CDMA2000 1X网络规划与其优化研究

文章首先介绍了CDMA2000 1X所采用的关键技术,由CDMA2000 1X的无线网络结构出发,对一般优化措施进行了简单分析,最后对CDMA2000 1X数据业务网络优化进行探讨,对CDMA2000 1X网络的数据业务速率的计算和影响数据业务性能的关键因素以及其他一些优化手段进行了分析。     

中兴通讯CDMA2000 1X ReleaseA系统特性和优势

CDMA2000无线侧标准是一个协议族，可分为以下几个阶段，分别为CDMA2000 1X、CDMA2000 1xEV-D0和CDMA2000 1xEV-DV。CDMA2000 1X能在125MHz无线传输带宽内提供语音业务以及高速分组数据业务，其中1x Release0系统已经在全球大规模商用，技术已经非常成熟，IX ReleaseA系统还未有成熟商用。     

乱弹:"一切即将改变"

小编:2003年3月28日,为外界关注已久的CDMA2000 1×(以下简称为CDMA 1×)以及基于CDMA 1×网络的移动数据业务品牌“联通无限”正式宣告诞生。中国联通此次推出的以“联通无限”(“U—MA×”)为品牌名的CDMA无线数据业务,可以向用户提供包括WAP浏览、彩色图片下载以及速率高达153.6kbds的CDMA 1×无线数据上网服务,并计划在不久后推出无线视频点播、卫星定位服务、电子地图导航和移动电子商务等服务。     

1xEV-DO与HSDPA技术分析与介绍

1.1xEV-DO的特点分析 1xEV-DO是CDMA2000标准系列中专门提供高速分组数据业务的无线标准通信技术.与CDMA2000 1X相比,1xEV-DO技术具有如下特点.     

CDMA2000 1X数据业务无线网络性能测试

本文介绍了CDMA2000 1X无线数据业务，并从CQT和DT两个方面提出了数据业务无线网络性能的测试方法。     

CDMA2000 1x-EV-DO系统空中接口无线链路性能分析计算

首先介绍了CDMA2000 1x-EV-DO技术的产生背景,以及CDMA2000 1x-EV-DO空中接口在系统中的位置及其无线链路性能测试的重要性和必要性,然后描述了CDMA2000 1x-EV-DO系统中空中接口的前向及反向无线链路性能的测试与计算方法,重点介绍了空中接口前向链路和反向链路性能计算所需要的统计信息的生成与获取方法,并针对CDMA2000空中接口测试应用协议的具体功能及其实现过程中所涉及的几个关键步骤进行了分析、讨论,分别提供了相应的解决方案.     

1xEV—DO与HSDPA技术分析与介绍

1xEV—DO的特点分析 1xEV—DO是CDMA2000标准系列中专门提供高速分组数据业务的无线标准通信技术。与CDMA20001X相比，1xEV—DO技术具有如下特点：     

CDMA2000 1X系统反向功率控制性能分析

本文主要分析了CDMA2000 1X蜂窝系统反向链路的功率控制性能，在分析过程中假设无线信道为独立的瑞利衰落信道，分别从功率调节步长、移动台移动速度、功控比特的BER以及信道参数几个功控参数来加以分析研究，并由此得出提高功率控制性能的一些方法。     

lxEV-DO与HSDPA技术分析与介绍

1xEV—DO的特点分析 1xEV—D0是CDMA2000标准系列中专门提供高速分组数据业务的无线标准通信技术。与CDMA20001X相比，lxEV—DO技术具有如下特点：     

新闻

“联通无限”业务家庭再添新丁“神奇宝典”、“定位之星”业务正式开通 目前,联通新时空CDMA 1X网络运行稳定,CDMA用户总数已突破1100万户,其中使用CDMA 1X数据业务的用户已经突破70万户,预计年底将达到300万户。中国联通正在与70多家内容应用开发商合作,大力开发更多的“联通无限”新业务和新应用,以推动CDMA 1X无线数据业务的发展。 据介绍,CDMA 1X网络传输速率最高可达153.6kbit/s,远高于普通Modem拨号上网和ISDN上网速度,这为移动数据业务“联通无限”的发展提供了坚实的基础。CDMA 1X网络及“联通无限”多项数据业务的成功推出,为广大用户提供了全新的移动通信服务选择,也为中国联通提供差异化服务提供了前所未有的机遇。     

Empirical evaluation of receiver‐based TCP delay control in CDMA2000 networks

Wide‐area broadband wireless technologies such as CDMA2000 often suffer from variable transfer rate and long latency. In particular, TCP window‐based rate control causes excessive buffering at the base station because of the lower transfer rate of the wireless link than that of the wired backhaul link. This performance characteristic of TCP further increases the end‐to‐end delay, and additional resources are required at the base station. This paper presents a practical mechanism to control the end‐to‐end TCP delay for CDMA2000 networks (or other similar wireless technologies). The key idea is to reduce and stabilize RTT (round‐trip time) by dynamically controlling the TCP advertised window size, based on a runtime measurement of the wireless channel condition at the mobile station. The proposed system has been implemented by modifying the Linux protocol stack. The experiment results, conducted on a commercial CDMA2000 1x network, show that the proposed scheme greatly reduces the TCP delay in non‐congested networks, while not sacrificing the TCP throughput in congested networks. Copyright © 2006 John Wiley & Sons, Ltd.     

cdma 1X VPDN行业应用无线信道资源优化探讨

通过对"机器到机器"行业应用的cdma 1X VPDN的接入方式的分析,指出行业无线终端接入cdma 1X无线广域网可能导致对cdma1X无线信道高占用、低效率的影响,及cdma1X无线网络资源造成的压力的弊端所在;提出了通过无线信道休眠和唤醒机制的cdma1X VPDN行业应用无线信道资源优化方案。     

