Sensors: Smart RF Antennas for Reliable and Real-Time Sensor Networks

传感器：用于可靠、实时传感器网络的智能射频天线

• 批准号: 0330016
• 负责人: Saurabh Bagchi
• 金额: --
• 依托单位: Purdue University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2008-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0330016&HistoricalAwards=false
• 关键词: Sensors; Smart; RF; Antennas; Reliable

Wireless networks of sensor nodes cooperating among themselves for information gathering and analysisare becoming an important platform in several domains. The area has seen growing research interest indifferent layers - devices, communication, network protocols and to a limited extent, applications. Forsensor networks to become viable platforms for the large class of applications it is being targetedtowards, there is the need to consider the cross-interaction between the different layers. For example, thefact that the sensors are equipped with smart antennas capable of power optimization should be utilizedby the routing protocols. The novelty of the proposed research is manifold. We propose to design asensor node that integrates innovative ideas for the radio frequency (RF) based communication device,the MAC layer, and a fault-tolerant and real-time middleware. The integrated node will be used in buildinga sensor network and evaluating the network for tradeoffs of performance, cost, robustness, simplicity,and flexibility.Uncertainty will be an undeniable fact of life with sensor networks in their real world deployments. Theuncertainty will stem from environmental variability (e.g., lack of line of sight communication), nodevariability (e.g., faster drainage of battery than expected), traffic variability (such as, higher than expectedsensed data traffic due to frequent occurrence of the event of interest) and attacker induced variability(e.g., jamming of the physical channels by a malicious intruder). In our research, we propose to providein-built support in the nodes to tolerate the uncertainty in the different dimensions. We propose severalnovel low power modes of operation based on the features of our proposed smart antenna in the RFcommunication equipment. Our proposed sensor node will be capable of not simply tolerating uncertainty,but exploiting the uncertainty to its advantage. We propose to make use of limited mobility in case itcauses the neighbors of a node to be aligned in a narrow band. In such a situation, the antenna can beswitched from its omni-directional mode of operation to a lower power unidirectional mode.Adaptivity of the sensor node will be another important driving factor in its design. The sensor nodeshould lend itself to reconfiguration in the face of uncertainty through easy to use mechanisms. In ourproposed node, a common thread of adaptivity will be built in at all the three levels under investigation.The issues of trade-off between adaptivity or flexibility and performance, cost, and simplicity will beconsidered for each layer as well as for the cross-interaction between layers. For example, at thecommunication device layer, the key tradeoff against cost will feature prominently since expensiveantenna arrays can provide the flexibility we require, but at a cost infeasible for the sensor nodes.Adaptivity at the system software level will focus on performing tasks on an as-needed basis, such asactivating the sensor only when there is an event of interest. Adaptivity at the middleware level will focuson adjusting the communication and computation to tune the fault -tolerance and real-time quality ofservice provided by the node.The proposed research comprises three key tasks: (i) Building diverse and intelligent RF hardware onelectrically small nodes, which will enable more robust and lower power operation. The key issuesaddressed here will be directionality, electromagnetically small size, and tradeoff between attractiveradiation shaping and cost and complexity; (ii) Building MAC and networking mechanisms which canleverage the flexibility provided by the RF hardware and provide hooks to the middleware. The MAC andnetwork layers will balance the tradeoffs of resource cost against performance and optimize it based onthe application requirements; (iii) Building a middleware layer that optimizes the operations for fault-tolerance and real-time requirements and balances these criteria against the cost and performanceimpact.Broad Impact in Technology and Teaching: An important goal of the research is to develop sensornodes with the new technology and create a sensor network testbed with the nodes equipped withmobility. The testbed will serve as an intuitive and attractive vehicle for disseminating the researchresults. This trend of popularizing research follows the earlier experience of the co-PI Rosenberg who hasdeveloped and deployed locality aware wireless services (such as, printing services) on the Purduecampus for widespread community use. The research findings will be disseminated to the RF, network,and middleware research community through publications and conference presentations. This project willhelp in teaching and training the graduate and undergraduate students who are implementing thetechniques and performing the testbed development and evaluation. The research results may beincorporated in several graduate and undergraduate courses taught by the PI and the co-PIs (i-FaultTolerant System Designlt, ieAdvanced Course in Networkingl., ieDistributed Parameter Systemslr).

