爱立信完成cdma 2000 1xEV-DV演示

近日,爱立信完成了基于商用cdma20001x产品系列的cdma20001xEV-DV的应用演示。爱立信通过其商用cdma2000基站控制器、分组核心网络、移动交换中心和无线基站连接分组平台(CPP)的组成设备,在其位于圣地亚哥的cdma20001xEV-DV实验室进行了一系列数据呼叫。此次cdma20001xEV-DV的测试环境有助于爱立信实现1xEV-DV应用,并先期进一步开发1xEV-DV功能,以加速其商业化应用。爱立信的cdma2000方案还有助于运营商在现有的cdma20001x解决方案基础上实现平稳和经济高效的升级,使其具备提供1xEV-DO服务的灵活性。爱立信完成cdma 2000 1xEV-D…     

cdma2000 1x无线网络规划设计

中国联通CDMA网络二期工程,将主要铺设cdma2O00 1x(以下简称1X)网络,因此该文主要对1X网络的建网方案、基站配置、基站设置和覆盖能力进行了探讨。     

上海贝尔阿尔卡特cdma2000解决方案

为了满足不同客户需求,有效协助运营商节约运营成本,阿尔卡特朗讯开发出了一系列适合不同需要和环境使用的cdma2000基站,包括9216、9224紧凑型基站、9222微基站等,具有多种配置,满足各种组网结构。基站站型丰富,适合各种环境,体积小,容量最大,支持IP Backhaul,降低传输成本。     

朗讯科技扩建VIVO电信3G网络

朗讯科技公司与南半球移动服务运营商VIVO达成一项协议，即扩建和增强VIVO在巴西的cdma2000 1x和cdma2000 1x EV-DO数字网络。此次合作将进一步扩大VIVO网络的覆盖范围，让更多的用户享受到移动语音和高速数据业务。作为项目的一个组成部分，朗讯科技公司将提供移动网络设备，包括移动交换中心和模块化蜂窝40基站以及VitalSuite性能管理软件，用于监控应用和网络基础设施设备的性能。朗讯全球服务部将提供项目的部署与维护服务。     

朗讯推出可延长CDMA设备使用寿命的新基站系统

日前,朗讯科技推出了一种旨在帮助移动运营商使基站容量比原Lucent基站高出3倍的新的cdma2000TM基站系统。原来的Lucent基站配置投入实际使用已经接近十年。随着可进一步提高容量的智能天线等新技术问世,FlexentR CDMA高密度(HD)4.0借助支持新技术,也提供更多的投资获利保障。 (本刊讯)朗讯推出可延长CDMA设备使用寿命的新基站系统     

华为cdma1x网络解决方案

从1995年开始,华为公司就致力于CDMA相关技术的研究积累,1996-1998年承接了国家863项目CDMA WLL系统的开发,成功开发出CDMA原型机,掌握了CDMA的关键技术。2000年成功推出了cdma 1x移动交换系统,2001年又成功推出了基于先进的宽带分组平台的cdma 1x基站。 华为cdma 1x基站系统,是在华为公司成熟的数据通信及移动通信技术平台上开发出的新一代CDMA基站设备。空中接口遵循IS-2000-A标准,提供高质量的语音和高达153.6kbps的数据业务;A接口遵循IOS4.0标准,具有良好的开放性和兼容性。设备在设计上充分考虑我国建设CDM…     

华为cdmalx网络解决方案

从1995年开始,华为公司就致力于CDMA相关技术的研究积累,1996-1998年承接了国家863项目CDMA WLL系统的开发,成功开发出CDMA原型机,掌握了CDMA的关键技术.2000年成功推出了cdma 1x移动交换系统,2001年又成功推出了基于先进的宽带分组平台的cdma lx基站.     

