共查询到18条相似文献,搜索用时 174 毫秒
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将认知无线电中的动态频谱分配技术应用在无线传感网中,针对工作在ISM(industrial,scientific and medical)频段的无线传感网面临的频谱资源紧缺问题,提出一种基于改进自适应遗传算法的动态频谱分配方案.该算法以图论着色模型为基础,以最大带宽收益和最小切换频率为目标函数,在交叉和变异过程中采用自适应交叉概率和变异概率代替固定的交叉概率和变异概率.仿真结果表明,与传统遗传算法和颜色敏感图论着色算法相比,该算法可以实现提高频谱利用率、降低能量消耗的预期目标. 相似文献
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功率控制是感知无线电重配置的重要内容之一。结合功率控制的动态频谱分配策略可以有效提高频谱分配的性能。文章构建了一种潜博弈模型,通过在授权链路保护算法中加入功率控制机制,进一步降低对系统中授权用户和其它感知用户的干扰,提高通信链路的信干噪比,改善分配算法的性能。仿真结果表明算法达到了预期的效果,保证了感知无线电系统可靠通信。 相似文献
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为了更好解决目前可见光通信(visible light communication,VLC)中干扰管理方案存在的动态优化问题,提出了一种兼具优化功率分配与时隙分配的自适应干扰管理机制。首先,在每个时隙依据用户的位置建立每个用户的接入点(access point,AP)协作集,寻找所有由最多数量互不干扰用户组成的极大独立集,以此自适应地避免同频干扰;在每个时隙为每个极大独立集采用改进的线性注水功率分配算法为信道自适应地分配发送功率,以此优化每个极大独立集的用户和速率;基于用户和速率、速率公平性及时延公平性的归一化优先因子,选出具有最大优先因子的候选极大独立集,其中包含的用户在该时隙被调度。通过仿真且与代表性文献中的算法比较可得,本文提出的自适应干扰管理与优化资源分配方案在网络频谱利用率、能效、用户速率公平性与时延公平性方面具有明显优势。 相似文献
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针对恶意干扰场景下无人机群动态频谱分配问题,构建了基于斯坦伯格博弈的动态频谱分配模型,干扰机为斯坦伯格博弈的领导者,无人机群为斯坦伯格博弈的跟随者,设计了不同博弈参与者的效益函数,并证明了该博弈存在稳定的斯坦伯格均衡解。在此基础上设计了一种分层动态频谱分配算法,针对领导者采用Q学习选择干扰信道的场景下,跟随者采用随机学习自动机来确定信道分配策略。仿真结果表明,所提算法能够得到无人机用户的最优信道分配策略,有效提升无人机用户的总吞吐量性能,实现效益最大化。 相似文献
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在传统的无线通信系统中,频谱的分配是固定的。但是由于通信过程的突发性,这些频谱的使用率很低。另一方面,随着无线通信和多媒体的高速发展和广泛应用,无线频谱资源日趋紧张。如何提高频谱利用率已经成为迫切需要解决的问题。一种可行的思路是把这些授权频谱向未授权用户开放,未授权用户采用动态频谱接入技术,在不对授权用户造成干扰的前提下使用频谱。本文以认知无线电技术(Cognitive Radio,CR)为基础,提出了一种基于CR的动态频谱接入MAC方案(CR-Ad Hoc-MAC)。该方案允许未授权用户自适应地选取可用带宽,实现了动态频谱接入,有效地提高了频谱利用率。 相似文献
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Jian Liang Hui Yin Li Feng Jian Zhang Shouyin Liu 《Wireless Personal Communications》2013,71(3):1663-1681
This paper considers the problem of spectrum sharing in orthogonal frequency division multiple access cellular relay networks. Firstly, a novel dynamic full frequency reuse scheme is proposed to improve the spectral efficiency. Different from the conventional full frequency reuse scheme which only allows the base station (BS) reusing the subcarriers in the specific regions, an improved full frequency reuse scheme is proposed to allow the BS reusing all the subcarriers in the whole BS coverage region to exploit additional multiuser diversity gain. In order to dynamically reuse the frequency resource among the BS and relay stations (RSs) to further improve the spectral efficiency, the adaptive subcarrier scheduling is introduced into the improved full frequency reuse scheme to obtain more multi-user diversity gain, which forms the proposed novel dynamic full frequency reuse scheme. Secondly, in order to further increase the system throughput, the opportunistic spectrum sharing scheme is introduced to allow the RSs selectively reusing the subcarriers among each other, which joint with the proposed dynamic full frequency reuse scheme to intelligently allocates the subcarriers originally reused by the BS and a RS to another suitable RS which can best improve the system performance after considering the additional interference. Thirdly, in order to select The optimal reusing combination scheme of BS and RSs to exploit more potential system performance, a heuristic approach based on genetic algorithm is proposed to search the optimal BS and RSs combination to opportunistically share the frequency resource. Simulation results show that the proposed dynamic full frequency reuse scheme can obtain high spectral efficiency, fine fairness and low outage probability compared to the conventional full frequency reuse scheme. Furthermore, the system performance can be improved when considering the opportunistic spectrum sharing among RSs. Finally, after adopting the genetic algorithm, the system performance can be greatly improved by the frequency reusing among the optimal BS and RSs combination. 相似文献
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Vanbien Le Zhiyong Feng Didier Bourse Ping Zhang 《Wireless Personal Communications》2009,49(2):275-293
Future wireless systems are expected to be characterized by the coexistence of different radio access technologies (RATs) resulting in complex heterogeneous wireless environments. In parallel with this, the tremendous demand for spectrum
has inspired the requirement of dynamic spectrum management (DSM). This paper aims at designing a cell based dynamic spectrum management (CBDSM) scheme to enhance the spectrum utilization and maximize the profit of operators in wireless heterogeneous networks.
