Experimental Analysis of Link Estimation Methods in Low Power Wireless Networks

Wireless sensor networks are envisioned to be an integral part of cyber-physical systems, yet wireless networks are inherently dynamic and come with various uncertainties. One such uncertainty is wireless communication itself which assumes complex spatial and temporal dynamics. For dependable and predictable performance, therefore, link estimation has become a basic element of wireless network routing. Several approaches using broadcast beacons and/or unicast MAC feedback have been proposed in the past years, but there is still no systematic characterization of the drawbacks and sources of errors in bea- con-based link estimation in low-power wireless networks, which leads to ad hoc usage of beacons in rout- ing. Using a testbed of 98 XSM motes （an enhanced version of MICA2 motes）, we characterize the negative impact that link layer retransmission and traffic-induced interference have on the accuracy of beacon-based link estimation, and we show that data-driven link estimation and routing achieve higher event reliability （e.g. by up to 18.75%） and transmission efficiency （e.g., by up to a factor of 1.96） than beacon-based approaches These findings provide solid evidence for the necessity of data-driven link estimation and demonstrate the importance of addressing the drawbacks of beacon-based link estimation when designing protocols for low-power wireless networks of cyber-physical systems.

Low Power Transceiver Design Parameters for Wireless Sensor Networks

Designing low power sensor networks has been the general goal of design engineers, scientist and end users. It is desired to have a wireless sensor network (WSN) that will run on little power (if possible, none at all) thereby saving cost, and the inconveniences of having to replace batteries in some difficult to access areas of usage. Previous researches on WSN energy models have focused less on the aggregate transceiver energy consumption models as compared to studies on other components of the node, hence a large portion of energy in a WSN still get depleted through data transmission. By studying the energy consumption map of the transceiver of a WSN node in different states and within state transitions, we propose in this paper the energy consumption model of the transceiver unit of a typical sensor node and the transceiver design parameters that significantly influences this energy consumption. The contribution of this paper is an innovative energy consumption model based on simple finite automata which reveals the relationship between the aggregate energy consumption and important power parameters that characterize the energy consumption map of the transceiver in a WSN;an ideal tool to design low power WSN.

M-ary FSK Modulation Using Short Packet without a Preamble and Error Detection Codes for Low Power Wireless Communication

Since power of a wireless sensor node is limited, low power communication technology has been required. M-ary frequency shift keying (MFSK) modulation with orthogonal signals is one of the methods to decrease the power. However, if the amount of transmitted data including such as an identification number (ID) of a node and measured data is small, a ratio of the data length to the total packet length, which means transmission efficiency, becomes quite low. Because a preamble and error check codes are generally added to a packet for synchronization between a transmitter and a receiver and for decrease in reception errors, respectively. In this research, we have developed a method with digital filters which eliminates the other signals from time series frequency spectra not to use a preamble and error check codes. Although estimated synchronization loss of the method was less than 1.6 dB, it was found that the loss of the method on error packet rate was almost 0 dB at more than 0.001 of packet error rate by a simulation made by BASIC. These results indicate a possibility to realize that a packet which consists of only two symbols can be received with no error if the transmitted data is less than 14 bits using 128-FSK.

A 2.4-GHz-Low-Power CMOS RF Transmitter for IEEE 802.15.4 Standard

This paper presents the experimental results of a low-power RF transmitter for 2.4-GHz-band IEEE 802.15.4 standard in 0.18-μm CMOS technology. In order to make an adaptive RF transmitter, several factors must be considered. The most important factors are performances, power consumption, output power, noise factor, and cost. The RF transmitter comprises a quadrature passive mixer, and a power amplifier. The proposed RF transmitter consumes only 10.8-mW under a supply voltage of 1.8-V.

A Study of Efficient Power Consumption Wireless Communication Techniques/ Modules for Internet of Things (IoT) Applications

A study of wireless technologies for IoT applications in terms of power consumption has been presented in this paper. The study focuses on the importance of using low power wireless techniques and modules in IoT applications by introducing a comparative between different low power wireless communication techniques such as ZigBee, Low Power Wi-Fi, 6LowPAN, LPWA and their modules to conserve power and longing the life for the IoT network sensors. The approach of the study is in term of protocol used and the particular module that achieve that protocol. The candidate protocols are classified according to the range of connectivity between sensor nodes. For short ranges connectivity the candidate protocols are ZigBee, 6LoWPAN and low power Wi-Fi. For long connectivity the candidate is LoRaWAN protocol. The results of the study demonstrate that the choice of module for each protocol plays a vital role in battery life due to the difference of power consumption for each module/protocol. So, the evaluation of protocols with each other depends on the module used.

