Transcript Extreme Networked Systems: Large Self-Organized Networks of Tiny Wireless Sensors David Culler Computer Science Division U.C.

Extreme Networked Systems:
Large Self-Organized Networks
of Tiny Wireless Sensors
David Culler
Computer Science Division
U.C. Berkeley
Intel Research @ Berkeley
www.cs.berkeley.edu/~culler
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
• Low-power Wireless Communication
• Imagine, all sorts of chips
that are connected to the
physical world and to
cyberspace!
8/8/2001
EECS Visions
I SDQ SD
PLL
baseband
filters
mixer
LNA
2
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
Habitat Monitoring
systems of hundreds or
thousands of devices.
Condition-based
Circulatory Net
maintenance
8/8/2001
EECS Visions
3
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
8/8/2001
EECS Visions
4
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
–
–
–
–
8/8/2001
provide framework for concurrency and modularity
never poll, never block
interleaving flows, events, energy management
allow appropriate abstractions to emerge
EECS Visions
5
application
Appln = graph of event-driven components
Route map
router
sensor appln
packet
Radio Packet
byte
Radio byte
bit
Active Messages
RFM
8/8/2001
Serial Packet
UART
Temp
photo
SW
HW
ADC
clocks
EECS Visions
Example: ad hoc, multi-hop
routing of photo sensor
readings
6
Pushing Scale
8/8/2001
EECS Visions
7
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
8/8/2001
EECS Visions
8
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
8/8/2001
EECS Visions
9
To learn more
•
•
•
•
http://www.cs.berkeley.edu/~culler
http://tinyos.millennium.berkeley.edu/
http://webs.cs.berkeley.edu/
http://ninja.cs.berkeley.edu/
8/8/2001
EECS Visions
10
Characteristics of the Large ...and Small
• 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
8/8/2001
EECS Visions
11