【導讀】首先每個認知用戶基于雙檢測門限獨立進行頻譜感知，但只。有部分可靠的認知用戶通過控制信道向認知無線網(wǎng)絡基站發(fā)送本地感知結(jié)果。有的用戶都不可靠時，選取信任度最高的認知用戶發(fā)送本地感知結(jié)果進行判決。條件下，以較少的網(wǎng)絡開銷獲得更好的頻譜感知性能。矛盾越來越突出。然而根據(jù)現(xiàn)有的固定分配頻譜資源策略，絕大多數(shù)頻譜資源得不。據(jù)FCC的調(diào)查統(tǒng)計，70%的已分配頻譜資源沒有得到有效利用]1[。通常它又可以分為。能量檢測法、匹配濾波器法和循環(huán)平穩(wěn)特征法[4]。能量檢測算法因為應用簡單且無。需知道任何授權(quán)用戶信號的先驗知識成為研究熱點。認知用戶在接入授權(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，否則會對授權(quán)用戶造成干擾。的性能并不樂觀，針對這個問題D.Cabric等人提出了協(xié)同頻譜感知算法[5]-[6]。后做出最終判決。戶與認知用戶之間信道的衰落因子。的指數(shù)分布，22mX表自由度為2m的。如果出現(xiàn)所有認知用戶都不作出判決的情況，則選

　　

【正文】 ision will be reported without any error. So AP stand for the probability of the event that under hypothesis 0H , all the K users claim 0H and other NK users make no local decisions. dA QHKuPP ????? 1}|0,0{ 1 =????????????NKKNk FFFKN1 121 ))()(()( ??? = 02)( ?? ?NF （ 16） 12)( ?? ??GPB （ 17） ))(_1)(1( 020 ??? ??? Nf FQ （ 18） ))(_1)(1( 121 ??? ??? Nf GQ （ 19） IV. SIMULATION RESULTS In this section, some simulation results are presented to illustrate the system performance of our cooperative spectrum sensing algorithm based on reputation. The results of the conventional one threshold energy detection method are also shown for a parison. In our simulation, the mon simulation parameters are given as follows: Table 1. Simulation parameters 10?N db10_ ?? 5?m ?op ?p depicts the performance of cooperative spectrum sensing dQ and fQ . ?? .It can be observed that, pared it with the conventional method, the detection performance has improved significantly. For example, while fQ = , our method achieves extra detection probability. shows the decrease of the normalized transmission bits for different values of fail sensing, . 0? = 0, , , . Compared with conventional method, ., when 0? = 0, the normalized average number of sensing bits is dramatically decreased and bandwidth limited problem of the reporting channel is relieved. For example, when fQ = , almost 44% and 38% reduction of the normalized average number of sensing bits can be obtained for 0? = and 0? = , respectively. In our algorithm, fQ is upper bounded and lower bounded because of the probability of fail sensing 0? and the false alarm probability are based on (7), (13). Fig 2. dQ vs. fQ , ?? Fig 3. navgK vs. fQ , 0? =00, V. CONCLUSION In this paper, a new scheme in cooperative spectrum sensing for cognitive radio works under bandwidth constraints was proposed. In our method, only the secondary users with reliable information are allowed to report their sensing results. When no user has reliable information, only he secondary user with highest reputation will report its sensing result. We analyzed the closed expression for the probability of the detection and the falsealarm. From the preliminary simulation results, we demonstrated the average number of sensing bits decrease greatly and the sensing performance is also improved. REFERENCES [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 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.