Extreme Networked Systems: Large Self-Organized Networks of Tiny Wireless Sensors

1. Extreme Networked Systems: Large Self-Organized Networksof Tiny Wireless Sensors David Culler Computer Science Division U.C. Berkeley Intel Research @ Berkeley www.cs.berkeley.edu/~culler

2. Low-power Wireless Communication I SD Q SD baseband PLL filters mixer LNA Emerging Microscopic Devices • CMOS trend is not just Moore’s law • Micro Electical Mechanical Systems (MEMS) • rich array of sensors are becoming cheap and tiny • Imagine, all sorts of chips that are connected to the physical world and to cyberspace! EECS Visions

3. Circulatory Net What can you do with them? Disaster Management • Embed many distributed devices to monitor and interact with physical world • Network these devices so that they can coordinate to perform higher-level tasks. => Requires robust distributed systems of hundreds or thousands of devices. Habitat Monitoring Condition-based maintenance EECS Visions

4. Getting started in the small • 1” x 1.5” motherboard • ATMEL 4Mhz, 8bit MCU, 512 bytes RAM, 8K pgm flash • 900Mhz Radio (RF Monolithics) 10-100 ft. range • ATMEL network pgming assist • Radio Signal strength control and sensing • I2C EPROM (logging) • Base-station ready (UART) • stackable expansion connector • all ports, i2c, pwr, clock… • Several sensor boards • basic protoboard • tiny weather station (temp,light,hum,prs) • vibrations (2d acc, temp, light) • accelerometers, magnetometers, • current, acoustics EECS Visions

5. A Operating System for Tiny Devices? • Traditional approaches • command processing loop (wait request, act, respond) • monolithic event processing • bring full thread/socket posix regime to platform • Alternative • provide framework for concurrency and modularity • never poll, never block • interleaving flows, events, energy management • allow appropriate abstractions to emerge EECS Visions

6. Appln = graph of event-driven components Route map router sensor appln application Active Messages Serial Packet Radio Packet packet Temp photo SW HW UART Radio byte ADC byte Example: ad hoc, multi-hop routing of photo sensor readings clocks RFM bit EECS Visions

7. Pushing Scale EECS Visions

8. Re-explore networking • Fundamentally new aspects in each level • encoding, framing, error handling • media access control • transmission rate control • discovery, multihop routing • broadcast, multicast, aggregation • active network capsules (reprogramming) • security, network-wide protection • New trade-offs across traditional abstractions • density independent wake-up • proximity estimation • localization, time synchronization • New kind of distribute/parallel processing EECS Visions

9. Larger Challenges • Security / Authentication / Privacy • Programming support for systems of generalized state machines • language, debugging, verification • Simulation and Testing Environments • Programming the unstructured aggregates • Resilient Aggregators • Understanding how an extreme system is behaving and what is its envelope • adversarial simulation • Constructive foundations of self-organization EECS Visions

10. To learn more • http://www.cs.berkeley.edu/~culler • http://tinyos.millennium.berkeley.edu/ • http://webs.cs.berkeley.edu/ • http://ninja.cs.berkeley.edu/ EECS Visions

11. ...and Small Characteristics of the Large • Concurrency intensive • data streams and real-time events, not command-response • Communications-centric • Limited resources (relative to load) • Huge variation in load • Robustness (despite unpredictable change) • Hands-off (no UI) • Dynamic configuration, discovery • Self-organized and reactive control • Similar execution model (component-based events) • Complimentary roles (eyes/ears of the grid) • Huge space of open problems EECS Visions