university of southern california embedded networks laboratory 1 wireless sensor networks ramesh...
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UNIVERSITY OFSOUTHERN CALIFORNIA
Embedded Networks Laboratory
1
Wireless Sensor NetworksWireless Sensor Networks
Ramesh [email protected]
Lab Home Page: http://enl.usc.edu/Personal Home Page: http://cs.usc.edu/~ramesh/
UNIVERSITY OFSOUTHERN CALIFORNIA
Embedded Networks Laboratory
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The Progress of TechnologyThe Progress of Technology• Platforms with
– Processors
– Memory (flash, RAM)
– Low-power radios
– Sensors!» Temperature
» Light
» Humidity
» Acceleration
• Battery operated
UNIVERSITY OFSOUTHERN CALIFORNIA
Embedded Networks Laboratory
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Networked Embedded SensingNetworked Embedded Sensing• Put many of these nodes close to phenomena• Network them
– Wireless, multi-hop» Deployment becomes easy!
• Computation and processing is necessarily distributed– Nodes are battery-powered– … and communication requires energy
• … and likely to stay that way
UNIVERSITY OFSOUTHERN CALIFORNIA
Embedded Networks Laboratory
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Application AreasApplication Areas
Seismic Structure response
Contaminant Transport
Marine Microorganisms
Ecosystems, Biocomplexity
StructuralCondition Assessment
Computers in the Physical World!
UNIVERSITY OFSOUTHERN CALIFORNIA
Embedded Networks Laboratory
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Where are we today?Where are we today?
UNIVERSITY OFSOUTHERN CALIFORNIA
Embedded Networks Laboratory
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UNIVERSITY OFSOUTHERN CALIFORNIA
Embedded Networks Laboratory
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Sensor
Data Logger
UNIVERSITY OFSOUTHERN CALIFORNIA
Embedded Networks Laboratory
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UNIVERSITY OFSOUTHERN CALIFORNIA
Embedded Networks Laboratory
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Where’s the Computer Science in this?Where’s the Computer Science in this?
To build a software infrastructurefor developing networked embedded sensing applications
UNIVERSITY OFSOUTHERN CALIFORNIA
Embedded Networks Laboratory
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An ExampleAn Example• Treat a sensor network as a database and use in-network
storage.
• Provide an efficient solution for multi-dimensional range queries.– e.g. List all events whose temperature lies between 70 and 80 and
whose light levels are between 10 and 15.
• Useful for searching and correlating events of interests with multiple attributes.– Drill-down searching, trigger and action, …
• Fascinating example of the confluence between databases and networking!
UNIVERSITY OFSOUTHERN CALIFORNIA
Embedded Networks Laboratory
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Distributed Index for Multi-Dimensional Data (DIM)Distributed Index for Multi-Dimensional Data (DIM)
• Functionality– Efficient range query for
multidimensional data.• Approaches
– Divide sensor field into bins.– Locality preserving mapping
from m-d space to geographic locations.
– Use geographic routing such as GPSR.
• Assumptions– Nodes know their locations and
network boundary– No node mobility
E2= <0.6, 0.7>E1 = <0.7, 0.8>
Q1=<.5-.7, .5-1>
UNIVERSITY OFSOUTHERN CALIFORNIA
Embedded Networks Laboratory
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Building ZonesBuilding Zones
• Divide network into zones.
• Each node mapped to one zone.
• Encode zones based on division.
• Each zone has a unique code.
• Map m-d space to zones.
• Zones organized into a virtual binary tree.
6
5
1110
1111
43
21
78
10
9
1100111
0110
010
0001
0000 001 10
L[1/2, 1)L[0, 1/2)
T
[1/2
, 1)
T
[0, 1
/2)
L[0, 1/4) L[1/4, 1/2) L[1/2, 3/4) L[3/4, 1)
T[3/4, 1)
T[1/2, 3/4)
T[1/4, 1/2)
T[0, 1/4)
L: Light, T: Temperature
UNIVERSITY OFSOUTHERN CALIFORNIA
Embedded Networks Laboratory
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8
6
Virtual Binary TreeVirtual Binary Tree
0 1
9
10
6 5
104
10
10
1
10
2 3
108
10
10 7
10
1110
1111
L[1/2, 1)
L[0, 1/4)
110
L[0, 1/2)
0111
0110
010
T
[1/2
, 1)
0001
0000 001 10
T
[0, 1
/2)
L[1/4, 1/2) L[1/2, 3/4) L[3/4, 1)T
[3/4, 1)T
[1/2, 3/4)T
[1/4, 1/2)T
[0, 1/4)
5
10
43
2
97
1
UNIVERSITY OFSOUTHERN CALIFORNIA
Embedded Networks Laboratory
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Data InsertionData Insertion
• Encode events
• Compute geographic destination
• Hand to GPSR
• Intermediate nodes can refine the destination estimation
1110
1111
L[1/2, 1)
L[0, 1/4)
1
110
L[0, 1/2)
0111
0110
010
T
[1/2
, 1)
0001
0000 001 10
T
[0, 1
/2)
L[1/4, 1/2) L[1/2, 3/4) L[3/4, 1)
T[3/4, 1)
T[1/2, 3/4)
T[1/4, 1/2)
T[0, 1/4)
2
34
5
6
987
10
E1= <0.8, 0.7>Store E1
L: Light, T: Temperature
UNIVERSITY OFSOUTHERN CALIFORNIA
Embedded Networks Laboratory
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QueryQuery
• Split a large query into smaller subqueries.
• Encode each subquery.
• Process subqueries separately, resolving locally or forwarding to other nodes based on their codes.
1110
1111
L[1/2, 1)
L[0, 1/4)
1
110
L[0, 1/2)
0111
0110
010
T
[1/2
, 1)
0001
0000 001 10
T
[0, 1
/2)
L[1/4, 1/2) L[1/2, 3/4) L[3/4, 1)
T[3/4, 1)
T[1/2, 3/4)
T[1/4, 1/2)
T[0, 1/4)
2
34
5
6
987
10
Q10= <.75-1, .5-.75>
Q1= <0.5-1, 0.5-1>
Q12= <.75-1, .75-1>Q11= <.5-.75, . 5-1>
L: Light, T: Temperature
UNIVERSITY OFSOUTHERN CALIFORNIA
Embedded Networks Laboratory
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Implementation on the MotesImplementation on the Motes
• Use TinyDB Schema
• Tuple Storage on Flash/RAM– Insertion, deletion, search
• GPSR implemented with priority-based hop-by-hop reliability
– Favor query and reply messages different over other messages.
• DIM’s components– Zone, Query, Insertion,
– Dispatcher
Zone Query Insertion
GPSR
Protocol- Independent
Routing Shim
Flash/RAM
Tuple Storage TinyDB
Schema
DIM Dispatcher
UNIVERSITY OFSOUTHERN CALIFORNIA
Embedded Networks Laboratory
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Some ScreenshotsSome Screenshots