Low-energy adaptive clustering hierarchy: Difference between revisions

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'''Low Energy Adaptive Clustering Hierarchy ("LEACH")''' is a [[routing protocol]] in [[wireless sensor network]]s (WSNWSNs). It is an hierarchical protocol. Stochastic Cluster head selection [[algorithm]] is used in this protocol.

{{Cleanup|date=November 2006}}

The goal of LEACH is to provide data aggregation for sensor networks while providing energy efficient communication that does not predictably deplete some nodes more than others.

'''Low Energy Adaptive Clustering Hierarchy ("LEACH")''' is a [[routing protocol]] in wireless sensor network (WSN). It is an hierarchical protocol. Stochastic Cluster head selection [[algorithm]] is used in this protocol.

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. Each node uses a stochastic [[algorithm]] at each round to determine whether it will become a cluster head in this round.

It is

*a Cluster based approach

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 round. 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 [[Code Division Multiple Access|CDMA]] so that each cluster uses a different set of CDMA codes, to minimize interference between clusters.

Properties of this algorithm include:

*a Cluster based approach

*Random cluster head selection each round with rotation

*Communication done with cluster head via TDMA communicating with non cluster nodes)

*Cluster membership adaptive

*Data aggregation is done at cluster head

*Cluster head communicate directly with sink or user

*TDMA within clusters

*Based on the model the following can be said about

*CDMA across clusters

**The sources and users are stationary and events monitored

**The interest propagation is predetermined

**Data dissemination mechanism is broadcasting

== External Links ==

Together, these features allow LEACH to achieve the desired properties. Initial simulations show that LEACH is an energy-efficient protocol that extends system lifetime.

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

Wireless distributed microsensor systems will enable the reliable monitoring of a variety of environments for both civil and military applications. Communication protocols, which can have significant impact on the overall energy dissipation of these networks. It has been found that the conventional protocols of direct transmission, minimum-transmission-energy, multi-hop routing, and static clustering may not be optimal for sensor networks, because of this reason LEACH (Low Energy Adaptive Clustering Hierarchy) has been proposed which is a clustering-based protocol that utilizes randomized rotation of local cluster base stations (cluster-heads) to evenly distribute the energy load among the sensors in the network. LEACH uses localized coordination to enable scalability and robustness for dynamic networks, and incorporates data fusion into the routing protocol to reduce the amount of information that must be transmitted to the base station. Simulations show that LEACH can achieve as much as a factor of 8 reduction in energy dissipation compared with conventional routing protocols. In addition, LEACH is able to distribute energy dissipation evenly throughout the sensors, doubling the useful system lifetime for the networks we simulated.

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