一种新的分布式协作能量检测算法

针对集中式协作能量检测算法严重依赖中心节点的问题,提出了一种基于一致滤波器 的完全分布式的协作能量检测算法。该算法不需要中心节点,次用户可以通过与其邻居次用 户进行局域的数据交换,实现基于数据级融合的协作频谱感知。仿真结果表明,该算法比现 有的集中式协作能量检测算法优越,能够实现安全的频谱感知。     

基于可信度计算的分布式共识合作感知算法

对于分布式的认知无线网络,由于不存在融合中心节点,次级用户节点之间的合作感知往往 采用信息交互的渠道进行,其中一种基于共识合作的感知机制受到广泛的研究,但这种机制 在鲁棒性方面存在一定的缺陷,当恶意节点存在时,其错误信息将影响局部的感知判决结果 ,为此,提出一种基于感知节点可信度的共识合作感知机制。在该机制中,各节点对邻居节 点的可信度进行计算,并把计算出的可信度值发送给其他节点,通过对各节点可信度的累加 计算,最终计算出各节点的可信度,各节点以此决定是否与其邻居节点合作以及如何合作。 仿真结果证明,在恶意节点存在的情况下,该算法在感知性能和收敛速度上都较未改进算法 有不同程度的提升,减轻了不可靠节点对合作感知结果的影响。     

卫星稀疏信道中频谱空穴的新型检测算法

面对宽带移动卫星通信中信道占用呈现的稀疏状态和时而存在的稀疏干扰,以低速率 采样和运算是简化设备的必要途径。针对宽带频谱范围内稀疏信道信号和干扰信号的检测, 提出了一种用于直接估计频谱空穴的压缩采样算法,以低速率对信号进行采样,通过相 关向量机进行迭代优化,给出检测估计值。该算法基于最大似然贝叶斯估计,具有良好的抗 噪性能,同时能够降低设备复杂度。仿真结果表明,其抗噪性能明显好于CVX方法而略逊于理 想情况,而前端随机序列的相关性是影响检测性能的重要因素。     

海上遇险搜救综合通信系统的设计与实现

为了提高我国海上搜救应急反应的调度、指挥能力,利用现代通信、计算机、计算机 电信合成（CTI）等技术,实现了海上遇险搜救综合通信系统。该系统采用程控调度交换和 无线电台适配的方案,使用无线电台适配器将无线通信转换为有线通信,再通过程控交换机 将各级海上搜救中各类卫星、语音电话、视频系统等异构终端综合互联,实现有线通信系统 与无线通信系统的无缝连接,从而为值班和搜救指挥人员提供专业、便捷的通信、操作手段 ,提高指挥判断的准确性和效率。     

感知/传输帧结构下基于有效容量的多功率分配策略

传统认知无线网络功率分配时,一般假定主用户（Primary User,PU)状态在一帧内不发生变化,并且未考虑传输时延的问题。在下一代移动网络中,由于主用户活跃程度的提高以及严格的时延要求,上述问题是功率资源分配时亟需考虑的重要方面。针对这种问题,以最大化认知用户可获得的有效容量为目标,采用基于感知/传输帧结构的四状态三功率传输策略,从而满足时延约束要求,且考虑了主用户的活跃程度。建立了系统以及状态转移模型,设计了使用服务质量(Quality of Service,QoS)约束的平均信道有效容量优化函数,采用Lagrangian方法详细分析推导了最佳有效容量的理论近似值,并对影响有效容量的不同因素进行了仿真分析。与传统的传输策略相比,在保证主用户正常通信的前提下,采用所提算法,认知用户的有效容量得到了显著提高。     

The evolving 5G case study in United States unilateral spectrum planning and policy

