单轨交通信号系统无线覆盖重叠问题解决方案

在重庆单轨交通三号线信号系统项目中,正线和试车线线路部分重叠,因为正线与试车线的网络相互独立,无法完全避免正线行驶的车辆与试车线轨旁AP的关联以及试车线行驶的车辆与正线轨旁AP的关联所引起的通信中断。介绍针对无线重叠问题进行研究提出的解决方案。     

蜂巢恒温调控机理检测装置的研究

为了研究蜂巢恒温调控机理,设计了一种能够在蜂群处于原生态环境下进行温湿度测量的装置。该系统根据巢脾摆放特点,按蜂巢空间对称原则放置温湿度传感器。上位计算机控制下位单片机何时采集,单片机采集温湿度传感器信号经处理后输出并通过无线发送模块发送数据,无线接收模块接收数据并传送给计算机,计算机实时显示温湿度和相应时间并保存。实际应用表明:系统使用方便,数据传输可靠,所测数据符合蜜蜂生物学特点,为后续进一步研究蜂巢恒温调控机理提供数据支持。     

基于UWB技术的船舶避碰系统抗干扰研究

为了保证船舶航行安全,在船舶上采用基于UWB技术的船舶避碰系统,分析了UWB信号传输的信道和超宽带通信系统存在的窄带干扰,针对UWB系统和窄带系统的共存问题,提出了适用于发射信号谱会在窄带系统工作频段处形成陷带的方法,仿真结果表明,使用经过设计的TH序列,UWB系统的BER性能得到了提高,解决了UWB信号和窄带信号的相互干扰。     

无线传感网络的海上多信道通信技术

在现代海上通信系统中,基于多信道传输的无线通信技术因具有良好的信道吞吐容量及较高信号传输率而应用广泛。但海面多信道传输具有多径干扰及通信传输网络在多信道分布不均匀的缺点,因而基于无线传感器的信号采集及传输网络在海上开发及军事方面也得到了应用。本文在研究现代海上无线传感网络及多信道通信系统的基础上,利用分簇原理设计优化现有的多信道无线传感网中的MAC算法,并进行仿真。     

A Novel Practical Cooperative Diversity Method for the Power-Limited Wireless Sensor Network

A novel practical cooperative diversity method for power-limited wireless sensor network system was proposed. At first, the system model was presented and the cooperation problem is formulated under the minimum outage probability criterion, then the focus was put on the power efficiency of system, such as the relay selection, cooperation strategy and power allocation etc. At last the uniform procedure of the proposed method was given. The results of the simulation clearly demonstrate that our method not only has the properties of simple operation and wide applying scope, but also outperforms those of current classical methods on the aspect of outage probability under the basis of the same power limitation.     

A Distributed Virtual Backbone Formation for Wireless Ad Hoc and Sensor Networks

The virtual backbone is an approach for solving routing problems in wireless ad hoc and sensor networks. A connected dominating set (CDS) was proposed as a virtual backbone to improve the performance of wireless networks. The quality of a virtual backbone is measured not only by approximation factor, which is the ratio of its size to that of minimum CDS, but also time complexity and message complexity. In this paper, a distributed algorithm is presented to construct a minimum CDS for ad hoc and sensor networks. By destroying triangular loops in the virtual backbone, the proposed algorithm can effectively construct a CDS with smaller size. Moreover, our algorithm, which is fully localized, has a constant approximation ratio, linear message and time complexity, and low implementation complexity. The simulation results and theoretical analysis show that our algorithm has better efficiency and performance than conventional approaches.     

无线传输技术在行车安全监控系统中的应用

应列车提速的要求,采用无线传输技术实时地将列车运行状态的关键技术参数传输到地面服务站,使机务部门及时了解列车运行状况,并对列车运行中的突发情况提供应急处理指导,能有力保障列车运行的安全性．文章在分析列车安全监控系统的基础上,给出了利用GPRS进行无线数据传输的解决方案,详细介绍了系统的构建方法,同时就系统的特点进行分析,结果表明无线传输技术应用到行车安全监控系统中具有较高的可靠性和实用性．     

专用道条件下电动公交线路静态无线充电设施布局优化

为了减少电动公交线路静态无线充电设施的布设成本，从而提高时间控制点的有效利用率，提出了考虑时间控制点影响的静态无线充电设施布局优化方法。首先建立电动公交车运行状态表达模型，提出乘客出行时间成本增加量计算方法；随后在总松弛时间、电池剩余电量、准点率的约束下，将每个站点是否布设静态无线充电设施、是否设置为时间控制点以及对应的松弛时间作为优化变量，将充电设施总布设成本与乘客出行时间成本增加量最小以及站点有效利用率最大作为优化目标，建立专用道条件下静态无线充电设施布局优化模型，并采用嵌入随机模拟技术的麻雀搜索优化算法进行求解；最后以一条实际线路为例进行案例分析，并对电池容量、充电功率进行敏感性分析。研究结果表明：在满足不同班次电量需求的前提下，充电设施的总布设成本、乘客出行时间成本增加量随着电池容量或者静态无线充电功率的增加而减少，且充电设施的总布设成本呈阶梯形状变化。