共查询到20条相似文献,搜索用时 15 毫秒
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In this paper, we propose a cognitive radio based multi-user resource allocation framework for mobile ad hoc networks using multi-carrier DS CDMA modulation over a frequency-selective fading channel. In particular, given preexisting communications in the spectrum where the system is operating, in addition to potential narrow-band interference, a channel sensing and estimation mechanism is provided to obtain information such as subcarrier availability, noise power and channel gain. Given this information, both frequency spectrum and power are allocated to emerging new users (i.e., cognitive radio users), based on a distributed multi-user resource allocation framework, in order to satisfy a target data rate and a power constraint of each cognitive radio user, while attempting to avoid interference to the existing communications as well as to minimize total power consumption of the cognitive radio users. 相似文献
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摘 要: 本文提出一种适用于下行认知无线电系统的正交频分多址接入资源分配算法,在总发射功率、误比特率和对授权用户的干扰受限的条件下最大化系统信息传输速率.本算法分两步实现:首先通过比较各认知用户在各子载波上单位信号发送条件下接收信号的信干噪比实现子载波分配;然后利用凸优化理论求解非负实数域内的比特数和功率值的最优解,并将其调整为符合实际系统需要的比特数和功率值,实现比特和功率分配.仿真结果表明,相比传统的基于频谱空洞的资源分配算法,本算法可以提供显著的系统信息传输速率增益. 相似文献
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Wireless Personal Communications - Spectral precoders in OFDM based cognitive radios can significantly reduce the sidelobe leakage in primary user’s band. However, how to allocate power... 相似文献
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基于认知无线电系统的协作中继分布式功率分配算法 总被引:2,自引:0,他引:2
协作通信与直接通信相比能够显著地提高系统性能。协作通信中的一个关键问题是管理中继节点及有效地进行功率分配。尤其对于频谱共享的认知无线电(Cognitive Radio,CR)系统,协作方案的设计不仅要最大限度地提高认知网络协作的功率效率,而且需要最小化对主系统的干扰。该文针对认知无线电系统的协作通信问题,在多个中继节点与源节点协同通信的场景下,提出了一种基于放大转发(Amplify and Forward,AF)模式下的功率分配及联合优化算法,在保证主系统传输性能不受影响的前提下,提高认知系统的传输速率。仿真结果表明该文提出的自适应协作传输方案,和直接传输及等功率传输方案相比获得了进一步的性能增益,中断概率显著下降。 相似文献
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Performance of cluster-based cooperative spectrum sensing is more greatly improved than that of the traditional cooperative spectrum sensing.However,the style of clusters is not pointed out on traditional cluster-based method.In view of all the fading in the cooperative spectrum sensing,space diversity,and selective diversity,a robust cooperative spectrum sensing scheme based on clusters is proposed.Simulation results show that the detection performance of this new scheme is more close to that of the ideal cluster-based cooperative spectrum sensing scheme,and the excellent performance with higher reliability is gained relative to the actual cluster-based cooperative spectrum sensing scheme.Finally,the number of users in a cluster of the proposed scheme is discussed.The two users in a cluster are not the optimal solution to the overall implementation of cognitive radio. 相似文献
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针对认知无线电中的双向中继网络,研究了基于非完美感知的频谱机会式接入和频谱共享接入下的资源分配问题.与传统基于认知的双向中继的资源分配方法不同,提出的算法联合考虑了感知时间和次级系统的发射功率.在感知时间和发射功率满足条件的情况下,使次级系统的吞吐量最大.为了有效地保护主用户不受干扰,在每一跳都考虑了平均干扰功率约束,同时考虑次级系统总的功率约束.在非完美感知的频谱机会式接入和频谱共享接入机制下,新算法能够获得最优的感知时间和功率分配.最后,仿真比较了两种方案的性能,验证了新算法的有效性. 相似文献
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频谱分配技术是认知无线电的关键技术之一,为适应认知无线电系统的时变特性,频谱分配算法必须有较快的收敛速度。在干扰温度模型下,提出一种基于Kuhn-Munkras算法的认知无线电频谱分配策略。该策略利用Kuhn-Munkras算法可以实现最佳匹配并且收敛速度快的特性,根据不同的用户在不同信道上所产生的效益的差异性,实现认知用户和信道的最佳匹配。仿真表明,基于Kuhn-Munkras算法的频谱分配在性能上优于传统的配对算法和greedy算法。 相似文献
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Wireless Personal Communications - When the number of users in the radio environment is increasing and the rapid development in the wireless environment is examined, the efficient use of the... 相似文献