用于移动宽带基础设施的新一代无线电数字前端解决方案

网络运营商在通过使用新型空中接口、更高带宽和更多蜂窝基站努力扩大网络容量的同时,要求显著地降低设备成本。为提供能够满足所有这些需求的设备,无线基础设施设备的制造商正在寻求具有更高集成度、更低功耗和成本但灵活性更高的解决方案。本文将分析赛灵思提供的新型器件Zynq TM可扩展处理平台（EPP）将如何帮助设备制造商解决这些问题。     

软件无线电中的宽带射频前端

本文简要介绍了软件无线电的概念、特点和基本结构,着重分析了软件无线电技术对射频前端的性能要求,以及射频前端设计中的实际问题.     

Protection of Digital TV from Cognitive Radio Interference

Analytic modeling and computational simulation for the protection of DTV from cognitive radio interference are performed. Protection is achieved by using the protection ratio, which is derived through system modeling and its analysis. On the frequency coordination between digital TV and cognitive radio, an analysis in a co‐channel environment, in a rural area in Korea, is performed.     

认知无线电中下变频信号处理的频谱研究

针对认知无线电中下变频处理中的信号抽取过程对信号频谱的影响进行了研究,信号抽取由积分梳状(CIC)滤波器、半带(HB)滤波器及多相滤波器级联而成,利用傅里叶变换对各环节处理后的信号频谱进行理论推导,得出各级抽取后信号频谱的变化规律及各参数选择要注意的问题。通过实验仿真,对整个抽取系统进行测试,仿真结果表明,采样率为fs的信号经过3级抽取,且抽取倍数为D_(CIC)·D_(HB)·D_(多相)时,输出信号的采样率变为fs/(D_(CIC)·D_(HB)·D_(多相)),与理论推导结果一致,实现了多速率信号处理。     

Application of Cognitive Radio in TV and Radio Field

介绍了认知无线电技术的发展背景和当前的研究状况,论述了发展认知无线电的重要性,讨论了认知无线电领域的几种关键技术,论述了认知无线电在广电领域的应用范围和发展前景.举例说明了广电运营商可通过认知无线电系统接入除传统电视业务之外的多种业务.     

Digital Control of a Front-End Loader Linkage

A control system for a front-end loader linkage is specified and developed. Using a microcomputer, the controller is capable of positioning the linkage in either Cartesian or angular motion with the ability to store and recall trajectories. The hardware and software used in a scale model, and the typical response of the linkage are shown.     

Multifrequency Cryogenically Cooled Front-End Receivers for the Westerbork Synthesis Radio Telescope

Four of the fourteen 25-m antennas of the Westerbork Synthesis Radio Telescope have been equipped with 6- and 21-cm wave-length receivers based on cryogenically cooled parametric amplifiers and up-converters. Special care has been given to the design of the input network to achieve maximum sensitivity. An integrated feed launcher and preamplifier system are housed in a dewar at cryogenic temperatures. The receiver noise temperature at 21- and 6-cm wavelength are on the average 14 K and 20 K, respectively. At 21 cm, two systems have even yielded receiver noise temperature as low as 11 K. This paper concentrates particularly on the cooled section of the receiver system.     

2.45GHz电子射频标签模拟前端芯片的研制

分析了RFID系统的组成和基本原理,针对超高频EPC C1G2协议,提出半无源及有源电子标签前端结构及参考电路,包括整流器、偏置单元、上电复位、解调、反向散射调制、振荡器等部分.采用多种方法,极大程度上实现了电路整体的低功耗,并且采取了限幅、ESD电路,保障了电路的稳定性.采用标准CMOS工艺,设计出了低功耗、低电压工作的2.45 GHz射频模拟前端芯片电路,芯片在0.8～1.8 V电压内均可正常工作.芯片的静态工作电流为2μA,芯片工作时,平均工作电流约为65μA.     

DIFFS: A Low Power,Multi-Mode,Multi-Standard Flexible Digital Front-End for Sensing in Future Cognitive Radios

Cognitive Radios provide communication devices with the flexibility to adjust to varying network and channel conditions. For this to be fully realizable spectrum sensing and signal reception have to happen simultaneously and have to require as little power as necessary to function in handheld devices. This work argues for the need of flexible digital-front ends as indispensable building block, able to perform control operations over the analog front-end and to perform sensing and synchronization procedures without the need of power consuming baseband processors. A low power, reconfigurable digital front-end that supports concurrent synchronization and sensing of high-throughput wireless standards is presented. Multiple operating modes, useful for various communication standards, such as LTE, WLAN and DVB-T are introduced and analyzed. The digital front-end has been implemented in 65 nm CMOS technology resulting in a chip area of 6.4 mm2. Fine grain clock gating allows synchronization at 4 mW and sensing at 7 mW power consumption. Experiments in combination with a reconfigurable analog front-end show that a 1.7 GHz wide frequency band can be scanned based on energy detection in an exceptionally low time window of 10 ms while consuming 13 mW power and that coarse energy detection can speed-up the sensing process. Furthermore, advanced feature detection for DVB-T and LTE signals is implemented and measured. Low power sensing of DVB-T signals shows that a target false alarm rate of 10 % and a detection probability of 90 % at an input power level of?106 dBm while consuming 7 mW power are possible. Synchronization-aided FFT-based LTE sensing with leakage cancellation was experimentally validated for various bandwidths showing a power consumption of maximum 20 mW.     

