Cran Laboratory, Nancy University, CNRS France

Presented By

Santosh Regmi

Mtech In Information

Technology

CLUSTER-BASED ROUTING PROTOCOLS FOR ENERGYEFFICIENCY IN WIRELESS SENSOR NETWORKS

Moufida Maimour, Houda Zeghilet And Francis Lepage

Table Of Content

1)Background

2) Pre-established cluster-based routing algorithms

2.1 Low energy adaptive clustering hierarchy (LEACH)

2.2 Energy efficient hierarchical clustering(EEHC)

2.3 Hybrid energy-efficient distributed clustering(HEED)

2.4 Distributed energy efficient hierarchical clustering(DWEHC)

2.5 Unequal clustering

2.6 Qos-aware cluster-based routing protocols

3) On-demand cluster-based routing algorithms

3.1 Passive clustering(pc)

3.2 Energy level-based passive clustering(ELPC)

3.3 Clique

5) Conclusion

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Cluster Based Topology

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Type of communication:

a) Intra-clustering communication

b) Inter clustering communication

Intra – Cluster Connectivity

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One-hop Inter Cluster Communication

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Multi-hop Inter-cluster Communication

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Energy Efficiency And Load-balancing

• Load balancing among all nodes:

• Cluster head rotation among nodes in each cluster.

• Load balancing among cluster heads:

• Formation of nearly equal size (uniform) clusters.

• Hot spot problem:

• Condition in multi-hop inter-cluster communication,

nodes close to the base station are burdened with heavier

traffic load leading. 11/20/2014 7

2. Pre-Established Cluster-based Routing Algorithms:

2.1 Low Energy Adaptive Clustering Hierarchy (LEACH):

- cluster-based protocol with distributed cluster formation with random

cluster head election.

• Two phases per round:

• Setup phase

• Advertisement: execute election algorithm.

• Members join to cluster.

• Cluster-head broadcasts schedule.

• Steady-state phase:

• Data transmission to cluster-head using TDMA

• Cluster-head transfers data to BS (base station)

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9

LEACH(CONTD...)

9

where p is the desired fraction of nodes

to be clusterheads, r is the current

round and g is the set of nodes that

have not been clusterheads in the last

1/p round.

Thresshold

Value

Advertisement phase Cluster setup phase Broadcast schedule

Time slot

1

Time slot

2

Time slot

3

Setup phase Steady-state phase

Self-election of cluster

heads

Cluster heads compete

with CSMA

Members

compete with

CSMA

Cluster head Broadcast

CDMA code to members

Fixed-length cycle

LEACH-C

• a centralized version of LEACH where only the advertisement

phase differs:

• At this phase, each node sends information about its current

location, and residual energy level to the sink.

• Based on nodes location, the sink builds clusters.

• Collected information about nodes energies allows the sink to

discard those with energy below the average.

• Result:

• Energy load is evenly distributed among all the nodes.

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2.2 ENERGY EFFICIENT HIERARCHICAL CLUSTERING (EEHC)

a) Single-level clustering algorithm:

• Each sensor in the network becomes a cluster-head (CH) with probability p, advertises to the sensors within its radio range and forward advertisement no more than k hops away from the cluster-head.

• Any sensor that receives such advertisements and is not itself a cluster-head joins the cluster of the closest cluster-head.

• If a sensor does not receive a CH advertisement within time

duration t ,it can infer that it is not within k hops of any volunteer

cluster-head and hence become a forced cluster-head.11/20/2014 11

Contd…

B) Hierarchical clustering algorithm

Similar to single-level clustering

algorithm

• Each sensor decides to become a

level-1 CH with certain probability

p1

• Advertise to k1-hop of neighbors

• Neighbor joins the cluster of the

closest level-1 CH.

• Level-1 chs then elect themselves

as level-2 chs with a certain

probability p2

• Advertise to k -hop of neighbors.

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2.3 HYBRID ENERGY-EFFICIENT DISTRIBUTED CLUSTERING (HEED)

• Designed to select different cluster heads in

a field according to the amount of energy

that is distributed in relation to a

neighboring node.

• Parameters for electing cluster heads

• Primary parameter: residual energy (er)

• Secondary parameter: communication

cost (used to break ties)

I.E., Maximize energy and minimize cost 11/20/2014 13

CONTD…Initialization Discover neighbors within cluster range

Compute the initial cluster head probability CHprob = f(Er/Emax)

Main processing If v received some cluster head messages, choose one head with min costIf v does not have a cluster head, elect to become a cluster head with CHprob .CHprob = min(CHprob * 2, 1)Repeat until CHprob reaches 1

Finalization If cluster head is found, join its clusterOtherwise, elect to be cluster head

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CLUSTERING METHOD FOR ENERGY EFFICIENT ROUTING (CMEER)

• A node declares itself as a candidate to be a clusterhead.

