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Energy-Driven Adaptive Clustering Hierarchy (EDACH) for Wireless Sensor Networks Kyung Tae Kim, Hee Yong Youn (Sungkyunkwan University) Research supported.

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Presentation on theme: "Energy-Driven Adaptive Clustering Hierarchy (EDACH) for Wireless Sensor Networks Kyung Tae Kim, Hee Yong Youn (Sungkyunkwan University) Research supported."— Presentation transcript:

1 Energy-Driven Adaptive Clustering Hierarchy (EDACH) for Wireless Sensor Networks Kyung Tae Kim, Hee Yong Youn (Sungkyunkwan University) Research supported by the “uAuto” Project

2 Outline Introduction System Model Proposed Protocol - EDACH Performance Evaluation

3 WSN Wireless sensor network enables the collection of useful information in real life. It is composed of hundreds or thousands of sensor nodes. Since sensor nodes carry constrained power source, power conservation is a critical design issue for routing protocol.

4 Clustering-based Routing Selects a set of cluster-heads among the nodes in the network, and clusters the rest of nodes (member nodes) with the cluster- heads 2 clustering-based routing protocol referred to: –LEACH –EDACH

5 LEACH Low-Energy Adaptive Clustering Hierarchy, a protocol proposed to solve the energy consumption problem Employs randomized rotation of the cluster- heads to evenly distribute the energy load among the sensor nodes in the network

6 EDACH Energy-Driven Adaptive Clustering Hierarchy, an enhanced version of LEACH Increases the lifetime and reliability of sensor network in the presence of faults at the cluster-head

7 Outline Introduction System Model Proposed Protocol - EDACH Performance Evaluation

8 Single-Hop Clustered Network Nodes and cluster- heads are homogenous Communication over wireless link

9 Energy Model of a Sensor 1st order radio model A radio dissipates E elec (e.g. 50nJ/bit) to run the transmitter or receiver circuitry and ε amp (e.g. 100pJ/bit) for the transmitter amplifier

10 Fault Model Consider only data transmission faults of cluster-head

11 Outline Introduction System Model Proposed Protocol - EDACH Performance Evaluation

12 LEACH Overview The operation is divided into rounds. Each of these rounds consists of 2 phases: a set-up phase and a steady-state phase. During the set-up phase cluster-heads are determined and the clusters are organized. During the steady-state phase data trans- ference to the base station occurs.

13 EDACH Overview Periodic operation of the following 2 phases: a set-up phase and a self-organized data collection and transmission phase. The set-up phase is identical to LEACH. The 2 nd phase is modified to deal with the possible problem that cluster-heads in the LEACH have no sufficient energy to carry out the duty of cluster-head.

14 Enhancement If a cluster encounters a problematic cluster-head, then a proxy is selected to operate in replace of the original cluster- head.

15 Set-up Phase In order to select cluster-heads, each node chooses a random number between 0 and 1. If the number is smaller than a threshold, the node becomes a cluster-head for the current round.

16 Set-up Phase The threshold is set as: where P is the desired percentage of cluster-heads, r is the current round, and G is the set of nodes that have not been cluster-heads in the last 1/P rounds. Every node becomes a cluster-head exactly once within 1/P rounds.

17 Set-up Phase After selection, every selected cluster-head advertises its token by CSMA/CA MAC protocol to all its neighbors. Comparing the signal strength of the token, non cluster-head nodes choose among the strongest and broadcasts an answer packet including node’s position and remaining energy also by CSMA/CA.

18 Set-up State At last, the cluster- head node creates a TDMA schedule telling each node when it can transmit.

19 Self-organized Data Collection and Transmission Phase Starts after the set-up phase. Every nodes collected local data, and sends the packet to the cluster-head in its allocated transmission time. No doubt that cluster-heads consumes much more power and more likely to suffer from depletion.

20 Ways to Save the Energy For member nodes, by using the minimal amount of energy to transmit according to the signal strength of the token received For member nodes, by turning off until its allocated transmission time A Cluster-head aggregates the data gathered before sending it to the base station.

21 Difference A threshold value E TH is used as a measure for deciding if the current cluster-head has become obsolete. where k j is the length of the aggregated message in the j-th cluster-head, d CH is the distance between cluster-head and the base station

22 Difference Once the energy of a cluster-head drops below the threshold, the proxy node selection process begins. A cluster-head of EDACH maintains a table of remaining energy and nodes’ position of its members so it can select a member node to be a proxy node by comparing the 2 factors.

23 Proxy Node Determination

24 Indicator Control Message Advertisement Process

25 Outline Introduction System Model Proposed Protocol - EDACH Performance Evaluation

26 Network Lifetime Energy (J/node) Protocol The round a node begins to die The round the last node dies 0.25 Direct4197 LEACH EDACH Direct91184 LEACH EDACH

27 Number of Alive Sensors as the round proceeds with 0.25J/node

28 Location of Alive (Circle) and Dead (Dot) Sensor Nodes

29 Conclusion EDACH outperforms the LEACH more significantly when the initial energy is relatively high. The residual energy is well balanced among all the sensors because the protocol select the most capable node to be a proxy when facing problematic cluster-head. The dead nodes of EDACH well dispersed.


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