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3 ETH Zurich Jan Beutel, October 19, 2001 The WearArm Platform Standard Bus Architecture based on commercially available Chipsets many different Interfaces Wired Connections parallel buses, concurrent operation, available at all times, no degradation, no loss
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Communication for the Wearable Platform
Jan BeutelComputer Engineering and Networks Lab
Swiss Federal Institute of Technology (ETH) Zurich
October 19, 2001
Computer EngineeringComputer Engineeringand Networks Laboratoryand Networks Laboratory
2
ETH
Zuric
h
Jan Beutel, October 19, 2001Jan Beutel, October 19, 2001
The Wearable Perspective
displaycontext sensor array: camera, light, microphone, GPS
distributed reconfigurable computer
body area network:wireless
communication:WLAN, GSM,
3
ETH
Zuric
h
Jan Beutel, October 19, 2001Jan Beutel, October 19, 2001
The WearArm Platform• Standard Bus Architecture based on
commercially available Chipsets many different Interfaces
• Wired Connections parallel buses, concurrent operation, available at all times, no degradation, no loss
4
ETH
Zuric
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Jan Beutel, October 19, 2001Jan Beutel, October 19, 2001
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…
– NetworkingTo the Access Network
To other Persons/Wearables
To Multiple Wearable Computer Systems per Person?
5
ETH
Zuric
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Jan Beutel, October 19, 2001Jan Beutel, October 19, 2001
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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ETH
Zuric
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Jan Beutel, October 19, 2001Jan Beutel, October 19, 2001
Communication Tradeoff
CPU
Sensor
NIC
UI/VGA
MemorySensor
Actor
Sensor
DSP
UI ?
Goal: To Find the best Medium for each required
Interaction
??
7
ETH
Zuric
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Jan Beutel, October 19, 2001Jan Beutel, October 19, 2001
The Wireless Difference• Shared Medium• Degradation on Use• Errors depending on Environment
Ad-Hoc Networking Advantages:• Simple Deployment• Adaptive to Heterogeneous Environment• On Demand Availability• Distributed Resources
Low Power/Cost Flexibility
Performance
Tradeoff
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ETH
Zuric
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Jan Beutel, October 19, 2001Jan Beutel, October 19, 2001
Network Protocol Services• Finding Network
Nodes• Service Discovery
• Setting up Connections
• Sending Data
• Maintaining Connections
• Maintaining Routes• Positioning
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ETH
Zuric
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Jan Beutel, October 19, 2001Jan Beutel, October 19, 2001
Component RequirementsDevice Datarate Access-
RateAsync/Sync
BER/PER
Uni/Bidi-rectional
Routing/Bridging
Multi-Access
Display textDisplay HiRes1280x1024x16k
<=100Bit/sec>>1Mbit/sec
Async/Sync
10-5/10-5
10-2/10-5
No No??
Mouse Very Low Regular, Bytewise
Sync 10-2/10-5 No
Memory Very High 0/0 No YesDisk High Burst 0/0 ?Coprocessor Medium to
Very HighOn-Demand
0/0 Yes
Network IF High 0/0 Yes ?Network Connection
Medium Asnyc 10-5/10-2 Yes ?
Audio/Video
Medium/High
Stream,On-Demand
Sync 10-2/10-2 Yes
…
10
ETH
Zuric
h
Jan Beutel, October 19, 2001Jan Beutel, October 19, 2001
First Generation Network Node
Communication via Bluetooth Transceiver
Generic Sensor InterfaceGPIO, I2C
UART Data Interface
Microprocessor and Memory Powermanagem
ent
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ETH
Zuric
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Jan Beutel, October 19, 2001Jan Beutel, October 19, 2001
Bluetooth Module
State Machine Programming Model• Modular State Machine
Model• Low Level Drivers
– 2 Serial Ports, ADC, Random Number Generator, System Clock, GPIO, I2C
• Simple Event Driven Scheduler with Callback Functions
• Stripped down Bluetooth Stack (HCI, L2CAP)
• ~50k Code
Bluetooth Module
Bluetooth Module
Microcontroller
Connect
Button Event
I2C Event
Protocol Event
Scheduler
Comm
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ETH
Zuric
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Jan Beutel, October 19, 2001Jan Beutel, October 19, 2001
The Wearable Potential
BT
WearArmBT
SensorBT
SensorBT
KeyboardBT
WearArmBT
SensorBT
SensorBT
BT
• Ad-Hoc Networking Prototype• Distributed Positioning Service
Needed are:• Detailed Interface Specification• Prototype Hard/Software Environment• Higher Application Layer API• Usage Scenario for Wearable System
BT