A Review of Wireless Body Area Networks for Medical Applications

Recent advances in Micro-Electro-Mechanical Systems (MEMS) technology, integrated circuits, and wireless communication have allowed the realization of Wireless Body Area Networks (WBANs). WBANs promise unobtrusive ambulatory health monitoring for a long period of time, and provide real-time updates of the patient’s status to the physician. They are widely used for ubiquitous healthcare, entertainment, and military applications. This paper reviews the key aspects of WBANs for numerous applications. We present a WBAN infrastructure that provides solutions to on-demand, emergency, and normal traffic. We further discuss in-body antenna design and low-power MAC protocol for a WBAN. In addition, we briefly outline some of the WBAN applications with examples. Our discussion realizes a need for new power-efficient solu-tions towards in-body and on-body sensor networks.

An Improved Wireless Sensor Network Routing Algorithm

High performance with low power consumption is an essential factor in wireless sensor networks （WSN）. In order to address the issue on the lifetime and the consumption of nodes in WSNs, an improved ad hoc on-demand distance vector routing （IAODV） algorithm is proposed based on AODV and LAR protocols. This algorithm is a modified on-demand routing algorithm that limits data forwarding in the searching domain, and then chooses the route on basis of hop count and power consumption. The simulation results show that the algorithm can effectively reduce power consumption as well as prolong the network lifetime.

基于6LoWPAN的物联网寻址策略研究

在6LoWPAN(IPv6 over Low-power Wireless Personal Area Network)的基础上,该文提出应用于物联网的寻址策略,实现基于IEEE 802.15.4协议的底层异构网络与互联网的实时通信。寻址策略包括IPv6地址自动配置和报头压缩。采用的分层地址自动配置策略,首先在底层网络内部允许节点使用16位短地址导出的链路本地地址进行数据分组传输,该链路本地地址需通过执行基于分簇的重复地址检测机制保证唯一性;其次,每个底层网络中的Sink节点通过上层IP路由器获取全球路由前缀,并与接口标识符相结合,形成Sink节点的全球地址,实现底层网络与互联网的数据交换。同时,通过在报头压缩编码中植入链路本地地址和全球地址控制位,提出了一种适用于物联网应用的报头压缩方案IIPHC(IoTs IPv6 Header Compression)。如果地址类型为链路本地地址,则采用简单灵活的IIPHC1方案,如果地址类型为全球地址,则采用相对复杂但有效的IIPHC2方案。仿真及测试结果表明,基于6LoWPAN的物联网寻址策略在网络开销、时延、吞吐量、能耗等性能方面存在一定的优越性。

基于Route-Over路由机制的6LoWPAN重组缓存管理机制

为了提高多个节点同时向一个转发节点发送不同数据包的重组效率,提出了一种基于Route-over路由机制的基于IPv6的低功耗无线个域网(IPv6over Low-Power Wireless Personal Area Networks,6LoWPAN)重组缓存管理机制.通过适当地扩大重组缓存容量,使其能够在同一时刻建立对多个数据包的重组过程.当重组缓存容量较大时,根据缓存中已经接收到的所有数据包分片的详细信息及剩余缓存容量的大小决定是否缓存刚接收到的数据包分片;当重组缓存容量低于一定门限时,根据缓存中已经接收到的所有数据包分片的详细信息,为每个数据包计算一个重组度,丢弃重组度最低的数据包分片,从而释放缓存.同时,针对每个数据包,都开启一个重组定时器,当定时器溢出时,直接丢弃该数据包的所有缓存分片.仿真结果表明,所提出的重组缓存管理策略能够有效地提高分片的重组率.

6LoWPAN中基于Mesh-under的备用缓存机制

在基于Mesh-under的IPv6低功耗无线个域网(IPv6over low-power wireless personal area networks,6LoWPAN)中,针对传输路径上中间节点重传缓存溢出导致重传数据分片丢失,造成网络性能下降等问题,提出一种基于Mesh-under的备用缓存机制。本文所提机制根据传输路径上各节点重传缓存使用情况及数据分片剩余跳数等信息,设置动态重传缓存门限,并为超过该门限的节点从其邻居节点中挑选合适的备用缓存节点,从而完成数据分片的缓存与重传过程,达到均衡使用各节点重传缓存的目的。结果表明,所提机制能够有效避免重传缓存溢出,减小网络能耗,同时进一步提高目的端重组成功率。

