异构无线网络中基于多用户分集的协作频谱感知算法

研究了协作通信与认知无线电的结合,针对TD-SCDMA系统和WiMAX系统组成的异构无线网络,提出了一种基于多用户分集的协作频谱感知机制.根据该算法,WiMAX用户被分成若干个簇,选择每个簇内瞬时信道条件最好的WiMAX用户协作检测频谱,并利用软硬结合的判决手段,既保证检测性能,又不增加复杂度.分析和仿真表明,该算法一方面保证了频谱检测的可靠性,降低了虚警概率,另一方面减少了通信开销,提高了判决消息传输的可靠性,达到了提升频谱利用率的目的.     

基于可信数据或门融合的合作压缩频谱感知算法

针对认知无线电(cognitive ratio,CR)中的频谱感知问题,提出一种基于可信数据或门融合的合作压缩频谱感知(reliable-OR rule data fusion cooperative compressed spectrum sensing,RFCSS)算法。首先,次级用户(secondary user,SU)利用压缩理论,获取低维观测数据,再利用基追踪去噪(basis pursuit denoising,BPDN)重构频谱,进而作出感知结果。然后,对SU的感知结果进行可信度估计,只有可信的感知结果的用户,才可向融合中心发送数据。融合中心依据所接收的数据,采用或门准则,作出最终的感知结果。仿真结表明,提出的算法能够降低系统复杂度以及提高感知结果的准确性。     

基于认知无线电网络的协作中继资源分配算法

频谱资源紧张己经成为制约下一代无线通信系统发展的主要因素之一.认知无线电技术通过大力发掘授权频谱的复用潜力,可有效解决频谱紧缺问题.本文把协作中继传输技术引入到认知网络中,建立了配置双天线的次用户帮助主用户传输的协作模型,基于此提出了基于译码转发的协作功率及频谱资源分配算法,并进行了详细的理论分析.仿真结果表明,本文提出的协作传输策略能够在保障主用户正常传输情况下提高次用户的传输机会并减小中断概率.     

认知网络中基于演化博弈的频谱感知技术

随着经济与科技的发展,频谱感知技术成为无线电网络的核心技术之一。本文提出了一种基于演化博弈来认知网络的频谱感知新办法,可以对次级用户的吞吐量和传输时间进行分析,建立感知协作的博弈模型并且探讨它的动态演化过程特征。在次级用户吞吐量最大的标准下,得到对应的均衡解答。在这基础上选出一种适应次级用户的分布式算法,通过预设门限和观测向量的比较,用户可以根据本地的感知来对可靠性做出判断,再决定是否向原始站发送结果,理论探索和仿真的结果证明,这种基于演化博弈的频谱感知技术可以在保证性能的情况下,提高次级用户的吞吐量,提高感知的能效,减少协作通信的开支。本文就认知网络中基于演化博弈的频谱感知技术作一定的说明。     

认知无线电系统的动态双门限协作能量检测算法

认知无线电系统中,认知用户间协作检测有利于提高频谱检测的准确性。基于OR(或)协作方式和多门限能量检测算法,提出了一种动态双门限协作能量检测算法,并根据认知用户接收到的主用户信噪比确定检测门限。理论分析和仿真结果表明,该算法可以有效提高频谱检测概率,降低系统漏检概率。     

部分线性模型基于稳健估计的拟合优度检验

本文用三步稳健估计方法来检验一个模型是否为部分线性模型,在零假设下构造了一个平方残差过程检验统计量,并给出了它的渐近分布.     

基于拟合优度检验的卷烟卷制过程质量一致性评价

目的 为解决当前卷烟卷制评价方式粗放,通常只重视质量结果而忽视过程质量差异的问题,建立同一牌号卷烟在不同机台、不同班组的加工质量一致性综合评价方法。方法 采用拟合优度检验的方法建立卷烟卷制过程质量一致性评价方法,并采用判断矩阵确定质量特性的权重,并进行质量一致性综合评价。结果 选取黄金叶(乐途)品牌在卷烟卷制过程中的在线监测数据,运用新构建的评价模型对3个机台的烟支质量、吸阻、端部落丝等7个质量特性进行质量一致性综合评价,并有效识别出了机台之间存在的质量差异。结论 该综合评价方法能够对卷烟多加工过程之间的差异进行有效识别和评价,实现了由结果评价向过程评价的转变,具有良好的评价能力和可操作性。     

认知无线电系统中的两判决门限能量检测算法

基于传统单门限能量检测算法,提出了一种适用于认知无线电系统的两门限能量检测算法.在算法分析中定义了两个性能指标,即认知用户和主用户间的碰撞概率以及限制认知用户对频谱使用的限占概率.理论分析与仿真结果表明,与传统单门限能量检测算法相比较,两门限能量检测算法降低了认知用户和主用户间的碰撞概率,同时也引起限占概率的增加,即该算法能够在牺牲部分频谱效率的条件下,明显降低认知用户对主用户的干扰,保证了主用户使用频谱的优先权.     

