CDMA无线网络优化流程和方法探析

随着我国无线网络的持续进步和网络优化工作的大规模开展,CDMA无线网络优化流程和方法得到了越来越广泛的关注。本文结合作者自身在安徽电信多年从事CDMA网优经验,从阐述CDMA无线网络优化流程入手,对CDMA无线网络优化方法进行了分析。     

CDMA无线网络优化方法及步骤

针对无线网络优化的各个环节，结合CDMA网络的实现原理、性能参数等，对CDMA无线网络优化的方法和步骤进行了详细的阐述。     

应对挑战 创新思维 全面提升CDMA网络优化水平和能力——专访中国电信集团公司无线网络优化中心处长方伟

2008年电信重组后,中国电信承接原中国联通的CDMA网络,正式开始运营移动通信业务。为全面提升CDMA网络质量,向用户提供更好的服务,中国电信于2008年7月成立中国电信无线网络优化中心,全面负责CDMA无线网络优化工作。在中国电信网优中心成立两周年之际,本刊记者专访了中国电信无线网络优化中心处长方伟,请他介绍了中国电信在CDMA网络优化方面的相关情况。     

Search Windows和Neighbor Lists优化--CDMA网络优化面临的重大挑战

随着CDMA网络规模的扩大和新技术的发展，CDMA网络优化正在逐渐深入。除了对掉话（Drop call）和主叫失败（Outgoing Failure）等非正常事件的分析外，越来越多的优化方案逐渐地转移到对更深层次的无线网络参数调整上来，因此“Search Windows”和“Neighbor Lists”优化就成为CDMA网络优化面临最重大的挑战。ACTIX公司针对CDMA网络优化的新特点，提供了针对“SearchWindows”和“Neighbor Lists”等无线网络参数优化的工具包“CDMAToolKit”和“CDMA StateTip”。CDMA Toolkit优化“Search Windows”Search Windows…     

衡炎高速云阳山隧道CDMA网络优化案例分析

为提供移动通信网络的无缝覆盖,保障通信的持续进行和通信质量,隧道无线网络问题的优化解决成为移动通信网络优化的重点。以衡炎高速公路云阳山隧道CDMA无线网络优化为例,通过综合运用邻区调整、前反向搜索窗调整、功率调整、导频增益调整等参数优化以及天馈调整等RF优化措施,使问题最终得到解决,为隧道CDMA无线网络优化提供了参考。     

一种cdma2000的无线网络规划和优化相结合的新技术

本文概述了当今CDMA无线网络优化的特点和问题所在,提出了一种新的将网络优化与网络规划充分结合的技术。并以中国北方某市的CDMA网络和真实路测为基础,利用无线网络状态评估工具Scanner分析,以一个真实的案例来说明该技术的可应用性。     

CDMA网络接入失败原因的分析

详细分析了CDMA移动台接入失败的原因，并提出了相应的解决措施，对CDMA无线网络的网络优化工作有一定的指导作用。     

前向功率控制参数优化分析

在CDMA1X无线网络中,业务信道掉话率的优化工作除了常规的优化方法与手段外,优化人员打破定向思维进行新的优化方法尝试往往会带来更加的效果.前向功率控制参数的调整对CDMA1X网络业务信道掉话率的改善有一定的效果!本文将结合梅州优化人员对CDMA1X无线网络前向功率控制参数的网优实例,阐述通过修改前向功率控制相关参数,...     

CDMA网络接入失败原因的分析

接通率是衡量CDMA移动通信网网络质量的一个重要指标，本文详细分析了CDMA移动台产生接入失败的原因，并提出了相应的解决措施，对CDMA无线网络的网络优化工作有一定的指导作用。     

CDMA无线网络测试及其方法

CDMA无线网络测试是网络工程验收、网络优化、网络评估的前提和依据。文章就CDMA无线网络测试的主要内容和方法进行了详细的介绍,包括基站的测试、呼叫质量CQT测试、移动情况下系统性能DT测试的各项指标及方法。     

基于MapInf0建立大比例尺符号库的方法研究

叙述了基于MapInfo建立地理信息系统地图符号库的必要性和意义，提出了利用MapInfo的二次开发工具MapBasic4．0和计算机图形学理论进行地图符号库的设计与开发的一种方法，可以有效地减少原有MapInfo下符号化的烦琐工作流程，降低地图符号化工作的劳动强度，提高了制图的自动化程度，在工程实践中具有重要意义．     

Communication Coverage in Wireless Passive Sensor Networks

System lifetime of wireless sensor networks (WSN) is inversely proportional to the energy consumed by critically energy-constrained sensor nodes during RF transmission. In that regard, modulated backscattering (MB) is a promising design choice, in which sensor nodes send their data just by switching their antenna impedance and reflecting the incident signal coming from an RF source. Hence, wireless passive sensor networks (WPSN) designed to operate using MB do not have the lifetime constraints of conventional WSN. However, the communication performance of WPSN is directly related to the RF coverage provided over the field the passive sensor nodes are deployed. In this letter, RF communication coverage in WPSN is analytically investigated. The required number of RF sources to obtain interference-free communication connectivity with the WPSN nodes is determined and analyzed in terms of output power and the transmission frequency of RF sources, network size, RF source and WPSN node characteristics.     

