EAST:Energy-efficient Adaptive Scheme for Transmission in Wireless Sensor Networks EAST:Energy-efficient Adaptive Scheme for Transmission in Wireless Sensor Networks Muhammad Tahir Department of Electrical Engineering COMSATS Institute of Information Technology Islamabad, Pakistan [email protected]February 02, 2013 1 / 23
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EAST:Energy-efficient Adaptive Scheme for Transmission in Wireless Sensor Networks
EAST:Energy-efficient Adaptive Scheme for Transmission in Wireless Sensor Networks
Outline
Outline
Introduction to the Problem
Related Work and Motivation
Proposed Energy Efficient Adaptive Transmission Scheme
Block Diagram of EAST
EAST Flow Chart
Parameters
Simulation Results
Conclusion
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EAST:Energy-efficient Adaptive Scheme for Transmission in Wireless Sensor Networks
Introduction to the Problem
Introduction to the Problem
Challenge in design of Wireless Sensor Networks (WSNs) is toreduce energy consumption of sensor nodes to prolong lifetimeof Network
Limited battery requires low power sensing, processing andcommunication system
In WSNs, sensor nodes are widely deployed in differentenvironments to collect data
Low power wireless link causes link quality variation due toenvironmental dynamics like temperature, humidity etc
Therefore, while maintaining good link quality with nodes weneed to reduce energy consumption
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EAST:Energy-efficient Adaptive Scheme for Transmission in Wireless Sensor Networks
Related Work and Motivation
Related Work and Motivation
Existing schemes set some minimum transmitter power levelfor maintaining reliability
To adjust transmitter power, reference node periodicallybroadcasts a beacon message
When nodes hear a beacon message from a reference node,these nodes transmit an ACK message
Through this interaction, reference node estimate connectivitywith nodes
In Local Mean Algorithm (LMA), a reference node broadcastsLifeMsg message
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EAST:Energy-efficient Adaptive Scheme for Transmission in Wireless Sensor Networks
Related Work and Motivation
Related Work and Motivation
Nodes transmit LifeAckMsg after they receive LifeMsg
Reference nodes count number of LifeAckMsgs andtransmission power is controlled by maintaining appropriateconnectivity
For example if number of LifeAckMsgs is less thanNodeMinThresh transmission power is increased
In contrast, if number of LifeAckMsgs is more thanNodeMaxThresh transmission power is decreased
Local Information No Topology/Local Information Link-stateTopology (LINT/LILT) and Dynamic Transmission PowerControl (DTPC) uses transmission power loss RSSIloss toestimate transmitter power level
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EAST:Energy-efficient Adaptive Scheme for Transmission in Wireless Sensor Networks
Related Work and Motivation
Related Work and Motivation
Transmission power also controlled by Packet Reception Ratio(PRR) metric
Since RSSIloss is directly proportional to temperature.Adaptive Transmission Power Control (ATPC) adjuststransmission power dynamically according to spatial andtemporal effects
In adapting link quality for environments where temperaturevariation occur, packet overhead for transmission powercontrol should be minimized. Reducing number of controlpackets while maintaining reliability is also an importanttechnical issue
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EAST:Energy-efficient Adaptive Scheme for Transmission in Wireless Sensor Networks
Proposed Energy Efficient Adaptive Transmission Scheme
Proposed Energy Efficient Adaptive Transmission
Scheme
Propose Energy-efficient Adaptive Scheme for Transmission(EAST) of data in WSN,s is IEEE 802.15.4 standardcompliant
In this approach, Open-loop for temperature-aware link qualityestimation and compensation and Closed-loop feedbackprocess for
a)Logical division of network into three regions
b) Minimization of control packets overhead
Threshold transmitter power loss (RSSIloss) for each regionhelps to adapt transmitter power according to
a)Link quality changes due to temperature variation
b)Current number of nodes in that region
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EAST:Energy-efficient Adaptive Scheme for Transmission in Wireless Sensor Networks
Proposed Energy Efficient Adaptive Transmission Scheme
Proposed Energy Efficient Adaptive Transmission
Scheme
By adopting both open-loop and closed-loop feedbackprocesses we can divide network into three regions on thebasis of threshold RSSIloss for each region
1: A for High RSSIloss
2: B for Medium RSSIloss
3: C for Low RSSIloss
EAST has two phases, i.e., initial and run-time phases
In the initial phase, reference node builds a model for nodes ofeach region
In the run-time phases, based on the previous model, EASTadapts the link quality to dynamically maintain each link overtime
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EAST:Energy-efficient Adaptive Scheme for Transmission in Wireless Sensor Networks
Proposed Energy Efficient Adaptive Transmission Scheme
Mathematical Formulation of Proposed Scheme
Transmission power loss due to temperature variationformulated using relationship between RSSIloss andtemperature experimented in Bannister et al:
RSSIloss [dBm] = 0.1996 ∗ (T [C o ]− 25[C o ]) (1)
To compensate RSSIloss , relationship for required power levelis given in Eq.(2) using least square approximation:
Plevel [dBm] = [(RSSIloss + 40)/12]2.91 (2)
To compensate path loss due to distance between sensornodes free space model help to estimate actual requiredtransmitter power as given in Eq.(3):
EAST:Energy-efficient Adaptive Scheme for Transmission in Wireless Sensor Networks
Conclusion
Conclusion
In this thesis , I have presented propose technique EAST tostudy temperature effect on wireless link qualityRelationship between RSSIloss and temperature has beenanalyzed for propose schemeThis scheme uses open-loop control to compensate forchanges of link quality according to temperature variationFurther extension of this scheme by dividing network intothree regions on basis of Threshold RSSIloss and assign powerlevel to each node in three regions on basis of current numberof nodes and desired number of nodes help to adapttransmitter power according to link quality variation andincrease network lifetimeCombining both open-loop temperature-aware compensationand close-loop feedback control cause significant reductionoverhead of transmission power control in a WSN
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EAST:Energy-efficient Adaptive Scheme for Transmission in Wireless Sensor Networks