Abstract: Wireless sensor networks consist of small battery-powered devices with limited energy resources. Hence, energy reduction of sensor nodes and the lifetime prolonging of the network are the focuses of wireless sensor networks routing protocol. LEACH (Low-Energy Adaptive Clustering Hierarchy) 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. However, LEACH is inappropriate in the selection of cluster heads, inducing the imbalance of energy over sensor nodes. In order to make the process of selecting cluster heads more reasonable and more flexible, in this paper, the node’s properties (such as the residual energy and position distribution of sensor nodes) are defined as the constraints. The authors take a rolebased collaboration model (i.e., E-CARGO model) with constraints into the wireless sensor networks system modeling, and improve LEACH from the mechanism view by considering the constraints of sensor nodes and using LEACH algorithm assign roles to them. Analysis shows that the new method has better scalability and flexibility. Experimental results present that this new method can effectively balance the sensor node energy consumption and prolong the lifetime of network.

Key words: wireless sensor networks; low-energy adaptive clustering hierarchy（LEACH）; environment-class, agent, role, group and object (E-CARGO); role; constraint