兼顾GPRS、EDGE数据业务的精细化网络容量需求分析方法

文章提出了一种兼顾GPRS、EDGE数据业务的精细化网络容量需求分析方法,并详细说明了分析流程和思路。通过新的网络容量分析方法可以得到小区级或网络级的容量配置需求,能够为各省市移动通信运营商的精细化网络规划和优化配置提供有价值的参考。     

EDGE无线网络规划技术

EDGE网络是一种基于包交换的，可提供多种速率和不同QoS数据业务的网络，因此EDGE网络规划和优化较GPRS单一业务有很大的不同。文章对EDGE网络覆盖、频率和容量的规划技术分别展开了探讨。     

采用8QAM调制的GSM/EDGE移动通信系统

在与现有GSM/EDGE系统兼容,且不改变该系统发送和接收滤波器的基础上,为了改善基于8PSK调制方案的GSM/EDGE的性能,建议将GSM/EDGE的8PSK调制方式改为8QAM调制方式.并给出相位旋转的方法,解决了功率放大器非线性引起的频谱再生问题.同时,调整了8QAM星座图上的信号点位置,保持了原有EDGE系统发送和接收滤波器.在Matlab仿真实验中表明,相对于现有的GSM/EDGE 8PSK调制方案,GSM/EDGE的8QAM调制方案能够在达到相同误码率的情况下,信噪比提高约5 dB.     

GPRS/EDGE无线信道配置方法

本文从GPRS/EDGE系统的特点出发,首先简单比较了常见的GPRS/EDGE无线信道配置方法,最后介绍了坎贝尔方法在GPRS/EDGE系统中的应用方法。     

基于GSM/GPRS/EDGE网络的业务量预测方法研究

本文具体阐述了三种模型的原理、以及运用三种模型进行预测的流程,同时给出了运用海量真实数据验证出来的结果。     

Statistical Estimation of Fast Varying Channels for Cellular Mobile Telecommunications Systems

The time variant environment in fast channels severely impacts on the performances of classical equalization techniques. A method is proposed here to circumvent this problem, particularly in the severe channel with fast behaviour. To improve the Bit Error Rate (BER) at the receiver, a new approach is proposed for the channel impulse response (CIR) estimation in the Enhanced Data rates for GSM Evolution (EDGE)cellular system. The computation of the CIR h(t) (finite impulse response filter) is performed by using the Least Squares algorithm. Then, a statistical estimation of the CIR is achieved to update the coefficients of the equalizer filter. Computer simulation results show that statistical estimation (CIR re-estimation) provides significant improvement with 250 km/h vehiclespeed (RA250): the bit error rate (BER) is 20% lowered for data bits far from the middle of the burst.     

EDGE在美国移动市场崛起的条件

2003年EDGE成为世界移动通信市场的亮点,先后有美国的CingularWireless和AT&TWire-less、智利的TelefonicaMoviles、我国香港特区的CSL和泰国的AIS开通了EDGE网络及业务。同时,EDGE还为进入欧洲市场开辟了道路。但是纵观当前EDGE的发展态势,美国无疑将率先成为EDGE繁荣的地区。通过对美国移动市场的深入分析揭示出EDGE在美国得以兴起的原因以及探讨EDGE在美国的崛起对世界产生的影响。     

Change in microstructure of Al–Si–Cu casting alloys during high temperature solution treatment

Abstract

The solution treatment in Al–Si system casting alloys is usually performed to obtain supersaturated solid solution and spheroidising Si particles. It can be inferred that a high temperature solution treatment enhances mechanical properties without any special apparatuses or techniques. However, it is well known that the solution treatment close to an eutectic temperature causes local melting. In this study, the change in microstructure of Al–Si–Cu casting alloys, which have been solution treated at temperatures ranging from 773 to 824 K, have been investigated from a viewpoint of Cu concentration and the distributions of micropores and locally melt regions due to eutectic reaction. Tensile and hardness tests were carried out to discuss the relationship between mechanical properties and microstructures. In addition to a surface observation, an internal microstructural observation was carried out using the high resolution X-ray computed tomography. The burnt regions during the high temperature solution treatment were identified to be Cu rich. Porosity increased with increasing the solution treatment temperature. The porosity in the sample solution treated above a binary eutectic temperature was confirmed to be >0˙2 vol.-%. The Cu concentration in the α-phase increased below the binary eutectic temperature.     

EDGE Phase 2核心技术：GERAN

本文介绍了ＥＤＧＥ（Ｅｎｈａｎｃｅｄ Ｄａｔａ ｒａｔｅ ｆｏｒ ＧＳＭ Ｅｖｏｌｕｔｉｏｎ）在第二阶段的无线接入网ＧＥＲＡＮ（ＧＳＭ／ＥＤＧＥ Ｒａｄｉｏ Ａｃｃｅｓｓ Ｎｅｔｗｏｒｋ）的技术标准、业务功能等，并总结出与目前ＧＳＭ网络结构兼容的ＥＤＧＥ Ｐｈａｓｅ ２网络结构布局。     

影响EDGE全曲下载业务速率因素的探讨

文章针对目前全曲下载方式不同于其速率差别较大的情况,通过大量测试,对比分析了WAP下载、随身听1.0、2.0版本3种方式的下载速率情况,探讨了WAP方式下载与随声听下载的工作原理的区别。