introduction to wireless sensor networks presented by sushanth sivaram vallath
TRANSCRIPT
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. Platform128 kB code, 4 kB data40kbps OOK/ASK radio512 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 4/04RobustLow Power250kbpsEasy to use
Mica2 12/0238.4kbps radioFSK
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
SinkSelect 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 Seventh
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 maintenance
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