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Our Crossbow SensorEquipment and Zigbee

Presentation by Philip Kuryloskiand Sameer Pai

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Presentation Outline

l Zigbee Overviewl Overview of Zigbee and its usesl Zigbee Protocol Stack

l 802.15.4 (Zigbee) Physical Layerl 802.15.4 (Zigbee) Medium Access Control Layerl Zigbee Network Layerl Zigbee Application Layer

l Overview of TinyOS

l Overview of Crossbow Equipmentl Demol Some Possible Projects

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What is Zigbee?

l Alliance of over 100 active membercompanies involved in development ofwireless specification for sensors & control

equipmentl IEEE 802.15.4 State-of-the-art PHY and

MAC layer Standard

l Zigbee Protocol stack finalized in Decemberof 2004

l Low data rate, low power, low cost solution

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Uses for Zigbee

ZigBeeLOW DATA-RATE

RADIO DEVICES

HOME

AUTOMATION

CONSUMER

ELECTRONICS

TVVCRDVD/CDremote

securityHVAClightingclosures

PC &

PERIPHERALS

TOYS &

GAMES

consolesportables

educational

PERSONAL

HEALTH CARE

INDUSTRIAL &

COMMERCIAL

monitorssensors

automationcontrol

mousekeyboardjoystick

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ZigbeeProtocol Stackl 802.15.4 PHY and MAC

based on the proposal sentby Zigbee Alliance to IEEE802.15 task group 4

l Small Protocol Stack

l Estimated to be !the sizeof 802.11 stack (< 32k)

l Simple and cost effective

l Only two states active(transmitting, receiving) or

sleepingl Low power cycle (~0.1%)

allows batteries to last foryears

PHY LAYER

MAC LAYER

NETWORK/SECURTIY

LAYERS

APPLICATION FRAMEWORK

APPLICATION/PROFILES

IEEE

ZigBee

Alliance

Platform

Application

ZigBee Platform Stack

Silicon

ZigBee or

OEM

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Data Rate and Range

~50m range (5-500m depending on environment)

l Data Rates of 250kbps when operating at 2.4 GHz,40 kbps when operating at 915 MHz, and 20kbps

when operating at 868 MHz

l Range ~50m range (5-500m depending on

environment)

SHORT

LONG

LOW < ACTUAL THROUGHPUT > HIGH

TEXT INTERNET/AUDIO COMPRESSED

VIDEO

MULTI-CHANNEL

DIGITAL VIDEO

Bluetooth1

Bluetooth 2

ZigBee

802.11b

802.11a/HL2 & 802.11g

802.15.3/WIMEDIA

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802.15.4 Physical Layer Specsl Operates in World ISM Bands

l North America, Australia, etc. 915 MHz or 2.4GHz bands

l Europe: 868 MHz or 2.4 GHz bands

l Our MicaZs operate in 2.4 GHz frequency bandl Multiple channels available, some overlapping with

802.11 channels

l 802.11 channel access considered as noise for our

MicaZs

l Uses DSSS

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802.15.4 MAC Layer Specs

l CSMA-CA (like 802.11) channel access scheme

l Unlike 802.11 no RTS/CTS mechanism (due to relatively low data rate collisionsare much less likely)

l Different Modes of Operation Depending on Nature of Trafficl Periodic Transmissions

l Beacon Model Intermittent Transmissions

l Disconnection Mode, node not attached to network when it doesn't need to communicate(energy savings!)

l Low Latency Transmissionsl Guaranteed Time Slot (GTS), allows for device to get an assigned time slot in super

frame (a TDMA scheme)

l

16 bit short addressing scheme or 64bit long addressing schemel Four MAC frame types:

l Beacon Frame

l Data Framel ACK Frame

l MAC Command Frame

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Beacon Mode and Non-BeaconModel 802.15.4 MAC using Slotted

CSMA-CA (with beacons) andGuaranteed Time Slots

l Timing diagrams for informationexchange at MAC layer usingslotted CSMA-CA and unslottedCSMA-CA

