kris pister eecs ucb

Prof. K.S.J. PisterUC Berkeley, March 2005

Wireless Sensor Networks“Real and Imagined”

Kris PisterEECSUCB


Decision Systems

Analog Sensorsand Actuators

Digital Sensors and Actuators

Serial Devices

MonitoringSystems

ControlSystems

EnterpriseApplications

Physical World

• Significant reduction in the cost of installing sensor networks

• Enables new class of services

• Increases sensor deployment

Wireless Sensor NetworkingJW9

Prof. K.S.J. PisterUC Berkeley, March 2005 Outline

• History in BSAC• Technology• Markets & Standards• Future


Autonomous Microsensor Networks with Optical Communication Links

• PI: Kris Pister• Source: Hughes (MICRO)• Funding: $25k, $10k matching, 0% ovhd, • Duration: 1 year• Comments: Collaboration w/ Prof. Joe

Kahn under separate MICRO

IAB 1997


Smart Dust

Kris PisterDARPA

$2.4M/ 3 years, under review

IAB Spring 1998


COTS DustGOAL:• Get our feet wetRESULT:• Cheap, easy, off-the-shelf RF systems• Fantastic interest in cheap, easy, RF:

– Industry– Berkeley Wireless Research Center– Center for the Built Environment (IUCRC)– PC Enabled Toys (Intel)

• Fantastic RF problems• Optical proof of concept

IAB Spring 2000


Low Power Radio Projects• LWIM (Bill Kaiser, UCLA)

– 902-928MHz, 1mW goal• 1-1-1 SHARC (Tom Lee, Stanford)

– 1 GHz, 1mW, 1mm2 goal• picoRadio (Rabaey/ Brodersen, BWRC, UCB)

– 100uW, 0.1nJ/bit goal• …

IAB Spring 2000


RF Sensor Future• RF tags + Sensors• Ultra Wide Band

– 10ps? digital pulse trains– LLNL

• 60 GHz– Major path loss problems– But oh, the bandwidth!

• MEMS RF components– Mechanical filters already dominate RF– Never ever bet against Al and Roger

IAB Spring 2000


Project:Low-energy circuits for cubic millimeter sensor nodes

Results:63mm3 autonomous communication mote system functionalDAC taped outCMOS micromachining process begun

Future Work: (March 20)1pJ/instruction laser reprogrammable μcontroller1nJ/sample ADC50pJ/bit optical receiver

Ultra-Low Power Circuits for Distributed Sensor Networks (Smart Dust)

K.S.J. PisterKSJP10

Brett WarnekeBrian Leibowitz

Mike ScottRichard Lu

Mn-Ti-Li 1.5V Cell

Corner Cube Reflector

ASIC

63mm3 mote

May 2001 Demonstration System

Optical InµController

SRAMCapacitive

XL(J. Perng)

ADC

Receiver CCR(L. Zhou)

Real-TimeClock

Solar Cells(C. Bellew)

IAB Spring 2001


Summary:Use COTS to develop and deploy sensor networksResearch applications, security, and management of networks

Recent results:TinyOS released (30+ students at first short course)Motes available from Crossbow (~$150)

Future work:Air-drop deployment of sensor networkLarge-scale networks on campus

Lance Doherty, Jason Hill, Michael Scott, Robert Szewczyk,

Alec Woo Off-the-shelf Macromote for Smart Dust and TinyOS

Prof. PisterKSJP12

Needle piercing pig skin

IAB Spring 2001


COTS-Dust, Tiny OS,& SensorwebsHardware, Software, and AlgorithmsJames McLurkin, Seth Hollar, Mike ScottJason Hill, Robert Szewczyk, Alec WooJulius Kusuma, Lance Doherty(Culler, Pister, Ramchandran, Sastry)

bAx

tttt

tv

pppp

=⎯→⎯

⎥⎥⎥⎥

⎦

⎤

⎢⎢⎢⎢

⎣

⎡

=⎥⎦

⎤⎢⎣

⎡

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⎦

⎤

⎢⎢⎢⎢

⎣

⎡

4

3

2

1

4

3

2

1

/1

1111

δ

IAB Fall 2001


Magnetometer data

Raw signal (green)

Bandpass filtered signal Threshold

Event detection

IAB Fall 2001


• 8 packaged motes loaded on plane

Last 2 of six being dropped

IAB Fall 2001


Synergy of DARPA Programs

Smart Dust (MTO)COTS-DustAutonomous UAV

Endeavour (ITO)TinyOS

Sensorwebs (ITO)Sensor network algorithms

Fun in the desert

IAB Fall 2001

Prof. K.S.J. PisterUC Berkeley, March 2005 IAB Spring 2003

875μ

m

650μm Oscillator

Divider

Transmitter

Receiver (in fab)