6LoWPAN中优化多路径路由吞吐率的数据包分片方案

6LoWPAN协议支持在IEEE 802.15.4低功耗无线个域网络中传递IPv6数据包,其主要功能包括对IPv6数据包进行分片与拼装、头部压缩和路由。该文利用概率论推导了6LoWPAN中一个IPv6数据包从信源到达信宿所需要的发送次数、传递时延和吞吐率,建立了基于多路径路由优化吞吐率的数学模型,并依此提出了IPv6数据包的最优分片方案,该方案可以提高6LoWPAN中IPv6数据包的吞吐率。

6LoWPAN中分布式TCP缓存队列策略

在多TCP连接的6Lo WPAN(IPv6 over Low-Power Wireless Personal Area Networks)网络中,针对丢包严重时存在频繁的端到端重传问题,提出分布式TCP缓存队列策略。该策略能够使中间节点合理地缓存不同TCP连接在链路层传输中丢失的分段,从而保证每个TCP连接的性能,减少网络能耗。另外,采用ARQ机制进行链路层数据帧传输时,由于中间节点判断丢包的准确率较低,导致缓存队列中存在一些实际未丢失的分段。对这些分段的重传会消耗额外的能量,降低了缓存队列的利用率。因此缓存管理采用询问邻居节点的方式检查分段是否丢失,及时地删除无效的缓存分段。实验结果表明,采用分布式TCP缓存队列策略可以使得多个TCP连接的网络性能以及缓存队列利用率得到了很大提高。

6LoWPAN中分层路由协议HiLow的改进

6LoWPAN标准将下一代互联网协议IPv6与IEEE802.15.4标准联系起来,使得在低速无线个人区域网络(LoWPAN)上进行基于IPv6的数据传输成为可能。HiLow作为一种基于Mesh-under原理的分层路由方式,大大减少了控制报文的数量及存储空间的需求。通过对HiLow的父节点选择策略及路由恢复策略进行改进,增强了6LoWPAN网络的稳定性及路由的可靠性。最后在NS2中通过仿真实验对所做改进进行了验证,结果显示当存在失效节点时改进后的协议仍能保持较高的转发成功率。

基于NAT64的6LoWPAN边缘路由器设计

针对目前基于6Lo WPAN边缘路由器只适用与IPv6设备互联、网络报文传输复杂繁琐、边缘路由器映射表复杂且开销大等问题,引入IEEE 802.15.4地址概念对6Lo WPAN网络内报文交互方式与数据包格式进行优化,提出一种6Lo WPAN与IPv4协议转换机制和边缘路由器地址映射转换方法,设计出适合在8位单片机上运行的轻量级微系统,最后用Co AP协议来访问节点数据,验证系统,实现6Lo WPAN网络与IPv4,IPv6网络之间的通信。该方法实现了6Lo WPAN与IPv4网络互联通信,保留6Lo WAPN与IPv6网络通信的功能,同时提高了6Lo WPAN内网络的吞吐量,降低边缘路由器维护地址映射表的开销,提高了边缘路由器效率,有效降低6Lo WPAN网络传输数据时的功耗,提高节点生存时间。

Design of low power common-gate low noise amplifier for 2.4 GHz wireless sensor network applications

This paper presents a differential low power low noise amplifier designed for the wireless sensor network （WSN） in a TSMC 0.18μm RF CMOS process.A two-stage cross-coupling cascaded common-gate（CG） topology has been designed as the amplifier.The first stage is a capacitive cross-coupling topology.It can reduce the power and noise simultaneously.The second stage is a positive feedback cross-coupling topology,used to set up a negative resistance to enhance the equivalent Q factor of the inductor at the load to improve the gain of the LNA.A differential inductor has been designed as the load to achieve reasonable gain.This inductor has been simulated by the means of momentum electromagnetic simulation in ADS.A ＂double-π＂ circuit model has been built as the inductor model by iteration in ADS.The inductor has been fabricated separately to verify the model. The LNA has been fabricated and measured.The LNA works well centered at 2.44 GHz.The measured gain S_（21） is variable with high gain at 16.8 dB and low gain at 1 dB.The NF（noise figure） at high gain mode is 3.6 dB,the input referenced 1 dB compression point（IP1dB） is about -8 dBm and the IIP3 is 2 dBm at low gain mode.The LNA consumes about 1.2 mA current from 1.8 V power supply.

