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[转载]认知无网络生态系统
treblestar 2014-1-23 15:49
转一篇文章,ieee上搜的,觉得值得关注一下。 《Research towards a cognitive network eco-system》 Marshall, P.F. ; Inf. Sci. Inst., Univ. of Southern California, Marina del Rey, CA, USA MILITARY COMMUNICATIONS CONFERENCE, 2010 - MILCOM 2010 Date of Conference: Oct. 31 2010-Nov. 3 2010;Page(s):1466 - 1471 Increasing demand for wireless information services, fixed, and inflexible access to spectrum, and overtaxing of cellular and backhaul infrastructure have combined to create opportunities for radically different wireless communications architectures. These emphasize devolved network control, adaptive topologies, and dynamic interference avoidance and mitigation that are inherent in the devices and networks. One incentive towards such architectures is a necessary transition from design and architecture approaches that emphasize individual link performance to a focus on maximizing aggregate throughput of node collections, even if this optimization is less ideal for individual links. This is critical to transition from a link to network density perspective. It will be shown that the optimal design points for network density and aggregate throughput are quite distinct from those appropriate for link optimization, and that some degree of interference may be necessary in order to maximize the aggregate capacity of the spectrum. The Dynamic Spectrum Access (DSA) community has focused on interference-free secondary sharing. This paper examines an alternative objective; “Interference Tolerant” operation, in which DSA is used to enable spectrum relocation in the event of unacceptable interference. It will be shown that there are significant increases in node density that are possible in these regimes. 相似的研究还有Haykin的研究,但是没有找到原始文章
个人分类: 科研笔记|1526 次阅读|1 个评论
认知无线电SCI发文居前10位期刊
热度 2 wanyuehua 2013-12-3 12:59
2005-2013 年 SCI 收录认知无线电( Cognitive radio )论文 3018 篇 (截至到 2013 年 12 月 3 日 ) , 3018 篇 论文包括学术论文 2,945 篇(其中会议论文 78 篇)、社论 37 篇、综述 30 篇、通讯 2 篇、新闻 2 篇、书评 1 篇、更正 1 篇等。 3018 篇 论文刊登在 204 种 SCI 收录期刊。 认知无线电( Cognitive radio ) 发文量居前十位的期刊见表 1 , 认知无线电( Cognitive radio ) 发文量居前 100 位的期刊见表 2. 表 1 认知无线电( Cognitive radio ) 发文量居前十位的期刊 排名 期刊名称 2012 年影响因子 发文量 占 3018 篇 总文章量的百分比( % ) 1 IEEE Transactions on Wireless Communications 《 IEEE 无线通信汇刊》 2.418 345 11.431 % 2 IEEE Transactions on Vehicular Technology 《 IEEE 运载工具技术汇刊》 2.063 213 7.058 % 3 IEICE Transactions on Communications 《电子信息通信学会汇刊:通信》 0.314 179 5.931 % 4 IEEE Journal on Selected Areas in Communications 《 IEEE 通信选题杂志》 3.121 159 5.268 % 5 IEEE Communications Letters 《 IEEE 通讯快报》 1.160 145 4.805 % 6 Wireless Personal Communications 《无线个人通信》 0.428 135 4.473 % 7 IET Communications 《 IET 通信》 0.637 122 4.042 % 8 IEEE Transactions on Communications 《 IEEE 通信汇刊》 1.750 113 3.744 % 9 IEEE Transactions on Signal Processing 《 IEEE 信号处理汇刊》 2.813 113 3.744 % 10 EURASIP Journal on Wireless Communications and Networking 《 EURASIP 无线通信与网络杂志》 0.540 106 3.512 % 表 2 认知无线电( Cognitive radio ) 发文量居前 100 位的期刊 排名 期刊名称 发文量 1. IEEE TRANSACTIONS ON WIRELESS COMMUNICATIONS 345 2. IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY 213 3. IEICE TRANSACTIONS ON COMMUNICATIONS 179 4. IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 159 5. IEEE COMMUNICATIONS LETTERS 145 6. WIRELESS PERSONAL COMMUNICATIONS 135 7. IET COMMUNICATIONS 122 8. IEEE TRANSACTIONS ON COMMUNICATIONS 113 9. IEEE TRANSACTIONS ON SIGNAL PROCESSING 113 10. EURASIP JOURNAL ON WIRELESS COMMUNICATIONS AND NETWORKING 106 11. IEEE TRANSACTIONS ON MOBILE COMPUTING 68 12. IEEE WIRELESS COMMUNICATIONS 55 13. IEEE COMMUNICATIONS MAGAZINE 47 14. WIRELESS COMMUNICATIONS MOBILE COMPUTING 46 15. IEEE TRANSACTIONS ON INFORMATION THEORY 41 16. IEEE JOURNAL OF SELECTED TOPICS IN SIGNAL PROCESSING 38 17. COMPUTER NETWORKS 35 18. MOBILE NETWORKS APPLICATIONS 33 19. KSII TRANSACTIONS ON INTERNET AND INFORMATION SYSTEMS 30 20. CHINA COMMUNICATIONS 29 21. JOURNAL OF COMMUNICATIONS AND NETWORKS 29 22. ELECTRONICS LETTERS 28 23. FREQUENZ 27 24. PROCEEDINGS OF THE IEEE 27 25. AD HOC NETWORKS 26 26. RADIOENGINEERING 26 27. EURASIP JOURNAL ON ADVANCES IN SIGNAL PROCESSING 25 