Auto‐management of energy in IoT networks

Wireless sensor network (WSN) based on IEEE 802.15.4 technology continues to gain considerable importance. The present work is based on this standard and a cluster tree network topology. This network is divided into many subgroups, each of which is characterized by its special IEEE parameters (beacon order [BO] and superframe order [SO]). A mathematical model for computing energy consumption was proposed to enable personal area network (PAN) coordinator to detect the current energy level in the battery. The proposed adaptive intervention is based on a comparison between the remaining energy and the diverse thresholds, which lead to an auto‐management of energy consumption. The proposed approach was evaluated using Inetmanet/Omnet++ simulator.     

Efficient topology construction and routing for IEEE 802.15.4m-based smart grid networks

IEEE 802.15.4m TVWS Multi-Channel Tree PAN (TMCTP) standard that uses the vacant TV frequency of a region is the key to provide a flexible, scalable and cost-effective AMI smart grid networks. However, the performance of the IEEE 802.15.4m based AMI network can suffer from network interruption, varying transmission reliability and energy consumption problems due to the excessive number of channels and periodic channel scanning. To resolve these issues, we presented an enhanced IEEE 802.15.4m TMCTP called TVWS Orphan channel scanning with Multi-Channel Tree PAN Routing (TOMTPR). The proposed TOMTPR framework includes pilot-channel based Multi-Channel beaconing and interleaving-based TVWS orphan channel scanning. Furthermore, a capacity-aware routing tree is constructed during the neighbor discovery procedure. The proposed protocol suite is designed to provide compatibility with the IEEE 802.15.4 family standards with lower architecture complexity. The simulation results in presence of realistic AMI traffic and AMI network model show that TOMTPR can not only satisfy delay requirements of the AMI traffic, but also outperforms IEEE 802.15.4m TMCTP with IEEE 802.15.5 layer 2 mesh routing in terms of topology construction delay, end-to-end transmission reliability, and energy efficiency.     

基于链路质量的WSN跨层功率控制研究

设计了基于森林监测的传感网功能结构和基于ZigBee/802.15.4标准的森林监测传感网体系结构。根据森林监测的特点,设计了基于CC2520和低功耗的MSP430F5437处理器的节点以及结合ARM处理器和协调器的控制节点,从物理层上实现了能量控制。利用基于ZigBee/802.15.4标准无线传感器网络节点,对无线电传播路径损耗模型以及CC2520的分析,用分段线性逼近的方法得到发送功率与RSSI、LQI及节点间距离的关系。通过进一步优化得到发送功率与片码错误率、节点间距离的关系,建立了一种适合在通信开销小、硬件要求低的场合下使用的基于节点间距离、接收信号强度指示和链路质量指示的跨层功率控制算法。     

Utilizing Neighbours-Table to Improve Tree Routing Protocol in ZigBee Network

ZigBee is an industrial standard for wireless ad hoc networks based on IEEE 802.15.4. It has been developed for low cost, low data rate and low power consumption. ZigBee??s network layer defines two routing protocols namely Ad Hoc On-demand Distance Vector and Tree Routing (TR). TR protocol follows the tree topology (parent?Cchild) in forwarding the data packets from source nodes to the sink node. However, the source does not find rather nor the location of the sink is close to the source node or if it is not in the sub-tree. In this case it will follow the tree topology which will use a lot of hops to deliver data packets to the sink node. This paper present an improvement of TR protocol for ZigBee network and is called Improved Tree Routing (ImpTR) protocol which is computationally simple in discovering the better path to transmit data packets to the sink node, and does not need any addition in hardware. ImpTR determines the better path to the sink node depending on the tables of the neighbouring nodes, which is part of the existing ZigBee network specification. Results show that the proposed algorithm provides shorter average end-to-end delay, increase throughput, decrease the average number of hops and decrease the energy consumption from the network when compared to the original TR routing protocol.     

