基于无线传感器网络的农业定位系统设计与实现

针对农业低成本定位需求,设计了一种基于无线传感器网络的农业定位系统,系统由定位平台和定位节点两部分构成,其中定位节点包括锚节点和移动节点。定位系统部署完成后,首先各锚节点向定位平台发送包含自身位置、节点ID的数据包,定位平台建立网络拓扑图和数据链表;然后移动节点向所有锚节点发出定位请求,接收并存储各锚节点的RSSI值;最后定位平台采集移动节点与各锚节点通信的RSSI值,并应用定位模型确定移动节点的估算位置。试验表明,该定位系统具有简单易实现、定位效果好等特点。     

一种基于可移动锚节点的DV-HOP改进定位算法

当节点不均匀分布时,DV-Hop的定位精度较差。针对DV-Hop定位算法的缺陷,提出一种基于移动锚节点的改进DV-Hop定位算法。在网络中引入具有一定移动能力的锚节点,并构建锚节点之间的虚拟力模型,锚节点受到虚拟力作用发生移动,从而均匀的分布于整个网络,修正了DV-Hop对不均与分布网络适应性差的特点。仿真实验表明,与原始算法相比改进后的算法定位精度有较大提高。     

信号强度和运动向量结合的无线传感器网络移动节点定位

无线传感器网络的定位是近年来无线传感器网络研究的重要课题.本文首先介绍了无线传感器网络的来源、重要性以及无线传感器网络定位的分类.然后提出了一种全新定位算法,信号强度和运动向量结合的无线传感器网络移动节点定位,简称SSMV算法,在外围布置四个锚节点,得用信号强度和未知节点在运动中向量的变化,对锚节点在内的未知节点进行定位,并对该算法进行了仿真和总结.通过与凸规划法进行比较,仿真结果表明,该算法有更高的定位精度.     

异步无线传感器网络定位算法研究

本文讨论了一种基于钟差补偿的异步无线传感器网络定位算法,网络中各个节点时钟是不同步的。在锚节点相对定位时利用锚节点钟差补偿信号飞行时间(TOF),减少钟差对锚节点相对定位的影响。标签定位时利用钟差的最小二乘估计补偿原始TDOA,实现标签的精确定位,解决了时间不同步造成的定位误差过大的问题。最后通过仿真验证了算法有效性。     

基于改进单锚节点的无线传感器网络节点定位算法

节点定位是无线传感器关键技术之一,针对固定多锚节点方法定位精度低的缺陷,为了提高无线传感器的定位精度,提出了一种基于改进单锚节点的无线传感器网络节点定位算法(SFOA-SVM)。首先采用单移动锚节点在无线传感器网络中移动,构建无线传感器定位模型的学习样本,然后采用SVM构建节点定位模型,并采用渔夫捕鱼算法模拟渔夫捕鱼行为找到最优SVM参数,最后采用仿真实验测试节点的定位性能。结果表明,相对于其它定位算法,SFOA-SVM提高了无线传感器节点的定位精度,具有一定的实际应用价值。     

基于自适应采样的移动WSN定位算法

节点自定位是无线传感器网络的关键技术之一。当前对无线传感器网络定位的研究主要集中静态节点定位,移动无线传感器网络定位研究相对较少。研究了基于序列蒙特卡罗方法的移动无线传感器网络定位。针对蒙特卡罗定位采用固定样本数,计算量大的缺点,根据蒙特卡罗定位盒（MCB）算法的锚盒子大小动态设置样本数,提出一种自适应采样蒙特卡罗盒定位算法。仿真表明,该算法在保持定位精度的同时有效地减小了采样次数,节约了计算量。     

单信道Mesh网MAC层握手机制的研究

本文介绍了802．16标准的Mesh模式和PMP模式,对单信道Mesh网络Mac层的帧结构和调度机制进行分析;介绍了隐藏终端和暴露终端的概念,通过分析,说明协调分布式调度能很好地解决隐藏终端和暴露终端的问题;通过仿真说明了节点数对网络吞吐量的影响。     

