无线传感器网络分析与仿真

计算机仿真是通信网络研究的有效评估方法之一。无线传感器网络强调对目标现象及其属性的实时感知能力，支持对感知信息的本地处理和节点间协同处理，而传统网络仿真平台并不支持。从网络体系结构和典型应用场景入手，分析无线传感器网络仿真需求，提出结合传统网络通信性能、能耗控制和基础功能实现的网络性能评价指标，并给出基于NS-2的扩展设计和实现。     

一种新的能量有效性无线传感网节点设计

当无线传感网运用于恶劣、时变的环境中,如何使网络的生命周期最大化,并满足一定QoS要求,成为无线传感网在这些应用领域广泛应用的关键问题。主要提出了一种基于直扩通信体制的双内核节点架构,不仅能满足复杂环境中的通信性能要求,并且功耗较低。该节点的设计主要采用了软硬件相结合的动态能量管理策略以及参数可调的软件无线电设计,通过底层的灵活设计为无线传感网各层协议的设计提供了一个良好的测试和实践平台,从而研究、设计新的物理层及上层协议来减少非理想硬件平台的功耗,提高整个网络的生存时间和通信性能。     

J-Sim下WSNs仿真框架的扩展设计与实现

随着无线传感器网络(WSNs)的应用,如何延长网络生命周期,对路由协议的研究提出了挑战。为了更好地研究能量高效利用的WSNs路由协议,建立对WSNs能耗支持较好的仿真平台具有十分重要的现实意义。针对J-Sim下WSNs框架对能耗仿真支持不好的问题,在现有的WSNs框架基础上提出了一种支持能耗仿真的WSNs仿真框架并在该框架上扩展实现LEACH协议。实验结果表明改进后的WSNs框架可以真实地仿真WSNs,获取有价值的仿真结果。     

Analytical and Simulation-based Design Space Exploration of Software Defined Radios

The proposed idea of software defined radios (SDRs) offers the potential to cope with the complexity and flexibility demands of future wireless communication devices. Unfortunately, the tight interaction of software and hardware as well as the high computational requirements make development of SDRs to one of the most challenging tasks system architects are facing today. The main challenge is to select the optimal or a sub-optimal solution within the large design space spread by the many design options. This paper introduces a novel design space exploration framework for particular early development stages. The key contribution is a pre-simulation based mathematical analysis based on synchronous data flow (SDF) graphs in order to take the right software and hardware design decisions. This analysis can be utilized right from the start of the design cycle with only limited knowledge of the final implementation. In addition, the proposed technique seamlessly integrates into an electronic system level (ESL) based simulation framework. This allows for a smooth transition from pure mathematical analysis to the simulation of the final implementation. The practical usage of the framework and its capabilities are highlighted by a case study from a typical SDR design.     

Connectivity and coverage maintenance in wireless sensor networks

One of the main design challenges for wireless sensor networks (WSNs) is to obtain long system lifetime without sacrificing system original performance such as communication connectivity and sensing coverage. A large number of sensor nodes are deployed in redundant fashion in dense sensor networks, which lead to higher energy consumption. We propose a distributed framework for energy efficient connectivity and coverage maintenance in WSNs. In our framework, each sensor makes self-scheduling to separately control the states of RF and sensing unit based on dynamic coordinated reconstruction mechanism. A novel energy-balanced distributed connected dominating set algorithm is presented to make connectivity maintenance; and also a distributed node sensing scheduling is brought forward to maintain the network coverage according to the surveillance requirements. We implemented our framework by C++ programming, and the simulation results show that our framework outperforms several related work by considerably improving the energy performance of sensor networks to effectively extend network lifetime.     

基于无线传感器网络的定位系统设计

无线定位应用需求日益增长,研究无线传感器网络的定位应用具有重要意义。首先介绍基于无线传感器网络的定位系统的软硬件结构,然后从能量消耗、网络通信量和可靠性等方面来分析和选择移动结点的工作方式,并提出了使信标结点实现动态快速组网、提高网络通信效率和通信链路稳定性等所采取的措施,最后给出了在TinyOS下传感器结点的程序结构和实现,以及在服务器端实现的改进的加权质心定位算法。     

无线传感器网络上超轻量化的IPv6协议栈

通过研究无线传感器网络中的树型拓扑结构、适配层的功能和IPv6协议，依据6LowPAN草案，对标准IPv6协议进行裁剪。设计并实现了一种应用在无线传感器网络通信节点上的超轻量化的IPv6协议栈，减少了代码空间和降低了协议自身的通信开销，满足了无线传感器网络中通信节点资源极其稀少和低功耗的需要。     

Low-complexity and energy efficient image compression scheme for wireless sensor networks

