战术通信网频谱管理系统设计

随着战术通信技术发展,认知无线电、软件无线电技术被广泛应用,无线电频谱管理也由传统的静态规划、分配、指配向动态管控、接入方向发展,频管系统设计所面临的挑战愈发严峻.本文采用基于策略的动态频谱接入思想进行频管系统设计,分别从系统设计的总体思路、主要功能、软件架构、接口关系、数据库设计等方面展开介绍,并在此基础上对动态频谱接入的原理进行阐述,形成完整设计方案.     

认知无线电技术发展及其对频谱管理政策的影响分析

认知无线电技术的核心就是对频谱采取动态的分配方式,在授权用户不使用的情况下,其他用户在不对授权用户产生干扰的情况下可使用授权用户频段或非授权频段,从而提高频谱的利用效率。本文首先分析了目前频谱管理面临的问题,在此基础上,对认知无线电关键技术以及对标准组织的研究进展进行了介绍,最后从频谱管理、运营、技术3个层面上阐述了认知无线电技术为频谱管理带来的机遇与挑战。     

基于生存系统模型的认知无线电网络频谱管理自治系统设计

针对动态频谱接入和认知无线电技术对频谱管理的新要求,采用分层的频谱管理理念,基于生存系统模型(Viable System Model,VSM)设计适合认知无线电网络的频谱管理自治系统,该系统通过节点参与频谱管理,网络自我约束等措施,实现认知无线电网络对频谱的自治。最后,将该系统应用于一种异构网络共存的频管案例设计中,仿真分析表明:本文提出的基于VSM的频谱管理自治系统响应时间大幅度降低;认证效率为O(1),较传统方式性能有很大提升。     

动态频谱技术接入研究

目前认知无线电技术受到了极大的关注,其中的动态频谱分配问题是不得不面对的一个问题.讨论了动态频谱接入的分类,尤其是讨论了机会式频谱接入,包括其基本组成以及各组成部分的功能,并提出了实现这些功能的过程中遇到的挑战.将对今后动态频谱接入的进一步研究起到积极的促进作用.     

基于多小区OFDMA网络的动态频谱分配算法

为了提高频谱效率,给二级认知用户提供更多的频谱接入机会,同时保证用户的服务质量(QoS),该文章基于传统的频率复用方法在多小区正交频分多址接入(OFDMA)系统的场景中提出了一种动态频谱分配(DSA)算法。该算法使得持有频谱执照者在认知无线电环境中在很大的区域内释放频谱给其他的二级市场,还建立了一个分配花费矩阵,使得小区间的干扰达到最小,保证了用户的服务质量(QoS)。与传统的频率复用方法相比,该算法有更好的频谱效率,并给二级市场的使用创造了更多的机会。     

动态频谱接入技术的分类和研究现状

动态频谱接入是认知无线电技术的一种重要应用,它利用通信过程中出现的频谱空洞机会式地接入频谱,能极大地提高频谱的利用效率.文章介绍了动态频谱接入的一种分类方法,重点分析了该分类中三个模型的特征、关键技术,以及在美国下一代(XG)无线通信计划、IEEE 802.22标准和欧洲端到端效率(E3)项目中对于动态频谱接入技术的研究现状,最后探讨了动态频谱接入技术的应用前景.     

动态自适应频谱的接入策略研究

认知无线电技术利用非授权频谱资源进行业务传输,缓和了目前通信业务飞速发展与频谱资源稀缺的矛盾。动态频谱接入技术通过感知频带,使认知用户能够伺机接入未被主用户占用的频谱空洞。但是在接入过程中,特别是在多个认知用户竞争接入相同的可用频谱资源时,往往面临认知用户间的冲突和各认知用户的QoS得不到保证的问题。文章重点介绍了目前国内外在多个认知用户接入策略上的一些研究成果,并对这些成果进行分析,提出了今后需要进一步研究的方向。     

无线认知电传感器网络动态频谱管理技术研究

WCSN(无线认知传感器网络)可以定义为无线认知传感器节点的分布式网络,它能够感知事件信号,机会地使用频谱空洞,并采用多跳方式,完成信息的动态协同通信,最终满足各种应用需求.文章分析了WCSN的基本概念和优势,给出了无线认知传感器网络节点硬件结构.研究了WCSN频谱感知、频谱分析决策和频谱切换技术的构成,列举了无线认知...     

