Post on 16-Jul-2015
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
11/20/2014 2
Cluster Based Topology
11/20/2014
Type of communication:
a) Intra-clustering communication
b) Inter clustering communication
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.
11/20/2014 10
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.
11/20/2014 12
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
11/20/2014 19
• 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.
11/20/2014 21
ENERGY LEVEL-BASED PASSIVE CLUSTERING (ELPC)
11/20/2014 22
-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
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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