The system architecture and the functional modules supporting the CBDSM scheme are designed. As a fundamental issue in spectrum
management, the inter-system interference issue is solved in the proposed CBDSM scheme. Furthermore, game theory, which is
a potential tool for studying the distributed autonomous resource optimization algorithms, is applied to design a spectrum
trading algorithm enabling the heterogeneous wireless networks to dynamically trade spectrum and to share the profit. In the
algorithm, we take into account the economic value of the spectrum of wireless systems in order to guarantee the rationality
for the spectrum trading. The simulation results show that the proposed CBDSM scheme effectively improves the spectrum utilization
and the profit of operators while it reduces the mutual interference between wireless networks to a tolerable level.
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Ping ZhangEmail: |
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A novel approach, which combines spectrum adaptation and orthogonal frequency division multiplexing (OFDM), is proposed to share the licensed spectrum dynamically for cognitive radio systems. Given spectrum sensing and channel estimation information by the receiver, an improved model due to signal power thresholds is adopted to achieve spectrum adaptation for unlicensed users. In order to efficiently allocate the unlicensed signal power, a dynamic power allocation algorithm is also proposed. Simulation results indicate that the propositional scheme solves the partial interference problem of interference temperature model (ITM) and improves the spectrum utilization. 相似文献
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IEEE802.22 WRAN网络中基于拍卖的频谱租借算法 总被引:1,自引:0,他引:1
在IEEE802.22WRAN网络中,基站间的频谱共享是一个重要的研究方向。若每个WRAN基站伺机占用信道,将带来信道分配不均的问题。利用拍卖理论激励基站间平衡信道分配,提出一种动态的频谱租借算法。该算法将频谱共享情况建模为一个拍卖基站和多个竞拍基站的拍卖模型,同时考虑竞拍基站间的信道需求和拍卖基站的收益,建立频谱共享的数学优化模型。仿真结果表明,与已有的频谱拍卖机制相比,该算法能获得较高的拍卖收益。 相似文献
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针对传统隐马尔可夫模型(HMM)方法提取时变线谱与多线谱的能力较弱以及动态规划过程计算量过大的问题,该文提出一种基于动态参数的1维隐马尔可夫模型(1D-HMM)的方法用于水声信号低频分析与记录(LOFAR)图中的线谱轨迹提取。该方法将时变频率状态建模为1阶马尔可夫过程,利用Viterbi算法循环提取多条线谱轨迹。在动态规划的迭代过程中,通过实时计算序列的1阶导数动态调整HMM中的状态转移概率矩阵,提升了对线谱轨迹的提取能力和多线谱的分辨能力;设计了一种基于动态滑动窗口的功率谱累积方法估计线谱的生灭,剔除虚假的线谱轨迹并判断线谱轨迹提取的结束。同时,该方法在实现过程中设计了对LOFAR图数据的块处理策略,大大减少了计算量。仿真和实际数据的处理结果表明,该方法在低信噪比条件下能够有效地检测和跟踪复杂时变频谱的频率状态,并有较好运行效率,为声呐设备的弱信号检测提供了良好的技术支持。 相似文献
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Muhammad Qadeer Sharif Pingzhi Fan 《中国电子科技》2007,5(2):97-101
This paper presents an efficient dynamic spectrum allocation (DSA) scheme in a flexible spectrum licensing environment where multiple networks coexist and interfere with each other. In particular, an extension of virtual boundary concept in DSA is proposed, which is spectrally efficient than the previous virtual boundary concept applied to donor systems only. Here, the same technique is applied to both donor and rental systems so as to further reduce the occurrences where the insertion of guard bands is obligatory and as a result provides better spectral efficiency. The proposed extension improves the spectrum utilization without any compromise on interference and fairness issues. 相似文献
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基于随机矩阵理论的DET合作频谱感知算法 总被引:4,自引:1,他引:3
针对认知无线电系统中的频谱感知问题,该文采用随机矩阵理论(Random Matrix Theory, RMT)对多认知用户(Secondary User, SU)接收信号采样协方差矩阵的最大特征值的分布特性进行了分析和研究,提出了一种新的基于双特征值判决门限(Double Eigenvalue Threshold, DET)的合作频谱感知算法。由该算法感知性能的理论分析可知:DET合作感知算法无需主用户(Primary User, PU)发射机信号的先验知识,也不需要预先知道信道背景噪声功率。仿真结果表明,与传统的频谱感知方法相比,该方法只需较少的认知用户就能获得较高的感知性能,并且对噪声的不确定性具有较强的鲁棒性。 相似文献