Low-energy adaptive clustering hierarchy: Difference between revisions

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'''Low-energy Energyadaptive Adaptiveclustering Clustering Hierarchyhierarchy ("LEACH")'''<ref>[[Wendi Rabiner Heinzelman|Heinzelman, W.]], Chandrakasan, A., and Balakrishnan, H., "Energy-Efficient Communication Protocols for Wireless Microsensor Networks", Proceedings of the 33rd Hawaaian International Conference on Systems Science (HICSS), January 2000. [http://pdos.csail.mit.edu/decouto/papers/heinzelman00.pdf Paper]</ref> is a [[Time division multiple access|TDMA]]-based [[Media access control|MAC]] protocol which is integrated with clustering and a simple routing protocol in [[wireless sensor network]]s (WSNs). The goal of LEACH is to lower the energy consumption required to create and maintain clusters in order to improve the life time of a wireless sensor network.

==Protocol explanation==

LEACH is a hierarchical protocol in which most nodes transmit to cluster heads, and the cluster heads aggregate and compress the data and forward it to the base station (sink). Each node uses a stochastic [[algorithmstochastic]] algorithm at each round to determine whether it will become a cluster head in this round. LEACH assumes that each node has a radio powerful enough to directly reach the base station or the nearest cluster head, but that using this radio at full power all the time would waste energy.

Nodes that have been cluster heads cannot become cluster heads again for ''P'' rounds, where ''P'' is the desired percentage of cluster heads. Thereafter, each node has a 1/''P'' probability of becoming a cluster head in each roundagain. At the end of each round, each node that is not a cluster head selects the closest cluster head and joins that cluster. The cluster head then creates a schedule for each node in its cluster to transmit its data.

All nodes that are not cluster heads only communicate with the cluster head in a [[Time Division Multiple Access|TDMA]] fashion, according to the schedule created by the cluster head. They do so using the minimum energy needed to reach the cluster head, and only need to keep their radios on during their time slot.

LEACH also uses [[Codecode Divisiondivision Multiplemultiple Accessaccess|CDMA]] so that each cluster uses a different set of CDMA codes, to minimize interference between clusters.

==Properties==

Properties of this algorithm include:

*Cluster based

*Random cluster head selection each round with rotation. Or cluster head selection based on sensor having highest energy

*Cluster membership adaptive

*Data aggregation at cluster head

*Cluster head communicate directly with sink or user

*Communication done with cluster head via TDMA

*Threshold value

*CDMA across clusters

== Shortcomings of LEACH ==

==External links==

Shortcomings of LEACH include:<ref>{{Cite book|last1=Varshney|first1=Shweta|last2=Kuma|first2=Rakesh|title=2018 8th International Conference on Cloud Computing, Data Science & Engineering (Confluence) |chapter=Variants of LEACH Routing Protocol in WSN: A Comparative Analysis |date=2018|language=en-US|publisher=IEEE|pages=199–204|doi=10.1109/confluence.2018.8442643|isbn=9781538617199|s2cid=52125657 }}</ref>

* [http://nms.csail.mit.edu/projects/leach/ A brief description of LEACH and SPIN]

* [http://wind.lcs.mit.edu/papers/leach-hicss.ps The original LEACH paper] (postscript) presented at the [[Hawaii International Conference on System Sciences]], 2000.

* Remaining energy among the nodes isn't considered when selecting Cluster Heads

* Random and variable size cluster formations

* Random and uneven distribution of cluster heads

* Single hop communication in situations where energy use is less efficient from cluster head to base station

* Multi-clustering might not be required at some point and, at some point, number of optimum clusters could be as high as N (number of live nodes in the network)<ref>{{Cite journal |last1=Roy |first1=Nihar Ranjan |last2=Chandra |first2=Pravin |date=2018 |title=A Note on Optimum Cluster Estimation in LEACH Protocol |journal=IEEE Access |volume=6 |pages=65690–65696 |doi=10.1109/ACCESS.2018.2877704 |s2cid=53779139 |issn=2169-3536|doi-access=free |bibcode=2018IEEEA...665690R }}</ref>

== References ==

{{reflist}}

[[Category:Wireless sensor network]]

[[Category:StochasticCluster analysis algorithms]]