动态频谱接入中的侦测与避让技术

动态频谱接入技术对频谱实行动态管理,允许未授权用户在无干扰的情况下使用已授权用户的闲置频带,是解决现今无线频谱资源紧缺和利用率低等难题的有效途径,已成为无线通信领域的研究热点。本文介绍了动态频谱接入的侦测与避让方法,分析和讨论了各自的优缺点,并指出动态频谱接入需要进一步研究的问题和可能的发展方向。     

动态频谱接入网络的路由技术研究

新一代宽带无线通信网络迫切需要引入认知无线电技术以提升系统性能。针对动态频谱接入(DSA)的无线网络环境,首先探讨了其路由技术研究所面临的新挑战,然后以体现动态频谱管理特征的独特分类方式,分析了其路由技术研究的最新进展,最后展望了路由技术研究的未来发展方向。     

在频谱仪上建立频谱数据库

频谱仪的应用很广泛,对于我们无线电管理部门来说,监测、检测、干扰分析等工作都可以利用它.现介绍我站对于频谱仪的一种用法. 我们尝试在频谱仪中建立频谱数据库.现以R/S公司的FSP13型频谱仪为例,介绍一下这种用法(无需安装键盘、鼠标).     

全球频谱规划方案及频谱管理政策演进分析

本文基于对全球频谱规划方案的系统全面的分析,深入透彻的研究了全球频谱管理政策的演进方向,为中国移动频率的申请、频率的使用、频率规划的推动等工作提供了有力的支持,也为TD-SCDMA及其演进技术的发展起到推动作用。     

ZnO broadens the spectrum

A new approach for growing zinc oxide crystals is underway at Cermet, Inc (Atlanta, GA, USA). The technique is a high pressure, direct melting technique, which has advantages over other ZnO growth techniques. To date, substrates with 1 cm² area have been fabricated. Two-centimetre and, subsequently, two-inch diameter substrates are the objective of a ZnO substrate development plan. This technique will enable the production of high quality, low cost ZnO crystals for a range of applications, including substrates for nitride-based light emitters and power devices, energy detectors, and oxide-based devices.     

蓝牙技术及其使用的无线电频谱

近年来,通信领域发展最快的就是移动通信和互联网.为满足人们对通信和信息与日俱增的需求,电信业务已不仅仅局限于语音通信,诸如移动数据、移动因特网接入、移动办公等应用以及"人与机"甚至"机与机"之间的通信,也将成为无线移动通信网中的主要业务.如今,应运而生的"蓝牙"技术,可让人们在不使用电线或电缆的情况下,方便而快捷地将各种办公设备甚至家用电器、电子设备连接起来,更加轻松地进行通信和工作.面向未来,蓝芽技术有着十分诱人的应用前景.     

Taking the next step beyond spectrum auctions: open spectrum access

The author presents the case for a better to approach to spectrum use involving a pragmatic and searching fashion rather than with an ideological mind set that equates the free market with one and only one particular allocation technique. Spectrum auctions are considered as an application for present times. The author goes on to look at the future     

Utilization and fairness in spectrum assignment for opportunistic spectrum access

