软件无线电在通信中的应用

软件无线电技术是90年代新技术之一,该技术是把硬件作为无线通信的通用平台,使它尽可能地脱离通信体制、信号波形和通信功能,尽可能多地由软件来实现,这样的无线通信系统具有很好的通用性、灵活性,而且系统升级也变得非常容易.软件无线电这些特点和优越性使它在通信领域中有着极广泛的应用天地.本文主要介绍了它在个人移动通信、军事通信、卫星通信中的应用.     

软件无线电在电子战系统中的应用探讨

简要地介绍了软件无线电的概念、特点,并较详细探讨了以软件无线电为核心的电子战干扰发射机、侦察接收机的组成方框图和工作原理,以及在应用中所要注意的问题.     

基于多信道软件无线电通用平台的测试及故障诊断技术研究

研究多功能可重构软件无线电开发、测试与评估通用平台技术,验证多信道软件无线电技术可实现性,突破平台设备实现级关键技术,通过论证,证明了基于通用平台的测试及故障诊断技术的可行性,及多信道软件无线电在不同应用领域通信系统的适应性和可重构性。     

软件通信体系结构CORBA 中间件应用及指标评测

软件通信体系结构采用“组件+ 框架”的架构设计，将软件无线电系统中的波形应用软件资源及平台 硬件资源抽象成具有标准接口的组件，通过核心框架对各类资源进行装配部署，形成相应的波形应用。在大规 模综合化软件无线电系统中，每个组件之间存在大量接口调用与数据通信，而每个组件都运行于独立的进程空 间中，这是典型的分布式应用场景，中间件是实现组件间互联互通互操作的关键技术。基于软件通信体系结构 对传输机制的要求，对目前主流的中间件进行了选择与应用分析，并完成CORBA 中间件的性能指标评测。     

民用航空通信发展之轨迹

在民用航空领域，及时可靠的通信是飞行安全和航班正常运营的最基本保障之一。早在民用航空发展初期，无线电、电话和电报等通信技术就被引入，应用于航空器与地面之间以及地面单位之间的通信联系。随着民用航空的快速发展和通信技术的不断突破，航空通信系统已发展为承载空中交通服务通信、航空运行控制通信等多种关键业务、由地空通信和地面网络组成的全球范围的通信系统。目前，     

软件无线电的可重构流处理器体系结构

 针对软件无线电中存在通用数字信号处理器（DSP）计算能力不足以及专用基带处理器缺乏扩展性的问题,提出了一种新的处理器：面向软件无线电的可重构流处理器及相应的专用指令集。仿真证明,该处理器的可重构设计具备指令集扩展能力,可以对多种无线通信标准甚至是新的通信标准提供支持;面向软件无线电的流体系结构和专用指令集保证了对多种高速无线基带信号的实时处理,运算能力是通用DSP的5~13倍。该处理器为软件无线电中的硬件设计难题提供了一种新的解决途径。     

正交调制解调算法在软件无线电中的应用

软件无线电中信号的调制与解调是研究的重点问题之一。在通用的硬件平台上,采用不同的软件算法来实现不同调制与解调是软件无线电的核心思想。本文提供了一种正交调制解调结构,并给出了用FPGA实现的简化算法,该方法能够很好地满足软件无线电中的要求,最高可达8Mbps的信息传输速率。     

软件无线电技术在测控系统中的应用研究

本文引出了软件无线电测控技术的概念，初步提出了软件无线电技术在航天测控领域的应用和总体方案，并对其关键技术进行了分析。     

美空军强化对新技术开发

美国空军作战司令部正在面临财政与结构调整的压力,但并没有阻碍他们对未来战争威胁与对策的研究。可以肯定地说,随着第一支无人机侦察和信息战中队的建立,侦察和信息战已成为美国空军作战司令部目前最优先考虑的领域。     

软件无线电雷达标准体系研究

简要分析了国内外软件无线电雷达及其标准体系研究现状,介绍了软件无线电雷达系统架构,最后提出了构建软件无线电雷达标准体系的初步设想。     

某型机VHF电台通讯距离短问题的解决

提出了某型机VHF电台通讯距离短的问题,简述了对某型机VHF电台进行地面试验、空中作用距离试飞情况。并用通讯原理,对VHF电台通讯距离短进行了理论分析,采取了整改措施。最终解决了某型飞机VHF电台通讯距离短的问题,使飞行通讯联络正常。     

直升机超短波通信链路分析

通过对超短波通信链路的分析,得出直升机超短波通信链路模型;以实现超短波电台通信距离要求为目标,分析通信链路中影响通信距离的各因素及其影响程度,并根据直升机实际情况,对机上配置多部超短波电台及与其他机载设备的电磁兼容性方面提出改善建议。     

A Brief History of Radar

In his report about experiments with radio communication in the Baltic Sea in 1897, Russian scientist Alexander Popov reported the detection of a warship "Lieutenant Il'in" when it crossed the radio communication link between two other ships "Europe" and "Africa". This observation was the first mention about the possibility of object detection by means of radio waves. The first patent on the phenomena was obtained in 1904 by German engineer Christian Hiilsmeyer who called this device the "Telemobiloskop". However, neither A. Popov's observation nor C. Hulsmeyer's invention was the subject of any development up to the 1930s of the 20th century. This is a partial summary of the work done by the Soviet Union and Russia in the field of radar.     

