CDMA DO网络与1X网络平滑切换技术实现方案

CDMA EVDO.A制式本身在技术体制上存在一定缺陷,即当DO网络信号恶化到一定程度时,系统会自动从DO网络切换到1X网络,当终端处于1X激活态时后续即便DO网络信号恢复,终端也无法重新切换到DO网络,用户所能体验到的最高下行速率仅为153Kbps,而不是DO网络能提供的最高3.1Mbps的下行速率,严重影响用户体验。为此,本课题重点研究在智能终端侧开发控件,利用控件监控网络状态变化,当终端从DO网络切换到1X网络并进入1X激活态时,强制终端进入休眠态,来重新捕获DO网络的问题,从而改善用户感知,提升网络流量。     

上海电信EV-DO信号已实现城郊连续覆盖

至2009年3月底,上海电信EV—DO信号已经实现外环以内及郊区城镇地区的连续覆盖．完成了该区域内宏站和室内覆盖系统寻址、新建、扩容和升级EV—DO的各项工作,为启动cdma2000 1XEV—DO业务试商用提供了保障,使上海成为率先开启电信3G业务的城市之一。     

CDMA2000 1x EV—DO网络技术探讨

文章分别介绍了CDMA2000 1x EV—DO网络结构各个逻辑实体的功能、接口及其相关协议;针对1x EV—DO与CDMA2000 1X混合组网的情况,重点介绍了混合终端的接入鉴权方式,对CDMA 1X与EV—DO网络的互操作进行了简单的阐述。     

CDMA2000标准化进展

依据演进次序．从CDMA20001X、1X EV—DO和1X EV—DV三个方面对CDMA 2000系列标准进行了概括的介绍，并对各标准的主要特点和新增功能进行了概述。     

室内分布系统有源放大设备EV—DO升级改造研究

在国内电信业重组和室内CDMA 1X／EV—D0网络升级的背景下,文章对目前CDMA室内分布系统现状进行分析,重点从室内分布系统有源放大设备升级改造的角度,研究和探讨了升级到EV—DO网络的可行性及方式,并给出了不同场景下的升级改造建议。     

CDMA2000 EV-DO系统与1X系统反向功率控制机制比较

文章对比了CDMA2000EVDO系统及1X系统反向功率控制机制的异同，并结合功率控制过程对EV—DO系统的反向外环功率控制参数进行了描述。     

cdma 2000 1X EV-DO与HSDPA技术分析与比较

1X EV—DO的特点分析 cdma 2000 1X EV—DO是cdma 2000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cdma 2000 1X相比，它具有如下特点。     

CDMA2000标准与技术发展现状

CDMA2000标准是一项不断演进的标准，如图1所示。CDMA2000标准是从最初的2GCDMA IS-95A标准演进到2．5G的CDMA IS-95B标准，然后再到CDMA2000 1X标准，之后，就出现两个分支：一个是CDMA2000标准定义的3X，即将3个CD—MA载频捆绑以提供更高速数据；另一个分支是1X EV，包括1XEV—DO(也称为HR—PD)和1x EV—DV，其中1X EV—DO系统主要为高速无线分组数据业务设计，1X EV—DY系统则能够提供混合高速数据和话音业务。所有系列标准都向后兼容。     

CDMA2000 1X EV—DO Rev．A无线网络特点及其部署策略

文章从CDMA2000 1X EV-DO Rev．A网络的技术特点和业务特征角度出发,以EV-DO Rev．A与1X网络的互干扰分析为基础．探讨在CDMA 1X网络存在的情况下EV—DO Rev．A网络建设的部署策略,并针对中国电信现网情况提出了若干部署建议。     

CDMA2000 1X增强型的演进与优势

CDMA2000 1X增强型是cdma2000技术演进的下一步,其设计目的是将现有CDMA2000 1X系统的语音容量增至4倍,同时显著提升现有无线广域技术的性能．通过高效地增加每个载波的语音容量,1X增强型将帮助运营商释放目前用于语音的频谱资源,并拓展基于版本A或版本B技术的EV—DO数据服务。该技术计划于2011年实现商用,它将以更少的系统设备与终端变更提升数据容量、系统覆盖范围和语音质量.     

