SmartSensorNode

SmartSensorNode

Impact GPS leveraged for geo-referenced identity, and low

power communications synchronization. Up to 100x communications power reduction.

Standard APIs implemented as Java class libraries and browser-based user interfaces provide code mobility, code reuse, and platform independence.

High-level spatial and context “anycast” addressing enables dynamic specialization for augmented awareness and collaborative consensus applications.

New Ideas Power-aware link and routing protocols. Exploit fine-

grained power control of radios for energy efficient connectivity. Maximize sensor network’s operational lifetime through energy-aware routing.

GPS-aware link protocols. GPS-synchronized ultra-low-power communication.

Spatial addressing and connectivity. High-level addressing, unicast, multicast, anycast, and gathercast communication based on spatial referencing of the nodes.

Mobile code and web technology. Embedded Java APIs for code portability and browser-based topographical map interface for visualizing dynamic data from sensor net.

Milestones

Sensor Control API Specification FY00 Q1

Topographical Map Interface Definition FY00 Q1

Network Services API Specification FY00 Q2

GPS-Aware Link Protocol Experiment FY01 Q4

Network Services PDA/Laptop Experiment FY01 Q4

Integrated Sensor-Kit Experiment FY02 Q4

SmartSensorNode

Event

Target

Target

COTSPDA

Brian Schott PI, Bob Parker (USC/ISI), Mani Srivastava (UCLA) Co-PI, Mark Jones (Virginia Tech) Co-PI

Dynamic Sensor Networks

Dynamic Sensor Networks

• DSN is focusing on three SenseIT areas:

1) Platforms– GPS-synchronized ultra-low-

power communication experimental platform.

2) Distribution and Aggregation– Network boot-up, low-power

link protocols, power-aware routing, and spatial addressing.

3) Declarative Language and Execution Environment– Topographical map interface.

– Java APIs for portability.

– sensor network emulation for rapid application development.

SmartSensorNode

SmartSensorNode

SmartSensorNode Target

TargetCOTSPDA

DSN Experimental Platform

DSN Experimental Platform• The primary purpose of the platform is to experiment with using GPS

synchronization to provide precise control over transmit/receive on radio.

• Uses COTS hardware/software to minimize cost and maximize code portability. No attempt to miniaturize subsystems.

Serial port

PDAApplication specific processing done in COTS PDA. Assumed in sleep mode unless activated by Comm Subsystem. May have other high-power sensors in PCMCIA slot.

Sensor SubsystemContains sensors, signal conditioning, signal processing, and optionally protocol processing to eliminate PDA for light-weight sensor node.

Comm SubsystemSynchronizes radios using GPS signal. Can store/forward packets in sensor net and perform routing without PDA. Goal: Runs on solar cell.

SensorSubsystemSerial port / TOD

CommSubsystem

GPS RadioComm

AntennaGPS

AntennaSensors

DSN Comm Subsystem (Concept)

GPSAntenna

CommAntenna

ClockOscillator

TOD(Time Of Day)

Microcontroller

DataTiming

Variable RatioDivider

CLK IN

TOD to Sensor Subsystem

DataBuffer

SleepMode

GPS Radio

1 pulse per second

Serial PortController

To PDA

External Devices(i.e.. Long-range radio)

ToSensor

Subsystem

Distribution and Aggregation

Mani Srivastava

UCLA (Co-PI)

Distribution and Aggregation

Internet +

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S +

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Target

Sensor Network

• Global spatial addressing that support referencing of individual or groups of sensor nodes by geographic location

• Capability-based addressing in the local neighborhood.

• External IP connectivity with DSN network gateways.

• Distribution of node location and capabilities to neighborhood application query servers at boot-up and reconfiguration.

• Low-power link protocols and power-aware routing for energy efficient sensor data distribution.

S

S

Power-Aware Link Protocols

• Optimize for computation and communication energy spent per bit distributed (Joules/bit) as opposed to traditional metrics such as throughput.

• Combine novel channel state estimation techniques with the capabilities of radios to adapt transmit power and other parameters such as spreading gain and symbol rate.

• Exploit GPS reference timing signal to synchronize communication amongsensor nodes and minimizetransmit/receive windows.

