A Systematic Approach to the Design of Distributed Wearable Systems Urs Anliker, Jan Beutel, Matthias Dyer, Rolf Enzler, Paul Lukowicz Computer Engineering

A Systematic Approach to the Design of Distributed Wearable Systems

Urs Anliker, Jan Beutel, Matthias Dyer, Rolf Enzler, Paul LukowiczComputer Engineering and Networks Lab & Wearable Lab

Swiss Federal Institute of Technology (ETH) Zurich

September 25, 2001

Computer EngineeringComputer Engineeringand Networks Laboratoryand Networks Laboratory

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Jan Beutel, September 25, 2002Jan Beutel, September 25, 2002

The Wearable Difference

• Distributed (Re-)(Configurable) Computing Platform

– Heterogeneous Components– Many Components (~10…20)– Varying Configurations of Components

– Distributed over whole Body, unreliable– Distributed Power Sources

– Dynamic Environment

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What is Communicating on a Wearable?

• Communicating Components of a single Wearable Computer System

– Processor Bus CPU, Memory, Storage, UI, NIC…

– Peripheral Interconnect UI, Audio, Sensors, Actors…

– Networking- To the Access Network

- To other Persons/Wearables

- To Multiple Wearable Computer Systems per Person?

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Computation Communication Tradeoff

CPU

Sensor

NIC

UI/VGA

Memory

Sensor

Actor

Sensor

DSP

UI

?

Goal: To Find the best Resource and Medium for each required

Interaction

??

storing

listening

computing

displaying

alerting

filtering

sleeping

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The Wearable Potential

BT

WearArm

BT

Sensor

BT

Sensor

BT

Keyboard

BT

WearArm

BT

Sensor

BT

Sensor

BT

BT

Needed are:• Detailed Interface Specification• Prototype Hard/Software Environment• Higher Application Layer API• Usage Scenario for Wearable System

BT

Low Power/Cost Flexibility

Performance

Tradeoff

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Exploration Methodology Overview

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System Specification

• Load Specification (task profiling)– Assembly of Scenarios, Applications and Tasks

• Architecture Specification– System Topology (tree structure)– Module Properties (hard and soft constraints)– Connection Properties (wired or wireless)– Task Mapping

• Resource Specification– Computing Devices (speed, power, form factor)– Communication Channels (bandwidth, delay,

power, form factor)

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Load Specification

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Generic System Model

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Task Mappings

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Communication Model

• Multiple periodic inputs• Deadline associated with each sample

• Four operating states: Standby, Idle, Transmit, Receive

• Two modes: Continuous vs. Burst• Optimal reduction of the duty cycle

Result: TWC

PCH

Ptx + Prx

2Pi 2PsPtx + Prx

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Results of an Exploration

• Pareto optimal points

• Communication costs strongly influence architecture

Power Consumption

Form

Fact

or

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DSE and Modeling Achievements

• Hierarchical Specification Model– Tasks, Applications and Scenario specification– Performance and resource requirements of Tasks

• Wearable Computing Architecture Specification– Modules consisting of individual computing

resources and communication channels– Associated performance parameters

• Determine relevant properties of a Wearable System– Centralized vs. Distributed

• Exploration of the Wearable Design Space

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Future Work

• Modelling– Improving communication model – Memory requirement and configuration – Hardware and initialization overhead– Abstract device model for different device

classes and hardware normalization– Profiling further applications, verification of

scenarios

• Exploration– Integration of new model– Dynamic binding and allocation

Documents

A Systematic Approach to the Design of Distributed Wearable Systems Urs Anliker, Jan Beutel, Matthias Dyer, Rolf Enzler, Paul Lukowicz Computer Engineering