Inductor Chip


UCB Smart Dust - Integration

Solar Cell Array CCR

XLCMOS

IC

16 mm3 total circumscribed volume~4.8 mm3 total displaced volume

SENSORS ADC FSMRECEIVER

TRANSMITTER

SOLAR POWER1V 1V 1V 2V3-8V

PHOTO 8-bits

375 kbps

175 bps

1-2V

OPTICAL IN

OPTICAL OUT


~4 mm^2 ASIC

UCB RF Mote on a Chip

• CMOS ASIC– 8 bit microcontroller– Custom interface circuits

• 4 External components

uP SRAM

RadioADC

Temp

Amp inductor

crystal

battery

antenna

~$1

Prof. K.S.J. PisterUC Berkeley, March 2005 Final UCB Hardware Results

• 2 chips fabbed in 0.25um CMOS– “Mote on a chip” worked, missing

radio RX (Jason Hill)– 900 MHz transceiver worked

• Records set for low power CMOS– ADC (Mike Scott)

• 8 bits, 100kS/s• 2uA@1V

– Microprocessor (Brett Warneke)• 8 bits, 1MIP• 10uA@1V

– 900 MHz radio (Al Molnar)• 20kbps, “bits in, bits out”• 0.4mA @ 3V

Prof. K.S.J. PisterUC Berkeley, March 2005 Power Consumption

• Sensing– Sensor Excitation– Sensor Interface

• Amplifiers, filters, ADC– Data processing

• Communication– PHY/MAC/NET Algorithms/computation– Encryption/security– Radio TX– Radio RX

• Distributed Signal Processing• Time keeping• Leakage

Prof. K.S.J. PisterUC Berkeley, March 2005 Example Dust Networks Results

• Mighty9 motes– TI MSP430f149– Chipcon cc1000– ITX = 25mA– IRX = 17mA

• 50 motes, two dimensional deployment, 5 hops deep– Monitoring: all motes report 6 readings

every 60 seconds• Measured current min/mean/max:

40/80/180 uA– Event reporting: < 0.1 event/mote/minute

• Average expected current: 60uA

• End-to-End Reliability– Spec.: 99.9%– Measured: routinely 4+ 9s in noisy

environments

Prof. K.S.J. PisterUC Berkeley, March 2005 Radio Performance

200k Bit rate (bps)100k 300k

I RX

(mA

)

5

10

20

15

25

Xcc1000

Xcc1000

Molnar (0.4mA)X

Xcc2400

Xcc2420

XXemicscc1000

X

XOtis (0.2mA)


2 weeksAA

Power consumption versus data rateA

pplic

atio

n D

ata

Rat

e (b

ps)

Average Power consumption (W)

802.15.4

100M

1 M

10k

100

1

1010m 100m 11m10μ 100μ

Cordlessphones

802.11a,b,g

Software

/algo

rithms

Impro

ved H

ardware

1yrAA

1yrcr2032

Prof. K.S.J. PisterUC Berkeley, March 2005 Dust Networks

• Incorporated July 2002• Pister on leave Jan 2003 Dec 2004• Series A Feb 2004• Series B Jan 2005• SmartMesh shipped Aug 2004


Configure, don’t compile

SmartMesh Manager

Mote

IP NetworkXML

SmartMeshTM

Console

~100 ft

Reliability: 99.9%+Power consumption: < 100uA average


Energy Monitoring Pilot

• SmartMeshTM Solution:– Energy is the #1 cost of

supermarkets after shelf stock

– Service: monitor, analyze and reduce power consumption

– Entire SmartMeshTM

network installed in 3 hours (vs. 3-4 days)

Prof. K.S.J. PisterUC Berkeley, March 2005 Micro Network Interface Card

μNIC• No network software

development• Variety of configurable data

processing modules• Integrators develop applications,

not mesh networking protocols• For compute-intensive

applications, use an external processor/OS of your choice.