cdma 1x分组域故障分析系统实现及其应用

基于cdma 1x分组域的无线数据业务及增值业务，是中国联通与其它电信运营商市场竞争的优势之一，因此cdma 1x分组域网络维护及优化在cdma 1x网络维护中占有非常重要的地位。本文从设计实现及应用两个方面介绍了一种实时监测cdma 1x分组域网络运行情况，并对网络中存在的故障进行分析的网络故障分析及优化系统，并用应用效果证明了系统在提高分组域PPP连接成功率、解决用户投诉及分组域网络优化等方面起到的作用。     

cdma2000 1x升级到EV-DO的建设策略

主要阐述了cdma2000 1x EV-DO RevA的覆盖、切换以及实际工程建设中的组网和载频配置方案。在实际网络实施中,建议EV-DO RevA建设应以VT等标志性业务的高质量覆盖为目标,采用叠加建网方案。此外,EV-DO RevA网络的规划还应重点关注它与cdma2000 1x网络之间存在的差异,引入新基站,并在核心网络引入服务器,实现2套网络之间的无缝互操作。     

阿尔卡特朗讯为中国联通在澳门部署高速EV-DO网络

阿尔卡特朗讯近日宣布获得中国领先的通信服务供应商——中国联通授予的合同，为其在澳门部署一个覆盖全岛的cdma2000lxEV—DO Revision A（Rev．A）高速无线网络。根据合同规定，阿尔卡特朗讯将为其现有的、由前朗讯为其安装的cdma2000基站提供硬件和软件的升级服务。升级完成后，中国联通将能够为其澳门岛的客户提供诸如多播广播和视频电话等高速的移动数据业务。     

探地雷达图中地下管径尺寸的SVM识别方法

在用探地雷达对地下管道进行探测时,地下管道的雷达图像呈现明显的双曲线特征,但地下管道的管径大小却无法在雷达图中直接反映出来。为了能够同时测量地下管道管径,本文首先采用一种改进的小波包阈值去噪法对雷达图进行去噪预处理,然后采用Hough变换对特征双曲线进行拟合,确定管道的位置,从而实现管道的检测,最后采用支持向量机的方法对拟合的双曲线进行分类,将双曲线分类结果对应到管径分类上,从而间接地实现地下管道管径的识别。实验结果表明:该方法对地下管道管径大小的正确识别率达到90%。该方法能够满足工程应用的实际需要。     

Packet loss and delay performance of feedback and feed-forwardarrayed-waveguide gratings-based optical packet switches with WDMinputs-outputs

This paper analyzes the packet loss and delay performance of an arrayed-waveguide-grating-based (AWG) optical packet switch developed within the EPSRC-funded project WASPNET (wavelength switched packet network). Two node designs are proposed based on feedback and feed-forward strategies, using sharing among multiple wavelengths to assist in contention resolution. The feedback configuration allows packet priority routing at the expense of using a larger AWG. An analytical framework has been established to compute the packet loss probability and delay under Bernoulli traffic, justified by simulation. A packet loss probability of less than 10^-9 was obtained with a buffer depth per wavelength of 10 for a switch size of 16 inputs-outputs, four wavelengths per input at a uniform Bernoulli traffic load of 0.8 per wavelength. The mean delay is less than 0.5 timeslots at the same buffer depth per wavelength     

基于NS2的局域网路由器队列调度算法仿真分析

通过对一中等规模局域网流量分析,得出其流量组成、大小分布等特征;使用实际采集数据,用NS2模拟器模拟分析路由器在实施区分服务前后不同队列调度算法下的性能表现,发现了一些新的特征,由这些新特征可知在实际设备配置过程中,要充分考虑网络实际流量和应用需求,并非所用配置越复杂越好。     

