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Explore a comprehensive approach to sensor role selection and energy-efficient routing in Wireless Sensor Networks (WSNs). The proposed model, DAPR (Distributed Activation with Predetermined Routers), balances energy consumption, redundancy reduction, and data coverage to optimize network performance and longevity.
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An Integrated Approach to Sensor Role Selection by Mark Perillo and Wendi Heinzelman
Outline • Motivation • Background • Modeling • Solution (DAPR) • Analysis • Comparison • Conclusion
1. MOTIVATION (WSN Energy Efficiency) • Limited energy supply VS long network lifetimes • Hardware, Operating System, Low-level protocol design • Balance/reduce energy consumption • Reduce redundancy but ensure QoS requirement • dynamic sensor selection, in-network aggregation, distributed source coding
BACKGROUND • Abundant data • Filter sensors • Multi-hopping • Design routing • Diverse importance • Assign duties
Relevant Work -- Sensor Selection(I) • Principle : desired coverage • PEAS • activeness probing/querying; • Gur game paradigm • state switching according to base station • Sensing coverage protocol • sleep/wake time scheduling according to neighbors’ with differentiated surveillance • neighbor redundancy, coverage redundancy • CCP • coverage and connectivity
Relevant Work -- Sensor Selection(II) • Principle: Considering routing • less sensors + some routings + short path = desired coverage
Relevant Work – Routing Protocols(I) • Principle: Shortest path • Table-driven routing protocol • destination-sequenced distance vector routing • clusterhead gateway switch routing • the wireless routing protocol • Source-initiated on-demand routing • ad hoc on-demand distance vector routing • dynamic source routing • temporally ordered routing algorithm • associativity-based routing • signal stability routing
Relevant Work – Routing Protocols(II) • Principle: considering energy efficiency • Power-awareMAClayerrouting • routethroughnodeswithsufficientremainingpower • routethroughlightly-loadednodes • Maximizingthenetworklifetime • minimizetheenergyconsumedeverypacket
PROPOSAL Sensor selection + Energy conserved routing PRINCIPLE To use the sensors not as important as data generators more liberally as routers
MODELING – Assumptions • Power consumption largely from traffic transmitted and received • Portion or entirety of an area A needs to be monitored by any one or multiple sensors • There may be one or several data sink locations
MODELING – Formalization(I) Coverage: Number of nodes: Nt = Ns + Nsink Data flow:
MODELING – Formalization(II) Energy consumption: Scheduling: Lifetime:
MODELING – Coverage-Aware Routing Cost Common cost (energy-aware cost): Total energy in a subset area x:
MODELING – Worst Coverage-Based Cost Finds out the least-covered subregion
E(Xa) = 2; E(Xb) = 3; E(Xc) = 2; E(Xd) = 1; Cwc(S1) = ½; Cwc(S2) = ½; Cwc(S3) = 1;
MODELING – Comprehensive Coverage-Based Cost Weighted sum (in terms of area of subregion) of 1/E(x) It provides a more balanced view of a nodes importance to the sensing task.
E(Xa) = 2; E(Xb) = 3; E(Xc) = 2; E(Xd) = 1; Ccc(S1) = area(A)/2 + area(B)/2 Ccc(S2) = area(A)/2 + area(B)/3+are(C)/2 Ccc(S3) = area(B)/3 + area(C)/2+are(D)/1
MODELING – Combining Cost Functions Most effective in extending lifetime with 100 percent coverage: Effective in providing long network lifetimes with graceful degradation:
SOLUTION – DAPR (Distributed Activation with Predetermined Routers) Thedecisionmadeinsensorselectionandroutediscoveryareinfluencedeachother. Procedure: RouteDiscoveryPhase SensorSelectionPhase Sensorquery
DAPR–RouteDiscoveryPhase(I) • Assumption: • Nodeshavelocationinformationofneighborswithredundantcoverageregions; • Lowpowerwakeupsystem Costofalink=routing cost nodei xenergyfortransmission+routing cost nodej xenergyforreception Costofaroute=sumoflinksintheroute
DAPR–RouteDiscoveryPhase(II) DataSink Node Initiatequery floodquery receivequery Calculatelinkcost Updatequerypacket forwardquery(delayscheme):proportionaltoClink(Si) Next Node
DAPR–SensorSelectionPhase* Initial:beinactivetosenseandgeneratedata • Assignactivationdelay(proportional to the route cost) • Checkreceivedactivationbeacon • checkiftheneighborhoodisalreadycovered • Sendactivationbeacon • sendactivationbeacontoneighborsifpossible • (Senddeactivationbeacon) • senddeactivationbeaconifinhighredundancyandinthehighestcostroute • * DAPR: A Protocol for Wireless Sensor Networks Utilizing an Application-based Routing Cost
DAPR(Cont’d) • Awarenessofneighbors • Location • Redundantcoverage • Givenhighestpriority • Nodesalonghighestroute • Reservingopt-out/deactivationbeacon • Sendingbeacon • Insinglehop(Dtransmission_range>>Dsensing_range) • Forwarding(noguarantee)
SIMULATION&ANALYSIS – Experiment Result for Sensor Selection Configuring activation/backoff delay in Worst Coverage-Coverage Routing Cost
SIMULATION&ANALYSIS – Experiment Result for Combing routing cost Worst coverage-based + energy-aware routing cost
COMPARISON – to Centralized Approach • Assuming subject to these conditions: data flow, energy consumption constraints and scheduling constraints, we try to maximize the operation time of the system
COMPARISON – to Centralized Approach Uniform scenario: worst coverage + energy-aware cost with DAPR gains 14% over the nonintegrated approach. 56% closer to centralized solution.
COMPARISON – to Centralized Approach (Cond’t) In clustered scenario: Worst coverage routing cost with DAPR improves lifetime by 56%. 77% closer to centralized solution, Due to use of the coverage-aware routing cost.
COMPARISON – to Centralized Approach (Cond’t) In video scenario: DAPR with the combined worst coverage and energy-aware cost makes lifetime gain 50%,Closing gap by 76%, Because the selection of sensors based on the cumulative route cost.
CONCLUSION Contribution Incorporation of coverage information into the routing protocol and the priority for sensor selection Worst coverage-based cost – maintaining 100% coverage for the maximum lifetime Comprehensive coveraged-based cost – giving a more balanced interpretation of a node’s value to the sensing task