28. WIRELESS NETWORKS 25 29. IEEE SIGNAL PROCESSING LETTERS 24 30. COMPUTER COMMUNICATIONS 23 31. AEU INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS 22 32. INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS 22 33. IEEE NETWORK 18 34. IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES 17 35. IEEE ACM TRANSACTIONS ON NETWORKING 15 36. IEEE JOURNAL OF SOLID STATE CIRCUITS 15 37. IEEE SIGNAL PROCESSING MAGAZINE 15 38. IEICE ELECTRONICS EXPRESS 15 39. COMPUTERS ELECTRICAL ENGINEERING 14 40. ETRI JOURNAL 14 41. IEEE COMMUNICATIONS SURVEYS AND TUTORIALS 14 42. IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION 14 43. IEEE VEHICULAR TECHNOLOGY MAGAZINE 14 44. IET SIGNAL PROCESSING 14 45. SCIENCE CHINA INFORMATION SCIENCES 14 46. ACTA PHYSICA SINICA 13 47. ANALOG INTEGRATED CIRCUITS AND SIGNAL PROCESSING 13 48. IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I REGULAR PAPERS 13 49. IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS II EXPRESS BRIEFS 11 50. INTERNATIONAL JOURNAL OF DISTRIBUTED SENSOR NETWORKS 11 51. CHINESE JOURNAL OF ELECTRONICS 10 52. CIRCUITS SYSTEMS AND SIGNAL PROCESSING 10 53. IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES 10 54. MICROWAVE AND OPTICAL TECHNOLOGY LETTERS 10 55. CHINESE SCIENCE BULLETIN 9 56. TELECOMMUNICATIONS POLICY 9 57. ANNALES DES TELECOMMUNICATIONS ANNALS OF TELECOMMUNICATIONS 8 58. IEEE TRANSACTIONS ON CONSUMER ELECTRONICS 8 59. JOURNAL OF SIGNAL PROCESSING SYSTEMS FOR SIGNAL IMAGE AND VIDEO TECHNOLOGY 8 60. SIGNAL PROCESSING 8 61. IEEE SYSTEMS JOURNAL 7 62. INTERNATIONAL JOURNAL OF ANTENNAS AND PROPAGATION 7 63. JOURNAL OF NETWORK AND COMPUTER APPLICATIONS 7 64. CONCURRENCY AND COMPUTATION PRACTICE EXPERIENCE 6 65. EUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS 6 66. IEEE ANTENNAS AND WIRELESS PROPAGATION LETTERS 6 67. IEEE SENSORS JOURNAL 6 68. JOURNAL OF INTERNET TECHNOLOGY 6 69. JOURNAL OF SYSTEMS ENGINEERING AND ELECTRONICS 6 70. SENSORS 6 71. TELECOMMUNICATION SYSTEMS 6 72. AD HOC SENSOR WIRELESS NETWORKS 5 73. APPLIED MATHEMATICS INFORMATION SCIENCES 5 74. IEEE TRANSACTIONS ON INFORMATION FORENSICS AND SECURITY 5 75. JOURNAL OF NETWORK AND SYSTEMS MANAGEMENT 5 76. MATHEMATICAL AND COMPUTER MODELLING 5 77. TRANSACTIONS ON EMERGING TELECOMMUNICATIONS TECHNOLOGIES 5 78. ANNALS OF TELECOMMUNICATIONS ANNALES DES TELECOMMUNICATIONS 4 79. IEEE CIRCUITS AND SYSTEMS MAGAZINE 4 80. IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT 4 81. IEEE TRANSACTIONS ON SMART GRID 4 82. INTERNATIONAL JOURNAL OF INNOVATIVE COMPUTING INFORMATION AND CONTROL 4 83. INTERNATIONAL JOURNAL OF MICROWAVE AND WIRELESS TECHNOLOGIES 4 84. JOURNAL OF CENTRAL SOUTH UNIVERSITY 4 85. MATHEMATICAL PROBLEMS IN ENGINEERING 4 86. PERFORMANCE EVALUATION 4 87. PERVASIVE AND MOBILE COMPUTING 4 88. PROGRESS IN ELECTROMAGNETICS RESEARCH PIER 4 89. SECURITY AND COMMUNICATION NETWORKS 4 90. APPLIED SOFT COMPUTING 3 91. COMPTES RENDUS PHYSIQUE 3 92. IEEE ANTENNAS AND PROPAGATION MAGAZINE 3 93. IEEE LATIN AMERICA TRANSACTIONS 3 94. IEEE MICROWAVE AND WIRELESS COMPONENTS LETTERS 3 95. IEEE MICROWAVE MAGAZINE 3 96. IEEE TRANSACTIONS ON INDUSTRIAL INFORMATICS 3 97. IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS 3 98. IETE TECHNICAL REVIEW 3 99. INFORMATION AN INTERNATIONAL INTERDISCIPLINARY JOURNAL 3 100. JOURNAL OF ELECTROMAGNETIC WAVES AND APPLICATIONS 3
个人分类: 文献计量|21366 次阅读|2 个评论
Good Readings on Spectrum Sensing
热度 1 wqhtxdk 2013-3-6 11:11
国内外代表性研究成果: A. Ghasemi and E. S. Sousa, Opportunistic Spectrum Access in Fading Channels Through Collaborative Sensing, Journal of Communications, vol. 2, no. 2, pp. 71-82, Mar. 2007. 这篇文章是关于Spectrum Sensing的早期最有代表性的技术性文章,建议入门必读。 I. F. Akyildiz, B. F. Lo, R. Balakrishnan,Cooperative spectrum sensing in cognitive radio networks: A survey, Physical Communication 4 (2011) 40–62. 这篇文章是关于Cooperative spectrum sensing(CSS)研究进展总结的最好的综述文章(Google上可以直接下载),读完它就可以基本掌握CSS全貌。 R. Tandra, S. M. Mishra, and A. Sahai, “What is a spectrum hole and what does it take to recognize one?” Proc. IEEE, vol. 97, no. 5, pp. 824-848, May 2009. R. Tandra, A. Sahai, and V. V. Veeravalli, “Unified space-time metrics to evaluate spectrum sensing,” IEEE Commun. Mag., vol. 49, no. 3, pp. 54-61, Mar. 2011. - 是UC BerkeleyA. Sahai教授研究组 关于Spectrum Sensing部分代表作,对于spectrum hole从空域、时域等角度进行了定义,并给出了新的metrics,值得一读。 