A Vector-Based Routing Protocol in Underwater Wireless Sensor Networks

One major concern shared by many researchers about underwater wireless sensor networks (UWSNs), with respect to the limitations and particularities of underwater environment, is the problem of routing. These limitations include three-dimensional topology, limited bandwidth, node movement, long delay, limited energy, and construction costs. The new routing protocols for underwater networks have been developed on the basis of voracious routing systems. The main problem with UWSNs is finding an efficient route between the source and the target to send more packets to the target with lower levels of energy consumption. In this research, by improving VBF algorithm, which is dependent on the radius of the routing pipe, an algorithm is introduced which considers pipe radius as a function of the environment’s dimensions and of the range and the number of nodes. Consequently, by changing one of these parameters, the radius of the routing pipe changes. However, to control the energy consumed by the nodes, there exists a function that, if the recipient node’s energy to receive the packet is much lower than that of the sender node, the proposed method reduces the size of the routing pipe’s radius to lessen its chance of being selected as the guiding node so that other nodes are able to have the chance of getting the packet’s guiding node. The proposed algorithm has been compared with VBVA, HHVBF, and VBF protocols; the simulation results obtained from NS-2 simulator indicate that the proposed protocol could cut back on energy consumption, especially in networks with high number of nodes, by relying on changing the width of the routing pipe in proportion to network density. It was also successful in delivering more packets in non-dense networks.     

DHCPv6 Relay报文转发功能实现研究

IPv6可以解决当前地址资源匮乏问题,而动态主机配置协议能够实现IPv6地址参数配置的自动化,降低维护人员的劳动强度.基于rfc3315区分不同类型的DHCPv6报文,对13种报文类型的中继过程做出相应处理.在路由器设备上实现中继配置功能和报文转发功能,使客户端即插即用.客户端和服务器不在同一链路时,中继代理有效解决地址配置问题,使IPv6地址成功申请.     

面向深度分组检测的高速数据分组解析结构

提出了一种面向深度分组检测的高速数据分组解析结构BiPPCS（bidirectional packet parsing architecture for content security）。结构采用内容萃取树描述协议的耦合关系从而提高了数据分组解析的灵活性;利用硬件双向并行流水线提升了数据分组解析的处理速率;通过使用节点映射算法来均衡各级流水线上的节点数目优化存储空间;分析和仿真显示BiPPCS在处理速率、空间利用率等方面能取得较好的均衡。     

Design of a scalable pipelined RAM system

This paper describes a scalable pipelined RAM system (SPRAMS) for packet switching. The SPRAMS consists of a two-dimensional array of small memory blocks which are fully pipelined and communicate with adjacent blocks in three directions. The maximum delay of a small memory block becomes the cycle time of the chip. The array configuration is scalable for large memory size without the cycle time variation. It has an initial latency of N+3 cycles with an N×N array configuration. We have designed an experimental 200 MHz 4 kbit static RAM chip with the 4×4 array configuration of 256 bit SRAM blocks. It was fabricated in 0.8 μm single-poly double-metal CMOS technology. Experimental results describe the advantages of SPRAMS     

A Service-Curve Framework for Packet Scheduling With Switch Configuration Delays

In modern packet switches, technology limitations may introduce switch configuration delays that are non-negligible compared with the time required to transmit a single packet. In this paper, we propose a methodology for scheduling of packets, in the context of these technology limitations. If the total tolerable delay through a packet switch is at least on the order of the switch configuration delay, we show that a near 100% utilization of the communication links is possible, while providing strict quality of service guarantees. The main idea is to increase the quantum with which data is scheduled and switched to beyond that of a single packet. This also decreases the rate at which scheduling need to be made, and hence decreases the implementation complexity. The quality of service guarantees we consider are in terms of a service curve. Specifically, we present a framework for the provision of service curves while coping with non-negligible switch configuration delays.     

All-Optical Switches in Optical Time-Division Multiplexing Technology: Theory, Experience and Application

All-Optical Switches in Optical Time-Division Multiplexing Technology: Theory, Experience and Application     

两种微型热管传热性能对比研究

以波形脉动热管和微槽平板热管为研究对象,基于Mixture模型构建了其三维非稳态数学模型,并对模型可靠性进行了验证。采用该数学模型对比了两种微型热管在相同散热空间和散热热流密度情况下的热阻、平均壁面温度和蒸发段壁面温度均匀性。结果表明:相对于微槽平板热管,波形脉动热管热阻更低,传热性能更好;波形脉动热管蒸发段稳态平均壁面温度更低,且随着热流密度的增加该优势更加明显;波形脉动热管在空间尺度上蒸发段壁面温度均匀性更好,且这种优势在高热流密度情况下更突出,但这种均匀性在时间尺度上变化相对剧烈。