The Open Spectrum approach to spectrum access can achieve near-optimal utilization by allowing devices to sense and utilize available spectrum opportunistically. However, a naive distributed spectrum assignment can lead to significant interference between devices. In this paper, we define a general framework that defines the spectrum access problem for several definitions of overall system utility. By reducing the allocation problem to a variant of the graph coloring problem, we show that the global optimization problem is NP-hard, and provide a general approximation methodology through vertex labeling. We examine both a centralized strategy, where a central server calculates an allocation assignment based on global knowledge, and a distributed approach, where devices collaborate to negotiate local channel assignments towards global optimization. Our experimental results show that our allocation algorithms can dramatically reduce interference and improve throughput (as much as 12-fold). Further simulations show that our distributed algorithms generate allocation assignments similar in quality to our centralized algorithms using global knowledge, while incurring substantially less computational complexity in the process. A part of this work has been presented at IEEE International conference on communications (ICC), May, 2005. Chun-Yi Peng received her B.E.degree (with highest honor) and M.E.degree (with highest honor) from Tsinghua University, Beijing, China, in July 2002 and Jan. 2005, respectively. Since Dec. 2005, she has been an assistant researcher in Wireless and Network Group, Microsoft Research Asia, Beijing, China. Prior to that, she was with T3G Technical Co. Ltd., Beijing, China, as a technical engineer on 3G TD-SCDMA development from Feb. 2005 to Nov. 2005; and a visiting student at Microsoft Research Asia from June 2004 to Jan. 2005. Her research interests include wireless communications and networking, and signal processing. Haitao (Heather) Zheng received her B.S.degree (with highest honor) from Xian Jiaotong University in July 1995, her M.S.EE and Ph.D degree in Electrical and Computer Engineering from University of Maryland, College Park, in May 1998 and July 1999, respectively. She joined wireless research lab, Bell-Labs, Lucent Technologies as a member of technical staff in August 1999, and moved to Microsoft Research Asia as a project lead and researcher, in March 2004. Since Sept. 2005, she has been an assistant professor in Computer Science Department, Univ. of California, Santa Barbara. Dr. Zheng was recently named as the 2005 MIT Technology Review Top 35 Innovators under the age of 35 for her work on cognitive radios. She received 2002 Bell Laboratories President’s Gold Award from Lucent Bell-Labs, and 1998—1999 George Harhalakis Outstanding Graduate Student Award from Institute of System Research, University of Maryland, College Park. Dr. Zheng was admitted to the highly gifted class of Xi’an Jiaotong Univeristy, P.R. China at age of 15, and graduated with the highest honor. She has served as guest editors of JSAC and EURASIP special issues and TPC members of many conferences. Dr. Zhengs research area includes wireless communications and networking and multimedia computing. Ben Y. Zhao joined the faculty at University of California at Santa Barbara in 2004. He received his Ph.D. from the University of California at Berkeley, where he worked under the direction of Professors John Kubiatowicz and Anthony Joseph. At Berkeley, he was the principal architect of the Tapestry peer-to-peer network and a co-founder of the Ocean Store global-scale storage project. He has co-authored over 30 papers in networking and systems research areas. Ben is on the TPC of a number of conferences and workshops. He is on the steering committee of AEPP, and the current Program Co-chair of IPTPS 2006. His research interests lie in computer systems and networking, particularly large-scale distributed and networked systems, network security, mobile computing and overlay networks. Ben received his B.S. degree in computer science from Yale University and his M.S. degree in computer science from University of California at Berkeley.     

基于能量和循环谱的两步频谱感知

频谱感知是认知无线电的重要技术之一,它通过实时感知电磁环境以判断频谱空穴的存在。根据能量检测的检测时间短,以及循环平稳特征检测在低信噪比情况下的检测准确性高的优点,提出了基于能量和循环谱的两步检测算法。通过实验仿真表明,与循环平稳特征检测相比,两步检测的检测时间大幅度缩短,同时检测准确性也得到了提高。     

Spread spectrum: Principles and possible application to spectrum utilization and allocation

Because of the continuing demand for more telecommunication capacity, to serve the world's need for commerce and public safety, there is a continuing need for more efficient ways of sharing the radio spectrum. The conventional way of allocating the spectrum is by frequency division; however, for many kinds of services this is inefficient. Hence, it seems desirable to reexamine whether alternative procedures might not be necessary if the benefits of telecommunications are to be assured in the face of increased demand. Spreadspectrum techniques, which are based on principles antithetic to those currently used in spectrum allocation for reducing necessary bandwidth, seem to offer benefits for spectrum sharing, for some applications, superior to those of frequency division. This paper provides a tutorial summary of some of the principles upon which spread-spectrum systems have developed. It is hoped the reader might consider what role such techniques may play in future spectrum sharing and allocation opportunities.