电子科大无线传感器网络课件wsn_chapter_1_概述

1、0University of Electronic Science and Technology of ChinaWireless Sensor Networks无线传感器网络黄乐天上课时间：上课时间：周三1、2节（立人楼 B109）email: Tel:61831105（O）Office:科研楼B224(B)-实验地点：实验地点：科B237（待定）-课程考核方式：课程考核方式：平时考核（15%）、期末考试（60%）和实验考核（25%）1University of Electronic Science and Technology of ChinaWireless Sensor Network

2、sCourse OverviewTextbook: “Wireless Sensor Networks无线传感器网络，Lan F.Akyildiz, Mehmet Can Vuran编，徐平平，刘昊，褚宏云等译，电子工业出版社，第1版，2013年3月。2University of Electronic Science and Technology of ChinaWireless Sensor Networks参考书及预备知识Reference books1无线传感器网络原理与应用，姚向华、杨新宇、易劲刚、韩九强，高等教育出版社，第1版，2012年4月。2. 智能网络传感器与无线传感器网络，景

3、博、张劼、孙勇，国防工业出版社，第1版，2011年1月。3物联网/无线传感网原理与实践，贾灵、王新宇、郑淑军，北京航空航天大学出版社，第1版，2011年1月。Prerequisite knowledge and/or skills 计算机通信网，计算机通信网，微机原理，微机原理，传感原理与信息感知技术传感原理与信息感知技术3University of Electronic Science and Technology of ChinaWireless Sensor NetworksWSN是一门交叉学科，涉及计算机、微电子、网络、通信、信号处理、传感器等诸多领域随着现代微电子技术、微机电系统（M

4、EMS)、片上系统soc、纳米材料、无线通信技术、信号处理技术、计算机网络技术等的进步以及互联网的迅猛发展传统传感器信息获取技术从独立的单一化模式向集成化、微型化，智能化、网络化方向发展，成为信息获取最重要和最基本的技术之一。无线传感器网络涉及这么多知识、技术。需要哪些基础？达到什么目标？需要掌握哪些重点？4University of Electronic Science and Technology of ChinaWireless Sensor NetworksWSN的定义（维基百科）无线传感器网络是由许多在空间中分布的自动装置组成的一种无线通信计算机网络，这些装置使用传感器协作地监控不同

5、位置的物理或环境状况（比如温度、声音、振动、压力、运动或污染物）。无线传感器网络的发展最初起源于战场监测等军事应用。而现今无线传感器网络被应用于很多民用领域，如环境与生态监测、健康监护、家居自动化以及交通控制等。起源于军事目的的无线传感器网络在民用化过程中会出现哪些问题？对其后续发展带来什么影响？5University of Electronic Science and Technology of ChinaWireless Sensor NetworksWSN的特征大规模为了获取精确信息，在监测区域通常部署大量传感器节点，可能达到成千上万，甚至更多。自组织在传感器网络应用中，通常情况下传感器

6、节点被放置在没有基础结构的地方，传感器节点的位置不能预先精确设定，节点之间的相互邻居关系预先也不知道。动态性传感器网络的拓扑结构可能因为下列因素而改变：环境因素或电能耗尽造成的传感器节点故障或失效；环境条件变化可能造成无线通信链路带宽变化，甚至时断时通；传感器网络的传感器、感知对象和观察者这三要素都可能具有移动性；新节点的加入。这就要求传感器网络系统要能够适应这种变化，具有动态的系统可重构性。6University of Electronic Science and Technology of ChinaWireless Sensor NetworksWSN的特征可靠性可靠性由于监测区域环境的

7、限制以及传感器节点数目巨大，不可能人工“照顾”每个传感器节点，网络的维护十分困难甚至不可维护。以数据为中心用户使用传感器网络查询事件时，直接将所关心的事件通告给网络，而不是通告给某个确定编号的节点。网络在获得指定事件的信息后汇报给用户。这种以数据本身作为查询或传输线索的思想更接近于自然语言交流的习惯。集成化集成化传感器节点的功耗低，体积小，价格便宜，实现了集成化。以上哪些特征是“普世化”的，哪些特征只针对特定的应用场景。7University of Electronic Science and Technology of ChinaWireless Sensor NetworksVWSN的特征

