Introduction to Wireless

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Nov 21, 2013 (3 years and 10 months ago)

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Introduction to Wireless
Sensor Networks




Presented by

Sushanth Sivaram Vallath

The most profound technologies are those that
disappear. They weave themselves into the
fabric of everyday life until they are
indistinguishable from it.


-

The late Mark Weiser, Father of Ubiquitous Computing and Chief
Technologist of Xerox PARC

Wireless Sensors

Small
microcontroller


8 kB code


512 B data

Simple, low
-
power
radio


10 kbps ASK

EEPROM (32 KB)

Simple sensors

WeC 99

“Smart Rock”

Mica 1/02

NEST open exp. Platform

128 kB code, 4 kB data

40kbps OOK/ASK radio

512 kB Flash

Rene 11/00

Designed for
experimentation

-
sensor boards

-
power boards

Dot 9/01

Demonstrate
scale

Spec 6/03

“Mote on

a chip”


Telos 4/04

Robust

Low Power

250kbps

Easy to use

Mica2 12/02

38.4kbps radio

FSK

Tiny sensing devices capable of wireless communication

What are sensor
networks

spatially distributed sensors to monitor
conditions at different locations, such as
temperature, sound, vibration, pressure,
motion or pollutants.

Platforms


Berkeley Motes


Tiny OS


nesC



Ns
-
2


TOSSIM

Applications of WSN


Temperature


Humidity


Vehicular movement


Pressure


Noise levels


Mechanical stress levels on attached objects


Speed, direction


Etc…

Factors Influencing Sensor
Network Design


Fault tolerance


Scalability


Operating environment


Sensor network topology


Transmission media


Power consumption

Sensors Representation


Communication Graph


Sensors are nodes


Link between the sensors are the edges

Routing Protocols


LEACH


Directed Diffusion


PEGASIS


TEEN


APTEEN


Etc…

Sensor Issues


Energy Constraint


High Communication cost



& Lot of other issues

Management Issues


Conversion of data to Information


Data access control

SQL


Underlying routing protocol transparent
to user


Some routing protocols are considered
to be aggregation protocols (implicit
aggregation)

Sensor Database


SQL type interface



SELECT avg(temperature), room,




FROM sensors




WHERE building = “Nedderman Hall”




ORDER BY temperature




GROUP BY room




SAMPLING PERIOD 10 min

SQL type interfaces


Cougar


TinyDB





Approximations




Query Propagation




Data Centric Storage




Aging Data

Query scenario

Sink

Select
temp
from

Efficiency achieved
through

In
-
network

aggregation

Different types of queries


Fully aggregated queries


Un
-
aggregated queries


Partially aggregated queries

Fully aggregated queries

Theorem: Finding maximum lifetime
routing tree for fully aggregated queries
with reception costs is NP
-
complete.


Similar to Minimum Degree Spanning
Tree(MDST) which is known to be NP
-
complete

Un
-
aggregated queries

Theorem: Finding maximum lifetime
routing tree for unaggregated queries is
NP
-
complete.


Reduced from decision problem for SET
-
COVER.

Partially aggregated
queries

Can be reduced to unaggregated queries


Approximation algorithms used to solve
the unaggregated routing tree problem
can be adapted.

Active areas in WSN


Routing


Topology control


Data management, aggregation and query


MAC protocols


Target tracking, resource discovery


Monitoring and maintenance


Sensor validation


Power issues


Coverage and Connectivity

Companies in Research


Crossbow


Intel


IBM


Microsoft


PARC


Fujitsu


Lot more…

References

[1] Cedric Florens and Robert McEliece, “Packet Distribution Algorithms for Sensor Networks”, IEEE INFOCOM 2003.

[2] Samuel Madden, Robert Szewczyk, Michael J. Franklin and David Culler, “Supporting Aggregate Queries Over Ad
-
Hoc Wireless
Sensor Networks”,

[3] Sartaj Sahni and Xiaochun Xu, Algorithms for Wireless Sensor Networks.

[4] Jamal N. Al
-
Karaki Ahmed E. Kamal, Routing Techniques in Wireless Sensor Networks: A Survey.

[5] Bhaskar Krishnamachari, D Estrin, Stephen Wicker, Modeling Data
-
Centric Routing in Wireless Sensor Networks.

[6] S.S Iyengar, Richard R. Brooks, “Distributed Sensor Networks”, Chapman & Hall/CRC.

[7] Wendi Rabiner Heinzelman, Anantha Chandrakasan, and Hari Balakrishnan, “Energy
-
efficient communication protocol for wireless

microsensors networks,” in 33rd Annual Hawaii International conference on System Sciences.

[8] David Braginsky and Deborah Estrin, “Rumor routing algorithm for sensor networks,” in First ACM International Workshop on

Wireless Sensor Networks and Application.

[9] Y.Xu, J. Heidemann, and D. Estrin, “Geography
-
informed energy conservation for ad hoc routing,” in Proceedings of the Sevent
h
Annual ACM/IEEE International Conference on Mobile Computing and Networking, 2001.

[10] B. Chen, K. Jamieson, H. Balakrishnan, and R. Morris, “SPAN: An energy
-
efficient coordination algorithm for topology mainte
nance
in ad
-
hoc wireless networks,” ACM Wireless Networks Journal, September 2002.

[11] Feng Zhao and Leonidas Guibas, “Wireless Sensor Networks, an Information Processing Approach”.

[12] Yong Yao, J. E. Gehrke. The Cougar Approach to In
-
Network Query Processing in Sensor Networks. Sigmod Record, Volume 31,
Number 3. September 2002.

[13] Yong Yao, J. E. Gehrke. Query Processing in Sensor Networks. In

Proceedings of the First Biennial Conference on Innovative Data
Systems Research (CIDR 2003).
Asilomar, California, January 2003.

[14] Xiuli Ma, Dongqing Yang, Shiwei Tang, Qiong Luo, Dehui Zhang, and Shuangfeng Li. Online Mining in Sensor Networks. NPC
2004: 544
-
550

[15] Chiranjeeb Buragohain, Divyakant Agrawal, and Subhash Suri, Power Aware Routing for Sensor Databases.


Thank You