Extending the Reach of Cognitive Radio

There has been significant research progress reported over the last few years in the development of cognitive radio technologies. This paper reviews some of these results, describes several critical issues to integrate these results in usable products, and describes the large-scale Defense Advanced Research Projects Agency efforts to further develop and exploit dynamic spectrum access, and initiate development and operational use of cognitive networking and a new generation of affordable wireless technology. This paper also describes future research needs to fully exploit cognitive radio technology and addresses the challenges that will arise with its large-scale deployment.     

一种新的认知无线电频谱感知方法

认知无线电是一种用于提高无线电通信频谱利用率的新的智能技术。首先简述了认知无线电的背景和概念,然后针对认知无线电频谱感知的能力,对比分析了现有的三种频谱检测方法：匹配滤波器法、能量检查法和循环平稳特征检测法,在对其进行研究的基础上,提出一种将能量检测法和循环平稳特征检测法相结合的双门限检测法,通过仿真验证了该方法的有效性和优越性。     

认知无线电技术及应用

认知无线电技术是目前无线传输领域的主要研究热点之一。对认知无线电的不同定义进行了讨论,并从认知无线电系统组成及认知无线电与其他无线电(特别是自适应无线电和智能无线电)的关系2方面分析了其内涵,重点介绍了无线频谱感知、智能资源管理、自适应传输和跨层设计等认知无线电系统主要关键技术;最后给出了认知无线电可能的应用场景。     

Signal Processing in Cognitive Radio

Cognitive radio allows for usage of licensed frequency bands by unlicensed users. However, these unlicensed (cognitive) users need to monitor the spectrum continuously to avoid possible interference with the licensed (primary) users. Apart from this, cognitive radio is expected to learn from its surroundings and perform functions that best serve its users. Such an adaptive technology naturally presents unique signal-processing challenges. In this paper, we describe the fundamental signal-processing aspects involved in developing a fully functional cognitive radio network, including spectrum sensing and spectrum sculpting.      

建设DVB-C平台,数字前端系统是关键

简要阐述DVB-C平台前端系统的一般结构、设计原则和设备选型等,强调配置较为超前的数字前端系统设备是建设高质量DVB-C平台的关键所在.     

认知无线电与WLAN的融合技术

随着无线局域网(WLAN)的迅速普及,有限的可用频谱资源日益紧张。认知无线电(CR)技术具有动态重用空闲频谱资源的能力,可以有效提高频谱利用率,得到了无线通信行业的关注。通过将CR技术与无线局域网相融合,可以为无线局域网提供更为灵活的通信,扩展无线局域网的工作频段。IEEE 802.11y无线局域网标准的制定进一步推动了CR技术的应用。CR技术与无线局域网融合的过程中,还需要完善包括频谱感知、频谱资源共享和分配、动态频率选择和传输功率控制等技术。     

认知无线电技术的研究和进展

简述了认知无线电的基本原理、相关理论研究和应用,并结合国内外当前的发展状况对该技术的发展趋势进行了介绍和分析.     

认知无线电标准化进展

认知无线电技术的出现，为解决频谱资源不足、实现频谱动态管理及提高频谱利用率提供了强有力的技术支撑。随着认知无线电技术的发展，各标准化组织和行业联盟也纷纷开展相关的研究，并且开始着手制订认知无线电的标准和协议。美国电气电子工程师学会（IEEE）、国际电信联盟（ITU）和软件无线电（SDR）论坛是研究认知无线电相关标准的主要组织和行业联盟，相关的标准制订工作推进了认知无线电技术的发展和应用。     

电台数字直播间数字化改造及应用

从空间布局、灯光、音频、视频等几个方面,对广播电台直播间数字化改造及应用分别作了阐述.介绍了数字直播台和直播间音频通道,详细阐述了输入通道配置和“N-1”功能实现,并就网络直播的同步延时和视频信号的格式、码流及分辨率的设置作了说明.     

认知无线通信系统的频谱资源管理

作为认知无线电（CR）技术核心问题的无线频谱资源管理技术是提高认知无线电性能的关键。通过引入资源空间的概念对认知无线电技术领域中的无线频谱资源管理技术进行说明,形成了无线频谱资源空间、资源网格、可用资源图谱等无线资源管理的数据体系,并且构建了相应的分层分布式管理结构和资源管理数据库。形成的资源描述体系和管理结构可以成为研究认知无线电资源管理技术的理论概念基础和借鉴支持。     

Transceiver Front-End Technology for Software Radio Implementation of Wideband Satellite Communication Systems

The evolution of satellite communication systems for the design of both the satellite’s communication payload and the ground-station are towards the implementation of such systems using the Software Radio (SR) technology. This paper focuses on a key element of the SR, that is, the wideband front-end which still poses the greatest technological challenge for design and proliferation of SR. In particular, we look at the front-end architecture of wideband receivers, outline the key aspects of the design of such front-end systems, specify the performance metrics associated with their design, present an architecture of a promising wideband analog to digital converter, and finally present the results of our design, implementation, and test campaign of a prototype PC-based SR system. This revised version was published online in July 2006 with corrections to the Cover Date.