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无线区域网和认知无线电技术 总被引:1,自引:0,他引:1
802.22工作组的主要任务是开发和建立一套基于认知无线电(CR)技术。在现有电视频段利用暂时空闲的频道进行无线通信的区域网空中接口标准。由于基于802.22协议的无线区域网(WRAN)工作在现有电视频段中,要求不能对正在广播的电视频道产生干扰,所以WRAN采用了认知无线电技术,对电视频段进行感知和测量。利用动态频谱管理技术找到空闲频道进行再分配。认知无线电技术将是未来无线通信的发展方向之一。本讲座分3期对无线区域网和认知无线电技术进行介绍,第1讲已经介绍无线区域网络和IEEE802.22工作组情况,包括WRAN背景、802.22系统、802.22空中接口等;第2讲已经介绍认知无线电技术和实现其的基础软件无线电(SDR)技术,包括无线电知识描述语言(RKRL)和认知循环、无线电频谱礼仪等;本讲介绍802.22WRAN频谱共存问题和认知无线电技术的应用。[编者按] 相似文献
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随着无线通信技术的发展,无线频谱资源越来越贫乏。同时,认知无线电技术以其灵活高效的利用频谱受到广泛的关注。文章结合认知无线电技术的特点,介绍了IEEE802.22系统中的关键技术。从无线区域网实现的频谱感知技术、共存技术、正交频分多址(OFDMA)、信道管理和多信道绑定等关键技术入手,理解认知无线电技术的核心思想。 相似文献
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近几年来,随着世界范围内通信业务的增长,频谱资源日渐紧张。认知无线电技术的提出为人们利用电视广播“白频谱”进行通讯提供了可能。IEEE 802.22工作组颁布的802.22标准对认知无线电技术进行了规范,在此标准上设计的超级WIFI设备理论上能够对低人口密度地区实现良好的网络覆盖。本文介绍了IEEE 802.22标准提出的背景和主要技术内容,阐述了Carlson RuralConnect 超级WIFI设备的工作原理,并利用该设备进行了实验室和场地数据测试和整理,给出超级WIFI和白频谱设备在不同环境不同模式下的数据率、接收灵敏度和邻道干扰等信息,为我国开展超级WIFI和白频谱通讯应用提供技术参考。 相似文献
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现代社会经济和技术的发展迅速,用户对于移动通信和接入宽带无线的需求急剧增长,而其无线资源变得越来越少,其分配也越来越不容易.认知无线电技术使用灵活,可以极速提高频谱的使用率,如今被公认为处理以上问题的最佳方式.它能够在时间与空间上共享动态频谱,因此能够提升频谱资源的利用率.本文分析了认知无线电技术,而且还对其在军事上的应用进行了认真的研究. 相似文献
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基于认知无线电技术及其运用研究 总被引:1,自引:0,他引:1
随着科技的发展,人们生活水平的提高,无线用户逐渐增多,这使得原本宽松的频谱资源越来越紧张。而认知无线电技术给出一种全新的频率资源综合利用思路,大大提高频谱资源的利用率。首先介绍认知无线电技术的基本概念,接着分析认知无线电技术的关键技术和目前的运用情况。 相似文献
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认知无线通信系统的频谱资源管理 总被引:1,自引:0,他引:1
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。 相似文献
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The emerging IEEE 802.22-based wireless regional area network technology will use the same radio spectrum currently allocated for TV service. This standard will use the concept of cognitive radio based on dynamic spectrum access to provide wireless access services in a large coverage area. A brief overview of the current state of the IEEE 802.22 standard is provided with a particular emphasis on the spectrum management (i.e., spectrum sensing and dynamic spectrum access) in this standard. Key research issues related to spectrum trading among TV broadcasters, WRAN service providers, and IEEE 802.22-based cognitive radio users are identified. To this end, a hierarchical spectrum trading model is presented to analyze the interaction among WRAN service providers, TV broadcasters, and WRAN users. In this model a double auction is established among multiple TV broadcasters and WRAN service providers who sell and buy the radio spectrum (i.e., TV bands), respectively. Again, multiple WRAN service providers compete with each other by adjusting the service price charged to WRAN users. We propose a joint spectrum bidding and service pricing model for WRAN service providers to maximize their profits. A non-cooperative game is formulated to obtain the solution in terms of the number of TV bands and the service price of a service provider. Numerical results are presented on the performance of this joint spectrum bidding and pricing model. 相似文献
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With rapid increase in new applications and services, there is huge demand for internet bandwidth. Several researchers around the world have found that, majority of licensed bands (mostly terrestrial TV band) are either unused or underused. These underutilized bands allocated for TV transmission are known as TV white space (TVWS). For effective utilization of TVWS, the IEEE 802.22 is proposed. The IEEE 802.22 wireless regional area network (WRAN) is the latest standard for effective utilization of TV bands. This standard is based on orthogonal frequency division multiplexing with various modulation techniques to provide different data rates. In this paper, an implementation framework for physical layer of IEEE 802.22 WRAN standard for normal mode is demonstrated and analyzed. This transceiver is implemented using the National Instruments Laboratory Virtual Instrument Engineering Workbench programming software on the National Instruments universal software radio peripheral 2952R. We have also analyzed different blocks of IEEE 802.22 based on their execution time, and identify the critical blocks of IEEE 802.22 that should be optimized for real-time applications for commercial product development and field deployments. We have also highlighted the difference between theoretical and practical performance of the considered error control codes for IEEE 802.22 specified block size. Additionally, various covariance based spectrum sensing methods are also analyzed for real-world environment. 相似文献