传感器节点之间相互协作进行信息收集和分析的无线网络正在成为多个领域的重要平台。该领域对不同层的研究兴趣日益浓厚--设备、通信、网络协议，以及有限程度的应用程序。为了使传感器网络成为它所针对的大类应用的可行平台，需要考虑不同层之间的交叉交互。例如，传感器配备了能够优化功率的智能天线这一事实应该被路由协议利用。这项研究的新颖性是多方面的。我们提出了一种融合了射频通信设备、MAC层以及容错和实时中间件创新思想的传感器节点。集成节点将用于构建传感器网络，并对网络的性能、成本、健壮性、简单性和灵活性进行权衡。不确定性将是传感器网络在现实世界部署中不可否认的事实。不确定性将源于环境可变性(例如，缺少视线通信)、节点可变性(例如，电池的排出速度快于预期)、业务量可变性(例如，由于感兴趣的事件的频繁发生而高于预期的感测数据业务量)以及攻击者引起的可变性(例如，恶意入侵者对物理信道的阻塞)。在我们的研究中，我们建议在节点中提供内置支持，以容忍不同维度的不确定性。根据我们提出的射频通信设备中智能天线的特点，我们提出了几种新的低功耗工作模式。我们提出的传感器节点将不仅能够容忍不确定性，而且能够利用不确定性来发挥其优势。我们建议使用有限的移动性，以防它导致节点的邻居在一个狭窄的频带内对齐。在这种情况下，天线可以从其全向工作模式切换到较低功率的单向模式。传感器节点的适应性将是其设计的另一个重要驱动因素。传感器节点应该能够通过易于使用的机制在面对不确定性时进行重新配置。在我们提出的节点中，将在所研究的所有三个层次上构建一条共同的自适应线程。每一层都将考虑自适应或灵活性与性能、成本和简单性之间的权衡问题，以及层之间的交叉交互。例如，在通信设备层，与成本的关键权衡将非常重要，因为昂贵的天线阵列可以提供我们所需的灵活性，但成本对传感器节点来说是不可行的。系统软件级别的适应性将专注于根据需要执行任务，例如只有在发生感兴趣的事件时才激活传感器。中间件级别的适应性将集中于调整通信和计算，以调整节点提供的服务的容错性和实时质量。提出的研究包括三个关键任务：(I)在电子小节点上构建多样化和智能化的射频硬件，使其能够更健壮和更低功率地运行。这里讨论的关键问题将是方向性、电磁小尺寸，以及在吸引人的辐射成形与成本和复杂性之间的权衡；(Ii)建立能够利用射频硬件提供的灵活性并提供到中间件的挂钩的MAC和联网机制。MAC层和网络层将平衡资源成本和性能，并根据应用需求进行优化；(Iii)构建中间件层，针对容错和实时需求优化操作，并根据成本和性能影响平衡这些标准。广泛的技术和教学影响：研究的一个重要目标是利用新技术开发传感器节点，并利用具有移动性的节点创建传感器网络试验台。试验台将成为传播研究成果的直观和有吸引力的工具。这一普及研究的趋势遵循了合作者Pi Rosenberg的早期经验，他在Purduecampus上开发和部署了位置感知无线服务(如打印服务)，供社区广泛使用。研究成果将通过出版物和会议演示文稿向射频、网络和中间件研究社区传播。该项目将有助于对正在实施该技术的研究生和本科生进行教学和培训，并进行试验台的开发和评估。研究成果可被纳入PI和共同PI教授的几门研究生和本科课程(I-容错系统设计、IE网络高级课程、IE分布参数系统)。