An Adaptive Beacon Scheduling Mechanism Using Power Control in Cluster-Tree WPANs

This paper presents an adaptive beacon scheduling mechanism using power control in cluster-tree network. We consider the emerging low-rate wireless personal area networks (LR-WPANs) technology as specified in the IEEE 802.15.4 standard that can support environmental monitoring applications. Node clustering is a useful topology management approach to reduce channel contention and improve the network lifetime in wireless sensor networks. A cluster-tree network conforming to the IEEE 802.15.4 standard is formed by several coordinators that periodically send beacon frames to the nodes of their cluster. However, if these periodic beacon frames are sent without any particular scheduling, they will collide with each other and those nodes that wait for them will lose synchronization with their coordinators. The purpose of this paper is to overcome this problem by proposing an adaptive beacon scheduling mechanism using power control, cluster grouping, and the group identifier (GID) in cluster-tree WPANs. This mechanism is designed such that all of the sensing devices send the measured received power level back to their cluster heads (CHs), thus enabling them to adjust their transmission power level after the construction of the topology. Following this, the PAN coordinator divides all of the CHs into several cluster groups (CGs) in order to transmit their beacon frames simultaneously without encountering any direct or indirect beacon frame collision problems. The PAN coordinator selects the group heads (GHs) and assigns the GID for each cluster group. In addition, the PAN coordinator controls the beacon transmission time of all of the CHs and GHs in the CGs using the GID information located in the beacon frame of the PAN coordinator in order to avoid beacon frame collisions. Accordingly, the overall lifetime of the network in cluster-tree WPANs is prolonged by solving the problem of beacon frame collisions. We evaluated the performance of our scheme through a mathematical analysis and a series of simulations using the Network Simulator 2 (NS-2).

甚低功耗无线通信技术——ZigBe

ZigBee技术作为无线传感器网络的主要支撑技术获得人们广泛的关注。完整的ZigBee协议套件由高层应用规范、应用会聚层、网络层、数据链路层和物理层组成。网络层以上协议由ZigBee联盟制订，物理层和媒体访问控制（MAC）层采用IEEE80215．4标准。IEEE802．15．4物理层简单采用比特到符号映射技术、符号到码片序列转换技术、偏移正交相移键控（OQPSK）调制技术，无须信道编码等复杂算法；MAC层采用载波监听多址一冲突避免技术，支持休眠模式。整个协议的设计使得ZigBee技术具有数据传输速率低、功耗低、成本低等特点，更加适合于工业监控系统、传感器网络、家庭监控系统、安全系统等应用。     

基于ZigBee的无线传感器网络节点的设计与通信实现

介绍了基于IEEE 802.15.4的无线通信协议ZigBee协议结构及其技术特点,从低功耗、低成本节点设计的角度提出了无线传感器网络(WSN)通用节点的基本构架,设计了一种具有实用价值的通用节点软硬件平台,节点通信采用短距离无线技术规范ZigBee,通过SPI接口实现单片机和ZigBee芯片的通讯,单片机与计算机通过USB连接。给出了系统的硬件结构及软件设计的方案,并从硬件和软件两方面考虑了节点的功耗问题。     

Cooperative Association/Re-association Approaches to Optimize Energy Consumption for Real-Time IEEE 802.15.4/ZigBee Wireless Sensor Networks

The major challenge of real-time Wireless Sensor Networks stills the optimization of both constraints: energy consumption, to get long network lifetime and the communication delay, to meet real-time requirements. In the context of IEEE 802.15.4/ZigBee networks, the association procedure has a direct effect on building paths optimizing those constraints. In this paper, we are interested on the definition of an ideal approach of load balancing to fairly distribute energy consumption among nodes in IEEE 802.15.4/ZigBee WSNs. This approach leads to conserve energy of each node in order to extend the network lifetime. To be closer to this ideal, we propose new dynamic association/re-association approaches allowing path alternation relative to association criteria and their threshold parameters. The implementation of those approaches in NS2 simulator highlights the efficiency of cooperative and dynamic association criteria particularly the one based on the sum of the inverses of remaining energy. Indeed, this approach gives better results with regard to energy distribution according to ideal approach which leads to a longer lifetime. It also performs lower latency for real time communication.     