Multi-objective optimization of spectrum detection in cognitive IoT using artificial physics

In cognitive Internet of Things (C-IoT), spectrum detection aims to find the available spectrum resources for cognitive sensor nodes. However, it always consumes more energy to get higher detection rate in spectrum detection, so energy consumption and detection rate are positively correlated in C-IoT. Different from the available algorithms, we model spectrum detection in C-IoT as a multi-objective optimization problem and aim to find the trade-off points of spectrum detection. An artificial physics optimization algorithm is proposed to solve spectrum detection problems in C-IoT. The simulation results show that the proposed algorithm can effectively reduce the energy consumption and keep a high detection rate.     

主用户链路深度衰落下的认知网络中继

针对主用户链路经历深度衰落而发生通信中断的问题,提出了一种认知网络对主用户进行"透明"中继的方案。在不改变主用户通信协议的前提下,该方案首先感知主用户的状态,以判断其是否需要中继服务。当主用户通信发生中断时,认知网络利用从用户的能量检测器选出一个最优的节点解码转发主用户信号。从中断概率角度证明了这种最优单节点中继具有与多节点中继相同的空间分集作用,能够提高主用户平均传输效率,有较大的中继信道容量。通过仿真分析,验证了其分集效果和传输效率的提升。     

Cooperative wireless networks for better green services

During the last two decades, mobile communication systems (such as GSM, GPRS and 3G networks), wireless broadcasting networks, wireless local area networks (WLAN or WiFi), and wireless sensor networks have been successfully developed and widely deployed through different technological routes for providing a variety of communication services in different application scenarios. While making tremendous contributions to social progress and economic growth, these heterogeneous wireless networks consume a lot of energy in achieving overlapped service coverage, and at the same time, generate strong electromagnetic interference (EMI) and radiation pollution, especially in big cities with high building density and user population. In order to guarantee the overall return on investment (ROI), improve user experience and quality of service (QoS), save energy, reduce EMI and radiation pollution, and enable the sustainable deployment of new profitable applications and services, this paper proposes a cross-network cooperation mechanism to effectively share network resources and infrastructures, and then adaptively control and match multi-network energy distribution characteristics according to actual user/service requirements in different geographic areas. Some idle or lightly-loaded Base Stations (BS or BSs) will be temporally turned off for saving energy and reducing EMI. Initial simulation results show the proposed approach can significantly improve the overall energy efficiency and QoS performance across multiple cooperative wireless networks.     

基于GPIB总线的HP8563E型频谱分析仪检定系统

文中介绍了一种频谱分析仪的全自动检定系统,通过GPIB总线接口将所有测试仪器连成一体,使用LABVIEW和VC＋＋开发系统的软件,通过PC机进行控制,实现了对HP8563E型频谱分析仪的全自动检定。     

On the evaluation of the method of finite spheres for the solution of Reissner–Mindlin plate problems using the numerical inf–sup test

In this paper we use the numerical inf–sup test to evaluate both displacement‐based and mixed discretization schemes for the solution of Reissner–Mindlin plate problems using the meshfree method of finite spheres. While an analytical proof of whether a discretization scheme passes the inf–sup condition is most desirable, such a proof is usually out of reach due to the complexity of the meshfree approximation spaces involved. The numerical inf–sup test (Int. J. Numer. Meth. Engng 1997; 40 :3639–3663), developed to test finite element discretization spaces, has therefore been adopted in this paper. Tests have been performed for both regular and irregular nodal configurations. While, like linear finite elements, pure displacement‐based approximation spaces with linear consistency do not pass the inf–sup test and exhibit shear locking, quadratic discretizations, unlike quadratic finite elements, pass the test. Pure displacement‐based and mixed approximation spaces that pass the numerical inf–sup test exhibit optimal or near optimal convergence behaviour. Copyright © 2007 John Wiley & Sons, Ltd.