• Each candidate advertises its intention to be a clusterhead within

its radio range.

• Each node decides to join a given clusterhead based on the

received signal strength of the advertisement message.

• Result:

• Avoid redundant creation of clusterheads in a small area.11/20/2014 15

2.4 DISTRIBUTED ENERGY EFFICIENT HIERARCHICAL CLUSTERING (DWEHC)

• Aims to improve HEED by generating balanced cluster sizes and

optimizing the intra-cluster topology.

• Each sensor s calculates its weight after locating the neighboring

nodes in its area using:

• In a neighbourhood, the node with largest weight would be elected

as a clusterhead and the remaining nodes become members.

• 1- level: nodes that communicates directly with clusterhead

• H-level: member node that reach its clusterhead using more than

one hope where h is number of hops11/20/2014 16

GEOGRAPHIC ADAPTIVE FIDELITY (GAF)

• Energy-aware location-based routing algorithm

• Ad hoc networks, GPS

• 3 states of GAF:

i. Discovery:

- For determining the neighbors in

the grid.

ii. Active:

- Active reflecting participation in

routing

iii. Sleep:

- When the radio is turned off.

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POSITION-BASED AGGREGATOR NODE ELECTION (PANEL)

• Position-based clustering algorithm.

• Clustering is determined before the deployment of the network,

and each sensor node is pre-loaded with the geographical

information of the cluster to which it belongs.

• Clusterhead (aggregator) : nodes in the cluster elect the node that

is the closest to reference point (computed at the beginning of

every epoch).

• Load balancing is achieved by re-computing reference point at

every epoch and hence electing cluster head11/20/2014 18

3.5 UNEQUAL CLUSTERING

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• Closer to the sink greater the

load to handle.

• Smaller cluster near the base

station.

• Signomial optimization problem:

• Problem of balancing energy

consumption among cluster

head.

3.6 QOS-AWARE CLUSTER-BASED ROUTING PROTOCOLS

• Qos is the performance level of service offered by a network to the

user.

• The goal of qos is to achieve a more deterministic network

behavior so that the information carried by the network can be

better delivered and the resources can be better utilized.

• In qos-based routing protocols, the network has to balance

between energy consumption and data quality.

• In particular, the network has to satisfy certain qos metrics, e.G.,

Delay, energy, bandwidth, etc. When delivering data to the BS.11/20/2014 20

3. ON-DEMAND CLUSTER-BASED ROUTING ALGORITHMS

3.1 PASSIVE CLUSTERING (PC)

• Known as on demand clustering algorithm.

• Cluster formation mechanisms:

i) first declaration wins:

- A node that first claims to be a clusterhead rules the rest of nodes in its clustered area.

ii) gateway selection heuristic:

- Provides a procedure to elect the minimal number of gateways.

fields in message header of each packet are:

i) id: identity of the originator of this message.

ii) state: sender status in the network.

iii) ch1 and ch2:fields only used by a gateway to announce its two clusterhead addresses.

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ENERGY LEVEL-BASED PASSIVE CLUSTERING (ELPC)

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-Proposed to achieve energy efficiency in

terms of network lifetime and energy

consumption.

- NEL:

- Mininum level of energy necessary

for a node to be a clusterhead or a

gateway.

- node is not allowed to declare itself as a

clusterhead ( or a gateway) if its energy

level is lower than this NEL.

- clusterhead can keep its role as long as

CONTD…

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NETWORK LIFETIME COMPARISION

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4.3 CLIQUE

• An approach for clusterhead selected based on machine learning

(q-learning)

• [Clusterhead role assignment must take into account not only the

current state of the selected clusterheads, but also those of its

neighbors and nodes on the paths to the clusterhead.]

• Role free:

• Each node decides on a per-packet basis whether to act as

clusterhead(aggregating some packets then sending the result

to the sinks) or to forward the packet to a better suited

neighbor. 11/20/2014 25

5. CONCLUSION

• Hierarchical (cluster-based) routing protocols hold a great

potential toward energy efficiency in WSN.

• A global management strategy with load balancing feature is

required.

• Optimal (or even approximate) parameters estimation for

successful clustering is very important

• Network dynamics have to be handled appropriately.

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THANK YOU.

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REFERENCES

• W. HEINZELMAN, A. CHANDRAKASAN, AND H. BALAKRISHNAN, “ENERGY-

EFFICIENT COMMUNICATION PROTOCOL FOR WIRELESS SENSOR NETWORKS,”

PROCEEDINGS OF THE 33RD HAWAII INTERNATIONAL CONFERENCE ON SYSTEM

SCIENCES, JANUARY 2000.

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