Currently most energy-constrained wireless sensor networks are designed with the object of minimizing the communication power at the cost of more computation. To achieve high compression efficiency, the main image compression algorithms used in wireless sensor networks are the high-complexity, state-of-the-art image compression standards, such as JPEG2000. These algorithms require complex hardware and make the energy consumption for computation comparable to communication energy dissipation. To reduce the hardware cost and the energy consumption of the sensor network, a low-complexity and energy efficient image compression scheme is proposed. The compression algorithm in the proposed scheme greatly lowers the computational complexity and reduces the required memory, while it still achieves required PSNR. The proposed implementation scheme of the image compression algorithm overcomes the computation and energy limitation of individual nodes by sharing the processing of tasks. And, it applies transmission range adjustment to save communication energy dissipation. Performance of the proposed scheme is investigated with respect to image quality and energy consumption. Simulation results show that it greatly prolongs the lifetime of the network under a specific image quality requirement.     

无线传感器网络能量优化与建模技术综述

由于无线传感器网络的能量受限,如何优化网络能量消耗和评估网络生存周期是当前无线传感器网络研究的首要挑战。在分析无线传感器网络能量消耗特征的基础上,调研传感器网络节点和网络系统的能量优化策略;并针对能量优化存在的不足,分析近几年兴起的无线传感器网络能耗建模工作;从基于无线通信、状态转换、协议栈等方面归纳总结无线传感器网络能耗模型的建模方法;指出跨层能量优化以及软硬件综合的能耗建模技术是无线传感器网络能量研究的重点。     

一种新型唤醒机制的无线传感器网络节点设计

寿命过短一直困扰无线传感器网络(WSNs)与实际应用结合的难题。通过对WSNs工作效率低问题的研究,提出了一种新型射频唤醒机制的WSNs节点的设计方法,对降低节点的功耗和延长WSNs的寿命都有帮助。详细说明了节点设计的硬件结构和软件中的程序流程。可行性分析论证了节点的实用性和低功耗特性。     

无线传感器节点实时能耗监测

无线传感器网络设计的关键技术环节之一是低功耗。首先要准确地检测到运行时各模块的能量消耗,然后才能够进行控制优化。然而,应用上的需求千差万别,导致硬件平台的多样性。本文选取无线传感器网络领域节点能量消耗检测作为研究方向,提出了一种便携的无线传感器节点能耗数据采集装置,能够实时采集节点的电压、电流信息。针对当前研究集中于仿真模拟,这种装置可用于实际环境的能量消耗检测,检测精度高。在MicaZ节点上的实验结果表明,该系统能以较高精度监测节点的能量效率。实际测量发现,传感器网络中传感器能耗也属能量消耗的一部分,且消耗量不可忽视,为今后的研究改进提供了新的参考。     

无线传感器网络协作通信技术综述

无线传感器网络的发展中存在生存周期和资源共享两大瓶颈,其重要原因之一在于缺乏射频信号级协作,通信能耗难以降低,通信资源难以虚拟化.协作通信技术通过节点间射频信号级的协作处理,使仅具单根天线的节点彼此共享天线,从而得到类似于“多入多出”系统的空间分集增益,显著地提升了通信的能量效率,它将是未来传感器网络的重要技术.综述了传感器网络中的协作通信技术,内容包括：在局部构造协作通信节点组以形成虚拟通信链路,利用协作通信组以直传或中继方式实现端到端的数据传输,协作通信与传感器网络的系统优化和资源虚拟化手段等.总结了传感器网络协作通信研究中的主要趋势、技术进展与关键问题.     

一种新型的无线传感器网络三维定位算法

节点定位在无线传感器网络的应用中起着重要作用,一直备受学术界和工业界的关注.现有的大多数定位算法针对平面应用而设计,而现实应用中的无线传感器网络节点往往分布在三维空间中,研究三维空间定位更加符合实际节点的应用情况.针对目前三维空间定位算法的不足,提出了一种新型的无线传感器网络三维定位算法.该算法无需额外的硬件支持,根据未知节点通信范围内锚节点数目,建立空间向量模型进行定位;并且在估计未知节点坐标时,根据该未知节点通信范围的锚节点对其所在位置进行约束.仿真结果表明,该算法通信开销小,提高了节点定位覆盖率和定位精度.     