无线Mesh自组网技术在室内定位的应用

针对目前一些要求较高的人员定位系统定位成本高、距离短、无法实时显示多个人员位置等问题,研究并设计一种基于无线Mesh网络与惯性传感器的室内定位系统。该定位系统解决了在室内较为封闭的环境下无法实现人员定位和定位距离受限等关键性问题。将惯性传感器与无线Mesh网络的优势结合,构建完整的星型多路径人员定位系统。通过测试该定位系统得到的数据,表明该定位系统能够较好地满足火灾救援等严峻工作环境下人员的定位需求。同时,与传统室内定位系统相比,基于无线Mesh网络的人员定位系统在组网的操作性、成本、稳定性等方面具有较大的优势。     

无线Mesh网络中激励机制研究

为了激励无线Mesh网络中自私节点转发数据,通过分析节点自私行为激励的原因和目标,将适用于无线Mesh网络中对节点自私行为的四类激励机制进行比较.讨论了无线Mesh网络博弈模型,并对无线Mesh网络中重复博弈模型进行理论分析.针对节点的自私行为提出了基于博弈论与信誉相结合的激励方案.仿真实验表明,该方案不仅降低了基于信誉的复杂度又能有效激励更多自私节点转发数据,从而提高了网络的整体性能.     

无线传感器网络中基于刚性的移动锚节点路径规划

在移动锚节点辅助定位中,锚节点通常沿着预设轨迹扫描或采用随机方式移动,当节点分布不均匀、待定位区域形状复杂时,存在锚节点冗余移动、位置冗余广播及定位性能难以确保等问题。该文提出了利用网络拓扑信息进行移动路径规划的新思路,首先利用刚性理论将网络划分为多个唯一可定位的单元,之后寻找一条遍历各单元的最短路径作为锚节点的移动轨迹,锚节点沿着该轨迹移动、依次定位各单元。大规模仿真结果表明,该策略可以有效避免锚节点的冗余移动和位置广播,灵巧适应各种布设情形,与经典的扫描式路径相比,大大降低了路径长度和位置数目。     

Cooperative Location Management for a Cellular Network with Ad Hoc Communication

The cellular network with ad hoc communication has been foreseen in the next-generation mobile communication system. For such a network, a distance-based (DB) location management scheme cooperated with the ad hoc assistance node (DBCAN) is proposed in this paper. Allowing a mobile terminal to pass its mobility information to the ad hoc assistance node (AAN) with appropriate location updating, DBCAN can effectively reduce the paging cost and limit the paging delay. Moreover, DBCAN includes a method to determine whether AANs should be utilized or not to make cost effective. Our simulation results show that DBCAN can effectively reach cost reduction and still get performance improvement even if the probability to successfully deliver mobility information to AANs falls to the median level.     

Communication Timing Control and Topology Reconfiguration of a Sink-Free Meshed Sensor Network With Mobile Robots

This paper deals with a unified system of fully distributed meshed sensor network and mobile robot cooperation that serves as a sink node. The meshed sensor network in this paper is composed of static wireless nodes, and is capable of fully distributed peer-to-peer (P2P) ad hoc communication with ZigBee-based protocol. A novel communication timing control employing coupled-oscillator dynamics, named phase-diffusion time-division method (PDTD), has been proposed so far, aiming at realization of an ad hoc collision-free wireless communication network. In this paper, we extend the basic PDTD so that it can exhibit flexible topological reconfiguration according to the moving sink node (robot). Unlike conventional sensor network, no static sink node is supposed inside the network; however, a mobile robot will function as a sink node and access the mesh network from an arbitrary position. A large-scale experiment was conducted, and its results show that satisfactory collaboration between the mesh sensor network and the mobile robot is achieved, and the proposed system outperformed the carrier-sense-multiple-access-based sensor system.     

Dynamic mobile user location update for wireless PCS networks

The basic architecture of a personal communication network consists of a wireline network and mobile terminals. Each mobile terminal communicates with the wireline network through a nearby base station. In order to route incoming calls to a destination mobile terminal, the network must keep track of the location of each mobile terminal from time to time. This is achieved bylocation update such that each mobile terminal reports its current location to the network at specific time points. When an incoming call arrives, the network will page the mobile terminal starting from the last updated location. A trade-off, therefore, exists between the frequency of location update and the number of locations paged in order to track down the mobile terminal. This paper introduces a location update policy which minimizes the cost of mobile terminal location tracking. A mobile terminal dynamically determines when to update after moving to a new cell based on its mobility pattern and the incoming call arrival probability. The performance of this scheme is close to that of the optimal policy reported earlier. However, the processing time requirement of this scheme is very low. The minimal computation required by this scheme enables its usage in mobile terminals which has limited energy supply and computational power.     