A. G. Fragkiadakis, E. Z. Tragos, and I. G. Askoxylakis, “A suvery on security threats and detection techniques in cognitive radio networks,” IEEE Commun. Surveys and Tutorials, accepted for pubilication, 2013. R.-P. Helena, J. B. Mercedes, and G. Carles, “Review of robust cooperative spectrum sesnsing techniques for cognitive radio networks,” Wireless Pers. Commun., vol. 67, pp. 175-198, 2012. - 是两篇关于安全感知(secure sensing)最新研究进展的比较好的综述。 S. M. Mishra, “Maximizing available spectrum for cognitive radios,” Ph.D. Dissertation, UC Berkeley, 2010. Alexander W. Min, Efficient and Robust Spectrum Management for Cognitive Radio Networks ,”Ph.D. Dissertation, University of Michigan, 2011. Emiliano Dall'Anese, Spatio-temporal Spectrum Reuse based on Channel Gain Cartography, Ph.D. Dissertation, University of Padova, 2011. - 是3篇关于Spectrum Sensing的欧美博士论文,感兴趣的研究生们可以下载看一看。 ... ... 课题组在Spectrum Sensing方向上得相关研究成果: Q. Wu, G. Ding, J. Wang, and Y. D. Yao, Spatial-temporal opportunity detection for spectrum-heterogeneous cognitive radio networks: Two-dimensional sensing, IEEE Transactions on Wireless Communications, vol. 12, no.2, pp. 516-526, Feb. 2013. TW-Sep-11-1638.pdf . 这是一篇考虑认知用户所处频谱环境不同时,如何进行有效地协同进行频谱感知的文章,研究还较为初步,特别是方案优化方面还存在很多提升余地。 G. Ding, Q. Wu, Y. D. Yao, J. Wang, and Y. Chen, Kernel-based learning for statistical signal processing in cognitive radio networks, IEEE Signal Processing Magazine,July 2013. 这是一篇应用非线性信号处理技术kernel-based learning来重新研究频谱感知的文章,此研究方向得到国内外著名学者的肯定与关注。 G. Ding, Q. Wu, J. Wang, F. Song and Y. Gong, Multi-Domain Cognition for Cognitive Wireless Networks, FREQUENZ. 点击查看文章基本信息 . 这是第一篇关于多域认知体系架构的系统介绍方面的文章。 J. Yao, Q. Wu, and J. Wang, “Attacker detection based on dissimilarity of local reports in collaborative spectrum sensing,” IEICE Trans. Commun., vol. E95-B, no. 9, pp. 3024-3027, Sep. 2012. 点击查看文章基本信息 . 这篇是关于安全感知的,针对的是频谱感知虚报数据攻击(SSDF)。
5881 次阅读|1 个评论
认知无线电各研究方向文章推荐
热度 1 wqhtxdk 2012-6-15 10:54
机会频谱接入 N. Nie and C. Comaniciu, “Adaptive channel allocation spectrum etiquette for cognitive radio networks,” Mobile Networks Applications, vol. 11, no. 6, pp. 779–797, 2006. Q. Zhao, L. Tong, A. Swami, et al., “Decentralized cognitive MAC for opportunistic spectrum access in ad hoc networks: A POMDP framework,” IEEE J. Sel. Areas Commun., vol. 25, no. 3, pp. 589-600, 2007. Y. Zhao, S. Mao, J. Neel, et al., “Performance evaluation of cognitive radios: Metrics, utility functions, and methodology,” Proceedings of the IEEE, vol. 97, no. 4, pp. 642-659, 2009. M. Maskery, V. Krishnamurthy, and Q. Zhao, “Decentralized dynamic spectrum access for cognitive radios: cooperative design of a noncooperative game,” IEEE Trans. Commun., vol. 57, no. 2, pp. 459-469, 2009. M. Felegyhazi, M. Cagalj, and J. P. Hubaux, “Efficient MAC in cognitive radio systems: A game-theoretic approach,” IEEE Trans. Wireless Commun., vol. 8, no. 4, pp. 1984-1995, 2009. Y. Gai, B. Krishnamachari, and R. Jain, “Learning multiuser channel allocations in cognitive radio networks: A combinatorial multi-armed bandit formulation,” in Pro. IEEE DySPAN 2010, pp. 1-9 2010. Qihui Wu,Yuhua Xu, Liang Shen, and Jinlong Wang, “ Investigation on GADIA algorithms for interference avoidance: A game-theoretic perspective,” IEEE Communications Letters, to appear. Yuhua Xu, Jinglong Wang, Qihui Wu, et al, “Opportunistic spectrum access in unknown dynamic environment: A game-theoretic stochastic learning solution,” IEEE Transactions on Wireless Communications, vol. 11, no. 4, pp. 1380-1391, 2012. Yuhua Xu, Jinglong Wang, Qihui Wu, et al, “Opportunistic spectrum access in cognitive radio networks: Global optimization using local interaction games,” IEEE Journal of Selected Topics in Signal Processing, vol. 6, no. 2, pp. 180-194, 2012. Yuhua Xu, Jinglong Wang, Qihui Wu, et al, “ Optimal energy-efficient channel exploration for opportunistic spectrum usage,” IEEE Wireless Communications Letters, vol. 1, no. 2, pp. 77-80, 2012. Yuhua Xu, Qihui Wu and Jinglong Wang, “ Game theoretic channel selection for opportunistic spectrum access with unknown prior information,” IEEE ICC2011 在线决策与学习 T. Ferguson, “Optimal stopping and applications” , retrieved on 21 June 2007. D. P. Bertsekas, “Dynamic Programming and Optimal Control” , 3rd ed. Athena Scientific, 2007. A. Sabharwal, A. Khoshnevis, and E. Knightly, “Opportunistic spectral usage: bounds and a multi-band CSMA/CA protocol,” IEEE/ACM Trans. Netw., vol. 15, pp. 533–545, June 2007. S. Guha, K. Munagala, and S. Sarkar, “Information acquisition and exploitation in multichannel wireless systems,” IEEE Transactions on Information Theory, 2007. N. B. Chang and M. Liu, “Optimal channel probing and transmission scheduling for opportunistic spectrum access,” IEEE/ACM TRANSACTIONS ON NETWORKING, vol. 17, pp. 1805–1818, 2009. T. Shu and M. Krunz, “Throughput-efficient sequential channel sensing and probing in cognitive radio networks under sensing errors,” in Proceedings of the 15th annual international conference on Mobile computing and networking, ser. MobiCom ’09. New York, NY, USA: ACM, 2009, pp. 37–48. H. Jiang, L. Lai, R. Fan, and H. V. Poor, “Optimal selection of channel sensing order in cognitive radio,” IEEE Transactions on Wireless Communications, vol. 8, no. 1, pp. 297–307, Jan. 2009. D. Zheng, W. Ge, and J. Zhang, “Distributed opportunistic scheduling for ad hoc networks with random access: an optimal stopping approach,” IEEE Trans. Inf. Theor., vol. 55, pp. 205–222, January 2009. A. Mahajan, D. Teneketzis, “Multi-armed bandit problems” (2009). P. Auer, N. Cesa-Bianchi, and P. Fischer, “Finite-time analysis of the multiarmed bandit problem,” Mach. Learn., vol. 47, pp. 235–256, May 2002. Y. Gai, B. Krishnamachari, and R. Jain, “Combinatorial network optimization with unknown variables: Multi-armed bandits with linear rewards,” CoRR, vol. abs/1011.4748, 2010. L. Lai, H. E. Gamal, H. Jiang, and H. V. Poor, “Cognitive medium access: Exploration, exploitation and competition,” CoRR, vol. abs/0710.1385, 2007. K. Liu and Q. Zhao, “Distributed learning in multi-armed bandit with multiple players,” IEEE Transactions on Signal Processing, pp. 5667–5681, 2010. A. Anandkumar, N. Michael, and A. Tang, “Opportunistic spectrum access with multiple users: Learning under competition,” in INFOCOM, 2010, pp. 803–811. A. Anandkumar, N. Michael, A. K. Tang, and A. Swami, “Distributed algorithms for learning and cognitive medium access with logarithmic regret,” IEEE Journal on Selected Areas in Communications, vol. 29, no. 4, pp. 731–745, 2011. Bowen Li, Panlong Yang, Jinlong Wang, Qihui Wu et al. “Optimal Frequency-temporal Opportunity Exploitation for Multichannel Ad Hoc Networks,” IEEE Transaction on Parallel and Distributed System, 2012, accepted. Bowen Li, Panlong Yang, Qihui Wu et al. “Optimal Action Point for Dynamic Spectrum Utilization Under Rayleigh Fading,” Ad Hoc Sensor Wireless Networks, 2012, accepted. 干扰管理与干扰概率 Federal Communications Commission, “Establishment of interference temperature metric to quantify and manage interference and to expand available unlicensed operation in certain fixed mobile and satellite frequency bands,” ET Docket 03-289, Notice of Inquiry and Proposed ulemaking, 2003. E. S. Sousa and J. A. Silvester, ”Optimum transmission ranges in a direct-sequence spread-spectrum multi-hop packet radio network,” IEEE Journal on Selected Areas in Communications, vol. 8, pp. 762–771, June 1990. M. Z. Win, P. C. Pinto, and L. A. Shepp, “A mathematical theory of network interference and its applications,” Proc. IEEE, vol. 97, no. 2, pp. 205–230, Feb. 2009, special issue on Ultra-Wide Bandwidth (UWB) Technology Emerging Applications. A. Ghasemi and E. S. Sousa, “Interference aggregation in spectrum sensing cognitive wireless networks,” IEEE J. Select. Topics Signal Processing, vol. 2, no. 1, pp. 41–56, Feb. 2008. M. Haenggi, “A geometric interpretation of fading in wireless networks: theory and applications,” IEEE Trans. Inf. Theory, vol. 54, no. 12, pp. 5500–5510, Dec. 2008. M. Haenggi, “Outage, local throughput, and capacity of random wireless networks,” IEEE Trans. Wireless Commun., vol. 8, no. 8, pp. 