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Network Nodes

l Two different types of nodes available (reduces cost

for large networks)

l Full Function Device (FFD) Capable of functioning in any

topology, capable of acting as a coordinator, capable oftalking to any other device in network

l Reduced Function Device (RFD) Capable of

communicating in a star topology and only to a FFD,

cannot be a coordinator

l Significant cost reduction for RFDs due to fewerrequirements for hardware

l MICAz motes are all FFDs

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Network Layer Responsibilities

l Starting a network able to establish a new networkl Joining and Leaving Network nodes are able to

become members of the network as well as quit beingmembers

l Configuration Ability of the node to configure itsstack to operate in accordance with the network typel Addressing The ability of a ZigBee coordinator to

assign addresses to devices joining the networkl Synchronization ability of a node to synchronize

with another node by listening for beacons or pollingfor data

l Security ability to ensure end-to-end integrity offrames

l Routing nodes can properly route frames to their

destination

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Network Layer and NetworkTopologiesl Self-Configuring (Network creation, Route

Discovery, Data Forwarding) and Self-HealingNetwork (Data routed around broken routes)

l The network layer uses a form of Ad hoc On-

demand Distance Vector routing (AODV)l Uses Motorolas clustering tree algorithm

l Clusters added, Networks can be combined or split

PAN coordinatorFull Function DeviceReduced Function Device

Star

Mesh

Cluster Tree

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Application Support LayerResponsibilities

l Zigbee Device Object (ZDO) maintains whatthe device is capable of doing and makesbinding requests based on these capabilities

l Discovery Ability to determine which otherdevices are operating in the operating spaceof this device

l Binding Ability to match two or moredevices together based on their services andtheir needs and allow them to communicate

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MicaZ,TinyOS, and Zigbee

l Our MicaZ motes do use the 802.15.4standard defined in 2003

l Our MicaZ motes do not use the network and

application layers defined by the ZigbeeAlliances network and application layersl Zigbee upper layers had not been finalized in time

for Crossbow

l Our MicaZ motes are using TinyOS 1.1.7 andCrossbows mesh networking stack

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Crossbow Network &Application Layers

l Network Layer:

l Any Network Layer/

Routing Algorithm canbe implemented in

TinyOS

l Many available already

l Application Layer:

open-source TinyOS

supportedl Applications can be

developed for use with

TinyOS

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More 802.15.4 Specs

l MicaZ Power Consumptionl 30 #W during sleep

l 33 mW while active

l MicaZ Lifetime

l ~ 1 year (Zigbee specifies upto 2 years)

l MicaZ Rangel 75 100 m (outdoors)

l 20 30 m (indoors)

l Indoor range tested in

Rhodes Hall

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Equipment

l 8 MICAz processor/radio boards (TinyOS & Surgesoftware preloaded)

l 18 MICAz (no software loaded)

l 4 light/temp/acoustic/seismic/magnetometer sensorboards

l 21 light/temp/acoustic boards

l A data acq. Board with temp/humidity sensor

l 1 ethernet gateway/programming boardl 1 serial gateway/programming board

l 5 Stargate Boards & Daughter Cards

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MICAz MOTE

l IEEE 802.15.4

l 250 kbps radio

l 128KB program flash memory

l 512KB measurement log memory (xbowestimates > 100000 samples)

l 10 bit Analog to Digital Converter

l Red, Green, & Yellow LEDs

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Stargate Gateway

l 400MHz RISC Processor

l 64MB RAM, 32MB flash

l Embedded Linux (10MB on flash)

l AC powered, optional battery

l Can be connected to MICAz

l Ethernet, USB, RS-232, PCMCIA, Compact

Flash

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TinyOS

l Open Source Operating System designed forMOTEs

l Programs written in an extension of C called

nesCl TinyOS is event driven

l nesC - wire together componentsthat handle

events/fire commandsthrough interfacesto buildan application (highly modular)

l Preinstalled (8 motes) Surge ad-hoc multi-hop (Destination-Sequenced Distance Vector

routing) software (xbow) written in nesC

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Software -> MOTES

l RS-232 serial connection gateway &programming/flashing board

l Ethernet gateway & programming/flashingboard

l Wireless mote programming via delugeTinyOS software

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Simulation Tools

l TOSSIM - TinyOS

simulatorl simulates application

code more so than a

network simulation like

ns2, Opnet

l TinyViz - graphical interface for TOSSIMl can be extended

with plug-ins

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Other Projects using TinyOS:FireBug

l GPS & thermal sensors on mote for monitoringforest fires

l motes route using mh6protocol used in surge

demo programl DSDV (Destination Sequence Distance Vector) table

based routing

l Separate data & route packets

l route packets used for calculating link efficiencyl motes forward data only to parent node with highest

link efficiency

l MySQL & PHP Web-based monitoring program24

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Robomote

l Custom mobile mote

l Atmel processor similar to

MICAz.