AnalogI/O

DigitalI/O

SerialPort

NetworkServices

ConfigurableData processing

Prof. K.S.J. PisterUC Berkeley, March 2005 SAIC & Dust Networks

Passive IR and Camera

Passive IR

MEMS and GPS

2.5 in

1.5 in

2.5 in

Prof. K.S.J. PisterUC Berkeley, March 2005 Sensor Nodes

Mighty Mote Sensor Node PackagingMicroprocessorAntenna Interface

Radio

Sensor and Power Interface

Single Main PCB includes the sensor board with its own CPU and memory

(Now called Mighty Mote)

Lithium Battery

Antenna Option

Passive IRGeophone

Camera

MEMS Microphone, Accelerometer, Magnetometer

GPS

Prof. K.S.J. PisterUC Berkeley, March 2005 Agilent ADMC 2650 Camera

• Grayscale difference images can be reduced to a few hundred bytes and offer potential as a detector

Base Image New Image Difference images at variable quality

Prof. K.S.J. PisterUC Berkeley, March 2005 Markets & Standards

Prof. K.S.J. PisterUC Berkeley, March 2005 The Wireless World

Size of market

YearsHours Days

Mb/s(Video)

Kb/s(Voice)

b/s(Sensor

& Control Data)

Increasing Battery Life

Dec

reas

ing

Ban

dwid

th

Wi-Fi

Cellphones

Sensors


Source: InStat/MDR 11/2003 (Wireless); Wireless Data Research Group 2003; InStat/MDR 7/2004 (Handsets)

0

100

200

300

400

500

600

700

800

2003 2004 2005 2006 2007

Uni

ts (M

illio

ns)

Wi-Fi nodesHandsetsWireless Sensor Nodes

Sensor Networks Take Off!

$8.1B market for Wireless Sensor

Networks in 2007


WDRG, 2003

Prof. K.S.J. PisterUC Berkeley, March 2005 Sensor Networking Evolution

Point-to-Point Wireless

• Low reliability

• $$ Installation

• Flexible Network

• Limited Reach

Wired Networks

• Very high reliability

• $$$$ Installation

• Inflexible Network

• Very high reliability

• $ Installation

• Very Flexible Network

• Long Reach

Wireless Mesh

Prof. K.S.J. PisterUC Berkeley, March 2005Low Data Rate WPAN Applications (Zigbee)

RESIDENTIAL/LIGHT

COMMERCIAL CONTROL

CONSUMER ELECTRONICS

TVVCRDVD/CDremote

securityHVAClighting controlaccess controllawn & garden irrigation

PC & PERIPHERALS

BUILDING AUTOMATION

securityHVACAMR

lighting controlaccess control

mousekeyboardjoystick

PERSONAL HEALTH CARE

patient monitoring

fitness monitoring

INDUSTRIALCONTROL

asset mgtprocess control

environmentalenergy mgt

Prof. K.S.J. PisterUC Berkeley, March 2005 Consumer vs Enterprise Class

RESIDENTIAL/LIGHT

COMMERCIAL CONTROL

CONSUMER ELECTRONICS

PC & PERIPHERALS

BUILDING AUTOMATION

PERSONAL HEALTH CARE

INDUSTRIALCONTROL

Consumer Class- Cost more

important than reliability

- Convenience driven- Deployed in small

area - ‘Device’ driven

Enterprise Class- Reliability more

important than cost- Installation & mtce

cost driven- Deployed in larger

area- ‘System’ driven DEFENSE

DUST NETWORKS

Prof. K.S.J. PisterUC Berkeley, March 2005 802.15.4, Zigbee

• Zigbee is an industry consortium created to apply 802.15.4 to commercial applications

• “Toolkit” functionality of PHY and low-level MAC in 15.4

• Device/application profiles defined in Zigbee

Prof. K.S.J. PisterUC Berkeley, March 2005 Network Types

Powered mesh infrastructure

Star-Mesh Full Mesh

Star-connected sensors

No infrastructure

Mesh-connected sensors

Star


Full function device

Reduced function device

Communications flow

Clustered stars - for example,cluster nodes exist between roomsof a hotel and each room has a star network for control.

Cluster-tree Topology

Prof. K.S.J. PisterUC Berkeley, March 2005 Techno-Rant

• Reduced function devices are a non-starter for most applications

• Tree-based routing is fatal• Cluster-tree combines both• Mesh != multi-hop• Mesh = path diversity• Wireless means no wires

Prof. K.S.J. PisterUC Berkeley, March 2005 IEEE 802.15.4 PHY Overview

Operating Frequency Bands

868MHz / 915MHz PHY

2.4 GHz

868.3 MHz

Channel 0 Channels 1-10

Channels 11-26

2.4835 GHz

928 MHz902 MHz

5 MHz

2 MHz

2.4 GHz PHY

Gutierrez

Prof. K.S.J. PisterUC Berkeley, March 2005 IEEE 802.15.4 PHY Overview

Packet Structure

PreambleStart ofPacket

Delimiter

PHYHeader

PHY ServiceData Unit (PSDU)

PHY Packet Fields• Preamble (32 bits) – synchronization • Start of Packet Delimiter (8 bits)• PHY Header (8 bits) – PSDU length• PSDU (0 to 1016 bits) – Data field

6 Octets 0-127 Octets

Gutierrez


15ms * 2n

where 0 ≥ n ≥ 14

Network beacon

Contention period

Beacon extensionperiod

Transmitted by network coordinator. Contains network information,frame structure and notification of pending node messages.