8、可靠性可靠性由于监测区域环境的限制以及传感器节点数目巨大，不可能人工“照顾”每个传感器节点，网络的维护十分困难甚至不可维护。以数据为中心用户使用传感器网络查询事件时，直接将所关心的事件通告给网络，而不是通告给某个确定编号的节点。网络在获得指定事件的信息后汇报给用户。这种以数据本身作为查询或传输线索的思想更接近于自然语言交流的习惯。集成化集成化传感器节点的功耗低，体积小，价格便宜，实现了集成化。以上哪些特征是“普世化”的，哪些特征只针对特定的应用场景。8University of Electronic Science and Technology of ChinaWireless Sensor

9、Networks网络体系结构网络体系结构从无线联网的从无线联网的角度来看，传角度来看，传感器网络节点感器网络节点的体系由分层的体系由分层的的网络通信协网络通信协议、网络管理议、网络管理平台和应用支平台和应用支撑平台撑平台三个部三个部分。分。9University of Electronic Science and Technology of ChinaWireless Sensor Networks物物 理理 层层数据链路层数据链路层网网 络络 层层传传 输输 层层应应 用用 层层能能 量量 分分 配配移移 动动 管管 理理应应 用用 优优 化化无线传感器网络协议网络通信协议类似于传统网络通信

10、协议类似于传统InternetInternet网络中的网络中的TCP/IPTCP/IP协议体系，它由协议体系，它由物理层、数据链路层、网络层、传输层和应用层组成。物理层、数据链路层、网络层、传输层和应用层组成。各层内容将在后续章节依次介绍讨论各层内容将在后续章节依次介绍讨论。10University of Electronic Science and Technology of ChinaWireless Sensor NetworksContents第1章 概述 -4学时 chap1、2第2章 传感器与执行器-2学时 chap14第3章 传感器网络设计影响因素-2学时 chap3第4章 物理

11、层 -4学时 chap4第5章 介质访问控制 -6学时chap5第6章 差错控制 -2学时 chap6第7章 网络层 -4学时 chap7实验 基础类实验 -8学时 实验指导书自学第8，9，10章了解第13，15，16，17，18章11University of Electronic Science and Technology of ChinaWireless Sensor NetworksChapter 1:Introduction12University of Electronic Science and Technology of ChinaWireless Sensor Networ

12、ks什么是无线传感器网络？巨型机说：巨型机说：“我认为全球大概只需要五台计算机就够了我认为全球大概只需要五台计算机就够了”；PCPC机说：机说：“每个家庭的桌面上都应该有一台电脑每个家庭的桌面上都应该有一台电脑” ” ；Pocket PCPocket PC说：说：“太大了，应该每人口袋里放一台太大了，应该每人口袋里放一台” ” ；WSNWSN说：说：“每粒沙子都应该是一台计算机每粒沙子都应该是一台计算机”。任务管理中心任务管理中心 Internet、卫星、卫星或移动通信网或移动通信网络等络等汇聚节点汇聚节点监测区域监测区域传感器节点传感器节点13University of Electronic

13、 Science and Technology of ChinaWireless Sensor Networks什么是无线传感器网络 WSN是一种分布式网络系统，采用无线多跳的通信方式，其网络拓扑结构动态变化，具有自组织、自控制以及自适应等智能属性。由传感器节点、感知对象和观察者三个基本要素组成。Sink传感器节点传感器节点Internet、卫、卫星或移动通星或移动通信网信网WSN体系结构体系结构终端终端用户用户检测区域检测区域14University of Electronic Science and Technology of ChinaWireless Sensor NetworksSe

14、nsor TypesLightThermopileUltravioletIRVisible LightColor sensorsMagneticSoundUltrasoundAccelerometerTemperaturePressureHumidityTouch sensors2.25 inMicrophoneAccelerometerLightTemperatureSounderMagnetometer1.25 in回顾微机原理或嵌入式系统内容理解无线传感器节点系统平台结构和组成，工作原理及应用无线传感器网络都是以此为基础15University of Electronic Science

15、 and Technology of ChinaWireless Sensor Networksn Smalln Low powern Low bit raten High density n Low cost (dispensable)n Autonomousn Adaptive传感器节点硬件SENSING UNITPROCESSING UNIT16University of Electronic Science and Technology of ChinaWireless Sensor Networks各种节点系统平台传感器节点的具体产品传感器节点的具体产品17University of

16、 Electronic Science and Technology of ChinaWireless Sensor NetworksSensor Node HardwareTwo main componentsBase (Processor + Transceiver)Sensor BoardBase + Sensor Board(s) = Sensor Node18University of Electronic Science and Technology of ChinaWireless Sensor Networks25 lb, 19.5 x 5.5 x 16 inch 64 W $

