边境地区无线电台站频率冲突分析与对策研究

 在分析边境地区无线电台站频率冲突及现状的基础上,从无线电体制、管理和技术3个方面,对边境地区无线电台站和无线电频率管理的对策进行研究,为国家进行中越边境频率协调提供有价值的数据参考.     

中短波段地波场强计算与分析

海上无线电导航系统一般工作在中短波段,利用地波进行导航定位。地波信号场强的计算是整个系统设计的理论基础,它决定系统的工作范围、接收机设计的灵敏度和动态范围。针对地波衰减函数计算复杂的问题,本文给出了试探逼近、精确计算以及对精确计算的改进等三种方法。并对精确计算的改进这个方法进行了不同频率下的仿真,结果表明该方法能够满足计算误差要求。通过仿真比较,验证了该算法可以用于工程上的快速计算。     

认知无线电中基于极大独立集的频谱分配算法

针对认知无线电系统的特点和要求,建立图论着色扩展模型,提出一种基于极大独立集的频谱分配算法.在不考虑频谱效益差异性的情况下,该算法能够有效兼顾频谱分配的利用率和公平性,并能够减小分配的收敛时间,更加适合认知无线电动态频谱分配的实际要求.对于算法的频谱利用率和公平性能,该算法与列表着色贪婪算法和列表着色公平算法进行比较,仿真结果分析验证了该算法的性能.     

基于决策理论的软件无线电调制信号的自动识别

对接收信号的调制类型进行自动识别,是实现软件无线电的关键技术之一。基于软件无线电信号通用调制模型原理,采用决策理论通过分析信号的特征参数来自动识别信号。     

依托长效机制 “保鲜”台站数据

我国是无线电台站使用大国。截至2011年底,已办理台站执照的无线电台站数量达到266.78万个。因此,台站管理是无线电管理中的重要组成部分,其数据是否准确至关重要。只有掌握规范、完整、准确的台站数据及其使用情况,才能实现台站科学规划及资源合理配置,提高频谱使用效率。     

来自稀薄空气中的电能

借助无线电技术,可以在不依赖电线的情况下传送电能。那么,其他的设备是否也可以借助环境中已经存在的信号辐射等来驱动呢?     

On opportunistic spectrum efficiency in cognitive radio systems

The performance bound of cognitive radio systems is analyzed.We use opportunistic spectrum effi-ciency(OSE)as the performance metric,and point out that the maximum achievable OSE can be used toevaluate the maximum value that the introduction of secondary users can add to the conventional wirelesssystems.Based on assumptions of the PU s traffic model and some reasonable approximations,the ex-pression of OSE is obtained and the maximum achievable OSE is derived by solving an optimization prob-lem.The resu...     

会议点击

WRC-15议题讨论会召开近日,国家无线电监测中心在北京组织召开了WRC-15议题专题讨论会。工信部无线电管理局、国家新闻出版广电总局、国家卫星海洋应用中心等相关单位代表到会。本次会议主要就卫星业务工作组和卫星规则工作组的部分议     

Joint channel assignment and cross-layer routing protocol for multi-radio multi-channel Ad Hoc networks

To study multi-radio multi-channel (MR-MC) Ad Hoc networks based on 802.11, an efficient cross-layer routing protocol with the function of joint channel assignment, called joint channel assignment and cross-layer routing (JCACR), is presented. Firstly, this paper introduces a new concept called channel utilization percentage (CUP), which is for measuring the contention level of different channels in a node’s neighborhood, and deduces its optimal value for determining whether a channel is overloaded or not. Then, a metric parameter named channel selection metric (CSM) is designed, which actually reflects not only the channel status but also corresponding node’s capacity to seize it. JCACR evaluates channel assignment by CSM, performs a local optimization by assigning each node a channel with the smaller CSM value, and changes the working channel dynamically when the channel is overloaded. Therefore, the network load balancing can be achieved. In addition, simulation shows that, when compared with the protocol of weighted cumulative expected transfer time (WCETT), the new protocol can improve the network throughput and reduce the end-to-end average delay with fewer overheads.     

水动力火箭发射器:伴你清凉一夏,快乐一夏!

<正>~~