place for all the major cellular standards in the world. In this article, we describe data rate adaptation procedures for CDMA (IS-95), wideband CDMA (cdma2000 and UMTS WCDMA), TDMA (IS-136), and GSM (GPRS and EDGE)     

Phone standby time in cdma2000: the quick paging channel in softhandoff

cdma2000 is one of the proposals currently being reviewed for the 3G systems. This paper addresses one of the areas of improvement of cdma2000 over the IS-95based systems-the standby time of the phone. This paper proposes a novel scheme for the paging channel by splitting it into three parts. It analyzes the design of the quick paging channel (QPCH) and characterizes its performance for various conditions. This paper also looks at a way to put this common channel in soft handoff, thereby improving the reliability and leading to a better standby time for the cdma2000 phones. Both the physical layer and network implications are analyzed in detail