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     

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。     

IS-95与CDMA2000技术的发展

目前,CDMA在成为第三代通信系统最主要的无线接入技术后,技术上出现了突习猛进,本文对现有的CDMA技术IS－95与CDMA2000技术作出比较,简要地介绍了CDMA2000的技术特点和其向3G平滑过度的演进过程,进一步探讨IS－95和CDMA2000在今后的发展趋势。     

数字可编程微波／射频集成锁相源的研制与应用

本文介绍一种数字可编程射频锁相源的设计,及其在ＩＳ－９５标准的码分多址（ＣＤＭＡ）移动通信系统中的应用,它由电荷泵型的数字频率合成器,无源三阶环路滤波器,以及压控振荡器构成。作为ＣＤＭＡ移动通信系统本振源,为其提供射频上／下变频器和中频调制／解调器的本振信号、以及基带部分的参考基准信号,具有低相噪、低工作电压、低功耗的特点。文中还给出了使用ＬＭＸ２３３２Ａ／ＬＭ２３３７双环数字频率合成器研制的锁相振荡源的实例及其测试结果,其相位噪声在偏离载频１０ｋＨｚ处,均优于－９２ｄＢｃ。     

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。     

IS－95CDMA系统提高容量的关键技术

容量的需求是推动移动通信技术迅猛发展的根本动力。本文以ＩＳ－９５系统为例，分析了该系统在围绕提高容量方面所采用的几项关键技术，从中反映出了ＣＤＭＡ（码分多址）数字蜂窝系统的一些特点。     

CDMA寻呼信道的容量分析

本文介绍了一种估算CDMA IS-95寻呼信道容量的方法,可用于指导无线网络的设计和规划.     

码分多址（CDMA）技术和公用空中接口综述

本文主要讨论数字移动通信中扩频码分多址技术，阐明了ＣＤＭＡ体制的优越之外，分析了ＣＤＭＡ的关键技术，全面介绍了ＣＤＭＡ系统设计的基本原则和ＩＳ－９５－Ａ空中接口标准的含义。     

Digital wireless local loop system

The digital access technologies for the wireless local loop (WLL) or fixed wireless system are discussed. WLL is an important means of providing telephone services more cheaply and quickly in the developing countries than through a wireline system. Capacities of a WLL system based on the IS-54 (now IS-136) TDMA, IS-95A CDMA, and ETSI GSM technologies are developed and compared     

IS—95CDMA系统的容量分析

容量的需求是推动ＣＤＭＡ数字蜂窝移动通信开发的主要动力。系统的容量受许多因素的影响，本文针对ＩＳ－９５ＣＤＭＡ系统在采用了功率控制、话音激活和扇区划分技术的情况下，对系统的容量进行了分析，同时也分析了功率控制精度对容量的影响。     

DS/CDMA closed-loop power control with adaptive algorithm

Closed-loop power control in the reverse link of a DS/CDMA system is analysed. The transmitter/receiver based on IS-95 and the radio propagation channel under mobile communication environments are modelled and a new power control algorithm is proposed. This algorithm utilises the burst error characteristics of the channel and can be directly applied to the current IS-95 system. The new power control algorithm, with respect to the SIR (signal to interference ratio), increases the service quality, and finally, enhances the system capacity     

Using RF filtering to reduce competitor-induced interference

This paper examines the success of RF filtering on mitigating interference that occurs between two wireless multiple-access systems operating within the same geographic area. Such interference is referred to as "competitor-induced interference" and can significantly degrade system capacity and performance. Three dual-system scenarios are considered: a dual code-division multiple-access (CDMA) (IS-95) system, a CDMA mobile in an FM (AMPS) cell, and an FM mobile in a CDMA cell     

Optimum Power Assignment for Maximum Throughput in CDMA Personal Communication Systems with Integrated Voice/Data Traffic

A CDMA personal communication system with integrated voice/data traffic is considered, in which the link error performance is controlled according to the voice error rate requirement, and the acceptable data traffic error rate is ensured by ARQ. Optimum power assignment (or allocation) between voice and data users is investigated to maximize the total system throughput. A graphical method (the tangent method) is described to obtain this optimum power allocation. The maximum throughput is expressed as a function of other system parameters. The tangent method is further used to measure the impact of transmission quality on the maximum data throughput. Numerical results and a design example are given for a power controlled wideband IS-95 type wireless personal communication system.     