S

S

S

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S

GPS time

Example of Impact of Link Layer Adaptation on Energy Efficiency

2

4

6

8

10

12

14

0 200 400 600 800 1000 1200 1400

Packet Length (bytes)

BER=10-4

BER=10-8

BER=10-3Energy per useful bit (J/bit)

Power-Aware Routing Protocols• Traditional multihop ad hoc

routing protocols focus on fast topology changes.– Power hot-spots that lead to

holes in coverage and network partitioning.

– Power inefficiency due to signaling messages in quiescent state.

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-S S

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Target

• Novel DSN routing protocols will focus on maximizing sensor network lifetime.– Power-based routing metrics.

– Leveraging location information during routing.

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Spatial Addressing

• Sensor applications typically not interested in node IDs. – Query destination in terms of node location and capabilities.– Any suitable node in target neighborhood can handle the query.

• DSN network addressing architecture and routing protocols optimized for the needs of sensor applications.– Node addresses encode their location.– Location-based global routing and capability-based local routing.– Intermediate nodes intelligently filter/combine query responses.– Java-based API for communicating with nodes and node groups.– Both native DSN architecture as well as IPv6 overlay-based will be

investigated for use within the sensor network.

• External users can tunnel into network across the IPv6 Internet via gateway nodes.

DSN Network Services API• Network Services Library

provides multihop connectivity and higher-level networking services.

• Java API choice provides portability to other wired and wireless platforms.

• Low-level link layer accessible to other efforts implementing their own routing protocols.

• API also supports DSN emulation environment.

Run-time Environment

Java-based API

Applications

Low-power link protocols

Power-aware spatial routing

Spatial addressing

Sensor Node Hardware

SensorNetwork

Emulation

ns-based DSN Simulation

• ns will be used as the primary DSN simulation platform.– Simulation of link and routing protocols.

– Comparison of alternative addressing architectures.

• Collaboration with Deborah Estrin’s SCADDS to define common ns modules and interfaces.– Preliminary interaction already started.

• ns module for DSN protocol stack will be made available to other members of SenseIT community.

Declarative Languages and Execution Environment

User Interface

• PDA-based platform– Windows CE

– Java 2 (Micro Edition)

– Color screen

– Pen-based interface

• Connects to DSN Comm Subsystem by serial port.

• Interface will easily operate on more powerful Java platforms.

Topographical Interface

• Topographical map interface to provide network status visually.

• Queries can be geographic, by sensor id/capabilities, or be application specific.

• Input using pop-up forms/menus.

• Browser plug-in approach to allow multiple applications to run on the same map.

• User query translated to query language defined by other SenseIT effort(s).

Any tracked vehicles inthis region?

Sensor Network Query Action

• User submits query via map browser interface.

• Local application (one of several) interprets query.

• Query sent using query language over network.

• Query arrives at appropriate application query server based on geographic address.

• Query is sent to appropriate sensor nodes.

• Local Java application acts on query.

Java Emulation Environment

• Java-based sensor network emulation tools for application development.– Allows for testing of components

before all hardware is ready.

– Allows for testing on a larger number of sensors nodes than available.

• The goal is to enable rapid application development by providing source-codecompatibility betweena workstation emulator and sensor node.

SummaryNew Ideas Power-aware link and routing protocols. Exploit fine-grained power control of radios

for energy efficient connectivity. Maximize sensor network’s operational lifetime through energy-aware routing.

GPS-aware link protocols. GPS-synchronized ultra-low-power communication. Spatial addressing and connectivity. High-level addressing, unicast, multicast, anycast,

and gathercast communication based on spatial referencing of the nodes. Mobile code and web technology. Embedded Java APIs for code portability and

browser-based topographical interface for visualizing dynamic data from sensor net.

Impact GPS leveraged for geo-referenced identity, and low power communications

synchronization. Up to 100x communications power reduction. Standard APIs implemented as Java class libraries and browser-based user interfaces

provide code mobility, code reuse, and platform independence. High-level spatial and context “anycast” addressing enables dynamic specialization for

augmented awareness and collaborative consensus applications