17、6K (today)160 KB Floppies16-256 KB RAM4.77 MHzOriginal IBM PC (1981)0.5 oz, 2.25 x 1.25 x 0.25 inch14 mW $125512 KB Flash128 KB RAM8 MHzMICAZ Mote (2005)Sensor Node Features19University of Electronic Science and Technology of ChinaWireless Sensor NetworksSensor Motes Timeline20University of Electron

18、ic Science and Technology of ChinaWireless Sensor NetworksRockwell WINSSmart DustJPL Sensor WebsDust Examples for Sensor Nodes21University of Electronic Science and Technology of ChinaWireless Sensor NetworksMICA MoteRene MoteweC MoteDot MoteExamples for Sensor Nodes22University of Electronic Scienc

19、e and Technology of ChinaWireless Sensor NetworksCurrent Platforms: 1st GenerationMica2DOT (2003)16Kb program memRFM TR1000 (CSMA/ASK)Lightweight and small Mica2 & Cricket platform (2003)128Kb program memChipconCC1000 (CSMA/FSK)40Khz Ultrasounders (Cricket only)MicaZ (2004) & Telos (2005)802

20、.15.4/Zigbee stackSpread Spectrum radio handles multipath betterIntegrated antenna (Telos only) 23University of Electronic Science and Technology of ChinaWireless Sensor NetworksCurrent Platforms: 2nd GenerationImote (2003) & Imote2 (2007)Higher processing powerBluetooth & 802.11 capable (Im

21、ote2 only)Stargate (2005) & Stargate 2.0 Pentium class processor Linux OS = easy development (C/C+)Higher processing capabilities = energy intensive802.11 capable24University of Electronic Science and Technology of ChinaWireless Sensor NetworksSENSOR NODE FEATURESProcessing and StorageFeatureImo

22、te (2003)Mica2 (2003)MicaZ (2004)Telos (2005)Stargate (2005)Imote2 (2009)Speed MHz1288840013-416*Flash kB(Program)5121281284832,00032,000Serial Flash kB(Measurement data)N/A#5125121024N/A#N/A#SRAM / EEPROM / SDRAM kB(Configuration)64441064,000256-32,000 * Multiple processor speed levels# Imote, Star

23、gate, and Imote2 use a single Flash for program and measurement data Imote, Imote2, and Telos use SRAM; Mica2 and MicaZ use EEPROM; Stargate uses SDRAM Imote2 will have different versions, SRAM changes accordingly25University of Electronic Science and Technology of ChinaWireless Sensor NetworksSENSO

24、R NODE FEATURESCommunication and PowerFeatureImote (2003)Mica2 (2003)MicaZ (2004)Telos (2005)ImoteRadio Frequency2.4 GHz300-900MHz2.4 GHz2.4 GHz2.4 GHzDataRate kb/s72015250250250 (720 /11,000 )Power CarrierSense/Rx./Tx. mA15 / 24 / 248 / 10 / 278 / 20 / 181 / 20 / 1840/20/18PowerSleep mA1-250 192761

25、-100 Radio Range32 ft (10 m)500 ft (150m)300 ft (100m)400 ft (125m)100ft (30m)Power sourceAA Battery2xAA2xAA2xAA3xAAA With external Bluetooth adapter With external WLAN adapter Different sleep levels26University of Electronic Science and Technology of ChinaWireless Sensor Networks MICAz PlatformMicr

26、oprocessor: Atmel ATmega128L7.3728 MHz clock128 kB of Flash for program memory4 kB of SRAM for data and variables2 UARTs (Universal Asynchronous Receive and Transmit)Serial Port Interface (SPI) busDedicated hardware I2C busRadio: Chipcons CC2420 (IEEE 802.15.4)250 kbit/sExternal serial flash memory:

27、 512 Kbxbow estimates 100000 samples51-pin expansion connectorEight 10-bit analog I/O21 general purpose digital I/OUser interface: 3 programmable LEDsPowered by two AA batteries 1850 mAh capacityLogger FlashATMega128L controllerAnalog I/ODigital I/OFreq. Tunable Radio51-Pin Expansion ConnectorAntenn

28、aMMCX connectorLEDs27University of Electronic Science and Technology of ChinaWireless Sensor NetworksTelos PlatformRobustUSB interfaceIntegrated antenna (30m-125m)External antenna capability (500m)High Performance10kB RAM, 48 KB ROM12-bit ADC and DAC (200ksamples/sec)Hardware link-layer encryption28

