University of Virginia

Wireless Sensor Networks

August, 2006

University of Virginia

Jack Stankovic

University of Virginia

Ad Hoc Wireless Sensor Networks• Sensors

• Actuators• CPUs/Memory• Radio• Minimal capacity• 1000s

Self-organize

University of Virginia

Mica2

and Mica2Dot

• ATMega 128L 8-bit, 8MHz, 4KB EEPROM, 4KB RAM, 128KB flash• Chipcon CC100 multichannel radio (Manchester encoding, FSK).

Up to 500-1000ft.

• Reality 50-100 feet when on the ground!

University of Virginia

Sensor Board

University of Virginia

Sensor Board

University of Virginia

Exciting Potential

• The Internet Gets Physical

• “Sensing technologies will be one of the hallmarks of this century”

• 1980 => decade of microcomputers• 1990 => decade of the Internet• 2000 => decade of WSN

University of Virginia

Application Spectrum

Hazard Detection

Biological Monitoring

MedicalDomain

Smart Environment

Wearable Computing

Transportation

Earth Science & Exploration

Context-Aware Computing

Interactive VR Game

Wireless Sensor Networks

Urban WarfareMilitary Surveillance

Disaster Recovery Environmental Monitoring

University of Virginia

Applications/Testbeds

• VigilNet – Military surveillance, tracking and classification

• AlarmNet – Assisted Living and Residential Monitoring Network

• Environmental Science

University of Virginia

1. An unmanned plane (UAV) deploys motes

2. Motes establish an sensor network with power management

3.Sensor network detects

vehicles and wakes up the sensor nodes

Zzz...

Energy Efficient Surveillance System

Sentry

University of Virginia

VigilNet Architecture

University of Virginia

Demo System Layout

2

0

1

Tent

•200 XSM Motes•3 Bases (Tripwires)•300 by 200 Meters in T-shape•Inter-tripwire communication Via 802.11 wireless LAN

300 meters, 30 motes each line, 4 non-uniform lines

200M

University of Virginia

Results of Actual Test

University of Virginia

Overview of Demo Scenarios

•Tracking multiple targets (people, vehicles, and then people and vehicles)– 3 crossing people– Vehicle followed by person– 2 vehicles following each other about 50 meters apart– Large versus small vehicles– People and people with weapons

•Fault Tolerance/Robustness– Kill 20% of the nodes– Kill base stations

University of Virginia

For related other publications: www.cs.umn.edu/~tianhe

Florida

University of Virginia

C&C Mote Field

N

300M by 200 M T shape

Berkeley

University of Virginia

Spotlight - Localization

μSpotlight (projector, Mica2 motes, laptop) – DEMO at ACM/IEEE IPSN 05

Spotlight (telescope mount, diode laser, XSM motes, laptop) (Sent to Berkeley) Demo at upcoming SenSys 2005

University of Virginia

Sentry-Based Power Management

(SBPM)• Two classes of nodes: sentries and non-sentries– Sentries are awake – Non-sentries can sleep

• Sentries – Provide coarse monitoring & backbone communication network

– Sentries “wake up” non-sentries for finer sensing

• Sentry rotation– Even energy distribution– Prolong system life

1

4

3

2

University of Virginia

Tripwire-based Surveillance

• Partition sensor network into multiple sections.• Turn off all the nodes in dormant sections.• Apply sentry-based power management in tripwire

sections• Periodically, sections rotate to balance energy.

Road

Dormant DormantDormant Active ActiveDormant ActiveActive Dormant Dormant

University of Virginia

Lifetime

Analysis

Network Life Time

Number of Tripwires

(10 regions, 30% sentry, 7 day life)

4 3 2 1

2 AA Batteries 50 days 70 days 105 days 210 days

4 AA Batteries 100 days 140 days 210 days 420 days

University of Virginia

Internet Scale WSN

Internet

LocalTransportProtocol

LocalTransportProtocol

ProgrammingStation

Server Server

Nodes Nodes

University of Virginia

System Architectur

eInternet

LocalTransportProtocol

LocalTransportProtocol

ProgrammingStation

Server Server

Nodes NodesInformation about

Services, InterfacesLocation

University of Virginia

System Architectur

eInternet

ProgrammingStation

Server Server

Nodes Nodes

LocalTransportProtocol

LocalTransportProtocol

High levelProgramming

Language

EXE

High LevelVirtual Machine

High LevelVirtual Machine

Low LevelVirtual Machine

Low LevelVirtual Machine

University of Virginia

System Architectur

eInternet

LocalTransportProtocol

LocalTransportProtocol

ProgrammingStation

Server Server

Nodes Nodes

Responsible forResource management

User access rights

University of Virginia

System Architectur

eInternet

LocalTransportProtocol

LocalTransportProtocol

ProgrammingStation

Server Server

Nodes Nodes

Omnix PhysicalNetwork

Omnix PhysicalNetwork

The Physicalnet

University of Virginia

Medical System Architecture

Internet

Internet

PDAs

Nurses Stations

University of Virginia

University of Virginia

Smart Living Health Spaces

University of Virginia

Research

Questions

• Flexible and Dynamic Privacy• Security• Form factors for sensor nodes

– Unobtrusiveness

• Mobility– Routing for 2 mobile end points

• Localization• In-network preliminary diagnoses• Define and meet real-time requirements

including alarms• Power Management• Data Association

University of Virginia

Summary - Research Approach

• Fundamental and Important Problems– Not incremental

• Application Driven– Military– Medical– Environmental

• Experimental Systems Research• Build Testbeds and Real Systems

University of Virginia

Summary - Our Research Areas

• Wireless Networking Realities• Localization• Real-Time• Hardware• Privacy• Security• The crowded spectrum - Multi-frequency

systems• OS for WSN

Spatial Temporal Systems

University of Virginia

Our Research Areas

• Power Management• Analysis• Programming Languages

– Across networks of networks

• Acoustic Streaming and other High Level Services• Real-Time Data Sharing• Self-Healing• Data Association• Auto-calibration• Pervasive Computing

University of Virginia

Research Partners

• CMU• UIUC• Harvard• Univ. of Minnesota• Berkeley• UVA Medical School