Modeling of state machines in VHDL for encapsulation of DNP3 Protocol in P2P ZigBee Network

Several countries have invested in technologies for Smart Grids. Among such protocols designed cover this area, highlights the DNP3 (Distributed Network Protocol version 3). Although the DNP3 be developed for operation over the serial interface, there is a trend in the literature to the use of other interfaces. The Zigbee wireless interface has become more popular in the industrial applications. In order to study the challenges of integrating of these two protocols, this article is presented the analysis of DNP3 protocol stack through state machines The encapsulation of DNP3 messages in P2P (point-to-point) ZigBee Network, may assist in the discovery and solution of failures of availability and security of this integration. The ultimate goal is to merge the features of DNP3 and Zigbee stacks, and display a solution that provides the benefits of wireless environment, without impairment of security required for Smart Grid applications.

Telemetria automotiva usando módulo de transmissão Wireless Zigbee

This paper presents a design and construct the system of data acquisition with wireless transmission of some important parameters like motor temperature, motor rotation and velocity of Unesp Racing´s formula car prototype from Universidade Estadual Paulista, Campus Guaratinguetá. This system development presents a contribution for the electrical technical features adding important points in the competition due car´s electric, in addition, enables preventive maintenance and fine adjustment of the car with the data obtained during training and racing

Design and implementation of wireless sensor networks for impedance-based structural health monitoring using ZigBee and Global System for Mobile Communications

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Redes dinâmicas de sensores sem fio ZigBee para aplicações de monitoramento e controle

Pós-graduação em Engenharia Elétrica - FEB

A Low Consumption Real Time Environmental Monitoring System for Smart Cities based on ZigBee Wireless Sensor Network

Nowadays, there is an increasing interest in wireless sensor networks (WSN) for environmental monitoring systems because it can be used to improve the quality of life and living conditions are becoming a major concern to people. This paper describes the design and development of a real time monitoring system based on ZigBee WSN characterized by a lower energy consumption, low cost, reduced dimensions and fast adaptation to the network tree topology. The developed system encompasses an optimized sensing process about environmental parameters, low rate transmission from sensor nodes to the gateway, packet parsing and data storing in a remote database and real time visualization through a web server.

Radio propagation modeling and measurements for ZigBee based indoor wireless sensor networks

The deployment of nodes in Wireless Sensor Networks (WSNs) arises as one of the biggest challenges of this field, which involves in distributing a large number of embedded systems to fulfill a specific application. The connectivity of WSNs is difficult to estimate due to the irregularity of the physical environment and affects the WSN designers? decision on deploying sensor nodes. Therefore, in this paper, a new method is proposed to enhance the efficiency and accuracy on ZigBee propagation simulation in indoor environments. The method consists of two steps: automatic 3D indoor reconstruction and 3D ray-tracing based radio simulation. The automatic 3D indoor reconstruction employs unattended image classification algorithm and image vectorization algorithm to build the environment database accurately, which also significantly reduces time and efforts spent on non-radio propagation issue. The 3D ray tracing is developed by using kd-tree space division algorithm and a modified polar sweep algorithm, which accelerates the searching of rays over the entire space. Signal propagation model is proposed for the ray tracing engine by considering both the materials of obstacles and the impact of positions along the ray path of radio. Three different WSN deployments are realized in the indoor environment of an office and the results are verified to be accurate. Experimental results also indicate that the proposed method is efficient in pre-simulation strategy and 3D ray searching scheme and is suitable for different indoor environments.

A power scalable receiver front-end at 2.4 GHz

We propose a Low Noise Amplifier (LNA) architecture for power scalable receiver front end (FE) for Zigbee. The motivation for power scalable receiver is to enable minimum power operation while meeting the run-time performance needed. We use simple models to find empirical relations between the available signal and interference levels to come up with required Noise Figure (NF) and 3rd order Intermodulation Product (IIP3) numbers. The architecture has two independent digital knobs to control the NF and IIP3. Acceptable input match while using adaptation has been achieved by using an Active Inductor configuration for the source degeneration inductor of the LNA. The low IF receiver front end (LNA with I and Q mixers) was fabricated in 130nm RFCMOS process and tested.

A fast and accurate performance analysis of beaconless IEEE 802.15.4 multi-hop networks

We develop an approximate analytical technique for evaluating the performance of multi-hop networks based on beaconless IEEE 802.15.4 ( the ``ZigBee'' PHY and MAC), a popular standard for wireless sensor networks. The network comprises sensor nodes, which generate measurement packets, relay nodes which only forward packets, and a data sink (base station). We consider a detailed stochastic process at each node, and analyse this process taking into account the interaction with neighbouring nodes via certain time averaged unknown variables (e.g., channel sensing rates, collision probabilities, etc.). By coupling the analyses at various nodes, we obtain fixed point equations that can be solved numerically to obtain the unknown variables, thereby yielding approximations of time average performance measures, such as packet discard probabilities and average queueing delays. The model incorporates packet generation at the sensor nodes and queues at the sensor nodes and relay nodes. We demonstrate the accuracy of our model by an extensive comparison with simulations. As an additional assessment of the accuracy of the model, we utilize it in an algorithm for sensor network design with quality-of-service (QoS) objectives, and show that designs obtained using our model actually satisfy the QoS constraints (as validated by simulating the networks), and the predictions are accurate to well within 10% as compared to the simulation results in a regime where the packet discard probability is low. (C) 2015 Elsevier B.V. All rights reserved.

