移动WiMAX无线网络规划

讨论移动WiMAX无线网络规划流程和方法，阐述规划中需要考虑的重要问题。     

移动WiMAX无线网络规划的流程和方法

WiMAX无线网络规划是当今宽带移动通信领域一个重要的研究课题。本文首先介绍TWiMAXN络结构,接着描述了移动WiMAX无线网络规划的流程,其中详细论述了传播模型校准、链路预算,最后给出了详细规划中频率规划和系统级仿真的过程和方法,为移动WiMAX的大规模建设提供了参考和经验。     

移动WiMAX网络规划中的若干技术问题

本文介绍了新一代移动宽带无线接入技术WiMAX,详细分析了该技术特点,针对WiMAX网络规划的基本要求,讨论了该技术在网络规划方面所面临的一些技术问题。     

关于移动WiMAX业务的探讨

文章探讨了宽带无线接入业务的设计原则,介绍了移动WiMAX的主要业务应用形式设计,包括话音业务、接入业务以及内容和服务类业务,最后指出了移动互联网内容服务是WiMAX业务的发展方向。     

浅谈WiMAX频率规划

简单介绍了WiMAX技术、提高WiMAX频率利用率的方法,并分析了影响WiMAX频率规划的2个因素。     

移动WiMAX的频率复用分析

本文首先简述了网络规划和频率复用问题,然后重点介绍了移动WiMAX在频率复用系数分别为1和3时的对比及分析,得出系统单扇区复用系数为3时的效率要优于复用系数1,但是基站的整体效率则是复用系数为1占优,而这时又会产生较大的干扰,采用部分频率复用则可很好地解决这个问题,最大化了整体频谱效率.     

移动WiMAX网络的移动IP机制分析

移动IP是移动WiMAX核心网络中的关键技术.本文分别从Client Mobile IP(CMIP)和ProxyMobile IP(PMIP)两种方式阐述移动IP在移动WiMAX网络中的实现原理,并对这两种方式进行了比较分析,最后从移动WiMAX网络运营的角度,对移动IP的具体实现进行了探讨并提出建议.     

WiMAX无线网络规划方法

随着宽带无线接入技术的发展,WiMAX无线网络的应用越来越广泛,因此WiMAX网络的规划方法和手段受到越来越多的重视.本文讨论了 WiMAX无线网络在规划中引入的新问题,介绍了WiMAX无线网络规划流程和方法,阐述了规划中需重点考虑的问题.     

WiMAX技术及其网络规划

本文介绍了基于IEEE802.16标准的新一代宽带无线接入技术的概况及网络架构,重点分析了它的技术特点,并讨论了WiMAX网络规划流程和应注意的问题。     

移动WiMAX技术与应用

随着固定WiMAX标准（16d）和移动WiMAX标准（16e）的提出，固定WiMAX的产品已经成熟，移动WiMAX的产品认证测试也即将开始，全球范围内WiMAX系统的试验和商用网络也逐渐展开。本文将就移动WiMAX的标准情况、运营商试验案例以及目前可能面临的问题做简要介绍与分析。     

Efficient signal transmission algorithms for remote sensing gamma radiation over developed mobil WiMax network

This paper overcomes two key issues within radiation monitoring networks. Secure and accurate transmission of detected gamma radiation in remote areas is the first challenge. The second one is related to the robustness of transmitted signal under different fading scenarios. These issues are handled during signal transmission over worldwide interoperability for microwave access (WiMax) networks. The signals are experimentally captured using a ¹³⁷Cs point source, a NaI (TI) detector, and an analog-to-digital converter with 16 MS/s. For the first issue, several algorithms are implemented for secure and efficient transmission of gamma-based signals. These algorithms include encoding of captured signal, decoding, interleaving, and frequency transformation of modulated signal. Encoding and decoding of target signals are conducted using the Reed Solomon technique and convolutional encoding with a Viterbi decoder. A superior algorithm for channel interleaver using the combinational interleaving method is introduced. Fast lifting transform (FLT) is applied for transforming modulated signal into frequency domain. The results declare that CC = 1/2 with BPSK-1/2 coding rate introduces a better BER of 0.00068. A higher SNR of 1.5 dB is accomplished by the combinational interleaving algorithm. For the second issue, several models are suggested for overcoming channel degradations under gamma, exponential, Poisson, and geometric fading. Closed-form expressions that describe outage probability, bit error rate (BER), and symbol error rate (SER) are suggested. Geometric and gamma fading achieve respectively a lower BER of 0.18 and 0.48. These channels demonstrate similar channel performances at 3.6 dB. The proposed models are validated through comparison with published work. Finally, the proposed algorithms enable higher data rate transmission of detected ¹³⁷Cs signals under higher robustness using WiMax networks.     