4350–4359, Aug. 2009. F. Baccelli, P. Mahlethaler, and B. Baszczyszyn, “Stochastic analysis of spatial and opportunistic ALOHA,” IEEE J. Sel. Areas Commun., vol. 27, no. 7, pp. 1105–1119, Sep. 2009. M. Haenggi, J. G. Andrews, F. Baccelli, O. Dousse, and M. Franceschetti, “Stochastic geometry and random graphs for the analysis and design of wireless networks,” IEEE J. Sel. Areas Commun., vol. 27, no. 7, pp. 1029–1046, Sep. 2009. K. Huang, V. K. N. Lau, and Y. Chen, “Spectrum sharing between cellular and mobile ad hoc networks: transmission-capacity trade-off,” IEEE J. Sel. Areas Commun., vol. 27, no. 7, pp. 1256–1267, Sep. 2009. W. Ren, Q. Zhao, and A. Swami, “Power control in cognitive radio networks: how to cross a multi-lane highway,” IEEE J. Sel. Areas Commun., vol. 27, no. 7, pp. 1283–1296, Sep. 2009. 空 - 时频谱机会检测 R. Tandra, S. M. Mishra, and A. Sahai, “What is a spectrum hole and what does it take to recognize one?” Proc. IEEE, vol. 97, no. 5, pp. 824-848, May 2009. S. M. Mishra, “ximizing available spectrum for cognitive radios,” Ph.D. Dissertation, UC Berkeley, 2010. R. Tandra, A. Sahai, and V. V. Veeravalli, “Unified space-time metrics to evaluate spectrum sensing,” IEEE Commun. Mag., vol. 49, no. 3, pp. 54-61, Mar. 2011. T. Duo and B. L. Mark, Joint spatial-temporal spectrum sensing for cognitive radio networks, IEEE Trans. Veh. Technol., vol. 59, no. 7, pp. 3480-3490, Sep. 2010. Alexander W. Min, Efficient and Robust Spectrum Management for Cognitive Radio Networks ,”Ph.D. Dissertation, University of Michigan, 2011. Emiliano Dall'Anese, Spatio-temporal Spectrum Reuse based on Channel Gain Cartography, Ph.D. Dissertation, University of Padova, 2011. Guoru Ding, Qihui Wu, Jinlong Wang, Fei Song and Yuping Gong. Multi-Domain Cognition for Cognitive Wireless Networks. FREQUENZ. 认知中继 Q. Zhang, J. Jia, and J. Zhang, “Cooperative relay to improve diversity in cognitive radio networks,” IEEE Commun. Mag., vol. 47, no. 2, pp. 111-117, Feb. 2009. J. Lee, H. Wang, J. G. Andrews, and D. Hong, “Outage probability of cognitive relay networks with interference constraints,” IEEE Trans. Wireless Commun., vol. 10, no. 2, pp. 390-395, Feb. 2011. Y. Zou, Y.-D. Yao, and B. Zheng, “Outage probability analysis of cognitive transmissions: Impact of spectrum sensing overhead,” IEEE Trans. Wireless Commun., vol. 9, no. 8, pp. 2676–2688, Aug. 2010. A. K. Sadek, K. J. Ray Liu, and A. Ephremides, “Cognitive multiple access via cooperation: protocol design and performance analysis,” IEEE Trans. Inform. Theory, vol. 53, pp. 3677-3696, Oct. 2007. O. Simeone, Y. Bar-Ness, and U. Spagnolini, “Stable throughput of cognitive radios with and without relaying capability,” IEEE Trans. Commun., vol. 55, pp. 2351-2360, Dec. 2007. Yulong Zou, Jia Zhu, Baoyu Zheng, and Yu-Dong Yao, "An Adaptive Cooperation Diversity Scheme With Best-Relay Selection in Cognitive Radio Networks," IEEE Transactions on Signal Processing, vol. 58, no. 10, Oct. 2010. Yang Han, Ashish Pandharipande, and See Ho Ting, "Cooperative Decode-and-Forward Relaying for Secondary Spectrum Access," IEEE Transactions on Wireless Communications, vol. 8, no. 10, Oct. 2009. Yan Chen, Guanding Yu, Zhaoyang Zhang, Hsiao-Hwa Chen, and Peiliang Qiu "On Cognitive Radio Networks with Opportunistic Power Control Strategies in Fading Channels," IEEE Transactions on Wireless Communications, vol. 7, no. 7, July 2008. Yan Chen, Vincent K. N. Lau, Shunqing Zhang, and Peiliang Qiu, "Protocol Design and Delay Analysis of Half-Duplex Buffered Cognitive Relay Systems," IEEE Transactions on Wireless Communications, vol. 9, no. 3, Mar. 2010. 宽带感知 Z. Quan, S. Cui, A. H. Sayed, and H. V. Poor, “Optimal multiband joint detection for spectrum sensing in cognitive radio networks,” IEEE Trans. Signal Process., vol. 57, no. 3, pp. 1128–1140, Mar. 2009. Y. Pei, Y.-C. Liang, K. Teh, and K. Li, “How much time is needed for wideband spectrum sensing?,” IEEE Trans. Wireless Commun., vol. 8, no. 11, pp. 5466–5471, Nov. 2009. R. Fan and H. Jiang, “Optimal multi-channel cooperative sensing in cognitive radio networks,” IEEE Trans. Wireless Commun., vol. 9, no.3, pp. 1128–1138, Mar. 2010. C.