民航地空通信干扰抑制系统的设计与实现

在中国民航空管地空通信经常受到无线电干扰,无法保障正常通信。从根本上解决民航地空通信干扰问题,对于有效保障民航安全具有重要的意义。结合民航VHF通信干扰源的特点,将基于恒模阵列的自适应信号处理技术应用于地空通信干扰抑制中,设计并实现了自适应干扰抑制实时系统,取得了很好的干扰抑制效果。     

Increasing Frequency Spectrum Utilization in Mobile Systems

In mobile radio communication systems, one of the most significant problems is to use the radio frequency spectrum as efficiently as possible, because the radio frequency spectrum is finite. This paper classifies a variety of techniques for increasing frequency spectrum utilization. Next, it is clarified that our proposed ``new channel assignment algorithm' is more efficient than other algorithms through simulation analysis.     

WiMAX dynamnic beamforming antenna

This presents our design and development of an 8-channel adaptive beaniforming antenna for new developments in radio technology: the emergence of chip-based components implementing the recently completed IEEE 802.16d-2004 (WiMAX) radio standard [1-4]. WiMAX offers the potential of long-range (up to 50 miles) and high bandwidth (up to 50 Mb~s) radio links. Although the new WiMAX standard offers the potential for using smart, adaptive antennas, this functionality has not been implemented. Our design will serve as a common platform for testing adaptive array algorithms including direction of arrival (DOA) estimation, beamforming, and adaptive tracking, as well as complete wireless communication with a WiMAX Radio. Heavy emphasis will be placed on ease of implementation in a multi-channel / multi-user environment. In the future, we hope to expand this interface to support dynamic radio channel selection via direct interaction with radio hardware or implementation of a cognitive radio system.     

Software radios: Survey, critical evaluation and future directions

A software radio is defined as a set of digital signal processing (DSP) primitives, a metalevel system for combining the primitives into communication system functions (transmitter, channel model, receiver, etc.), and a set of target processors on which the software radio is hosted for real-time communications. The performance of enabling hardware technologies is related to software radio requirements, portending a decade of shift from hardware radios toward software intensive approaches. Computational models and architecture are discussed, stressing the need for topological consistency of radio functions and host architectures. A layered topology-oriented design approach encapsulated in a canonical open architecture software radio model is presented. The model provides a unified mathematical framework for quantitative analysis of algorithm structures, host architectures, and system performance for CAD     

Trunking vs. conventional radio systems

Correctional Service Canada (CSC) has recently replaced the aging, out-of-date radio communications systems in all major CSC facilities with new conventional digital radio systems. Based on very specific and restrictive operational requirements coupled with developments in digital radio technology and the Associated Public Communications Officers (APCO) Project 25 digital radio standards, it was determined that digital radio communications would best meet CSC's needs. The CSC national radio replacement program was completed in March 2000. Switching to a digital radio communications system gave CSC an opportunity to consider changing the existing radio system from a number of conventional, single-site systems to a trunking system. Areas to be considered when determining the architecture for a radio communication network, whether radio trunking systems or conventional radio systems should be used, are presented, In addition, the paper will also outline the requirements and measures taken to keep the radio communication network active and operational while the equipment was converted from an analog technology to a digital one     

Communication system architecture for planetary exploration

Future human missions to Mars will require effective communications supporting exploration activities and scientific field data collection. Constraints on cost, size, weight, and power consumption for all communications equipment make optimization of these systems very important. These information and communication systems connect people and systems together into coherent teams performing the difficult and hazardous tasks inherent in planetary exploration. The communication network supporting vehicle telemetry data, mission operations, and scientific collaboration must have excellent reliability and flexibility. We propose hybrid communication architectures consisting of space-based links, a surface-based deployable mid-range communications network and a cluster of short-range links to solve the problems of connectivity and bandwidth, while meeting the other constraints of weight and power. A network of orbiting satellites could cover much of the planet surface, but this space-based capability may not be optimal for cost or performance. Specifically, a minimal space-based capability can be augmented using mobile cellular repeaters deployable by robots and human EVA. This method results in an increase in the number of radio nodes, but the distances separating them is decreased. This results in a significant increase in bandwidth and decrease in radio power, and therefore, node size, complexity, and power consumption. This paper will discuss the results of field testing such hybrid radio systems for the support of scientific surveys. System analysis of design tradeoffs will yield insight into optimal solutions that will be compared to other approaches providing a method of effectively evaluating new candidate architectures     

民用飞机甚高频通信天线设计

作为民用飞机甚高频(Very High Frequency,以下简称VHF)通信系统的重要组成部分,VHF通信天线不仅辐射和接收电磁波,还要进行能量转换。VHF通信天线的设计直接影响通信中射频能量的分布,进而影响通信质量和飞行安全。简要介绍了VHF通信系统,并在给出VHF通信天线设计要求的基础上,通过工程实例分析了VHF通信天线的设计过程,最后总结了VHF通信天线设计的特点。