GSM无线网的传播模型校正案例

结合GSM全向基站的传播模型校正实例,简要介绍了无线传播模型的种类和校正原理,以及无线传播模型校正的基本流程。     

丘陵地貌下的2.6GHz传播模型校正

从经典的SPM模型及校正流程出发,针对某丘陵地貌城市的2.6 GHz SPM模型校正,进一步结合该城市前期的TD-SCDMA 2 GHz SPM模型校正结果,经过仿真分析和对比,得出了丘陵地貌下的F/D频段传播路径损耗差异,可为有效指导丘陵地貌下的传播模型校正提供参考。     

3G无线传播模型校正

介绍了3G模型校正中CW测试方法和原理、模型校正的方法、模型校正的最小二乘法原理及评判模型正确与否的标准，最后给出了一个传播模型校正实例。     

A市WCDMA无线传播模型校正技术研究

在3G无线网络规划时,为了尽可能减少误差,提高无线覆盖预测和干扰预测的精度,需要对采用的传播模型进行参数校正。本文从传播模型校正原理和方法入手,结合测试环境,对A市市区WCDMA无线传播模型进行校正,并对校正结果进行验证。     

无线传播模型研究

分析了电波传播模型校正原理,探讨了无线传播模型的校正方法,并根据上述原理和方法对武汉密集市区的无线传播模型进行了校正.     

3G移动通信无线传播模型校正

阐述了3G无线传播模型校正的必要性，提出了模型校正的依据以及模型校正的步骤和方法，提出了检验校正结果的措施。     

基于TD-SCDMA系统的传播模型校正的研究

为了提高路径损耗预测的准确性,提出一种快速且精确的传播模型校正方法.该方法基于最小二乘理论,在现有校正方法和本地连续波(CW)实测数据的基础上对本地标准宏蜂窝传播模型进行校正.仿真结果表明,该方法的计算复杂性明显减少,且校正后的模型最大预测错误率减少20.5%,与本地无线传播环境更加匹配.     

无线网规划中的传播模型校正

本文简要介绍了移动通信中传播模型的概念和几种常用的传播模型,论述了模型校正的必要性,并详细介绍了模型校正的步骤,同时对模型校正中可能出现的误差进行了分析.     

WCDMA无线传播模型测试校正

无线传播模型测试与校正是移动通信网络建设的重要步骤．它为网络规划提供覆盖预测的基础。WCDMA系统的工作频段在2GHz左右．与第二代移动通信系统相差大,因此有必要在WCDMA的工作频段内开展传播模型测试与校正工作。     

基于FLAASH和6S模型的Spot 5大气校正比较研究

采用基于大气辐射理论的FLAASH和6S模型,对Spot5遥感影像进行了大气校正,通过比较校正前后地物光谱曲线和NDVI分析两种类型的实际校正效果,结果表明,FLAASH模型能较好地消除了大气影响,对Spot5遥感影像有更好的校正作用。     

Accelerated Microwave Design Optimization With Tuning Space Mapping

We introduce a tuning space-mapping technology for microwave design optimization. The general tuning space-mapping algorithm is formulated, which is based on a so-called tuning model, as well as on a calibration process that translates the adjustment of the tuning model parameters into relevant updates of the design variables. The tuning model is developed in a fast circuit-theory based simulator and typically includes the fine model data at the current design in the form of the properly formatted scattering parameter values. It also contains a set of tuning parameters, which are used to optimize the model so that it satisfies the design specification. The calibration process may involve analytical formulas that establish the dependence of the design variables on the tuning parameters. If the formulas are not known, the calibration process can be performed using an auxiliary space-mapping surrogate model. Although the tuning space mapping can be considered to be a specialized case of the standard space-mapping approach, it can offer even better performance because it enables engineers to exploit their experience within the context of efficient space mapping. Our approach is demonstrated using several microwave design optimization problems.      