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针对现有基于谱相关频谱检测算法中周期图法谱估计精确度较低的缺点,提出了一种用主用户发送信号与认知用户接收信号的最小方差无失真响应(MVDR)谱的谱相关量作为检测统计量进行频谱检测的改进方法.由于MVDR谱估计算法比周期图法具有更高的分辨率,因此所提频谱检测算法比现有算法具有更好的检测效果.模拟了两种电视信号作为主用户发送信号,仿真结果表明:对于两种电视信号,所提算法的检测性能都优于现有算法,同时通过分析算法的复杂度,证明所提算法能够满足IEEE802.22标准对于检测时间的要求. 相似文献
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Vivek Yenamandra Mohammed Ismail 《Analog Integrated Circuits and Signal Processing》2012,73(2):545-558
Continuous rise in the number of users as well as the increased requirement of bandwidth per user has created a need to use the spectrum efficiently. Cognitive radios are solutions proposed to address the problem of using the spectrum efficiently. Regulatory bodies around the world, FCC included, have introduced specifications intended for cognitive radio applications. TV White Space devices, which operate in the spectrum holes caused by transition from analog to digital transmission, were the first targeted applications for cognitive radio specifications (IEEE 802.22, ECMA-392). However, to maximize the potential of the idea of cognitive radios it is desirable to be able to sense the spectrum across a wide band and accordingly transmit ??smartly??. This paper presents a possible transceiver architecture meant for integrated solutions while providing tentative block level specifications for the proposed architecture. Existing spectrum sensing techniques are discussed and an integrated low power system architecture at the PHY level suitable for waveform-based spectrum sensing technique that utilizes co-operative spectrum sensing methods is proposed. 相似文献
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IEEE802.22工作组的工作范围是对工作在54~862MHz的VHF/UHFTV频带内的固定点对多点无线区域网(WRAN)制定基于认知无线电的空中接口。频谱资源分配是WRAN中的关键技术,目前对认知无线电的频谱分配算法的研究多集中在比较广义的范围,对WRAN等具体系统的频谱分配研究较少。根据WRAN的特点和OFDM的传输特性,提出一种OFDM多用户资源分配算法:多载波比例公平算法(MPF)和最大化吞吐量算法(KH)的组合算法(KH&MPF),该算法将最大化吞吐量算法和多载波比例公平算法进行优势互补,得到公平性和吞吐量都次优的结果,解决用户之间的公平性问题,考虑用户的Qos要求。最后对该算法进行仿真。 相似文献
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Stuber G.L. Almalfouh S.M. Sale D. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》2009,97(4):741-754
Cognitive radio (CR) has been suggested as a method for promoting more efficient spectrum usage through the principles of spectrum sensing and dynamic spectrum management. The IEEE 802.22 working group in particular is developing a wireless regional-area network (WRAN) standard that will employ unlicensed CR devices operating on a noninterfering basis in the commercial broadcast television (TV) bands. Before such TV-band CR networks can be deployed, the maximum levels of first adjacent and taboo channel interference that a digital television (DTV) receiver can tolerate must be determined. In this context, we will first provide an overview of the IEEE 802.22 WRAN system. Afterwards, we will report on an experimental study that was undertaken to characterize IEEE 802.22 WRAN interference limits into Advanced Television Systems Committee (ATSC) based DTV receivers. Lastly, we will discuss the implications of these WRAN interference limits in terms of the maximum allowable radiated power and out-of-band emission limits that are imposed on WRAN end-user devices. 相似文献
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Youping Zhao Shiwen Mao Jeffrey H. Reed Yingsong Huang 《Mobile Networks and Applications》2010,15(3):446-460
Cognitive Radio (CR) is a new wireless communication and networking paradigm that is enabled by the Software Defined Radio
(SDR) technology and the recent change in spectrum regulation policy. As the first commercial application of CR technology,
IEEE 802.22 wireless regional area networks (WRAN) aim to offer broadband wireless access by efficiently utilizing the unoccupied
TV channels. In this paper, we investigate the problem of utility function selection and its impact on streaming video quality
through an IEEE 802.22 WRAN base station (BS) cognitive engine (CE) testbed developed at Wireless@Virginia Tech. We find that significant improvement on received video quality can be achieved when CE adopts a dynamic, content-aware,
video-specific utility function rather than a static, predefined, general purpose utility function. This work indicates the
importance of video distortion modeling and cross-layer design, and the need for employing dynamic content-aware utility functions
at the CE for cognitive streaming video communication networks. 相似文献