【正文】 ????????????NKKNk FFFKN1 121 ))()(()( ??? = 02)( ?? ?NF (17) 12)( ?? ??GPB (18) 則： ))(1)(1( 020 ??? ???? Nf FQ (19) 黃石理工學(xué)院 畢業(yè)設(shè)計(jì)（論文）外文文獻(xiàn)翻譯 ))(1)(1( 121 ??? ???? Nf GQ (20) 由上式可知當(dāng) 0? =0 時(shí)，此算法與常規(guī)算法相同。同常規(guī)能量檢測(cè)算法即 0? =0 時(shí)相比較，本文所提出算法的歸一化平均感知位數(shù) avgK 急劇下降，控制信道帶寬與認(rèn)知用戶數(shù)量之間的矛盾得到了緩解。 參考文獻(xiàn) [1] Federal Communications Commission. Spectrum Policy Task Force, Rep. ET Docket no. 02135 [R]. Nov. 2020. [2] J. Mitola and G. Q. Maguire. Cognitive radio: Making software radios more personal[C],IEEE Personal Communication. vol. 6, pp. 13–18, Aug. 1999. [3] S. Haykin. Cognitive radio: brainempowered wireless munications [J]. IEEE J. Sel. Areas Communication. vol. 23, pp. 201–220, Feb. 2020. [4] AKYLDIZ IF. Next generation/dynamic spectrum access/cognitive radio wireless works: A Survey [J]. ELSEVIER Computer Networks, 2020(50):21272159. [5] D. Cabric, S. M. Mishra, and R. W. Brodersen. Implementation issues in spectrum sensing for cognitive radios[C]// in Proc. Of A silomar Conf. on Signals, Systems, and Computers, Pacific Grove,CA, USA, Nov. 710, 2020, pp. 772 776. [6] and E. S. Sousa. Collaborative spectrum sensing for opportunistic access in fading environments[C]// in Proc. 1st IEEES ymp. New Frontiers in Dynamic Spectrum Access Networks, Baltimore, USA, Nov. 8–11, 2020, pp. 131–136. [7] Chunhua Sun, Wei Zhang, Letaief . Cooperative spectrum sensing for cognitive radios under bandwidth constraints[C]// in Proc. IEEE WCNC, March 1115, 2020, pp. 15. [8] H. Urkowitz. Energy detection of unknown deterministic signals [C]. Proceedings of IEEE, , pp. 523531, April 1967. [9] Ruiliang Chen, JungMin Park, Kaigui Bian. Robust Distributed Spectrum Sensing in Cognitive 黃石理工學(xué)院 畢業(yè)設(shè)計(jì)（論文）外文文獻(xiàn)翻譯 Radio Networks[C]. in Proc. IEEEINFOCOM, April 2020, pp. 18761884. [10] F. F. Digham, M. S. Alouini, and M. K. Simon. On the energy detection of unknown signals over fading channels[C]. in Proc. IEEE ICC, Anchorage, AK, USA, May 1115, 2020, pp. 3575–3579. 黃石理工學(xué)院 畢業(yè)設(shè)計(jì)（論文）外文文獻(xiàn)翻譯 附原文： A New Cooperative Spectrum Sensing Algorithm for Cognitive Radio Networks Abstract—spectrum sensing is a critical phase in building a cognitive radio work. However, the bandwidth for reporting secondary users’ sensing results will be insufficient, when the number of secondary user is very large. In this paper, we propose a new cooperative spectrum sensing algorithm to alleviate the bandwidth problem of reporting channel. Compared with conventional method, only the secondary users with reliable information are allowed to report their sensing results. When no user with reliable information, only the secondary user with highest reputation will report its sensing result. Simulation results show that our algorithm achieves better sensing performance and the average number of sensing bits decrease greatly. Keywords— cognitive radio。 KNT? represent he event that there are K unlicensed users reporting 1bit decision and NK users not reporting to the mon receiver, respectively. The KiK pTP )](1[}{ 21 ??? ???? , KNiKN PTP ?? ??? )]([}{ 21` ???.and then the average number of sensing bits for our method can be derived as: ? ?? ? ?? ?????????????????? NK NK kNkKNkav g HTPHTPKNKPHTPHTPKNKPK 1 1 111039。當(dāng)所有的用戶都不可靠時(shí)，選取信任度最高的認(rèn)知用戶發(fā)射感知報(bào)告進(jìn)行判決。例如當(dāng) ?fQ 時(shí)，基于信任度的雙門限協(xié)同頻譜感知算法的檢測(cè)概率 dQ 比常規(guī)能量檢測(cè)算法高出。00 }|{}|{}|{}|{ (8) 定義： )|( 02110 HP ??? ???? ， )|( 02110 HP ??? ???? 則： 11001 ????? PPK a v g (9) 由 9 式 可得： 1?avgK 可知：基于雙門限的協(xié)同頻譜檢測(cè)算法的網(wǎng)絡(luò)開銷始終小于常規(guī)的能量檢測(cè)算法。 如果出現(xiàn)所有認(rèn)知用戶都不作出判決的情況，則選擇信用度最高的認(rèn)知用戶依據(jù)單門限能量檢測(cè)算法作出本地判決。 2 系統(tǒng)模型 假設(shè)一個(gè)認(rèn)知無線電網(wǎng)絡(luò)有 N個(gè)認(rèn)知用戶和 一個(gè)認(rèn)知無線網(wǎng)絡(luò)基站，如圖 1 所示。一旦授權(quán)用戶重新工作，認(rèn)知用戶必須退避，實(shí)現(xiàn)在不對(duì)授權(quán)用戶產(chǎn)生干擾的情況下對(duì)頻譜資源的共享。 關(guān)鍵詞 ： 認(rèn)知無線電；頻譜感知；信任度；雙門限 1 引言 隨著無線通信技術(shù)的飛速發(fā)展，有限的頻譜資源與不斷 增長的無線通信需求的矛盾越來越突出。理論分析和仿真表明，同常規(guī)能量檢測(cè)算法相比較，該算法能夠在控制信道帶寬受限條件下，以較少的網(wǎng)絡(luò)開銷獲得更好的頻譜感知性能 。認(rèn)知用戶在接入授權(quán)頻帶之前，必須首先感知該頻帶空閑即授權(quán)用戶沒有工作，否則會(huì)對(duì)授權(quán)用戶造成干擾。本黃石理工學(xué)院 畢業(yè)設(shè)計(jì)（論文）外文文獻(xiàn)翻譯 文對(duì)該算法進(jìn)行了性能分析并通過仿真表明，本文方法比較常規(guī)能量檢測(cè)算法，在減小網(wǎng)絡(luò)開銷的同時(shí)提高了檢測(cè)性能。而雙門限能量檢測(cè)算法本地判決如圖 3(b)黃石理工學(xué)院 畢業(yè)設(shè)計(jì)（論文）外文文獻(xiàn)翻譯 所示，本地 能量檢測(cè)器判決規(guī)則如下： （ 3） 其中 ND 表示認(rèn)知用戶接受到的能量值不可靠，認(rèn)知用戶不作出任何判決，發(fā)送感知報(bào)告給認(rèn)知無線電網(wǎng)絡(luò)基站。 設(shè) }{ 11 HPP ?