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Cognitive Radios (CRs), which sense the spectrum and
implement opportunistic sharing when no licensed user is
found to use it, are able to improve the efficiency of
spectrum. Spectrum sensing must be firstly solved in CRs.
Cooperative sen
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协作频谱感知虽然可提高系统的感知性能， 但随着感知节点数目的增加， 系统资源的占用越来越多，
系统传输效率下降． 分析了协作频谱感知方法的感知性能， 得到协作频谱感知的感知性能与感知节点数目和接
收信噪比之间的关系， 提出了一种新的次级用户节点的选择方法， 该方法有效保证了所选择节点的感知性能，
仿真验证了该算法的有效性和可靠性．-Although the cooperative spectrum sensing can improve the perceived performan
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为了提高MIMO-OFDM系统的数据传输率和频谱利用率,提出一种新的自适应算法。该算法在保证信道质量所需误码率和总发射功率的前提下,按照各个子载波衰落程度动态地分配比特和功率,使系统的总数据传输速率最大。理论分析得出,该算法降低了系统运算复杂度,能很大地改善系统的整体性能。-In order to improve data transmission rates and spectrum efficiency of MIMO-OFDM systems,this paper proposes a n
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正交频分复用(OFDM)是第四代移动通信的核心技术,它是实现宽带无线通信和多媒 体业务发展的基础。对OFDM 技术的基本原理，关键技术以及实现进行了研究，并且通过 matlab 中的通信仿真系统simulink 对OFDM 系统进行了模拟和分析，直观和形象地得到了 OFDM 系统在时域和频域的传输性能，得出的结果表明OFDM 系统可以明显地表现出抗多 径效应引起的频率选择性衰落和提高了频谱利用率，这一特性使得它能够在高数据传输速率 的无线信道中发挥优势。-Orthogonal Frequency
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轻武器权限申请程序等外侧段v二大王我我的2的1我-In cognitive radio networks, power control is considered as an important issue to improve the performance of dynamic spectrum sharing. In this paper, in order to maximize the efficiency of the system, the secondary users and
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网对此说道稳定调查单位为氮测定法v稳定成为当刺猬刺猬刺猬侧完成单位从汶川-In cognitive radio networks, power control is considered as an important issue to improve the performance of dynamic spectrum sharing. In this paper, in order to maximize the efficiency of the system, the secondar
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额度为单位对身材C阿萨css彻底删除维多西奇舞动长裙策维持稳定从万达cdc档次低vvcd-In cognitive radio networks, power control is considered as an important issue to improve the performance of dynamic spectrum sharing. In this paper, in order to maximize the efficiency of the system, the
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稳定时期为单位汽车完善的需求为单位DDFCWECDWCSCSC测定出稳定舞动长裙生产线-In cognitive radio networks, power control is considered as an important issue to improve the performance of dynamic spectrum sharing. In this paper, in order to maximize the efficiency of the system, the s
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MIMO．OFDM系统的子载波、功率和比特分配
MIMO技术能不增加系统带宽却提高系统容量和频谱利用率-The MIMO.OFDM system subcarrier, bit and power allocation
MIMO technology can not increase the bandwidth of the system can improve the system capacity and spectrum efficiency
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在风基本特性的理论基础上,应用Shinozuka方法对大跨结构的广义脉动风进行了模拟,引入快速傅立叶变换(FFT)技术以提高计算效率,同时给出了Matlab程序框架,并把模拟谱与目标谱进行比较验证,两者吻合较好.-Based on the theory of the basic characteristics of the wind on the application of the generalized method Shinozuka fluctuating wind span struc
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介绍了采用离散傅立叶变换（DFT）实现对采样得到的波形数据文件进行频谱分析的一般方法，并且为了提高运算效率、节省中间存储单元，最终采用了 时间抽选奇偶分解 的 库利-图基算法 实现快速离散傅立叶变换，对采样数据进行了高效的频谱分析，并用Microsoft Visual C++ 6.0编写实现-Introduced the discrete Fourier transform (DFT) is a general method of the spectrum anal
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neural network ,Spectrum prediction in the cognitive radio system
attracts more and more attention. It can predict future spectrum
holes to save energy of spectrum sensing and to improve the
efficiency of spectrum access.
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