基于主流移动操作系统的移动终端视频监控指挥通信技术研究

本文介绍的一种基于主流移动操作系统的移动终端视频监控指挥通信技术,提出使用移动中间件模式来解决视频监控软件在各种移动平台上的复杂性、差异性问题,将远程视频监控、会议、控制等重要功能有效地扩展到移动系统上,兼容各种无线网络和主流移动操作系统,能够很好地解决由于无线网络带宽的局限性以及视频编解码技术瓶颈所造成的分辨率低、延时等问题,可满足应急指挥过程实时监控、视频通信、可视化调度的应用需求;能让决策者及相关专家同步"巡视现场",制定科学的指挥调度方案,做到快速判断、科学决策、精准指挥,有效提高相关部门处置突发公共安全事件的能力。     

基于商用手机的全员测试分析系统的研究

通过对移动网络测试方法便捷、高效、低成本、真实性的研究,提出了一种基于Android操作系统普通商务手机的信号电平检测系统方案,开发出可以运行在任意一款Android终端上的客户端软件,能够捕获手机信号电平、位置等数据进行移动通信网络覆盖、质量、速率的分析和优化。并创造性设计木马测试版本,通过后台服务器端发送命令启动客户端进行测试,无需客户端开启软件,实现了后台控制前台功能。     

基于ZigBee无线技术的智能家居系统设计

论述了基于ZigBee无线通讯的智能家居控制系统设计,以Android手机为控制中心,ZigBee无线通讯为桥梁,实现一种星型的ZigBee网络在智能家居中的应用。该系统以TI公司的CC2530单片机为主控,通过ZigBee自组网,终端设备将采集到的数据通过Z-stack协议栈,发送到ZigBee协调器,通过串口将数据发送到电脑及手机上并显示出来,实现了对设备的集中管理与控制。测试结果表明,ZigBee组网成功,终端节点能轻易地检测到各子模块连接的传感器信号,并可通过手机控制节点信号。     

嵌入式系统移动视频监控终端平台安全性

提出基于INTEL IXP425嵌入式系统的移动视频监控终端实现方案,通过CDMA1x移动通信接入网络,复用四路IP数据通道,实现了高速上行数据传输。在此基础上,提出采用可信计算平台模块（TPM）与强制访问控制（MAC）的终端平台安全方案。实际测试表明,此方案能够满足移动视频监控应用需求。     

An improved handover algorithm based on signal strength plus distance for interoperability in mobile cellular networks

In future generation mobile cellular systems, position location of mobile terminal is expected to be available. In this paper, we propose an initiation algorithm for intersystem handover based on the combination of position location of mobile terminal and the absolute signal strength thresholds. Global System for Mobile communication (GSM) and Universal Mobile Telecommunication Systems (UMTS) networks are considered for interworking. The proposed algorithm reduces the handover rate by around 50% and thus improves the network resource efficiency as compared to that based on signal strength thresholds only.     

基于端侧计算的天地一体化SDN实现思路

天地一体化网络结构复杂，并且存在网络异构、拓扑动态、间歇连通、节点高度暴露等特性，传统SDN实现存在诸多限制，提出了一种基于端侧计算的SDN实现方法，基于SDN理念实现的天地一体化信息网络，将天基网络控制与数据分离，利用通信端（移动终端和固定地面骨干网络）的计算能力，卸载天基平面的SDN控制器的计算工作量，从而实现了数据转发平面的极大简化，并提出了切实有效的验证方法。     

Reducing overhead in movement based dynamic location management scheme for cellular networks

One of the key issues in cellular mobile communication is to find the current location of mobile terminal (MT) to deliver the services, which is called location management (LM). Much research has been done on dynamic LM that reduced the LM cost up to a large extent. In movement based dynamic LM scheme, the location area is defined in the form of ring of cells for individual user. Whenever an MT visits a cell outside of its current location area (LA), it triggers location update (LU). For this purpose, network must inform the mobile terminal about ID of all the cells present in its current location area. In this paper, a simple way of cell-ID assignment is proposed under which, network sends only the ID of center cell of LA ring to MT and then MT can compute IDs of all other cells in its location area. This saves a significant amount of wireless bandwidth by minimizing the signaling traffic at VLR level and thus reduces the mobility management overhead.