Space Mapping Design Framework Exploiting Tuning Elements

Inspired by the ideas of “simulator-based” tuning, implicit space mapping, and surrogate optimization, we propose an implementable microwave design framework. In this framework, we alter an electromagnetic (EM) model by embedding suitable tuning elements. The resulting tuning model is aligned with the original unaltered EM model. We then designate the aligned tuning model as surrogate for design optimization purposes. We illustrate our tuning space mapping framework using a simple microstrip line example. Several microwave examples, including a low-temperature co-fired ceramic filter demonstrate the framework's implementation and robustness.      

TD－SCDMA系统无线传播模型校正的工程应用研究

分析了2种典型的传播模型：Okumura—Hata模型和COST231－Hata模型,重点叙述了数据采集和数据处理、传播模型校正的原理、校正的具体过程及其校正准则。     

Automated computer-controlled tuning of waveguide filters usingadaptive network models

This paper describes a method for computer-controlled tuning of waveguide filters. The tuning algorithm is based on approximate filter network models, which take into account the effects of input/output coupling. Based on measurements of an initial filter design, the approximate network model is then corrected by optimizing the element values such that they minimize the mean square error between the measured and simulated response. The sensitivities of the tuning screws are determined directly from the sensitivities of the element values. Filter tuning is accomplished by gradient optimization of the corrected computer model rather than its physical realization. Only as a final step are the tuning screws of the physical model turned to the position determined by the optimization process     

H参量简化模型的调谐特性与双稳特性的关系

为了研究光栅调谐外腔半导体激光器的调谐特性和双稳特性之间的关系,采用建立H参量简化模型、以载流子密度表征阈值特性的方法,得到了以H参量表达的调谐范围解析式,对反共振所需剩余反射率的上限进行了理论分析,数值模拟了激光出射端反射系数、剩余反射率对调谐范围和双稳环环宽的影响,得到了环宽最大值的位置。结果表明,H参量简化模型能够阐明光栅调谐外腔半导体激光器的调谐特性与双稳特性的关系。     

Sequential tuning of microwave filters using adaptive models and parameter extraction

This paper describes a sequential procedure for computer-aided tuning and diagnosis of multiple-coupled resonator filters. The method is based on a sequential parameter estimation and a systematic tuning procedure and employs three different filter models. A detuned model represents the initial status of the filter after a well-defined detuning procedure. The target filter is described by an ideal model, whereas the actual state of the filter at each tuning step is represented by a coarse adaptive model. The goal of the procedure is the convergence of the coarse model to the ideal model and will be obtained by systematically centering resonant frequencies and coupling coefficients. Practical examples comprising low- and high-degree filters confirm the effectiveness of the proposed approach in both tuning and fault diagnosis.     

Analytic Model for Varactor-Tuned Waveguide Gunn Oscillators (Short Papers)

An analytic model for electronic tuning of an X-band waveguide transferred-electron oscillator is presented. The oscillator is electronically tunable by a varactor, and mechanically tunable by movement of a short circuit. The model is used to predict oscillation frequency, maximum electronic tuning range, and electronic tuning versus varactor bias voltage. Two different methods, the "zero reactance theory" and the Slater perturbation theory, are used to calculate the electronic tuning. The results of these calculations are compared to experimental results for two different oscillator configurations.     

Analysis of tuning in resonant inverter

A model and analysis are presented for tuning of a resonant inverter. The model uses linearised phase-frequency characteristic of a tank load near the resonant frequency. To demonstrate the validation of the model, a low-power prototype was implemented using a CD4046 phase-locked loop chip in the tuning circuit     

Modeling self-pulsating DFB lasers with an integrated phase tuningsection

A theoretical model of a self-pulsating three-section DFB laser with an integrated phase tuning section is established. It is based on traveling wave equations and the standard carrier rate equations. Parameters of an existing device are used for applying the model. Key conditions and characteristics of self-pulsations (SPs) are modeled and compared with experimental results. The important role of phase tuning for turning on the SP is pointed out. The dependence of the SP regime on the detuning between the Bragg wavelengths in the laser and reflector is determined and the essential role of phase-readjustment is identified. Frequency tuning via the laser currents, as well as the pulse shape at various frequencies, is investigated. This allows us to identify the mechanism for frequency tuning. The model turns out to be a good tool to improve our knowledge of the self-pulsation effect and to design optimized devices