Tensor methods for MIMO decoupling and control design using frequency response functions

Decentralized control design is commonly applied to design controllers for multi-variable control applications. The success of decentralized control design methodologies hinges on the quality of decoupling of the system. The aim of this paper is to develop a decoupling procedure that applies to multi-variable systems and only requires a frequency response function of the system. The proposed method builds on recent tensor decomposition methods. The potential of the method is shown both in a simulation and using experimental data. When applied on noisy data and on real-life systems, which are not possible to be exactly decoupled, the proposed method typically performs better compared to eigen-decomposition based method.     

5G终端MIMO OTA测试方法研究现状与展望

MIMO(multi-input multi-output)OTA(over-the-air)测试是评估天线系统辐射性能的重要方法,也是设备在研发、生产阶段必经的步骤之一。随着5G移动通信系统的到来,毫米波等新特性的引入,为传统MIMO OTA测试方法带来了新的挑战,也使得OTA测试成为5G毫米波终端唯一可行的测试解决方案。首先论述了5G OTA测试所面临的挑战,分析了4G移动通信系统OTA测试方法在5G OTA性能测试中的适用性,并探究了如何将低频测试方法扩展到毫米波终端测试。然后总结了3GPP对于MIMO OTA测试的研究现状,详细阐述了简单扇形排列的多探头吸波暗室(simple-sectored multi-probe anechoic chamber,SS-MPAC)的系统模型、测试原理以及性能评价指标等,并验证了SS-MPAC配置中利用更少的探头仍可以获得合理的测试精度。最后对未来的研究趋势进行了展望。     

移动WiMax参数指标及射频测试浅析

WiMax技术要在具体的应用场景中体现出自身的优势,才能得到市场的认可,这就需要通过应用测试来衡量系统的性能参数.根据WiMax论坛制定的系统参数指标以及测试要求,WiMax的测试方法分为三部分:协议分析、无线射频分析、传输性能分析.本文主要介绍移动WIMAX参数指标,介绍了一些针对802.16d(2004)、802.16e(2005)的标准信号射频性能测试.     

面向产品制造的MIMO WLAN测试方法

多输入多输出(MIMO)无线通信技术正快速发展,并随着IEEE 802.11n WLAN标准的推进而走入人们的现实生活.虽然802.11n标准草案2.0版刚刚在三月份得以通过,但市场上已经出现了大量相关产品设备.MIMO技术能够在不增大功耗或带宽需求的情况下大幅度提高系统吞吐量.日益复杂的MIMO WLAN芯片组增加了产品线测试的成本,进而增大了最终产品的成本.这将是人们不愿意看到的结果,因为WLAN消费市场无力承受更高的成本.     

Filter design for MIMO sampling and reconstruction

We address the problem of finite impulse response (FIR) filter design for uniform multiple-input multiple-output (MIMO) sampling. This scheme encompasses Papoulis' generalized sampling and several nonuniform sampling schemes as special cases. The input signals are modeled as either continuous-time or discrete-time multiband input signals, with different band structures. We present conditions on the channel and the sampling rate that allow perfect inversion of the channel. Additionally, we provide a stronger set of conditions under which the reconstruction filters can be chosen to have frequency responses that are continuous. We also provide conditions for the existence of FIR perfect reconstruction filters, and when such do not exist, we address the optimal approximation of the ideal filters using FIR filters and a minmax l/sub 2/ end-to-end distortion criterion. The design problem is then reduced to a standard semi-infinite linear program. An example design of FIR reconstruction filters is given.     

为发射器或组件测试选择合适的分析仪

目前,市场上有许多可供选择的分析仪,有些具备非常特殊的专业用途,有些则提供了较多的通用射频测量能力;有些被称为频谱分析仪,有些则被称为信号分析仪.这些分析仪都是用来测量和显示信号频率与幅度之间的关系的.如何在众多型号的分析仪中选择合适的一款需要多方面的考虑,本文将为您解答在挑选市场上各种分析仪时所遇到的疑问,并帮助您做出正确的选购决定.     

Linear transceiver design for multi-user MIMO downlink

An iterative linear transceiver design scheme under sum mean squared error minimisation criterion is proposed. By modifying the structure of the transceiver, the complex computation of the Lagrangian multiplier within the traditional MMSE transceiver design can be effectively obviated, and thus the whole system complexity can be greatly reduced. Because the Lagrangian multiplier has an analytical solution, the transmit precoding matrix also has a closed-form solution, and can be solved easily with fixed-point iterations.     

Geodesical codebook design for precoded MIMO systems

We propose a numerical method for finding packings of multiple-input and multiple-output (MIMO) semi-unitary precoding matrices in Grassmannian manifolds with different metrics. The proposed expansion-compression algorithm (ECA) is practical, simple and produces efficient packings without the need for a sophisticated initialization. With chordal distance metric, the algorithm tends to converge into a degenerated point constellation, where two points contain identical as well as orthogonal columns and distance between them cannot increase further along geodesic. Therefore, we alternate between max-min and min-max clustering parts of ECA algorithm, where the latter prevents degenerated constellations. With Fubini-Study distance metric, the algorithm converges to best known packings without extra min-max processing.