29、University of Electronic Science and Technology of ChinaWireless Sensor NetworksTelos PlatformSingle board philosophyRobustness, Ease of use, Lower CostIntegrated Humidity & Temperature sensorUses 802.15.4CC2420 radio, 2.4 GHz, 250 kbpsMotorola HCS08 processorLower power consumption, 1.8V operat

30、ion, faster wakeup time40 MHz CPU clock, 10K RAM; 48K Flash50m indoor; 125m outdoor ranges29University of Electronic Science and Technology of ChinaWireless Sensor NetworksSunSPOT PlatformMicroprocessor: 32 bit ARM920T core180 MHz clock512 kB of Flash for program memory4 MB of Flash for dataUSB Conn

31、ectionRadio: Chipcons CC2420 (IEEE 802.15.4)250 kbit/s3.7V rechargeable 720 mAh lithium-ion batterySoftware: Squawk VMFully capable J2ME CLDC 1.1 Java VM with OS functionalityVM executes directly out of flash memoryDevice drivers in JavaAutomatic battery management30University of Electronic Science

32、and Technology of ChinaWireless Sensor Networks实验平台31University of Electronic Science and Technology of ChinaWireless Sensor Networks无线传感器网络的通信标准传感器网络中的应用一般不需要很高的信道带宽，却要求具有较低的传输延时和极低的功率消耗，使用户能在有限的电池寿命内完成任务IEEE 802.15.4标准把低功耗、低成本作为主要目标，为传感器网络提供了一种互连互通的平台，各大射频芯片厂商也陆续推出支持该标准的无线收发芯片ZigBee、无线HART和6LoWPAN

33、等无线传感器网络标准或规范均是基于IEEE 802.15.4-2006低速率无线个域网标准。 32University of Electronic Science and Technology of ChinaWireless Sensor Networks无线网络标准33University of Electronic Science and Technology of ChinaWireless Sensor NetworksThe 802.15.4 / Zigbee sandboxRangePeak Data RateCloserFartherSlowerFasterUWBHomeRFW

34、ireless Data ApplicationsWireless Video ApplicationsIrDA802.11g802.11b802.11a2.5G/3GZigBee802.15.4BluetoothISM LinkWiFi34University of Electronic Science and Technology of ChinaWireless Sensor NetworksWireless Technologies ComparedCommon NameZigbeeBluetoothWiFiUWBIEEE standard802.15.4802.15.1802.118

35、02.15.3Max Data Rate250Kbps750Kbps54Mbps1000+ MbpsTX power30+ mA40+ mA400+ MaStandby ldd3ua200ua20maStack Size8-60KB100+ KB100+ KBNetwork TypeStar, Cluster, MeshStar(8 nodes max)StarNetwork Join/FormationmssecondssecondsMax Packet Size(bytes)1323594095RangeOver 1200 meters100 meters100 meters 10 met

36、ersDevices216835University of Electronic Science and Technology of ChinaWireless Sensor NetworksZigBee联盟简介ZigBee联盟组成成立于2001年9月成员为半导体厂商、无线IP供应商、OEM厂商及终端用户拥有150个成员，包括飞思卡尔、菲利普、三菱、三星、IBM及华为等ZigBee联盟的宗旨在一个开放式全球标准的基础上使稳定的、低成本的、低功耗的、无线联网的监控和控制产品成为可能36University of Electronic Science and Technology of China

37、Wireless Sensor NetworksZigBee标准ZigBee来源于蜜蜂群使用的赖以生存和发展的通信方式。蜜蜂通过跳ZigZig形状的舞蹈传递新发现的食物源的位置、距离与方向等信息ZigBee是一种近距离、低复杂度、低功耗、低数据速率、低成本的双向无线通信技术。ZigBee联盟在制定ZigBee标准时，采用了IEEE802.15.4作为其物理层和媒体接入层规范。在其基础之上，ZigBee联盟制定了数据链路层（DLL)网络层（NWK）和应用编程接口API规范，并负责高层应用、测试和市场推广等方面的工作ZigBee技术将主要嵌人在消费性电子设备、家庭和建筑物自动化设备、工业控制装置、

38、电脑外设、医用传感器、玩具和游戏机等设备，支持小范围的基于无线通信的控制和自动化等领域中的应用，同时还支持地理定位功能37University of Electronic Science and Technology of ChinaWireless Sensor NetworksZigBee & 802.15.4ZigBeeIEEE 802.15.438University of Electronic Science and Technology of ChinaWireless Sensor NetworksZigBee Stack Architecture39University

