EVDO网络掉话率指标优化的几种方法

主要对CDMA网络中的EVDO掉话理论进行了深入的探讨,并通过一个项目阐述了EVDO掉话优化思路和方法,通过邻区优化,搜索窗调整实践了充分继承1x射频优化成果的原则,并创新性提出了1X与DO功率参数设置最优比例范围。     

cdma 2000无线传输技术

ｃｄｍａ ２０００是面向下一代移动通信设计的宽带无线技术。它采上层、链路层和物理层三层设计，具有较好的灵活性和可伸缩性，可应用于室内外、步行、车载等多种环境。它实现了从现有ＴＩＡ／ＥＩＡ９５－Ｂ系统到下一代移动通信系统的平滑过渡，同时支持系统的信令协议和消息以及与该系统间的切换。     

Low‐complexity robust adaptive generalized sidelobe canceller detector for DS/CDMA systems

A novel low computational complexity robust adaptive blind multiuser detector, based on the minimum output energy (MOE) detector with multiple constraints and a quadratic inequality (QI) constraint is developed in this paper. Quadratic constraint has been a widespread approach to improve robustness against mismatch errors, uncertainties in estimating the data covariance matrix, and random perturbations in detector parameters. A diagonal loading technique is compulsory to achieve the quadratic constraint where the diagonal loading level is adjusted to satisfy the constrained value. Integrating the quadratic constraint into recursive algorithms seems to be a moot point since there is no closed‐form solution for the diagonal loading term. In this paper, the MOE detector of DS/CDMA system is implemented using a fast recursive steepest descent adaptive algorithm anchored in the generalized sidelobe canceller (GSC) structure with multiple constraints and a QI constraint on the adaptive portion of the GSC structure. The Lagrange multiplier method is exploited to solve the QI constraint. An optimal variable loading technique, which is capable of providing robustness against uncertainties and mismatch errors with low computational complexity is adopted. Simulations for several mismatch and random perturbations scenarios are conducted in a rich multipath environment with near–far effect to explore the robustness of the proposed detector. Copyright © 2008 John Wiley & Sons, Ltd.     

移动通信网基于智能HLR的一卡多号业务实现方式探讨

介绍了一卡多号业务的特点，分析了现有一卡多号业务的实现方法，然后分别以某运营商GSM网和CDMA网为例，对基于智能HLR的一卡多号业务的设计与实现过程进行了详细的论述，最后提出了实现一卡多号业务对现网的配合需求。     

关于CDMA网络掉话原因分析

掉话率是网络优化中的一项重要指标，直接影响到移动用户对运营商的满意度。本文主要介绍了CDMA网络优化中经常碰到的几种掉话。通过分析各种掉话的产生原因，从而提出解决办法。并通过实例来说明效果。     

Performance analysis of 3G systems in presence of UWB interference

In this paper,the impact of the interference from multiple ultra wideband(UWB) transmitters to a 3rd-generation(3G) terminal is evaluated under UWB emission power limit regulations of federal communications commission(FCC),european telecommunications standards institute(ETSI) and Japan respectively.A three-dimensional interference model is presented where a discrete spatial distribution of UWB transmitters is considered.It is assumed that a mobile terminal and a large number of UWB devices exist in one room simultaneously.A parameter which characterizes the link budget degradation at the victim receiver is defined to measure the UWB interference to 3G systems.The maximum acceptable density of UWB transmitters and the minimum acceptable distance between UWB transmitters and the 3G terminal are analyzed under different link budget degradations.The simulation results demonstrate that the performance of time division-synchronous code division multiple access(TD-SCDMA) is the best,the one of code division multiple access 2000(CDMA2000) is the worst and the one of wideband code division multiple access(WCDMA) lies between them in presence of UWB interference.     

A real-time dual watermarking algorithm of H.264/AVC video stream for Video-on-Demand service

A real-time dual watermarking algorithm of H.264/AVC compressed video is proposed for Video-on-Demand (VOD) service. The copyright information and user information are modulated by CDMA spreading strategies as watermark. At the encoder side, copyright information is embedded into the first non-zero coefficient of Intra 4 × 4 coded blocks in the luminance components of I frames. An effective error compensation mechanism is simultaneously introduced into the embedding process, which strictly restricts the distortion caused by quantization and watermark embedding within a step size of quantization. At the server side, a XOR based mapping rule is utilized for watermark embedding because the number of non-zero coefficients after quantization is quite less in P frames. Every two bits of the private user information is mapped to three non-zero coefficients of P frames. Experimental results on test sequences demonstrate that the proposed approach has just slight influence on bit rate and PSNR with real-time performance for VOD services, and achieves the dual purposes of copyright protection and pirate tracking.     

CDMA2000 1x增强型技术：将语音容量增至4倍

CDMA2000 1x增强型技术通过干扰消除及其他增强技术,可使客量增至4倍,更高的容量释放了宝贵的频段资源,用于提供更多的语音或基于EV-DO的宽带数据服务.1x增强型技术是基于新型CSM的简单信道卡升级,可以帮助运营商保护现有投资,是现有CDMA2000 1x网络最具成本效益、自然演进的下一步.     

四个核心指标搞定CDMA网络优化常见问题

文章提出了CDMA网络优化中的四个核心指标:FFER、Ec/Io、MTx和MRx,并通过对网优工作中最常见的四类问题的分析指出,熟练掌握这四个指标的意义.就可以快速定位日常网优中遇到的问题,进而大大提升网优效率.     

京津高速铁路CDMA2000 1x网络的性能和优化

文章通过搭建实验室测试系统，模拟时速350公里的高速铁路手机使用场景，分析路测发现的网优问题并给出了解决方法，取得了商用产品抗衰落的实验数据。