Optimization of energy-constrained wireless powered communication networks with heterogeneous nodes

In this paper, we generalize conventional time division multiple access (TDMA) wireless networks to a new type of wireless networks coined generalized wireless powered communication networks (g-WPCNs). Our prime objective is to optimize the design of g-WPCNs where nodes are equipped with radio frequency (RF) energy harvesting circuitries along with constant energy supplies. This constitutes an important step towards a generalized optimization framework for more realistic systems, beyond prior studies where nodes are solely powered by the inherently limited RF energy harvesting. Towards this objective, we formulate two optimization problems with different objective functions, namely, maximizing the sum throughput and maximizing the minimum throughput (maxmin) to address fairness. First, we study the sum throughput maximization problem, investigate its complexity and solve it efficiently using an algorithm based on alternating optimization approach. Afterwards, we shift our attention to the maxmin optimization problem to improve the fairness limitations associated with the sum throughput maximization problem. The proposed problem is generalized, compared to prior work, as it seemlessly lends itself to prior formulations in the literature as special cases representing extreme scenarios, namely, conventional TDMA wireless networks (no RF energy harvesting) and standard WPCNs, with only RF energy harvesting nodes. In addition, the generalized formulation encompasses a scenario of practical interest we introduce, namely, WPCNs with two types of nodes (with and without RF energy harvesting capability) where legacy nodes without RF energy harvesting can be utilized to enhance the system sum throughput, even beyond WPCNs with all RF energy harvesting nodes studied earlier in the literature. We establish the convexity of all formulated problems which opens room for efficient solution using standard techniques. Our numerical results show that conventional TDMA wireless networks and WPCNs with only RF energy harvesting nodes are considered as lower bounds on the performance of the generalized problem setting in terms of the maximum sum throughput and maxmin throughput. Moreover, the results reveal valuable insights and throughput-fairness trade-offs unique to our new problem setting.

     

一种新的大信号射频功率器件建模方法

对小信号网络分析而言,单一的S参数已足够描述器件的特性.但对大信号网络分析而言,则需要更多的数学工具来描述器件的特性.本文采用了一个新的适用于描述大信号非线性特性的描述函数——非线性散射函数.利用非线性散射函数可以完成对大信号射频功率器件的精确建模.     

Fundamental limitations in RF switching and phase shifting using semiconductor diodes

When semiconductor diodes are used as variable impedance switching elements in RF transmission networks, the maximum power and minimum attenuation depend upon the characteristics of the diodes and the function being performed. Equations and theorems are derived which define these limits for quantized RF control networks used in on-off switches, selection switches, and phase-shift devices. The relationships are quite general and the limits are shown to apply to a wide variety of network configurations. It is shown that the maximum power of a switch is proportional to the maximum RF current of the forward-biased diode and also to the maximum RF voltage when reverse-biased. The maximum power in phase shifters is a sinusoidal function of the phase change required. Minimum attenuation depends upon the switching function performed, the frequency of operation, and a newly defined cutoff frequency which includes diode resistance in both forward-bias and reverse-bias states.     

VC中MapInfo地理信息系统的二次开发

介绍了VC中MapInfo地理信息系统的二次开发方法，并着重以VC显示地图和对图层进行操作为例，说明了利用MapX组件进行MapInfo地理信息系统二次开发的方法。     

Resistance Compression Networks for Radio-Frequency Power Conversion

A limitation of many high-frequency resonant inverter topologies is their high sensitivity to loading conditions. This paper introduces a new class of matching networks that greatly reduces the load sensitivity of resonant inverters and radio frequency (RF) power amplifiers. These networks, which we term resistance compression networks, serve to substantially decrease the variation in effective resistance seen by a tuned RF inverter as loading conditions change. We explore the operation, performance characteristics, and design of these networks, and present experimental results demonstrating their performance. Their combination with rectifiers to form RF-to-dc converters having narrow-range resistive input characteristics is also treated. The application of resistance compression in resonant power conversion is demonstrated in a dc-dc power converter operating at 100MHz     

基于CC2420的ZigBee无线网络节点设计

CC2420是适用于ZigBee产品的射频收发器,结合CC2420的性能特点和工作原理,设计了以PIC18F4620单片机为处理器,CC2420为射频收发器的低功耗无线传感器网络节点。给出了CC2420参考应用电路和功放电路原理图。测试表明：当射频发送功率调整到18dBm时,在空旷地域实测两相邻节点最大传输距离为500m。     

Hybrid Optical RF Airborne Communications

The use of hybrid free-space optical (FSO)/radio-frequency (RF) links to provide robust, high-throughput communications, fixed infrastructure links, and their associated networks have been thoroughly investigated for both commercial and military applications. The extension of this paradigm to mobile, long-range networks has long been a desire by the military communications community for multigigabit mobile backbone networks. The FSO communications subsystem has historically been the primary limitation. The challenge has been addressing the compensation of propagation effects and dynamic range of the received optical signal. This paper will address the various technologies required to compensate for the effects referenced above. We will outline the effects FSO and RF links experience and how we overcome these degradations. Results from field experiments conducted, including those from the Air Force Research Laboratory Integrated RF/Optical Networked Tactical Targeting Networking Technologies (IRON-T2) program, will be presented.      

千瓦级快轴流CO2激光器的射频系统

在千瓦级快轴流CO2激光器中,我们用单个射频源通过50Ω传输线和π型网络给8段光管馈电,在这样的安排下将15kw连续波射频功率有效并均匀地耦合到8段光管的等离子体中。这种技术的关键是阻抗匹配。