PADS Power Aware Distributed Systems Architecture Approaches USC Information Sciences Institute Brian Schott, Bob Parker UCLA Mani Srivastava Rockwell Science Center Charles Chien

Sensor Network Baseline Instrument a state-of-the-art sensor node to understand and baseline power consumption in current sensor systems. Rockwell WINS is modular:  Power Board  StrongARM Board  Radio Board  Sensor Board WINS representative of other sensor nodes in the community. We plan to adapt this node to allow module-level power instrumentation and logging both in the lab and in the field.

Power Instrumentation Goals  Insert a power isolation board between each module.  Signals are passed through, power supplies are isolated.  Microcontroller provides power monitoring and power control from a host’s serial port (workstation, laptop or iPAQ). Status  Four channel instrumentation board completed and was used at SITEX01.  Power isolator currently in fabrication. PADS Power Isolator StrongARM PADS Power Isolator Radio PADS Power Isolator Sensor Battery Pack

Measurement Approach Measurement Device – Configured to measure the power performance of sensor node in real time Measurement Data - Used in SensorSim to characterize the nodes’ power performance Sensor Node Measurement Device

Research Platform Status PADS team has been surveying existing sensor node platforms inside and outside community.  mAMPS-1, MIT, StrongARM, ECOS. Not available to community until Fall  PicoNode, UCB, StrongARM, ECOS. Still a candidate architecture. Would have to produce own radio with proper P-A hooks and migrate to  WINS, Rockwell, StrongARM, MCOS/ECOS Some aspects of design are closed.  WINS 2.0, Sensoria, SH4, Linux Closed architecture.  ARL CAuS? Limitation of these nodes is direct dependence on StrongARM (bus master, signaling, control).

 AMPS-1 Node Processor Architecture StrongARM SA-1110 Intel GDS1110BB Flash MEMORY System Connector IEEE 1386 Mezzanine DATA ADDRESS [31:0] [15:0] USB RS232 [4:1] IRQ Peripheral Pwr. En. SPI DC/DC +3.3V Buck DC/DC +5V Boost DC/DC V Buck [4:0] Core Power Core Voltage Select +3.3V +5V Battery (3.3-5V) On-Board Sensor Digital logic supply Threshold Gain Select [19:2] [19:1] Peripheral Chip Sel. [1:0] SPI

System Connector Data Bus [15:0] Address [4:1] Peripheral Chip Select [1:0] RS-232 USB peripheral port Synch. Serial Port (SPI) Peripheral Power Enable [1:0] +3.3V~IRQ Battery Supply Power Ground Signal Ground Memory Control (~WE, ~OE) 64-pin IEEE 1386 Mezzanine connector

PicoNode I Currently supporting the following efforts  Sensors for smart buildings  Seismic monitoring  Local Positioning research  Ad-hoc networking and media-access research  New physical layers (Bluetooth and others) sensordigitalpowerbluetooth radio Off-the-shelf fully programmable communication/computation node 20 nodes operational; new bluetooth and power boards Orders for nodes due by July 1!

FY99 CA  S Gen I FY01 CA  S Gen II ARL CAuS Implementation Proof of concept system achieved 4 orders of magnitude reduction in Size x Weight x Power metric Enabled by Adaptive Computing Supports a wide range of sensors Move the processing to the sensor head Low power, high computational throughput Field upgradeable to support emerging algorithms Courtesy of Bae/ARL

UCLA Medusa II Initial prototype competed: Medusa Design of Medusa II (using non-SensIT resources)  Longer range ultrasound (15-20m)  Radio Power Control & RSSI circuitry  More computation (Atmel THUMB) Goal: Hybrid Radio-acoustical localization  use radio for long-range when ultrasound is unable to find a neighbor  Medusa used standalone or as a location coprocessor to sensor nodes Atmel AVR RFM Radio Ultrasound Receiver Ultrasound Transmitter INT

Research Platform Technology Integration / Emulation Distributed node architecture makes it much easier to integrate PAC/C modules that don’t fit.  Most existing sensor modules and systems have an serial port.  Form factor not an issue for initial laboratory experiments. Enables simple module emulation and module testing from a workstation or laptop. Power control and power monitoring can be incorporated into bridge board.  Basically the same design as the WINS power isolator boards! I2C Serial Port Bridge Serial Port Bridge Experimental V-scaling StrongARM Board Serial Port Bridge Radio Board WINS Node

Power Management for Wireless Sensor Nodes SensorsRadio CPU Real Time Operating System Power Manager Dynamic Voltage Scaling Scalable Signal Processing Dynamic Modulation Scaling Coordinated Power Management

Distributed Sensor Node Approach Make each module an independent actor on a multi-master serial bus such as I2C (400Kb, 4Mb*).  87C554 Microcontroller - 16 mA Active, 4 mA Idle, 50 uA Shutdown. Create common command set for peer to peer communication and control of modules. Localize specific processing as close to modules as possible (perform energy threshold on seismic board, packet forwarding on radio board, etc.). A StrongARM may be used for application control and data processing, but could distribute “event handlers” to local microcontrollers and power down most of the time. I2C + Power

PADS Research Platform Plan Focus code development in summer using existing SA1/SA2 development boards, radios, and sensors. Activate ISI hardware team to invent or leverage existing node stack definition that can be reasonably replicated and deployed.  Build TI TMS320VC5509 DSP processor module.  Build SA2 processor module. Deploy PADS research platform at ARL Summer ’02 exercise demonstrating 10X power improvement over existing baseline node capabilities.