39、 of Electronic Science and Technology of ChinaWireless Sensor NetworksIEEE 802.15.4为满足低功耗、低成本的无线网络要求，城服标准委员会在2000年12月正式批准并成立802.15.4工作组，工作组的任务是开发一个低速率数据传输的WPN(LR-WPAN)标准IEEE 802.15.4标准就是802.15.4工作小组开发出的标准，它具有复杂度低，成本极少，功耗很小的特点，能在低成本设备之间低速率传输数据标准满足国际标准组织开放系统互联（OSI）参考模式,包括物理层、介质访问802.15.4标准定义了无线个域网中的设备

40、互联进行无线通信的协议，它采用了CSMA/CA介质访问机制，支持星型和对等（点到点）拓扑结构网络40University of Electronic Science and Technology of ChinaWireless Sensor NetworksIEEE 802.15.4标准的主要特征l四种传输速率：20kbps、40kbps、100kbps、250kbpsl在网络中采取两种地址方式：16位地址和64位地址l采用可选的时槽保障(Guaranteed Time Slots,GTS)机制l采用CSMA/CA信道访问机制l支持ACK机制以保证可靠传输；l低功耗机制；l信道能量检测（En

41、ergy Detection，ED）；l链路质量指示（Link quality indication，LQI）；l工作在ISM频段上，其中在2450MHz波段上有16个信道,在915MHz波段上有10个信道，在868MHz上有1个信道l数据安全策略41University of Electronic Science and Technology of ChinaWireless Sensor Networks802.15.4 has 16 channels 2.4GHz band42University of Electronic Science and Technology of China

42、Wireless Sensor NetworksIEEE 802.15.4标准网络组成及拓扑结构 物理层信道分配及调制方式 物理层帧格式 MAC子层的帧格式 43University of Electronic Science and Technology of ChinaWireless Sensor NetworksReduced Function Device (RFD)Limited to being leaf devicesCannot become a network coordinatorTalks only to a network coordinatorVery simple

43、 implementationsimple devices; e.g. Light switch, infrared sensor38 primitivesFull Function Device (FFD)Any topologyNetwork coordinator capableTalks to any other device3 modes: PAN Coordinator, Coordinator, Device49 primitives (14 PHY+ 35 MAC) (1/3 of Bluetooth)IEEE 802.15.4 TopologiesCluster TreeMe

44、shStarPAN Coordinator44University of Electronic Science and Technology of ChinaWireless Sensor Networks802.15.4 Topology：Peer-Peer Topology Combined TopologyFull function deviceReduced function deviceClustered stars - for example,cluster nodes exist between roomsof a hotel and each room has a star n

45、etwork for control.Point to point45University of Electronic Science and Technology of ChinaWireless Sensor NetworksNetwork Pieces PAN CoordinatorPAN Coordinator“owns” the networkStarts itAllows other devices to join itProvides binding and address-table servicesSaves messages until they can be delive

46、redAnd more could also have i/o capabilityA “full-function device” FFDMains powered46University of Electronic Science and Technology of ChinaWireless Sensor NetworksNetwork Pieces - RouterRoutersRoutes messagesDoes not own or start networkScans to find a network to joinGiven a block of addresses to

47、assignA “full-function device” FFDMains powered depending on topologyCould also have i/o capability47University of Electronic Science and Technology of ChinaWireless Sensor NetworksNetwork Pieces End DeviceEnd DeviceCommunicates with a single deviceDoes not own or start networkScans to find a networ

48、k to joinCan be an FFD or RFD (reduced function device)Usually battery powered48University of Electronic Science and Technology of ChinaWireless Sensor Networks物理层信道分配和调制方式频段频段 (MHz)扩频参数扩频参数数据参数数据参数片速率片速率 (kchip/s)调制方式调制方式比特速率比特速率 (kb/s)符号速率符号速率 (ksymbol/s)符号符号868868.6300BPSK2020二进制902928600BPSK4040

49、二进制868868.6*400ASK25012.520-bitSPSS902928*1600ASK250505-bitSPSS868868.6*400O-QPSK1002516-ary正交902928*1000O-QPSK25062.516-ary正交24002483.52000O-QPSK25062.516-ary正交注：* 项为可选项目，系802.15.4-2006新增内容49University of Electronic Science and Technology of ChinaWireless Sensor NetworksIEEE 802.15.4 PHY - Operatin