无线传感网混合类MAC协议研究综述

在无线传感网( WSN)体系结构中,介质访问控制( MAC)协议负责调配网络中节点的信道接入,具有保障网络高效通信的重要作用。混合类MAC 协议综合了竞争类MAC 协议以及调度类MAC协议的特点,在融合两种机制的优点的同时克服其缺点,为无线信道资源的分配提供了更加灵活和全面的策略。首先概述了无线传感网MAC协议设计要点及分类,然后重点分析了无线传感网中经典的混合类MAC协议及国内外前沿的研究进展,并进一步归纳对比了各协议运行机制、性能及不足,得出混合类MAC协议的应用相关性及差异性的结论,最后总结了无线传感网混合类MAC协议研究现状并指出了未来的研究重点,以期为相关领域的研究人员提供参考。     

协议组合逻辑安全的4G无线网络接入认证方案

针对4G无线网络中移动终端的接入认证问题,基于自证实公钥系统设计了新的安全接入认证方案,并运用协议演绎系统演示了该方案形成的过程和步骤,用协议组合逻辑对该方案的安全属性进行了形式化证明.通过安全性证明和综合分析,表明该方案具有会话认证性和密钥机密性,能抵御伪基站攻击和重放攻击,并能提供不可否认服务和身份隐私性,同时提高了移动终端的接入效率     

Evaluation of a Split-Connection Mobile Transport Protocol

A performance evaluation is presented for a split-connection protocol for wireless Internet access which is denoted Split-Connection Mobile Tranport Protocol (SCMTP). It uses the general approach of the previously introduced Mobile End Transport Protocol (METP) but with differences that include a wireless-link channel-access protocol better matched with current cellular networks and more general ARQ methods for error control in the wireless link. In common with METP, SCMTP uses a standard TCP protocol on the wire-line connection and isolates the data flow in the wire-line network from the effect of wireless packet errors.Performance is considered for the important case of a single SCMTP split connection between a fixed host and a mobile host with heavy downlink traffic from the fixed host to the mobile host. It is shown for these conditions that if the wire-line packet-error rate is small, a steady state is reached in which the connection's data flow in the wire-line network remains under the control of the receiver-advertised window of the TCP entity at the base station. Performance is evaluated for the steady-state operation of the SCMTP protocol, and relationships are established between the key properties of the split connection and the end-to-end performance of the connection.It is shown that for heavy downlink traffic, the delay in the wire-line part of the connection does not affect steady-state throughput if the receiver buffer is sized appropriately. It is also shown that use of the go-back-N ARQ protocol on the wireless link yields better performance than the stop-and-wait ARQ protocol, although the performance with go-back-N ARQ is more sensitive to the characteristics of the wireless channel. It is shown that under a broad range of conditions, SCMTP with go-back-N ARQ provides nearly optimal utilization of the capacity of the wireless link.     

A near-optimum MAC protocol based on the distributed queueingrandom access protocol (DQRAP) for a CDMA mobile communication system

This paper presents and analyzes a new near-optimum medium access control (MAC) protocol. The proposed access scheme is suitable for a CDMA mobile communication environment, and keeps under control and upper bounded the number of simultaneous transmissions. It has a delay performance approaching that of an ideal optimum M/M/K system, where K is the number of spreading codes being used (maximum number of simultaneous transmissions). The protocol is a free random access protocol when the traffic load is light, and switches smoothly and automatically to a reservation protocol when traffic load becomes heavier. It is based on distributed queues and a collision resolution algorithm. Moreover, a physical receiver structure is proposed and analyzed in order to preserve the robustness of the protocol in a wireless link. The results obtained show that the protocol outperforms other well known medium access protocols in terms of stability and delay, even when taking into account the loss caused by channel propagation conditions     

使用EHN-WS-HP机制提高移动切换的TCP性能

无线移动网络的发展日新月异。TCP协议是目前互联网上使用的最为广泛的端到端可靠传输协议，但其应用在无线网络上的时候，TCP性能下降明显。文中详细分析并比较了现有几种机制在移动切换时的性能，针对现有机制不能有效地感知频繁切换的弱点，提出EHN-WS-HP机制。EHN-WS-HP机制在现有EHN-HP协议上进行改进，增加了抗摆动机制（withstand Swing）以处理频繁的切换。     

请求计时到引起手机WAP接入失败的协议分析

针对请求计时到引起GPRS网络中手机WAP接入失败的情况,从WAP协议栈中的WSP协议层、WTP协议层、GPRSRLC/MAC协议层以及GSMUm接口第三层对同时在GPRSGb接口和GSMUm接口采集到的消息进行了关联的协议分析。分析结果表明,请求计时到引起GPRS网络中手机WAP接入失败是由于在超时重传消息过程中手机侧的WTP协议层无响应所致,与GPRS无线承载网络及GSMUm接口无关。     

基于CDMA2000 1x移动台的一种捕获方案及其性能分析

针对CDMA2000的物理层协议．根据并行结构的快速捕获．以及自适应门限控制的方法．提出了一种移动台系统中实用的捕获方案，并对此方案在瑞利衰落信道中的性能进行理论分析。     

基于 CDMA 网络监测系统的研究

将CDMA2000作为无线频谱移动监测系统中数据传输的通道,为无线频谱移动监测系统提供实时的数据,它使得无线频谱移动监测系统更为方便和快捷地对系统内的各种资源进行管理