基于CC1020的煤自燃无线温度传感器自组网络监控系统的研究

针对采空区遗煤自然发火问题,文章提出了一种基于CC1020的煤自燃无线温度传感器自组网络监控系统的设计方案,给出了系统总体结构,详细介绍了基于CC1020煤自燃无线温度传感器自组网络节点的硬件及软件设计。实验测试结果表明,基于CC1020的煤自燃无线温度传感器自组网络监控系统具有通信距离较远、穿透性和绕射性较强等特点,更适用于煤矿井下存在障碍物、巷道空间狭小、巷道弯曲等复杂多变的环境。     

LoRa射频芯片的无线激光甲烷传感器设计

为解决目前煤矿无线甲烷传感器在实际应用中存在的功耗高、通信距离近、响应速度慢以及精度低等诸多问题,本文基于LoRa通信技术,以ARM主控制器STM8L151C8T6和LoRa射频芯片SX1268为核心,设计了一种无线激光甲烷传感器。重点介绍了传感器的工作原理及低功耗的实现方案,给出了硬件电路设计和软件程序流程。经实验验证该无线激光甲烷传感器具有通信距离远、功耗低、精度高等优势,解决了现存的问题,对提升安全监控系统运维的智能性和可靠性具有重要意义。     

无线传感器网络轻量级数据加密机制设计

针对无线传感器网络处理能力、存储空间、能量等有限的特点,设计了轻量级数据加密机制。该机制对RC6算法进行了改进,添加了"对称层"运算,使改进后的RC6算法在运算工作量变化不大的情况下,硬件实现更加容易,硬件资源消耗更小。为进一步提高密文的安全性与数据加密强度,使用双密钥对明文进行两级加密,并引入了随机密钥管理机制,使网络节点每次加密时都能使用不同的密钥,提高了密钥的安全性。数据加密机制还使用了节点ID认证、带有身份标识的密钥池认证等多种安全认证机制来阻止非法节点的接入。实验基于低功耗Cortex-M3内核的控制芯片搭建无线传感器网络节点硬件平台,设计了通信协议,并在硬件平台上移植与实现了该机制。实验结果表明,该加密机制能够很好地在低功耗平台上运行。     

无线传感器网络仿真平台能耗模型研究

GloMoSim不具备能耗模型,无法对能耗进行仿真,将其应用于无线传感器网络仿真时存在较大局限性.为了使GloMoSim能够满足无线传感器网络能耗仿真的需要,根据GloMoSim的平台架构和仿真原理,结合无线传感器网络的工作特性,提出了基于节点状态能耗权值和持续时间的能耗模型,并扩展了GloMoSim的能耗仿真功能.利用扩展后的GloMoSim对AODV协议能耗进行了仿真实验,并与NS2的仿真结果进行了比较.实验结果表明,能耗模型能够正确的仿真协议的能耗,且相对NS2,能耗模型配置更加方便.因此,能耗模型具有良好的可靠性和易用性.     

带状无线传感器网络能量高效的节点部署策略

带状无线传感器网络具有特殊的拓扑结构,满足很多重要领域的应用需求。针对带状网络中的能量消耗不均衡问题,分析了带状无线传感器网络在多跳通信时的拓扑结构和能耗模型,在对带状网络进行分簇的基础上,提出一种非均匀的节点部署策略,该策略量化了带状传感器网络中簇内节点的数目关系,并设计了相应的路由协议。仿真结果表明,非均匀的节点部署策略可以缓解带状网络的能量空洞问题,使网络能耗趋于均衡,延长整个网络的生命周期。     

A Methodology for Reliability of WSN Based on Software Defined Network in Adaptive Industrial Environment

As communication technology and smart manufacturing have developed, the industrial internet of things (IIoT) has gained considerable attention from academia and industry. Wireless sensor networks (WSNs) have many advantages with broad applications in many areas including environmental monitoring, which makes it a very important part of IIoT. However, energy depletion and hardware malfunctions can lead to node failures in WSNs. The industrial environment can also impact the wireless channel transmission, leading to network reliability problems, even with tightly coupled control and data planes in traditional networks, which obviously also enhances network management cost and complexity. In this paper, we introduce a new software defined network (SDN), and modify this network to propose a framework called the improved software defined wireless sensor network (improved SD-WSN). This proposed framework can address the following issues. 1) For a large scale heterogeneous network, it solves the problem of network management and smooth merging of a WSN into IIoT. 2) The network coverage problem is solved which improves the network reliability. 3) The framework addresses node failure due to various problems, particularly related to energy consumption. Therefore, it is necessary to improve the reliability of wireless sensor networks, by developing certain schemes to reduce energy consumption and the delay time of network nodes under IIoT conditions. Experiments have shown that the improved approach significantly reduces the energy consumption of nodes and the delay time, thus improving the reliability of WSN.      

基于无线传感器网络的环境监测系统的设计

文章提出了一种基于无线传感器网络的企业环境监测系统的设计方案,详细阐述了环境监测系统的体系结构以及无线传感器网络节点的硬件设计和软件功能的实现方法。该系统采用低功耗设计,运行稳定、精度高,可实现对企业环境在无人值守下的远程实时监测。