短程及多跳的工业无线网络实时性和可靠性研究

无线通信技术极大地推动了科技发展和社会进步，已成为国际技术竞争的焦点和制高点之一。其中工业环境下无线网络技术的开发和应用，成为继模拟仪表控制系统、集散控制系统、现场总线控制系统之后，在过程控制和工业自动化领域拥有广阔市场前景的应用技术。随着无线通信技术的进一步发展，在未来的工业过程自动化领域，无线网络技术将会有更为广阔的应用前景。 工业无线网络技术的发展所面临的主要问题是：如何保证工业通信过程中的实时性和可靠性。本论文较为详尽地研究、探讨了工业无线网络中的实时性和可靠性问题，阐述了实时性和可靠性的涵义，分析了工业无线网络对实时性和可靠性的特殊需求，在借鉴已有研究成果并进行创新的基础上提出了问题解决方案。本文重点在网络的数据链路层和网络层展开了研究工作。主要的研究内容与创新点包括以下几个方面： 在数据链路层的媒体访问控制层，针对恶劣的工业环境对数据传输的实时性和可靠性的较高要求，和以往工业无线网络中采用的无线通信技术，如无线局域网、蓝牙和Zigbee等技术存在抗干扰能力差的严重缺陷的现实，本论文采用目前无线通信技术领域的热点技术——超宽带技术作为物理信道的通信介质，在对超宽带技术的特点和工业无线信道模型进行研究的基础上，充分利用超宽带技术抗干扰能力强的特点，采用跨层设计的思想——物理层和媒体访问控制层联合设计的方式，提出了基于信道状态的信道选择和速率自适应的多信道媒体访问控制协议，该协议一方面根据射频环境的动态变化，使用信道估计技术从多个可选数据信道中，选择可用的或者相对理想的信道用于数据的传输；另一方面在传输过程中，根据物理信道反馈的误码率值来判断当前的通信质量，可以要求物理层执行参数修改策略，实现发射速率的调整，解决由于多用户干扰、碰撞和工业环境干扰等因素造成的误码率增大问题，来满足工业无线网络的实时性和可靠性需求。该协议优于目前已有的协议，可以缓解干扰带来的延迟增大和吞吐量下降的问题，更好地满足工业通信的实时性和可靠性需求。 在数据链路层的逻辑链路控制子层，针对已有的无线网络缓存管理策略在通信中发生拥塞时，无法提供对实时数据的实时性保证，以及不适当的报文丢弃机制无法提供对非实时数据提供可靠性保证的问题，本文借鉴有线通信网络中缓存队列数据分组的动态概率丢弃思想，提出了一种适用于工业实时数据通信的超时早期检测机制，其基本思想在于节点的缓存队列在接纳新到的实时数据时，对其能否在规定的时延限制之内到达目的节点进行估计，并根据估计结果进行早期丢弃，防止无效的传输占用宝贵的无线资源；建立分别存储实时数据和非实时数据的双队列缓存管理策略，两类队列采用循环调度的方法实现数据传输的公平性，以保证数据传输的实时性和可靠性。本文提出的节点缓存管理策略有利于减小排队时延、降低后继分组超时丢弃和缓存队列拥塞发生的概率，与已有的无线网络缓存管理策略相比，可以提高实时数据传输的实时性和非实时数据传输的可靠性。 在网络层，本文重点在路由协议方面进行了研究，针对已有路由协议在工业无线网络应用中存在的不适用性问题，以及工业无线网络传输路径可靠性较差的特点，本文采用可靠性理论，对不相交和相交的多路径选择策略的可靠度进行了分析；针对工业无线网络对通信的可靠性和实时性的特殊需求，本文提出了路径可靠性评估模型。在对基于节点的邻居列表链路稳定性预测的基础上，通过路径的可靠性因子和延时因子的计算来建立可靠的多路径路由。在模拟了不稳定和不可预测的工业通信现场环境后，通过与传统的单路径路由协议和多路径路由协议性能的对比，验证了本文提出的多路径路由协议的有效性。在不稳定和不可预测的通信环境下，其可靠性和实时性性能优于已有的同类多路径路由协议。 针对已有无线网络路由协议由于对节点故障类型分析不充分，使得网络中的关键节点更新和路由重构次数增加，从而造成工业无线网络的可靠性和实时性难以得到满足的问题，本文借鉴D.Pradhan在经典理论文献中提出的系统可靠性性能改进的思想，根据工业无线网络的工作环境和特点，研究了分簇结构的工业无线网络中的关键节点——簇首节点的容错算法。本文根据对网络中簇首节点的故障类型的分类，提出了能够及时判断故障类型和有效解决相应故障的簇首容错算法，进而保证在簇首发生故障的情况下，使其能够得到及时的检测和恢复，从而满足工业无线网络的可靠性和实时性需求。本文提出的簇首容错算法在网络中的簇首节点发生故障或通信链路出现异常情况时，能够有效地提高数据发送和接收效率，降低通信延迟，其可靠性和实时性明显优于无容错机制的路由协议算法和已有节点容错机制的路由协议算法，因此本文提出的簇首容错算法更适用于环境恶劣的工业现场环境。