50、g Frequency Bands868MHz / 915MHz PHY868.3 MHzChannel 0Channels 1-10928 MHz902 MHz2 MHz2.4 GHzChannels 11-262.4835 GHz5 MHz2.4 GHz PHY50University of Electronic Science and Technology of ChinaWireless Sensor NetworksThe 2.4GHz ISM band802.11 DSSS2.4122.402.412.482.472.462.452.442.432.422.4622.4372.48

51、35(end of ISM Band)Possible 802.11 Channel(North America)802.11 Spectrum Occupancy (Typical)51University of Electronic Science and Technology of ChinaWireless Sensor NetworksIEEE 802.15.4 PHY帧格式PHY 负载物理帧头(PHR)同步头(SHR)PSDUReserved(1 比特)Frame length(7 比特)SFD前导码（preamble）可变1 字节1 字节Ocets:4 字节SFD，Start-o

52、f-Frame DelimiterPSDU，PHY Service Data Unit52University of Electronic Science and Technology of ChinaWireless Sensor NetworksIEEE 802.15.4 MAC帧格式l帧头帧头MHR，MAC Header：包括帧控制域，帧序列号，地址和用于加解密的附加安全头部l帧尾帧尾MFR，MAC Footer：16位CRC校验码53University of Electronic Science and Technology of ChinaWireless Sensor Netwo

53、rks802.15.4：General Frame Structure4 Types of MAC Frames:lBeacon FramelData FramelAcknowledgment FramelMAC Command Frame54University of Electronic Science and Technology of ChinaWireless Sensor Networks无线 HART无线HART（WirelessHART）标准是HART通讯协议的扩展，专为如过程监视和控制等工业环境应用所设计。IEC 6259（Ed. 1.0）是国际电工委员会于2010年4月批准

54、发布的完全国际化的无线HART标准，是过程自动化领域的第一个无线传感器网络国际标准。图示网络有5种组件55University of Electronic Science and Technology of ChinaWireless Sensor Networks6LoWPANIEEE于2004年11月成立了一个6Lowpan（IPv6 over IEEE 802154或IPv6 over LR PAN）工作组，专门致力于如何实现IPv6数据包在IEEE 802.15.4上的传输，研究基于1Pv6 over IEEE与无线传感器网络协议相关的通信标准6LoWPAN是“IPv6 over Lo

55、w power Wireless Personal Area Networks”（低功率无线个域网上的IPv6）缩写属IETF（因特网工程任务组）中的一个工作组，负责制订基于IEEE802.15.4标准个域网上IPv6传输的通讯技术标准。现已发布了RFC4944基础性的技术规范。56University of Electronic Science and Technology of ChinaWireless Sensor Networks6LowPan草案6Lowpan是IPv6 over Low Power wireless Personal Area Network的缩写，该草案的目标是

56、制订如何在Lowpan上传输IPv6报文。当前Lowpan采用的开放协议主要指IEEE 802. 15.4 MAC 层标准,在上层并没有一个真正开放的标准支持路由等功能。由于IPv6是下一代互联网标准，在技术上均趋于成熟，并且在Lowpan上采用IPv6协议可以与现有网络实现无缝连接，因此IETF成立了专门的工作组制定如何在802.15.4协议上发送和接收IPv6报文等相关技术标准57University of Electronic Science and Technology of ChinaWireless Sensor NetworksOverview6LoWPAN is an acro

57、nym of IPv6 over Low power Wireless Personal Area Networks. A simple low throughput wireless network comprising typically low cost and low power devices.Common topologies include star, mesh, and combinations of star and mesh.The Phy and MAC layers conform to IEEE 802.15.4-2003 standard58University o

58、f Electronic Science and Technology of ChinaWireless Sensor Networks6LoWPAN CharacteristicsSmall packet size (127Byte)16-bit short or IEEE 64-bit extended media access control addressesLow bandwidth. (250kbps)Low power, typically battery operated Relatively low cost59University of Electronic Science

59、 and Technology of ChinaWireless Sensor Networks6LoWPANThe Working Group will generate the necessary documents to ensure interoperable implementations of 6LoWPAN networks and will define the necessary security and management protocols and constructs for building 6LoWPAN networks.6lowpan will work cl

60、osely with the Routing Over Low power and Lossy networks (roll) working group which is developing IPv6 routing solutions for low power and lossy networks (LLNs).60University of Electronic Science and Technology of ChinaWireless Sensor NetworksROLLROLL: defining the routing solution within the LLN (Low power and Lossy Netwo