ZigBee无线网络规划与容量计算

ZigBee是基于IEEE 802.15.4的一种新兴的无线网络技术。介绍了ZigBee协议栈的架构、层协议的参考模型,分析了ZigBee无线网络的特点。根据ZigBee无线网络规划的原则,提出了几种网络拓扑的规划方案,总结了每种网络拓扑规划方案的最大网络容量和网络延时等参数。在无线网络建设过程中,通过网络规划,再进行网络优化,才能获得最佳的网络性能。因此,在实际ZigBee网络规划中有一定的指导作用。     

移动Sink传感网中基于IEEE 802.15.4的拓扑控制与路由

针对查询驱动的移动Sink无线传感器网络,基于IEEE 802.15.4标准,提出了一个联合簇树组网和移动路由的跨层协议设计方案。以能耗、网络连通度、负载均衡和子树深度等指标为评价因子,在多目标优化模型下定义了一个拓扑综合评价函数,构建稳定的最优簇树网络结构;改进了IEEE 802.15.4 MAC中基于信标帧调度的分布式睡眠同步算法,维护较低占空比下的网络同步与拓扑修正;利用拓扑形成过程中依"最早信标帧"、"最好链路"、"最小层次"3种准则确立的父子关系,建立移动Sink与N-Hop范围内节点的双向路由路径。最终将上述MAC层的拓扑控制方案与网络层的查询路由方法完整实现于TinyOS协议栈中。实验结果表明,评价函数能够有效地反映组网质量,N-Hop后验式路由结合睡眠同步机制,在"最好链路"拓扑下表现出较高的能量效率。     

Review of Energy Conservation Using Duty Cycling Schemes for IEEE 802.15.4 Wireless Sensor Network (WSN)

Energy conservation is one of the crucial issues in wireless sensor network (WSN). A significant solution to conserve energy is done by deploying duty cycle management mechanisms in the WSN applications. This paper reviews several duty cycle mechanisms in WSN such as Duty Cycle Learning Algorithm, adaptive media access control (MAC) protocol for efficient IEEE 802.15.4 (AMPE), distributed duty cycle management (DDCM), distributed duty cycle management low power broadcast (DDCM + LPB) and distributed beacon only period. These mechanisms change their parameters such as idle listening, packet accumulation and delay in the end device transmitting queue to improve the energy conservation in WSN. The performances of these different energy conservation mechanisms have been compared at the MAC layer of IEEE 802.15.4 standard. It is found that the DDCM + LPB has made approximately 100 % enhancement in terms of average energy efficiency as compared to the other mechanisms. DDCM + LPB has significant enhancements by adapting the duty cycle according to the network traffic load condition. Using this mechanism, the duty cycle is increased when the traffic load increases and vice versa. Its energy efficiency also outperforms the conventional DDCM by the average of 10 %.     

ZigBee无线传输技术综述

ZigBee技术是一种新兴的短距离、低复杂度、低功耗、低数据速率、低成本的无线网络技术。ZigBee协议采用IEEE802.15.4标准的物理层和链路层,并在其上增加了网络层,安全模块和应用支持子层模块,从而实现了大区域网络覆盖。ZigBee由于其在低功耗、低复杂度、自组织等方面的优势,逐渐成为无线传感器网络的首选通信协议。     

基于ZigBee技术的无线传感器网络构建与应用

对新的短距离、低速率无线网络技术Z igBee及其相关标准IEEE 802.15.4进行了分析和研究,着重探讨了基于Z igBee的无线传感器网络构建和ZigBee网络的应用,研究利用Siemens、旭昂等公司的通信模块和MSP430微控制器构建基于ZigBee技术的无线传感器网络,在GSM(全球移动通信系统)网络、CDMA(码分多址)网络或者以太网中实现大范围内的数据的传输与控制,达到更广泛的工业应用的目的。     

基于ZigBee和WLAN的智能家居监控系统的设计

综合zigBee无线传感器网络和无线局域网(WLAN),设计了集多传感、分布式处理和事件触发监视于一体的具有双层网络结构的智能家居多媒体监控系统.ZigBee网络由标量传感节点和多媒体传感节点(网关)基于IEEE 802.15.4/ZigBee协议构建.负责采集标量数据上传到WLAN或执行来自上层的指令.多媒体传感节点基于WLAN连接到远程监控中心形成远程视频监控网络,将ZigBee网络上汇聚来的传感数据、报警信号和压缩视音频流等多媒体数据发送到监控中心及用户.利用此系统,为用户提供家居环境参数监测、报警、事件触发或持续的远程家居监控功能.     

