An Energy-Efficient Clustering Solution for Wireless Sensor Networks

Abstract

Hot spots in a wireless sensor network emerge as locations under heavy traffic load. Nodes in such areas quickly deplete energy resources, leading to disruption in network services. This problem is common for data collection scenarios in which Cluster Heads (CH) have a heavy burden of gathering and relaying information. The relay load on CHs especially intensifies as the distance to the sink decreases. To balance the traffic load and the energy consumption in the network, the CH role should be rotated among all nodes and the cluster sizes should be carefully determined at different parts of the network. This paper proposes a distributed clustering algorithm, Energy-efficient Clustering (EC), that determines suitable cluster sizes depending on the hop distance to the data sink, while achieving approximate equalization of node lifetimes and reduced energy consumption levels. We additionally propose a simple energy-efficient multihop data collection protocol to evaluate the effectiveness of EC and calculate the end-to-end energy consumption of this protocol; yet EC is suitable for any data collection protocol that focuses on energy conservation. Performance results demonstrate that EC extends network lifetime and achieves energy equalization more effectively than two wellknown clustering algorithms, HEED and UCR.

Asynchronous clustering of multihop Wireless Sensor Networks

“…The announcement packet effectively notifies other nodes that they cannot become a CH since they are within node i's prospective cluster boundary. Similar election mechanisms have been used in previous protocols [6] [7].…”

“…UCS [16] considers powerful nodes pre-deployed in the network to serve as CHs, whereas others, e.g. UCR [6] and EC [7], elect CHs in regular time rounds. These protocols are aimed at improving network lifetime via elimination of network hot-spots caused by the imbalance in traffic loads on CHs due to multihop forwarding to the data sink.…”

“…When certain criteria are met, CH nodes initiate such operations either within their own clusters or over multiple neighbour clusters, covering a section of the network. Similar to most existing clustering protocols [5] [6] [7], each node i keeps a probability value P (i), called the CH-probability, which reflects its likelihood to claim the CH role. ACP updates CH-probability values dynamically, based on three main node variables: (i) residual node energy level E(i), (ii) latest incoming data traffic rate r in (i), and (iii) hop distance h(i) to the sink.…”

“…Sensor nodes dynamically change their transmission ranges to effectively modify the network hierarchy, considering residual node energy levels as well as the unbalanced traffic loads on CHs caused by multihop packet forwarding. In contrast to existing clustering protocols proposed for multihop WSNs, ACP does not require network-wide timesynchronisation [2] [5] [6] [7], estimation of inter-node distances [6], specific network topologies [7], or static estimations of energy consumption levels over multihop paths [7]. ACP is compared with the Unequal Cluster-based Routing (UCR) protocol in multihop WSNs in terms of gains in average throughput at the data sink and network lifetime.…”

HEER – A delay-aware and energy-efficient routing protocol for wireless sensor networks

“…In order to obtain a well-balanced network payload, the energy consumption of data communication and control overhead caused by route discovery should be considered. For this purpose, Energy-efficient Clustering (EC) [24] algorithm is proposed. EC determines suitable cluster sizes considering their hop distance to BS, EC effectively controls cluster sizes (which allows an approximately uniform use of the overall energy resources of a WSN) by adjusting the probability of a node being a CH.…”