Communication for the Wearable Platform Jan Beutel Computer Engineering and Networks Lab Swiss Federal Institute of Technology (ETH) Zurich October 19, 2001 Computer Engineering and Networks Laboratory

2 ETH Zurich Jan Beutel, October 19, 2001 The Wearable Perspective display context sensor array: camera, light, microphone, GPS distributed reconfigurable computer body area network: wireless communication: WLAN, GSM,

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

4 ETH Zurich Jan 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… –Networking To the Access Network To other Persons/Wearables To Multiple Wearable Computer Systems per Person?

5 ETH Zurich Jan 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

6 ETH Zurich Jan Beutel, October 19, 2001 Communication Tradeoff CPU Sensor NIC UI/VGA Memory Sensor Actor Sensor DSP UI ? Goal: To Find the best Medium for each required Interaction ? ?

7 ETH Zurich Jan 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

8 ETH Zurich Jan Beutel, October 19, 2001 Network Protocol Services Finding Network Nodes Service Discovery Setting up Connections Sending Data Maintaining Connections Maintaining Routes Positioning

9 ETH Zurich Jan Beutel, October 19, 2001 Component Requirements DeviceDatarateAccess- Rate Async/ Sync BER/PERUni/Bidi- rectional Routing/ Bridging Multi- Access Display text Display HiRes 1280x1024x16k <=100Bit/sec >>1Mbit/sec Async/ Sync / /10 -5  NoNo?? MouseVery LowRegular, Bytewise Sync10 -2 /10 -5  No MemoryVery High0/0  NoYes DiskHighBurst0/0  ? CoprocessorMedium to Very High On-Demand0/0  Yes Network IFHigh0/0  Yes? Network Connection MediumAsnyc10 -5 /10 -2  Yes? Audio/ Video Medium/ High Stream, On-Demand Sync10 -2 /10 -2  Yes …

10 ETH Zurich Jan Beutel, October 19, 2001 First Generation Network Node Communication via Bluetooth Transceiver Generic Sensor Interface GPIO, I2C UART Data Interface Microprocessor and Memory Powermanagement

11 ETH Zurich Jan 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 Microcontroller Connect Button Event I2C Event Protocol Event Scheduler Comm

12 ETH Zurich Jan Beutel, October 19, 2001 The Wearable Potential BT WearArm BT Sensor BT Sensor BT Keyboard BT WearArm BT Sensor BT Sensor 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