一种新的无线技术ZigBee

随着通信技术的不断发展,短距离无线通信技术已成为无线通信技术的新热点。未来的无线互连设备将具有低价格、近距离、低功率的特点,作为IEEE802.15.4标准的ZigBee技术正好具备上述优点,因而ZigBee将成为极具竞争力的新兴技术。文中首先介绍了ZigBee技术的发展状况、协议栈模型、相应的技术特点及其应用前景,然后把ZigBee技术与其他无线通信技术(如蓝牙技术、超宽带技术和NFC技术)做了性能对比,通过比较,分析和论证了ZigBee的技术优势。     

Energy-efficient neighbor discovery protocol for mobile wireless sensor networks

Low energy consumption is a critical design requirement for most wireless sensor network (WSN) applications. Due to minimal transmission power levels, time-varying environmental factors and mobility of nodes, network neighborhood changes frequently. In these conditions, the most critical issue for energy is to minimize the transactions and time consumed for neighbor discovery operations. In this paper, we present an energy-efficient neighbor discovery protocol targeted at synchronized low duty-cycle medium access control (MAC) schemes such as IEEE 802.15.4 and S-MAC. The protocol effectively reduces the need for costly network scans by proactively distributing node schedule information in MAC protocol beacons and by using this information for establishing new communication links. Energy consumption is further reduced by optimizing the beacon transmission rate. The protocol is validated by performance analysis and experimental measurements with physical WSN prototypes. Experimental results show that the protocol can reduce node energy consumption up to 80% at 1–3 m/s node mobility.     

基于Ns2的ZigBee网络节点接入的研究

根据IEEE 802.15.4和ZigBee Specification协议,分析介绍Zigbee网络节点接入机制,在Ns2上模拟实现ZigBee网络节点接入过程,并针对ZigBee网络的特点提出相应的改进方案,改善网络节点接入的成功率,缩短接入时间.     

IEEE802.15.4协议的性能分析与仿真

IEEE 802.15.4是一个自组织的无线网络标准,其中制定了PHY层和MAC层规范,主要应用场合为低成本、低功耗、低复杂度的无线个域网.许多参数在IEEE 802.15.4标准中仅给出取值范围而并未给出确定的值,虽然这些值对系统性能有着较为显著的影响.个域网中的设备大量采用电池供电,因此实现更低的能量消耗是该网络标...     

一种基于Zigbee的无线传感器网络教学实验系统

本文首先简要介绍无线传感器网络的体系结构,然后给出一个基于IEEE802．15．4和Zigbee协议的无线传感器网络教学实验系统。该系统中的多个传感器节点可以组成多种不同的拓扑结构,并可以将采集到的数据通过GSM网络发送到用户终端,用户也可以通过GSM网络对远程传感器节点进行控制。该教学实验系统已被许多院校采用,亦可直接应用于其他领域。     

一种与ZigBee/802.15.4协议兼容的RF模块XBee/XBee Pro及其应用

介绍了一种与ZigBee/802.15.4协议兼容的MaxStream公司推出的RF模块XBee/XBeePro的性能特点、引脚功能、操作模式及其在小型无线传感网络中的应用。该模块设计满足IEEE 802.15.4标准,具有DSSS(直接序列扩频)功能;硬件采用标准UART接口;具有接收、发送、睡眠、命令和空模式等5种操作模式。该模块具有体积小、功耗低、接口简单、易于组网以及升级方便等优点,适用于较低数据速率的短距离通信应用,尤其在智能无线传感网络设计中有着广阔的应用前景。