Unweighted Voting Method to Detect Sinkhole Attack in RPL-Based Internet of Things Networks

The Internet of Things(IoT)consists of interconnected smart devices communicating and collecting data.The Routing Protocol for Low-Power and Lossy Networks(RPL)is the standard protocol for Internet Protocol Version 6(IPv6)in the IoT.However,RPL is vulnerable to various attacks,including the sinkhole attack,which disrupts the network by manipulating routing information.This paper proposes the Unweighted Voting Method(UVM)for sinkhole node identification,utilizing three key behavioral indicators:DODAG Information Object(DIO)Transaction Frequency,Rank Harmony,and Power Consumption.These indicators have been carefully selected based on their contribution to sinkhole attack detection and other relevant features used in previous research.The UVM method employs an unweighted voting mechanism,where each voter or rule holds equal weight in detecting the presence of a sinkhole attack based on the proposed indicators.The effectiveness of the UVM method is evaluated using the COOJA simulator and compared with existing approaches.Notably,the proposed approach fulfills power consumption requirements for constrained nodes without increasing consumption due to the deployment design.In terms of detection accuracy,simulation results demonstrate a high detection rate ranging from 90%to 100%,with a low false-positive rate of 0%to 0.2%.Consequently,the proposed approach surpasses Ensemble Learning Intrusion Detection Systems by leveraging three indicators and three supporting rules.

Design of ultralow power receiver front-ends for 2.4 GHz wireless sensor network applications

This paper presents the design of an ultralow power receiver front-end designed for a wireless sensor network （WSN） in a 0.18 μm CMOS process. The author designs two front-ends working in the saturation region and the subthreshold region respectively. The front-ends contain a two-stage cross-coupling cascaded common-gate （CG） LNA and a quadrature Gilbert IQ mixer. The measured conversion gain is variable with high gain at 24 dB and low gain at 7 dB for the saturation one, and high gain at 22 dB and low gain at 5 dB for the subthreshold one. The noise figure （NF） at high gain mode is 5.1 dB and 6.3 dB for each. The input 1 dB compression point （IPldB） at low gain mode is about -6 dBm and -3 dBm for each. The front-ends consume about 2.1 mA current from 1.8 V power supply for the saturation one and 1.3 mA current for the subthreshold one. The measured results show that, comparing with the power consumption saving, it is worth making sacrifices on the performance for using the subthreshold technology.

特高压直流输电换流阀设备数字化思考与实践

在能源和电网数字化转型要求大背景下,作为我国电网核心资产的特高压直流输电换流阀设备正面临全面数字化的挑战。文章首先在梳理目前特高压换流阀设备数字化现状及其数字化提升意义基础上,结合目前研究热点——数字孪生及相关技术,提出了换流阀设备数字化的总体目标及其数字孪生体架构和数据基础构建方法。然后,为了实现换流阀设备底层数据的高可靠低成本获取,文章介绍了在特高压换流阀设备上开展高可靠低功耗无线智能传感关键技术应用研究的成果和经验,主要包括低功耗无线传感网络系统开发、多物理量智能传感器研制、验证测试等方面。最后,对换流阀设备数字化的思考和实践进行总结,对未来换流阀设备数字化工作进行了展望。

基于无线Mesh自组网煤矿液压支架压力传感器设计与应用

通过研究现有无线矿山压力监测系统中液压支架传感器应用情况,发现普遍存在数据传输不稳定与传感器功耗高问题,为此利用无线Mesh自组网技术设计煤矿液压支架压力传感器,克服数据传输不稳定及功耗高的问题。以STM32L412单片机为核心处理器,定时采集液压支架压力数据,对压力数据进行处理和存储,并控制数据通过无线Mesh网络传输至监测分站,最终到达地面监测系统。设计中将无线Mesh模块唤醒机制与STM32L412单片机低功耗模式结合设计,保证数据传输可靠性同时,兼顾传感器低功耗。经过现场实际应用,所设计的液压支架压力传感器在矿井下环境中数据传输稳定、传感器功耗低,适合煤矿工作面液压支架压力采集监测。

基于无线传感网NB-IoT分簇RPL组播路由算法的研究

为了在已有RPL组播路由协议的基础上,改进无线传感网关键转发节点轮换机制,在DAO消息option选项中增加能量剩余参数和转发节点更换阈值后,根据网络规模和组播接收节点数,转发节点轮换阈值,使能量充足的转发节点参与到分组转发中。当节点能量减少到设定的阈值后,切换转发节点,保证各节点的能耗均衡,从而设计出最优转发节点集。通过仿真可知;该算法可以有效控制节点能耗,提高网络节点的平均使用时间,延长网络生存周期。