l TinyOS softwarel Bacterium inspired

movement -> biased random walk

l biased random walk towards light source

l 20-30 min. running timel actuation (motors) highest drain @ .72 W

l simultaneous RX/TX @ .588 W25

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Sensor Scope

l Testbed deployed at theEPFL campus

l 20 mica2 and micadot

motesl Reports sensor data in

real time on the

internet, also allowssending of commandsto motes with passwordauthentication.

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MANTIS

l MANTIS operating system running on Mica2 & MicaZmotes

l Multi-threaded OS in place of TinyOS with more C-like

APIl Projects dealing with security,

sensor user interfaces, time

synchronization, routing protocols,

low power operationl Used to teach a WSN class which

implemented above topics as well as

a flash file system. 27

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Open Questions

l What happens to temporal accuracy if wesense and store before broadcasting?l energy savings from a sensing only state

l What battery life will we typically see, howdoes TX power affect this?l we have several transmitting powers to choose

froml How accurate are our sensors?

l various types of sensors on mote

l Complexity of code possible on a MicaZ?28

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Demonstration of Equipment

l Surge & Surge Network Viewerl xbow existing multi-hop software

l Blinkl LEDs on motes blink independently

l CntToLedsl LEDs used as 3 digit binary display

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Surge-Viewer Data

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Questions

l A survey was conducted mid-2002 on the characteristics of awireless sensor network most important to its users

l In order of importance, these characteristics are

l 1. Data Reliability

l 2. Battery Life

l 3. Cost

l 4. Transmission Range

l 5. Data Rate

l 6. Data Latencyl 7. Physical Size

l 8. Data Security

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References

l Crossbow Website, www.xbow.com

l Website of Zigbee Alliance, www.zigbee.org

l IEEE Standard for Information technology-Telecommunications and informationexchange between systems-Local and metropolitan area networks-Specificrequirements. Part 15.4: Wireless Medium Access Control (MAC) and Physical Layer(PHY) Specifications for Low-Rate Wireless Personal Area Networks (LR-WPANs),(October 2003).

l Patrick Kinney, Chair of IEEE 802.15.4 TG, ZigBee Technology: Wireless Control thatSimply Works, White Paper (October 2003)

l William C. Craig, Zigbee: Wireless Control That Simply Works, White Paper (2004)

l Bob Heile, ZigBee Alliance Chairman

l Taekyoung Kwon, IEEE 802.15.4, Presentation http://mmlab.snu.ac.kr/~tk/802_15_4.ppt#34

l Samir Goel and Tomasz Imielinski, Etiquette protocol for Ultra Low Power Operationin Sensor Networks, Presentation http://www.winlab.rutgers.edu/pub/docs/iab/2004Fall/14%20Goel.pdf

l Robomote: Enabling Mobility In Sensor Networks KARTHIK DANTU MOHAMMADRAHIMI HARDIK SHAH SANDEEP BABEL AMIT DHARIWAL and GAURAV

SUKHATME Dept of Computer Science University of Southern California

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References (cont.)

l nesC Website, nescc.sourceforge.net

l Robomote Home Page, http://www-robotics.usc.edu/~robomote/

l FireBug Home Page, http://firebug.sourceforge.net/index.php

l TinyOS Tutorial, www.tinyos.net/tinyos-1.x/doc/tutorial/lesson5.html

l Joseph Polastre, Robert Szewczyk, Cory Sharp, David Culler, The Mote Revolution:

Low Power Wireless Sensor Network Devices, Presentation http://webs.cs.berkeley.edu/papers/hotchips-2004-motes.ppt#2

l MANTIS Project Home Page, http://mantis.cs.colorado.edu/tikiwiki/

l SensorScope Home Page, http://sensorscope.epfl.ch/index.php

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