An Energy-aware Distributed Clustering Protocol in Wireless Sensor Network
CLUSTERING IN WIRELESS SENSOR NETWORKS
Transcript of CLUSTERING IN WIRELESS SENSOR NETWORKS
CLUSTERING IN WIRELESS SENSOR CLUSTERING IN WIRELESS SENSOR NETWORKSNETWORKS
BYKALYAN SASIDHAR
RESEARCH PROBLEMRESEARCH PROBLEM
• Understanding existing clustering algorithms and finding the problems stated and addressed
• Compare the pros and cons of each algorithm
• Simulate algorithms and compare performance with and without clustering mechanism
INTRODUCTION TO CLUSTERINGINTRODUCTION TO CLUSTERING
• Grouping of similar objects or sensors in our context distance or proximity Logical organizing
• Topology control approach Load balancing, network scalability
• Types of clustering• Static: local topology control
• Dynamic: changing network parameters
• Single hop and multi hop
• Homogeneous and heterogeneous
HEED[1]
ADVANTAGES OF CLUSTERINGADVANTAGES OF CLUSTERING
• Transmit aggregated data to the data sink reducing number of nodes taking part in transmission
• Useful energy consumption
• Scalability for large number of nodes
• Reduces communication overhead for both single and multi hop
LITERATURE SURVEY OF CLUSTERING LITERATURE SURVEY OF CLUSTERING ALGORITHMSALGORITHMS • HEED: A hybrid energy efficient distributed clustering approach for
ad-hoc sensor networks
• MRECA: Mobility resistant efficient clustering approach for ad-hoc sensor networks
• Energy efficient dynamic clustering algorithm for ad-hoc sensor networks
• LEACH-Energy efficient communication protocol for WSN
• EEDC-Dynamic clustering and energy efficient routing technique for WSN
Problem statementProblem statement• Set of nodes, identify set of CHs that cover the entire network
• Protocol distributed Local information
• One node-one cluster
• Node-cluster head: single hop
• CH-CH: multi hop using routing protocol
HEEDHEED
Assumptions Sensor quasi-stationary
Links are symmetric
Energy consumption non-uniform for all nodes
Nodes-location unaware
Processing and communication capability-similar
Algorithm:• Cluster head selection
hybrid of residual energy (primary) and communication cost (secondary) such as node proximity
• Number of rounds of iterations
• Tentative CHs formed
• Final CH until CHprob=1
• Same or different power levels used for intra cluster communication
Pros:• Balanced clusters
• Low message overhead
• Uniform & non-uniform node distribution
• Inter cluster communication explained
• Out performs generic clustering protocols on various factors
Cons:• Repeated iterations complex algorithm
• Decrease of residual energy smaller probability number of iterations increased
• Nodes with high residual energy one region of a network
Future work:• Only two level hierarchy provided but can be extended to multilevel hierarchy
MRECAMRECAAssumptions:• Sensor quasi-stationary
• Nodes-location unaware
• Every node as source and server
Algorithm:• Mobility resistant clustering approach
• Deterministic time without iterations
• Computed score value used to compute delay Delay used CH announcement
• Node mobility Local maintenance performed instead of re-clustering
Pros• Clusters generated as node speed increased
• Only one iteration against repeated iterations in HEED
• Each node one message saving on message transmission better energy efficiency
• Robust against synchronization errors
• Can be used for environmental monitoring and battlefield applications
Cons
• Inter cluster communication not explained
• CH rotation mentioned but not explained ‘how’
Future work• Extensive simulations on large scale
networks with elaborate power models,
• Extensions to k-hop clusters and integration of clustering with network applications
EEDCEEDC
Assumption:• Two tier hierarchy network
Routing limited to CHs route set up cost minimized
• Sensors clustered
Algorithm: • Active node estimation and optimum probability of becoming cluster head
Received Signal power
• Cluster formation CH with a certain probability by wining a competition with neighbors
• Data collection Node-CH using MAC protocol-p-persistent CSMA
• Data delivery CH-BS-multi hop routing protocol
Pros• Number of clusters and CH-Dynamic
Energy dissipation-even distribution Prolong network lifetime
• most efficient for large-scale sensor network
• Intra and inter cluster communication explained
Future work• Further investigating the applicability of the proposed clustering
technique and routing algorithm to more general wireless sensor networks.
LEACHLEACHAssumptions:• Fixed and remote base station
• Nodes homogeneous and energy constrained
• Radio channel is symmetric
EA-EB=EB-EA
• Sensing rate for all sensors fixed
Algorithm• CH position rotated among the nodes
energy load distributed .
• Number of active nodes in the network and the optimal number of clusters assumed a priori
• Nodes join a target number of CHs
• Node-CH communication-TDMA
Pros• Incorporates data fusion into routing protocols
Amount of information to base station reduced
• 4-8 times effective over direct communication in prolonging network lifetime
• Grid like area
Cons• Only single hop clusters formed
Might lead to large number of clusters
• No discussion on optimal CH selection
• All CHs should directly transmit to the data sink
DYNAMIC CLUSTERDYNAMIC CLUSTER• Energy efficiency distributed:
CH selection-both residual energy and PT
Number of nodes-network size and PT
CH -center of the cluster
Rotating CH to average power consumption
Breaking clusters and reforming compensate for differences of power consumption in different areas
Unique route Only CH with lowest ID and high residual energy What is only one CH is present and that CH as low residual energy?
Pros• Reduce flooding in route discovery
• Avoid duplicate data transmission
Cons• Inter cluster communication not explained
• Number of iterations needed for CH selection and cluster formation not mentioned
CONCLUSIONSCONCLUSIONS• Problem statement seems to be unique
Reduce energy consumption Prolong network lifetime Form set of clusters from a set of nodes Cluster the whole network with the selected CH Rotate CHs for energy distribution
• Algorithms differ in CH selection and cluster formation
• Some address intra and inter cluster communication
• Some address real world applications
REFERENCESREFERENCES
[1]. A hybrid energy efficient distributed clustering approach for ad-hoc sensor networks