Performance evaluation of throughput in optical burst switching

Optical burst switching (OBS) provides a promising solution to utilize the huge terahertz bandwidth of optical wavelength division multiplexing (WDM) transmission technology. To exploit this bandwidth, several reservation schemes have been proposed that include just‐in‐time (JIT) signaling, just‐enough‐time (JET) signaling and burst segmentation (BS). It is necessary to investigate the performance of these schemes under the same constraints for a prescribed OBS application. Accordingly, in this paper, we analyzed and compared the performance of JIT, JET and BS techniques under various scenarios such as network size, delay variation and load variation in an OBS network using various performance metrics, such as the offset time and switch configuration time. Also, the performance of the network under various switching delays was also investigated. The modified BS reservation scheme has been found to yield significantly better performance and better throughput compared with the JIT and JET reservation schemes. Test results show that the effect of varying loads as well as delays significantly impacts the performance of the OBS network. The results presented in this paper are expected to lead further performance improvements in OBS networks using the BS reservation scheme. Copyright © 2010 John Wiley & Sons, Ltd.     

A simple linear multiuser precoding technique in cellular relay networks

In this paper, we propose a simple linear multiuser precoding scheme for downlink cellular systems with a decodeand forward (DF) based relay, where the available information at a base station (BS) and a relay station (RS) is asymmetric. The proposed scheme not only eliminates the interference from a RS for the mobile station (MS) served by a BS but also provides the MS supported by a RS with a macro diversity gain without any information exchange between a BS and a RS. Consequently, the proposed scheme outperforms a conventional scheme and approaches an ideal scheme using dirty paper coding (DPC) in the information asymmetric configuration.     

Direct-coupled microwave filters with single and dual stopbands

This paper presents new ideas for the design and implementation of microwave filters with single and dual stopbands. They can be realized with waveguide, coaxial, dielectric resonators, or in a planar technology. The new methods represent an advance over present methods in that the resonators are direct coupled, thus avoiding the need for transmission line phase lengths between resonator stubs that tend to degrade performance due to their dispersion and are difficult to adjust during tuning. Three bandstop (BS) configurations are presented. The first will accommodate even or odd characteristics and also asymmetric responses, although some negative or diagonal cross-couplings will be needed. The second resembles the cul-de-sac configuration for bandpass filters and needs no diagonal or negative couplings even for asymmetric characteristics. The third is an application of the cul-de-sac synthesis technique to dual-band bandstop (DBBS) filters. All these BS designs are very similar to regular bandpass filters in their design and realization. The design of a DBBS filter is presented and compared with an equivalent bandpass filter to demonstrate its advantages. Finally, the simulated and measured results of a fourth-degree BS filter design in the novel cul-de-sac configuration are presented.     

Finger Replacement Method for Rake Receivers in the Soft Handover Region

We propose and analyze a new finger replacement technique that is applicable for RAKE receivers in the soft handover (SHO) region. More specifically, the receiver uses in the SHO region by default the strongest paths from the serving base station (BS) and only when the combined signal-to-noise ratio falls below a certain pre-determined threshold, the receiver uses more resolvable paths from the target BS to improve the performance. Instead of changing the configuration for all fingers, the receiver just compares the sum of the weakest paths out of the currently connected paths from the serving BS with the sum of the strongest paths from the target BS and selects the better group. Using accurate statistical analysis, we investigate in this letter the tradeoff between error performance, average number of required path comparisons, and SHO overhead offered by this newly proposed scheme.     