-H. Hwang, G.-L. Lai, and S.-C. Chen, “Spectrum sensing in wideband OFDM cognitive radios,” IEEE Trans. Signal Process., vol. 58,no. 2, pp. 709–719, Feb. 2010. K. S. Hossain, “Wideband Spectrum Sensing for Cognitive Radios in the Presence of Correlation Between Subband Occupancy,” M.Eng. thesis, McGill Univ., Montréal, QC, Canada, Aug. 2010. Jinlong Wang, Han Han, Qihui Wu, Yuhua Xu, Optimal Wideband Spectrum Sensing Order in Cognitive Radio , Frequenz, issue 7/8, 2010. Qihui Wu, Han Han, Jinlong Wang, Zhitao Zhao, Ze Zhang, Sensing Task Allocation for Heterogeneous Channels in Cooperative Spectrum Sensing , Radio engineering, vol. 19, no. 4, 544-551, Dec. 2010 . 异构网络、网络选择 Shu-Ping Yeh, Shilpa Talwar, Geng Wu, Nageen Himayat, And Kerstin Johnsson, ” Capacity And Coverage Enhancement In Heterogeneous Networks,” IEEE Wireless Communications, June 2011,pp.32-38 Chittabrata Ghosh And Sumit Roy, Dave Cavalcanti ,” Coexistence Challenges For Heterogeneous Cognitive Wireless Networks In Tv White Spaces,” IEEE Wireless Communications, August 2011, pp.22-31 Gabriel P. Villardi, Yohannes D. Alemseged, Chen Sun, Chin-Sean Sum, Tran Ha Nguyen, Tuncer Baykas, And Hiroshi Harada, “Enabling Coexistence Of Multiple Cognitive Networks In Tv White Space,” IEEE Wireless Communications, August 2011, pp.32-40 Shin-Ming Cheng, Shou-Yu Lien, Feng-Seng Chu, And Kwang-Cheng Chen, ” On Exploiting Cognitive Radio To Mitigate Interference In Macro/Femto Heterogeneous Networks,” IEEE Wireless Communications, June 2011,pp.40-47. Aleksandar Damnjanovic, Juan Montojo, Yongbin Wei, Tingfang Ji, Tao Luo, Adhavan Vajapeyam, Taesang Yoo, Osok Song, an Durga Malladi, “A Survey On 3gpp Heterogeneous Networks”. IEEE Wireless Communications, June 2011,pp.10-21. Ruogu Zhou, Yongping Xiong, Guoliang Xing , Limin Sun, and Jian Ma, “ZiFi: Wireless LAN Discovery via ZigBee Interference Signatures”, Proc. IEEE MOBICOM, 2010. S. Hong, S. Katti, "DOF: A Local Wireless Information Plane", ACM SIGCOMM, 2011 Majed Haddad, Salah Eddine Elayoubi, Eitan Altman, and Zwi Altman, ”A Hybrid Approach for Radio Resource Management in Heterogeneous Cognitive Networks,” IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, VOL. 29, NO. 4, APRIL 2011,pp.831-842. Dong Ma, Maode Ma, “A QoS Oriented Vertical Handoff Scheme for WiMAX/WLAN Overlay Networks,” IEEE Transactions On Parallel And Distributed Systems, Vol. 23, No. 4, April 2012,pp.598-606. 认知定位 Jun Wang, Paulo Urriza, Yuxing Han, and Danijela Cabric , ”Weighted Centroid Localization Algorithm:Theoretical Analysis and Distributed Implementation” IEEE Transations On Wireless Communications, VOL. 10, NO. 10, October 2011 Z. Ma, W. Chen, K. Letaief, and Z. Cao, “A semi range-based iterative localization algorithm for cognitive radio networks,” IEEE Trans. Veh. Technol., vol. 59, no. 2, pp. 704–717, Feb. 2010. S. Liu, Y. Chen, W. Trappe, and L. J. Greenstein, “Non-interactive localization of cognitive radios based on dynamic signal strength mapping,” in Proc. Intl. Conf. on Wireless On-demand Network Systems and Services, Feb. 2009. D. Gong, Z Ma. Y. Li, W. Ches, and Z. Cao, “High geometric range free localization in opportunistic cognitive sensor network,” IEEE International Personal Commun., pp. 139-143, 2008. S. Kim, H. Jeon, and J. Ma, “Robust localization with unknown transmission power for cognitive radio,” in Proc. IEEE MILCOM, Orlando, FL, Oct. 2007, pp. 1–6. 认知路由 Sharma, S.; Shi, Y.; Hou, Y.T.; Sherali, H.D.; Kompella, S.; Midkiff, S.F.; , "Joint Flow Routing and Relay Node Assignment in Cooperative Multi-Hop Networks," IEEE Journal on Selected Areas in Communications, vol.30, no.2, pp.254-262, February 2012; Kaushik R. Chowdhury and Ian F. Akyildiz , “CRP: A Routing Protocol for Cognitive Radio Ad Hoc Networks,” IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, VOL. 29, NO. 4, APRIL 2011; Yi Shi; Hou, Y.T.; Huaibei Zhou; Midkiff, S.F., "Distributed Cross-Layer Optimization for Cognitive Radio Networks,", IEEE Transactions on Vehicular Technology , vol.59, no.8, pp.4058-4069, Oct. 2010; Lei Ding, Tommaso Melodia, Stella N. Batalama, John D. Matyjas, and Michael J. Medley , “Cross-layer Routing and Dynamic Spectrum Allocation in Cognitive Radio Ad Hoc Networks,” IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, VOL. X, NO. X, XXXX 2010 ; Matteo Cesana , Francesca Cuomo , Eylem Ekici , “Routing in cognitive radio networks: Challenges and solutions” , Ad Hoc Networks. 