Energy Efficient for Real Time Data Aggregation in Wireless Sensor

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Energy Efficient for Real Time Data Aggregation in Wireless Sensor Powered By Docstoc
					   Research Issues in
Wireless Sensor Networks
         Prof. Xiaohua Jia
    Dept. of Computer Science
   City University of Hong Kong

                  CS Dept, City Univ.   1
Characteristics of Sensor Networks
   Low power and limited energy supply
   Simple CPU (low speed, small memory)
   Low network speed, unreliable data link, small
    transmission range
   Large deployment and dynamic replacement
   No infrastructure and self & dynamic organization

                        CS Dept, City Univ.             2
Layered Structure of Sensor Networks


                    Database Queries

         Data Aggregation                           Routing
  Localization   Time Synch        Topology Cont’l       Security

                     OS / Network
                 Hardware / MAC layer
                              CS Dept, City Univ.                   3
Localization / Time Synchronization

   Localization of tagged and untagged objects
   Finding locations of sensors without GPS
   One-hop or multi-hop time synchronization
    (important for scheduling of sensor nodes)

                        CS Dept, City Univ.       4
Topology Control
Adjust transmission power of nodes or determine
  logical neighbors of nodes.
 Achieving desirable connectivity / reducing
  interferences / increasing throughput
 QoS topology control

 Dynamic, distributed (localized), and efficient.

                       CS Dept, City Univ.           5
Placement and Coverage Issues
   Placement of sensor nodes for good coverage or
    network connectivity.
   Placement of data-sinks for efficient data
    collection or network throughput.
   Network connectivity (or area coverage) and
    node density.
   Scheduling of nodes sleep / active for energy
    saving under desirable area coverage.

                       CS Dept, City Univ.           6
Security of Sensor Networks
   Light-weight cryptographic primitives
   Light-weight security protocols for key distribution
    / key management / authentication
   Intrusion detection / intrusion tolerance
   Secured routing (lack of security infrastructure)

                         CS Dept, City Univ.               7
Routing & Data Aggregation
   Data centric routing (data push / pull / hybrid)
   Backbone computation / clustering
   Geographic routing (GPSR, etc)
   QoS routing
   Energy efficiency & real-time issues
   Broadcasting / multicasting / anycasting
   Data aggregation & query optimizations

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Data Query & Data Processing
   Database systems for sensor networks
   Application data processing / signal processing /
    pattern recognition
   Location sensitive database / spatial database

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Applications of Sensor Networks
   Environment monitoring
   Agriculture
   Manufacturing industries
   Medicine
   Disaster warning / prevention / relief operations
   Military applications

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Concluding Remarks
Strategic Research Directions of Sensor Networks:
 Special-purposed hardware design (application
  tailored, low cost).
 Security issues in sensor networks.

 Sensor network applications.

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