Analysis of peak-to-average power ratio for IS-95 and thirdgeneration CDMA forward link waveforms

The peak-to-average power ratio (PAR) of IS-95-type code division multiple-access (CDMA) forward link waveforms is an important parameter which directly relates to system capacity performance. In this paper, analytical expressions are derived for the PAR. The probability that the instantaneous-to-average power ratio (IAR) exceeds a given value is also derived. The analysis is carried out parametric in 1) the number of active traffic channels; 2) the fractions of power allocated to different forward link channels; and 3) other parameters related to the forward link power budget. An analysis is also given for the distribution of the IAR for the forward link modulation planned for third generation (3G) versions of the IS-95 system and a simple modification to present and future IS-95 modulation schemes is shown that reduces the forward link PAR by up to 3 dB     

Performance analysis of channel-borrowing handoff scheme based onuser mobility in CDMA cellular systems

Code-division multiple-access (CDMA) cellular systems use soft handoff. Although the capacity of CDMA systems is interference-limited in nature, channel shortages may occur because soft handoff uses several channels simultaneously. To cope with this problem, we propose an improved handoff method that borrows channels from stationary calls participating in soft handoff and allocates the borrowed channels to handoff requests by moving calls when a channel shortage occurs. Borrowing from stationary calls is possible because these calls do not undergo fast-fading and do not require receiver diversity. The proposed method is designed to avoid increased interference resulting from channel borrowing. The proposed channel-burrowing handoff scheme is analyzed in a situation involving both moving and stationary calls. A comparison is made between the performances of the typical IS-95-based handoff scheme and the proposed scheme. Numerical results show that the proposed scheme is better than the IS-95 scheme in view of the handoff refused probability, the handoff queuing delay, and total interference     

Evaluation of Capacity and Spectral Efficiency of the Emerging Digital Mobile Systems

Digital cellular systems will have profound implications for the integration of mobile computing and communications allowing true networking on the move. The European-developed GSM system is rapidly becoming the de-facto world standard for mobile communications. Other emerging standards include IS-54 in North America and PDC in Japan, in addition to the CDMA standard (IS-95) in the USA. The aim of this article is to compare the four emerging standards, with particular emphasis on their user capacity and spectrum utilization efficiency.     

码分多址（CDMA）系统设计面面观

本文简要介绍ＩＳ－９５ ＣＤＭＡ系统的重要特性，然后论述ＣＤＭＡ系统规划的几个关键因素。包括通信容量、覆盖范围、传输质量和经济规模之间的利弊关系，同时，本文还说明，由于ＣＤＭＡ系统具有独特的扩频波形，功率控制和软切换等功能，因此，即使是最困难的工程技术问题也可以迎刃而解。     

A new block interleaver and noniterative decision feedback decodingenhance performance of IS-95 CDMA uplink or similar M-ary system

This paper investigates the combination of a new block interleaver design and a noniterative decision feedback receiver/decoder for IS-95 code-division multiple-access (CDMA) uplink in additive white Gaussian noise and a Rayleigh fading multipath environment. The new interleaver design yields better performance than the currently used IS-95 interleaver, with E_b/N₀ improvements of 0.27 to 0.76 dB. At the same time, the new interleaver design improves the effectiveness of a noniterative decision feedback receiver/decoder herein presented. The performance of the proposed design is measured via computer simulation for both coherent and noncoherent detection. A mathematical justification is also given to show the reason why the performance is improved using the proposed design. Based on these results, it is concluded that the use of the new interleaver design with noniterative decision feedback decoding can improve the quality of service and/or capacity of a modified cellular IS-95 system or a system using a similar concatenation of convolutional coding, interleaving, and orthogonal Walsh modulation. Although the approach presented is applied to the uplink of IS-95, it can also be applied to similar M-ary systems