2010. doi:10.1016/j.adhoc.2010.06.009; Hicham Khalife, Naceur Malouch and Serge Fdida , “Multihop Cognitive Radio Networks:To Route or not To Route,” IEEE Network (2009) 20-25; Chunsheng Xin, Bo Xie, Chien-Chung Shen, “A novel layered graph model for dynamic spectrum access networks” , Proc. IEEE DySPAN 2005, November 2005, pp.308-317;
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认知无线电技术的研究及发展 (转载自互联网)
kinglandom 2008-11-30 13:13
摘要 认知无线电技术作为软件无线电技术的一个特殊扩展,受到日益广泛的关注。由于该技术能够自动检测无线电环境,调整传输参数,从空间、时间、频率、调制方式等多维度共享无线频谱,可以大幅度提高频谱利用效率。本文首先从认知无线电技术的定义入手,分别讨论了认知无线电的基本概念、功能与实现、标准化的进程。然后介绍了当前应用状况,最后分析了未来的发展及面临的挑战。 1、引言 随着无线通信技术的发展,人们可以获得的带宽不断地增加,移动通信的数据速率从10 kbit/s增长到2 Mbit/s,在不久的将来还可能提高到上百兆比特每秒。但即使如此,也无法满足人们日益增长的无线接入需求。为了缓解这一矛盾,一方面,人们不断开发新的无线接入技术,利用新的频段来提供各种业务;另一方面,不断改进各种编码调制方式,提高频谱效率。但由于移动终端天线尺寸和功率的限制,可以用于无线接入的频段很有限。在提高频谱效率方面,目前较为先进的CDMA空中接口技术,如HSDPA可以达到1 bit/(sHz)的频谱效率,将来OFDM和MIMO技术的应用也只能达到3-4 bit/(sHz)的频谱效率。3-4倍的频谱效率的提高对于人们成百上千倍的带宽需求增长是微不足道的。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开创了崭新的局面。 2、认知无线电的基本概念 认知无线电(cognitive radio,CR)的概念是由Joseph Mitola博士提出的,他在1999年发表的一篇学术论文 中描述了认知无线电如何通过一种无线电知识表示语言(RKRL)的新语言提高个人无线业务的灵活性。随后在2000年瑞典皇家科学院举行的博士论文答辩中详细探讨了这一理论 。 认知无线电也被称为智能无线电。从广义上来说是指无线终端具备足够的智能或者认知能力,通过对周围无线环境的历史和当前状况进行检测、分析、学习、推理和规划,利用相应结果调整自己的传输参数,使用最适合的无线资源(包括频率、调制方式、发射功率等)完成无线传输。认知无线电能够帮助用户自动选择最好的、最廉价的服务进行无线传输。甚至能够根据现有的或者即将获得的无线资源延迟或主动发起传送。 由定义可以看出。认知无线电的一个最大优势就是无线用户可以通过该技术实现频谱共享。目前大多数频谱已经被划分给不同的许可持有者(又称为首要用户),包括移动通信、应急通信、广播电视等。但是随着用户需求的增长,简单地通过开发新的无线接入技术和使用新的频点已经无法充分满足市场需求。 近年来,很多学者通过监测分析当前无线频谱使用状况发现,虽然大部分频谱已经被分配给不同的用户,但是在相同时间、相同地点频谱的使用却非常有限。常常是大部分频点未被使用,而某些热点频率又处于超负荷运行。美国联邦通信管理委员会(FCC)充分注意到了这一点,于2002年11月出版了频谱政策任务组撰写的一份报告 ,该报告指出,当前分配的绝大多数频谱的利用率为15%-85%。因此FCC认为当前存在的最主要问题并不是没有频谱可用,而是现有的频谱分配方式导致资源没有被充分利用。只有彻底改变当前固定频谱分配政策,部分甚至全部采用动态频谱分配政策,使多种技术可以实现频谱共享,才能彻底改变频谱缺乏的问题。如果采用频谱共享技术,允许部分免许可用户在不影响首要用户的前提下动态共享部分频点可以极大地缓解目前频谱资源紧张的问题。 与学术研究给出的定义略有不同,FCC的定义相对狭义一些:认知无线电技术是无线终端利用与周围无线环境进行交互所获取的无线背景知识,调整传输参数,实现无线传输的能力。即只要具备环境探测,并且能够调整传输频点和相关传输参数的设备就是认知无线电设备。 实际上,认知无线电技术是对频谱资源从时间、空间和频率等多维度的重复利用和共享。认知无线电在特定频段上进行探测,如果发现该频段当前未被使用,可以在不影响首要用户的前提下使用该频段。如果该频段的首要用户恢复无线传输,那么认知无线电设备就跳转到其他频段或者通过改变传输功率、调制方式等手段来避免对首要用户产生干扰。 3、认知无线电的功能与实现 从认知无线电的概念我们可以看到,与传统的以发射机为中心的设计思想所不同,认知无线电是以接收机为中心的以目标为驱动的框架;与传统的通信系统结构不同的是,仅仅实现底层的功能是远远不够的,如果要确保大量认知无线电设备正常工作必然要涉及到更高层次的协议设计。 3.1 认知无线电的主要功能 由于认知无线电技术尚处于起步阶段,对于该技术的主要功能还处于讨论过程中。Mitola博士提出的认知循环过程相对比较复杂,包括一系列认知学习步骤 。当前,不同组织机构在设计实现认知无线电的总体框架中所涉及的具体内容也有所不同。从比较完整的意义上一般认为,认知无线电系统应该具备检测、分析、调整、推理、学习等能力。事实上,这些具体功能就是一个认知循环的主要组成部分。 (1)检测 由特殊应用环境所决定,认知无线电必须具备精确的无线频谱检测能力,必须在可使用的全频段范围内多维度进行频谱检测,从而发现可使用的频段。由于是免许可使用,认知无线电必须具备迅速发现首要用户的能力,在工作过程中时刻检测首要用户是否处于活动状态,从而确保不对其产生干扰。更为困难的一点是,由于广播电视用户多为哑终端,即仅仅完成接收功能。而作为认知无线电用户又必须能够发现他们的存在,从而避免对其产生干扰,这就为频谱检测提出了更为艰巨的要求。目前有些研发人员提出通过检测接收机本振的频谱泄漏来完成对哑终端的定位,但是仍处于研究阶段。 (2)分析 认知分析包括对自身性能、网络内部状态、外部相关数据(包括频谱使用、策略使用等)和用户自身需求等相关知识的分析。如果说检测是信息的获取,那么分析就是对相关信息的初步处理。认知无线电设备通过所获取的频谱检测结果分析首要用户的位置、使用的频点和发射时间,同时分析可用频点位置、可用带宽、信道状况、自身传输可能会对其他用户产生的影响以及完成业务传输所需的带宽和时间。 (3)调整 调整能力是完成传输的关键,根据检测和分析的相关结果,认知无线电设备通过先进的功率控制技术、不同的编解码以及调制技术,选择合适的频点和发射时机,从而成功地完成传输。这就要求认知无线电设备具备较强的性能,能够在较宽的频段内实现不同传输方案之间的切换,并且在突发事件发生后能够及时暂停或恢复传输,确保在不干扰首要用户的情况下获取最大限度的传输能力。 (4)推理和学习 由于当前无线频谱环境的复杂性,简单的检测、推理和分析可能无法获得较好的传输性能。如何根据无线背景环境的相关数据进行分析预测是一个非常重要的课题。根据历史数据进行推理,获得一定的参考信息,在此基础上进行调整是一个较好的解决方案。一般来讲,这种推理和学习分为三种:第一种是基于简单固定规则,即输入、输出可以预测;第二种是基于较为复杂的模型,运用一些模糊规则,输出结果不可完全预测;第三种是基于学习型的模型,系统运行过程中能够不断调整模型及其参数,从而获得较好的预测结果。当前这一部分研究相对来讲更为滞后。 3.2 认知无线电的实现关键 (1)高灵敏度接收机 认知无线电在开始使用之前必须先对频谱功率密度进行估计,以确定哪些频点正在使用。为了精确测量频谱,需要有高灵敏度的接收机来测定小区边缘的信号功率。以一个位于小区边缘的数字电视机为例,接收到的信号可能刚刚超过接收机的灵敏度要求。为了能够检测出这一信号,认知无线电需要具有比数字电视机更高的灵敏度。如果认知无线电不能检测到数字电视信号,就会错误地认为该频点未被使用,从而对数字电视机的解码产生干扰,这种情况被称作隐藏节点问题。同时,这一技术也是对首要用户发射状态的检测、首要用户定位和可用频谱资源检测的关键所在。 (2)智能处理平台 高速智能处理平台是认知无线电设备根据无线检测结果分析无线传输背景,包括首要用户的存在、定位、频谱空穴的发现、信道状况估计和传输带宽选择等多方面参数确定的基础。当频谱被分配后,认知无线电必须还能够估计首要用户的干扰容限,从而确定自身的传输功率。很多情况下,这个限定的量为0.5-1dB,但还要取决于首要用户接收机的链路余量。干扰程度至少可以通过两个信息来确定:首要用户信号带宽的估计,认知无线电和被干扰设备之间的距离。