Single-input four-output voltage-mode universal filter using single DDCCTA

An electronically tunable universal voltage-mode biquadratic filter with single input and four outputs using one differential difference current conveyor transconductance amplifier (DDCCTA), two resistors and two grounded capacitors is proposed. All the five standard biquadratic filter functions; lowpass (LP), bandpass (BP), highpass (HP), bandstop (BS) and allpass (AP), can be obtained from the circuit configuration. The LP, BP and HP are simultaneously available without component matching condition. By imposing component choice, the BS and AP responses can also be realized from the same circuit configuration. In addition, the proposed circuit provides an electronic control of its natural angular frequency (ω₀) and quality factor (Q) by adjusting the bias current of the DDCCTA. The simulation results together with the ideal values are also given to demonstrate the performance of the proposed circuit.     

Image alignment for 3D reconstruction in a SEM

In a previous paper [1] a procedure to extract the third dimension from back-scattered electron has been proposed. The 3D recovery process involves the acquisition of four images and the computation of surface gradients; thus, a specific algorithm finds the depth map of the given surface. The image acquisition process may require or specific instrumentation (4-sector, independent channel axial BS detector), or very standard SEM configuration and specimen rotation/translation. In this last case an alignment procedure should be developed, which results troublesome because of the different image shadowing. The paper deals with an alignment method based on the parallel acquisition of the BS images and of their respective uniformly shaded twins obtained by the specimen current detector, or by the standard annular axial BS detector.     

5G基站智能节能方案研究

提出一种5G基站智能节能方案,用于降低5G基站设备能耗、节省5G网络运营成本、实现移动通信行业节能减排.所提方案是基于人工智能技术,从网络层面统一配置4G/5G基站节能策略,根据网络选定区域内小区的历史业务数据,构建基站业务负荷预测模型,并生成最优的网络节能策略,根据网络节能策略分别执行各基站的节能任务.在节能任务执行...     

移动通信基站共建共享的工程应用分析

针对基站建设密度增大、选址日益困难的问题,提出了共建共享基站的模式,介绍 了共建共享防雷接地系统、站点空间、AC/DC电源、温控系统、走线架、馈管、传输和塔 桅的基本方法,着重分析了基站共建共享的工程实践应用,并 提供了范例。理论分析和工程应用表明,提出的共建共享具体应用方法具有可行性和有 效性。     

Cross‐layer technique for boosting base‐station anonymity in wireless sensor networks

A wireless sensor network (WSN) principally is composed of many sensor nodes and a single in situ base station (BS), which are randomly distributed in a given area of interest. These sensor nodes transmit their measurements to the BS over multihop wireless paths. In addition to collecting and processing the sensed data, the BS performs network management operations. Because of the importance of the BS to the WSN, it is the most attractive target of attacks for an adversary. Basically, the adversary opts to locate the BS and target it with denial‐of‐service attack to temporarily or indefinitely disrupt the WSN operation. The adversary can intercept the data packet transmissions and use traffic analysis techniques such as evidence theory to uncover the routing topology. To counter such an attack, this paper presents a novel technique for boosting the BS anonymity by grouping nodes into clusters and creating multiple mesh‐based routing topologies among the cluster heads (CHs). By applying the closed space‐filling curves such as the Moore curve, for forming a mesh, the CHs are offered a number of choices for disseminating aggregated data to the BS through inter‐CH paths. Then, the BS forwards the aggregated data as well so that it appears as one of the CHs. The simulation results confirm the effectiveness of the proposed technique in boosting the anonymity of the BS.     

RIGOROUS FULL-WAVE ANALYSIS OF THE BASE-STATION ANTENNAS

Rigorous analysis of the Base-Station (BS) antennas with reflector is made in this letter. The wire-grid modeling of BS antenna is established. In order to improve the solution accuracy and efficiency, some efficient techniques such as three-term sinusoidal interpolation basis function and discrete wavelet transform are used. Numerical examples considered here are the typical vertically polarized and the dual-polarized BS antennas. The calculated results for the vertically polarized BS antenna are in good agreement with the measured data, which show that the analysis modeling used is accurate and reliable.