This paper tracks increasingly aggressive initiatives by the United States government to reallocate spectrum on an expedited and unilateral basis well before conclusion of inter-governmental coordination. Rather than embrace the customary commitment to achieve consensus on global spectrum allocations at the International Telecommunication Union (“ITU”), the Federal Communications Commission (“FCC”) has auctioned off large blocks of frequencies for the next generation (“5G”) of wireless services.The FCC might have framed its first 5G auction, reassigning Ultra High Frequency (“UHF”) spectrum, as a one-time deviation from compliance with long standing, intergovernmental coordination procedures. These frequencies have ideal signal propagation characteristics and the Commission could use financial incentives—unavailable in most nations—to expedite “repacking” by incumbent broadcasters willing to move, share or abandon spectrum in exchange for ample financial compensation. However, the FCC has continued to auction off 5G spectrum on grounds that it must find ways to abate an acute shortage of wireless bandwidth and doing so will regain or maintain global leadership in wireless technologies. This paper offers a critical rebuke to unilateral spectrum management, because the short-term benefits expected by the U. S. government likely will be offset by countervailing harms to 5G manufacturers, carriers and consumers. The paper tracks fractious preparation for the ITU's 2019 World Radio Conference by the U.S. delegation and the mixed record achieved there. Additionally, the paper explains how injecting trade, industrial policy and national security issues at the ITU can trigger more delays and disputes, including possible retaliation by nations displeased with U.S. efforts to subvert traditional technology optimization goals.A worst case scenario has the ITU deadlocked and unable to reach closure on “mission critical” spectrum planning issues at World Radio Conferences, convened every four years. The paper concludes that costs and likely challenges to the efficacy and legitimacy of the ITU will reduce the benefits accruing from the FCC's unilateral, spectrum planning campaign.     

Competition in shared markets and Major League Baseball broadcast viewership

This work evaluates the cross-quality elasticity of related products in the context of local market Nielsen Local People Meter ratings of Major League Baseball (MLB) regular season broadcasts from 2010 through 2013 from six teams in three shared markets. We employ a fixed effects panel regression with multi-way error clustering, finding that fans exhibit nuanced behaviour related to the absolute quality and relative quality of the two local teams. Our estimates imply quality-related competition for viewership between teams in the face of large disparities in quality. However, when both teams are of high quality, viewership increased beyond what own-team success would predict alone for the competing team. The competitive effects are largely dominated by the spillover effects. These findings point to complementary effects of team success beyond own-team interest, and bring about an important nuance in the literature on market definition, competition and substitution in sport.     

一种嵌入式软件无线电频谱监测系统

为了降低研发成本，提高频谱系统的灵活性和缩短研制周期，提出了一种基于软件无线电的嵌入式频谱监测系统。首先研究了系统硬件平台组成和特点，在此基础上设计了一种灵活的软件定义系统架构；然后考虑到硬件平台自身性能的限制，重点研究了频率偏移校正、频谱扫描策略等关键技术，分别提出了基于GSM信号和温度传感器的频偏校正方法和基于相关性的扫频策略；最后通过具体实验，对系统性能进行验证与评估，结果表明所提出的频偏校正方法能够将绝对平均频偏控制在1.749×10-6以内，所设计的基于相关性的扫频策略对时变信号的频谱监测效果最好。     

基于图论的认知无线网络频谱动态分配

在认知无线电网络中，图论与量子遗传算法相结合的频谱分配策略能够提高频谱利用率，但存在早熟和收敛精度不够等缺点。为了解决该问题而实现算法的优化，对图着色理论的频谱分配模型进行数学建模，并针对该模型提出了改进的量子遗传算法。首先，通过使用小生境技术初始化种群，使种群分布更加广泛、算法的收敛度更高；其次，根据进化代数对量子旋转角进行实时动态调整，对染色体进行阈值变异，防止个体陷入早熟，跳出局部解；然后，对干扰约束条件进行重新设计，有效地避免盲目性，提高了网络的公平性和网络效益。仿真结果表明，所提算法有效地提高了频谱利用率，极大地增强了网络系统的性能。