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Academic Editor:Thomas Wook Choi
Department of Computer Engineering, Chonbuk National University, Jeonju-si, Jeollabuk-do 561-756, Republic of Korea
Received 29 December 2013; Revised 28 May 2014; Accepted 3 June 2014; 3 July 2014
This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
1. Introduction
Wireless sensor networks (WSNs) have been broadly studied in ubiquitous computing environment because of its widespread utilization. The application area of WSNs includes environmental management, health-care services, and military monitoring [1-3]. WSNs are composed of many sensor nodes equipped with processors, memory, and short-range wireless communication. In real applications, the sensor nodes are distributed in the areas of interest, and they sense data from surrounding environments. The sensor nodes cooperate with each other to transmit the sensed data to the central base station, called sink node. A routing protocol is a way of determining a path between a source node and a destination (i.e., sink node) for sensed data transmission. The efficiency of WSNs is highly dependent on routing protocols that directly affect the network lifetime. The main objective of routing protocols is to enhance both reliability and lifetime of WSNs by considering the capability of a sensor node with resource constraints, such as limited power, slow processor, and low communication bandwidth. Hence, the challenging issue of routing protocols is to reduce the communication overhead for data transmission by determining an optimal path.
Clustering is one of the most popular techniques for routing protocols. The cluster-based routing is an efficient way to reduce energy consumption within a cluster by decreasing the number of transmitted messages to the sink node. Hence, there have been many researches on cluster-based routing protocols [4-9]. A popular cluster-based protocol, called LEACH [4], proposes a two-phase operation based on a single-tier network using clusters. LEACH randomly selects a portion of nodes as cluster headers, and the cluster headers gather the neighboring nodes to construct clusters. Each node forwards its sensed data to a cluster header, which collects and delivers data to the sink node. There are several extensions of the LEACH protocol to increase energy efficiency, but the existing protocols have...