信号带宽可以用来确定被干扰设备的噪声门限,距离可以用来确定被干扰设备接收到的认知无线电信号功率强度。假设被干扰设备的噪声门限可以允许提高一个预先设定的量值,可以很容易计算出认知无线电最大允许发射功率。当然,这种分析过于简单,可以进一步细化,如果认知无线电能够对首要用户的信号类型和对应的数据速率进行盲识别,这些额外的知识可以确定被干扰设备灵敏度的具体数值。 (3)可重配置的无线电设备 根据无线背景分析所获得的可用频谱空穴、干扰强度以及先验知识,认知无线电通过调整传输功率和其他主要参数从而保证在不干扰首要用户的前提下获得最大的传输速率。因为认知无线电设备工作频带较宽,可采取的传输方案、可选择的传输参数较多,要求的切换时间较短,因此必须具备高性能的、可重配置的无线电平台。从无线电发展的历程上看,认知无线电可以看作是软件无线电技术在环境探测能力方面的扩展。从未来的发展趋势也可以看出,未来的大部分认知无线电设备可能是基于软件无线电的,但这并不表明认知无线电设备必须具备软件或现场可编程器件,软件无线电技术只不过是认知无线电技术的一种实现方案。 (4)组网应用 从前面的讨论可以看出,认知无线电是一个非常复杂的系统。当多个认知无线电系统共同工作时,问题就变得更加棘手了。当各个认知无线电设备独立工作的时候就不可避免地产生冲突。而且由于各个设备都具有一定的智能,这种相互之间的躲避往往会产生一连串的碰撞。目前针对这个问题有人采用分组策略,即将某一地区的认知无线电分为不同的组,组内共享某些必要信息,每一个新加入的成员可以选择加入这个组或者单独成立一个新组,从而避免冲突。也有人应用博弈理论,提高系统智能避免冲突。 4、认知无线电的标准化 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,并且开始着手制定认知无线电的标准和协议。下面主要介绍ITU、软件无线电论坛(software defined radio forum)和IEEE相关工作的进展。 ITU关于认知无线电的研究工作目前仍隶属于ITU-R 8A工作组中的软件无线电研究课题。因为软件无线电不足以涵盖认知无线电的所有范畴,所以ITU-R于2006年3月提出一项新的建议,将认知无线电单独作为一个研究课题进行研究,这说明ITU已经充分认识到认知无线电技术在未来通信发展中的重要意义。 2003年8月软件无线电论坛就开始探讨放松当前严格的频谱划分政策的可能性,研究通过开发新的智能无线电设备从而提高频谱利用效率。该论坛于2004年10月成立了认知无线电工作组,专门开展有关认知无线电技术研究。鉴于软件无线电论坛的特殊任务,该工作组主要致力于开展认知无线电平台的分析和多模式调整功能的研究。 IEEE于2004年11月正式成立IEEE802.22工作组 ,这是第一个世界范围的基于认知无线电技术的空中接口标准化组织。IEEE802.22也被称为无线区域网络(wireless regional area network,WRAN),系统工作于41-910 MHz VHF/UHF频段上未使用的TV信道,工作模式为点到多点。WRAN设备的关键是无需频率许可。与电视等已有的首要用户共存。当首要用户工作时,WRAN不占用相应频段;当检测到某些频段没有被首要用户使用时,WRAN设备可以自动使用这些频率资源;WRAN设备在工作期间发现首要用户在相同频段开始工作时,将迅速退让出相应频段。 802.22标准工作组于2005年9月完成了对WRAN的功能需求和信道模型文档,2006年开始对各个公司提交的提案进行审议和合并,并于2006年3月形成了最终的合并提案作为编写标准的基础,预计2008年最终的标准将会被批准。 WiMAX由于缺乏可用频段,专门成立了致力于解决共存问题的802.16h工作组,可以使WiMAX适用于UHF电视频段,利用认知无线电技术使802.16系列标准可以在免许可频段获得应用。 802.22和802.16h都只是认知无线电的简单应用,为了进一步研究认知无线电,IEEE于2005年成立了IEEE1900标准组,进行与下一代无线通信技术和高级频谱管理技术相关的电磁兼容研究。该工作组对于认知无线电技术的发展和与其它无线通信系统的协调与共存有着极其重要的意义。 5、认知无线电的管制与应用情况 认知无线电在提高频谱利用率方面的价值引起了各国电信管制机构的兴趣,不过由于认知无线电的技术和概念都非常超前,多数国家仍在研究讨论当中,只有美国的FCC已经正式批准具备认知无线电性能的设备进入市场。 近年来美国希望大力发展宽带无线接入业务,但由于频谱资源匮乏,亟需寻找新的频段给新的接入技术。美国是最早推动和批准使用认知无线电设备的国家。FCC从2003年就开始尝试引入认知无线电提高频谱的利用。2003年12月,FCC公布了《使用认知无线电技术促进频谱利用的通知》,就《FCC规则第15章(FCC rule part 15)》(用于数字式设备和低功发射机的法规)进行了修订,并于2005年10月,正式批准了关于引入认知无线电技术、使用认知无线电设备的法规。 FCC认为目前最适合应用认知无线电技术的是UHF中分配给电视广播业务的6 MHz频段,因为目前该频段在美国利用率很低,通过允许其它免许可设备使用这个频段,不仅可以提高频率利用率,而且还可以推广宽带无线接入业务,因为这个波段传播距离远,适合为偏远地区提供服务,可以促进美国社会的宽带普及。FCC认为认知无线电技术还可以在高频率频段发挥作用,如100 GHz以上的频段在美国的使用率只有5%-10%。 认知无线电听起来是个十分新颖的概念,但事实上无线局域网(WLAN)领域已经开始利用认知无线电技术。 WLAN是最早利用认知无线电技术的无线通信系统。FCC等法规机构要求802.11a无线电能检测雷达信号并避免与它们形成干扰,这种躲避雷达的能力要求系统具有强大的CR类自适应能力,而这只是WLAN CR功能的开始。 目前Atheros公司推出的基于Super G技术的无线局域网技术,加入了自动检测功能,可以根据检测到的邻近无线局域网用户情况自适应调整信道占用,最大限度提高系统传输速率。基于该技术的无线局域网设备可以工作在两种模式,一种为基本模式,另一种为Dynamic Turbo模式。在Dynamic Turbo模式下,通过扩展信号传输带宽可以将传输速率提高到传统802.11g的三倍。当检测到周围其它无线局域网络运行时,具备Dynamic Turbo功能的Super G设备可以自动调整为单一频道,避免对其它用户产生影响,当没有其它用户存在时又可以自动调整为多信道传输,获得最大的传输速率。 无论在军用还是民用领域,认知无线电的研究与应用都处于起步阶段。在军用领域,美国国防部高等研究计划署(DARPA)于2003年成立了下一代通信计划(XG),着眼于开发认知无线电的实际标准和动态频谱管理标准。2003年开始,Raytheon公司与DARPA签订了下一代无线通信计划的合同。从事认知无线电相关的技术研究与开发。在民用领域,Motorola、Intel等公司也已经成立认知无线电研究组并开始开展相关的研究。 6、未来发展与展望 认知无线电是无线电技术发展的下一个里程碑。该技术的应用会带来历史性的变革。对于频谱管制者而言,该技术可以大大提高可用频谱数量,提高频谱利用率,有效利用资源;对于频谱持有者而言,可以在不受干扰的前提下开发二级频谱市场,在相同频段上提供不同的服务,该技术可以为设备厂商带来更多的机会,具备认知无线电功能的设备将更具竞争力;对终端用户而言,可以带来更多带宽,在认知无线电技术成熟后。用户则可以享受到单个无线电终端接入多种无线网络的优势。 当然,认知无线电技术的发展目前还存在一些障碍:首先,目前频谱管制政策尚没有完全放开,认知无线电技术的应用还存在很大障碍;其次,认知无线电的灵活性还需要不断提高,必须能够随着应用策略的更改灵活配置;认知无线电技术需要强大的可重配置硬件平台,目前的硬件技术发展还满足不了相关需求;另外认知无线电组网工作的语言和协议目前很不完善,需要开发专门语言和协议在设备之间共享无线背景信息。 作为无线通信领域的最新进展,认知无线电技术受到日益关注,虽然由于技术的限制,认知无线电近几年内市场不会很大,但在不久的将来将会获得突破性的进展,为无线电资源管理和无线接入市场带来新的发展契机和动力。 参考文献 l Mitola J.Cognitive radio:making software radios more personal.IEEE Pers Commun,1999,6(4) 2 Mitola J. Cognitive radio:an integrated agent architecture for software deftned radio.In:Doctor of Technology, Royal Inst Technol(KTH),Stockholm,Sweden,2000 3 Krenik W.Cognitive techniques for wide area networks.Rep ET Docket No02-135,Federal Communications Commission,Nov 2002 4 Mitola J.Cognitive radio for fexible mobile multimedia communications. In:Mobile Multimedia Communications, IEEE International Workshop, 1999 5 IEEE 802.22 working group on wireless regional area networks,http://WWW.ieee802.org/22/
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