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认知无线电网络的一种协作频谱感知方案 总被引:3,自引:3,他引:0
认知无线电技术能够让非授权用户利用已经分配给授权用户的频段.为了不对首要用户的工作造成干扰,认知用户需要对频谱进行不间断的监测来判断首要用户是否存在.因此,频谱的感知是认知无线电技术的关键.协作频谱感知能够充分的利用网络资源,提高网络中的认知用户的检测概率.文中笔者简单地介绍了一种协作频谱感知的方案.仿真结果表明,通过该方法能够提高网络中认知用户的检测概率,提高网络的检测灵敏度. 相似文献
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认知无线电的提出,能够有效的解决目前频谱资源匮乏的问题,频谱感知是认知无线电中必不可少的关键技术之一.着重对低功率复杂无线场景的频谱感知技术进行研究,在待测区域布置大量传感器或阵列天线,对授权用户的信息进行估计,得出区域性的干扰温度估计. 相似文献
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认知无线电的提出,能够有效地解决目前频谱资源匮乏的问题,频谱感知是认知无线电中必不可少的关键技术之一.着重对低功率复杂无线场景的频谱感知技术进行研究,在待测区域布置大量传感器或阵列天线,对授权用户的信息进行估计,得出区域性的干扰温度估计. 相似文献
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在认知无线电系统中,认知用户利用授权用户的频谱空洞进行通信,达到提高频谱利用率的目的。动态频谱接入技术是认知无线电系统的关键技术,在文中我们提出了一种使用呼叫接纳控制(CAC)的动态频谱接入机制,经过仿真验证该机制能有效地减小认知无线电系统中认知用户的切换概率,同时次用户对信道的使用率会略有下降。 相似文献
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Spectrum sensing is a key technology to detect spectrum holes in cognitive network. It has been demonstrated that collaboration among cognitive users can improve the probability of detecting the primary users, but the fusion center is the bottleneck when a lot of collaborative information is transmitted. In this paper, we consider the cognitive radio users only transmit part of sensing information to relieve the transmission load. Besides, the sensing information will be inevitably influenced by various noise in the process of transmission. Therefore, the challenge is how we can detect spectrum holes successfully from these incomplete and inexact measurements. Most recently, there are some research results on this but the detection performance is not satisfactory. In this paper, we firstly formulate the collaborative spectrum sensing as an optimization model and then present a novel adaptive orthogonal matching pursuit algorithm by exploiting the sparsity of active primary users. Statistical property of the sensing data plays a crucial role in spectrum sensing. Theoretical analysis shows the presented scheme can detect active primary users rapidly and efficiently. Simulation results verify that the proposed method can obtain better detection performance with stronger noise background, which is more attractive in real applications. 相似文献
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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。 相似文献
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Qun Yu 《Wireless Personal Communications》2013,73(3):949-966
Cooperative cognitive radio networks are new cognitive radio paradigm. Cooperative communication approaches, such as cooperative spectrum sensing and cooperative spectrum sharing, are playing key roles in the development of cognitive radio networks. To achieve the high performance, a cooperative cognitive communication framework is often used to model various cooperative spectrum sensing or sharing scenarios. However, its implementation faces numerous challenges due to the complexity of mobility and traffic models, the needs of dynamic spectrum access, the heterogeneous requirements from different users, and the distributed structure of the network. Fortunately, cooperative game theory can be used to formulate and model the interactions among licensed and unlicensed users for spectrum sensing and spectrum sharing to efficiently allocate spectrum resource in the highly dynamic and distributed radio environment. In this paper, we first present the cooperative communication technologies and describe their existing challenges, then introduce different game solutions, after that, we discuss several cooperative game strategies, and analyze the associated their applications in cognitive radio networks, at final, some open directions for future research on economic strategies in cooperative communication in cognitive radio networks are proposed. 相似文献
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Cognitive radio (CR) is a novel and promising spectrum management technique, which aims to cope with the spectrum scarcity problem occurring in unlicensed bands and alleviate the inefficient spectrum utilization of licensed bands. To ensure that the operation of licensed users will not be adversely affected and that the licensed bands can be efficiently utilized by unlicensed users, this paper proposes a cognitive radio MAC protocol called SMC-CR-MAC. When any primary user is detected, the proposed SMC-CR-MAC protocol applies Contiguous Channel Switching and Sender-Receiver Channel Swap rules to cope with the rendezvous, packet collision, and channel congestion problems. Simulation results show that the proposed SMC-CR-MAC protocol can significantly improve the network performance in terms of utilization of licensed bands, standard deviation of traffic load on each channel, and probability of successful rendezvous. 相似文献
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Due to the openness of the cognitive radio network, spectrum sensing data falsification (SSDF) can attack the spectrum sensing easily, while there is no effective algorithm proposed in current research work, so this paper introduces the malicious users removing to the weight sequential probability radio test (WSPRT). The terminals' weight is weighted by the accuracy of their spectrum sensing information, which can also be used to detect the malicious user. If one terminal owns a low weight, it can be treated as malicious user, and should be removed from the aggregation center. Simulation results show that the improved WSPRT can achieve higher performance compared with the other two conventional sequential detection methods under different number of malicious users. 相似文献
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认知无线电及其原始用户检测 总被引:4,自引:0,他引:4
认知无线电系统必须能够及时检测到原始用户的工作状态以避免形成相互干扰,论文主要讨论用于频谱感知的信号检测理论。大部分人工合成的信号都可以看成是循环平稳随机过程,利用谱相关函数可以有效地检测这些信号,文中主要考虑用循环谱密度监测原始用户的可行性。此外,文章还对认知无线电中的协作检测法做了分析。 相似文献
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认知无线电中,协作频谱检测已经被证明可以有效提高系统的检测性能。但是在噪声不确定的情况下,认知用户会更加倾向于减少检测消耗来提高自身的吞吐量。本文主要是把进化博弈论应用到噪声不确定下的协作频谱检测中,认知用户可以动态地选择是否参加协作频谱检测,通过不断的迭代学习,得到一个进化稳定策略(ESS)。本文把所有认知用户作为整体参与博弈,由进化博弈论算法,得到其参与协作的认知用户平均吞吐量,并将其与所有用户的平均吞吐量对比。如不等则反复迭代直至相等,从而得到最终的进化稳定策略。仿真结果表明:噪声不确定度越高,达到平衡时认知用户参与协作检测的概率就越高;进化博弈论算法让认知用户选择性地参与协作检测比让所有用户都参与协作检测有更高的系统吞吐量。 相似文献
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Helena Rifà-Pous Mercedes Jiménez Blasco Carles Garrigues 《Wireless Personal Communications》2012,67(2):175-198
Cognitive radio networks sense spectrum occupancy and manage themselves to operate in unused bands without disturbing licensed users. The detection capability of a radio system can be enhanced if the sensing process is performed jointly by a group of nodes so that the effects of wireless fading and shadowing can be minimized. However, taking a collaborative approach poses new security threats to the system as nodes can report false sensing data to reach a wrong decision. This paper makes a review of secure cooperative spectrum sensing in cognitive radio networks. The main objective of these protocols is to provide an accurate resolution about the availability of some spectrum channels, ensuring the contribution from incapable users as well as malicious ones is discarded. Issues, advantages and disadvantages of such protocols are investigated and summarized. 相似文献