Space reserved for beacon growth due to pending node messages

Access by any node using CSMA-CA

GTS 2 GTS 1

GuaranteedTime Slot Reserved for nodes requiring guaranteed bandwidth [n = 0].

IEEE 802.15.4 MAC OverviewOptional Superframe Structure

Contention Access Period

Contention Free Period

Gutierrez

Prof. K.S.J. PisterUC Berkeley, March 2005 Interoperability

• Consumer• Enterprise/OEM

– Value of standards: • Speed adoption• Low cost components

– Vendor to vendor interoperability?– System to system interoperability?

Prof. K.S.J. PisterUC Berkeley, March 2005 So what should I use?

• Networking Research– Crossbow and/or Moteiv + TinyOS

• New Networking product– Buy chips and stacks, write software– 802.15.4– Zigbee?

• Home automation– Chipcon/Figure 8– “Ember University”?

• Application– Buy a network, develop a product– Dust Networks, Millennial Net


Future: Filters and Timebase will be Mechanical!

Prof. K.S.J. PisterUC Berkeley, March 2005 High-Performance Resonator Designs:

the Radial Bulk Annular Resonator

Substrate

ri rog

Sense Electrode

Drive Electrode RBAR

Bircumshaw, Pisano UC Berkeley 2003

Theory:g=30nmri,ro = 197, 200umω=1GHzReq = 50Ω


Mechanically Coupled Differential Checkerboard Filter

Input ports

Output ports

Input ports

Output ports

173.3 173.4 173.5 173.6 173.7 173.8Frequency (MHz)

-55

-59

-63

-67

-71

Tran

smis

sion

(dB)

173.3 173.4 173.5 173.6 173.7 173.8Frequency (MHz)

-55

-59

-63

-67

-71

Tran

smis

sion

(dB)

173.3 173.4 173.5 173.6 173.7 173.8Frequency (MHz)

-55

-59

-63

-67

-71

Tran

smis

sion

(dB)

f0= 173 MHzBW = 110 kHzRipple < 2dBRejection = 12dBAIR Operation

Footprint: 140 x 140 um

Sunil Bhave UC Berkeley 2004

Prof. K.S.J. PisterUC Berkeley, March 2005Electrostatic actuation with solid dielectric

Howe, Bhave UC Berkeley 2004/2005

Prof. K.S.J. PisterUC Berkeley, March 2005 Integration

• System in Package (SIP)• Post-CMOS MEMS

Prof. K.S.J. PisterUC Berkeley, March 2005 Integrated Poly-SiGe MEMS/CMOS

Resonator next to Amplifier• conventional layout

Resonator Stacked on Amplifiersmaller area → lower costreduced interconnect parasitics → improved performance

Andrea E. Franke, et al, IEEE/ASME JMEMS, 12, 160-171 (2003).

Source: R. Howe

Prof. K.S.J. PisterUC Berkeley, March 2005 Nano Dust?

• Nanotube sensors• Nanotube computation• Nanotube hydrogen storage• Nanomechanical filters for low-power RF

Prof. K.S.J. PisterUC Berkeley, March 2005 Conclusion

• Sensor networks are everywhere today• Installation is dominated by wiring costs• Wireless sensor networks are now

– Reliable– Easy to integrate & install– Low cost

• Projected to be a multi-billion $ industry• MEMS (&Nano?) will reduce cost and

improve capabilities moving forward


Important Players

• Universities– TinyOS (UC Berkeley, UCLA, UW, Vanderbilt, …)

• Startup Companies– Crossbow– Dust Networks– Ember– Figure 8– Millennial Net

• Major Corporate Research Groups– Intel– Microsoft– IT: Agilent, Cisco, HP, IBM, FranceTelecom, Nortel– Automation: GE, Honeywell, Johnson Controls,

Siemens• Zigbee Alliance

kris pister eecs ucb

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